[wpilibcintegrationtests] Fix deprecated Preferences usage (#3461)

This reverts commit d068fb321f (#3420).

The 18.04 docker images now use GCC 8, which was the original reason for
updating.  20.04 uses a much more recent libc, so staying with 18.04
enables more Linux platforms to use the binaries.

.clang-tidy

@@ -4,7 +4,6 @@ Checks:
   bugprone-copy-constructor-init,
   bugprone-dangling-handle,
   bugprone-dynamic-static-initializers,
-  bugprone-exception-escape,
   bugprone-forward-declaration-namespace,
   bugprone-forwarding-reference-overload,
   bugprone-inaccurate-erase,

.github/workflows/cmake.yml

@@ -10,7 +10,7 @@ jobs:
         include:
           - os: ubuntu-latest
             name: Linux
-            container: wpilib/roborio-cross-ubuntu:2020-18.04
+            container: wpilib/roborio-cross-ubuntu:2021-18.04
             flags: ""
           - os: macos-latest
             name: macOS

.github/workflows/gradle-wrapper-validation.yml

@@ -1,5 +1,5 @@
 name: "Validate Gradle Wrapper"
-on: [push, pull_request]
+on: [pull_request, push]
 
 jobs:
   validation:

.github/workflows/lint-format.yml

@@ -1,11 +1,16 @@
 name: Lint and Format
 
-on: [pull_request]
+on:
+  pull_request:
+  push:
+    branches-ignore:
+      - main
 
 jobs:
   wpiformat:
     name: "wpiformat"
     runs-on: ubuntu-latest
+    container: wpilib/roborio-cross-ubuntu:2021-20.04
     steps:
       - uses: actions/checkout@v2
       - name: Fetch all history and metadata
@@ -18,17 +23,20 @@ jobs:
         with:
           python-version: 3.8
       - name: Install clang-format
-        run: sudo apt-get update -q && sudo apt-get install -y clang-format-10
+        run: |
+          sudo sh -c "echo 'deb http://archive.ubuntu.com/ubuntu/ $(lsb_release -cs)-proposed restricted main multiverse universe' >> /etc/apt/sources.list.d/proposed-repositories.list"
+          sudo apt-get update -q
+          sudo apt-get install -y clang-format-12
       - name: Install wpiformat
         run: pip3 install wpiformat
       - name: Run
-        run: wpiformat -clang 10
+        run: wpiformat -clang 12
       - name: Check Output
         run: git --no-pager diff --exit-code HEAD
   tidy:
     name: "clang-tidy"
     runs-on: ubuntu-latest
-    container: wpilib/roborio-cross-ubuntu:2020-18.04
+    container: wpilib/roborio-cross-ubuntu:2021-20.04
     steps:
       - uses: actions/checkout@v2
       - name: Fetch all history and metadata
@@ -36,8 +44,15 @@ jobs:
           git fetch --prune --unshallow
           git checkout -b pr
           git branch -f main origin/main
-      - name: Install clang-format and clang-tidy
-        run: sudo apt-get update -q && sudo apt-get install -y clang-format-10 clang-tidy-10 python3.8
+      - name: Set up Python 3.8
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.8
+      - name: Install clang-tidy
+        run: |
+          sudo sh -c "echo 'deb http://archive.ubuntu.com/ubuntu/ $(lsb_release -cs)-proposed restricted main multiverse universe' >> /etc/apt/sources.list.d/proposed-repositories.list"
+          sudo apt-get update -q
+          sudo apt-get install -y clang-tidy-12 clang-format-12
       - name: Install wpiformat
         run: pip3 install wpiformat
       - name: Create compile_commands.json
@@ -45,4 +60,4 @@ jobs:
       - name: List changed files
         run: wpiformat -list-changed-files
       - name: Run clang-tidy
-        run: wpiformat -clang 10 -no-format -tidy-changed -compile-commands=build-cmake
+        run: wpiformat -clang 12 -no-format -tidy-changed -compile-commands=build-cmake

.styleguide

@@ -23,6 +23,7 @@ includeOtherLibs {
   ^cameraserver/
   ^cscore
   ^drake/
+  ^fmt/
   ^hal/
   ^imgui
   ^implot

CMakeLists.txt

@@ -59,6 +59,7 @@ option(WITH_EXTERNAL_HAL "Use a separately built HAL" OFF)
 set(EXTERNAL_HAL_FILE "" CACHE FILEPATH "Location to look for an external HAL CMake File")
 
 # Options for using a package manager (vcpkg) for certain dependencies.
+option(USE_VCPKG_FMTLIB "Use vcpkg fmtlib" OFF)
 option(USE_VCPKG_LIBUV "Use vcpkg libuv" OFF)
 option(USE_VCPKG_EIGEN "Use vcpkg eigen" OFF)
 
@@ -187,6 +188,12 @@ if (WITH_GUI)
     add_subdirectory(imgui)
     add_subdirectory(wpigui)
     add_subdirectory(glass)
+    add_subdirectory(outlineviewer)
+endif()
+
+if (WITH_WPILIB OR WITH_SIMULATION_MODULES)
+    set(HAL_DEP_REPLACE ${HAL_DEP_REPLACE_IMPL})
+    add_subdirectory(hal)
 endif()
 
 if (WITH_CSCORE)
@@ -195,9 +202,7 @@ if (WITH_CSCORE)
     add_subdirectory(cscore)
     add_subdirectory(cameraserver)
     if (WITH_WPILIB)
-        set(HAL_DEP_REPLACE ${HAL_DEP_REPLACE_IMPL})
         set(WPILIBC_DEP_REPLACE ${WPILIBC_DEP_REPLACE_IMPL})
-        add_subdirectory(hal)
         add_subdirectory(wpilibj)
         add_subdirectory(wpilibc)
         add_subdirectory(wpilibNewCommands)

ThirdPartyNotices.txt

@@ -27,6 +27,7 @@ JSON for Modern C++   wpiutil/src/main/native/include/wpi/json.h
 libuv                 wpiutil/src/main/native/include/uv.h
                       wpiutil/src/main/native/include/uv/
                       wpiutil/src/main/native/libuv/
+fmtlib                wpiutil/src/main/native/fmtlib/
 sigslot               wpiutil/src/main/native/include/wpi/Signal.h
                       wpiutil/src/test/native/cpp/sigslot/
 tcpsockets            wpiutil/src/main/native/cpp/TCP{Stream,Connector,Acceptor}.cpp
@@ -40,6 +41,9 @@ units                 wpimath/src/main/native/include/units/
 Eigen                 wpimath/src/main/native/eigeninclude/
                       wpimath/src/main/native/include/unsupported/
 StackWalker           wpiutil/src/main/native/windows/StackWalker.*
+TCB span              wpiutil/src/main/native/include/wpi/span.h
+                      wpiutil/src/test/native/cpp/span/
+GHC filesystem        wpiutil/src/main/native/include/wpi/ghc/
 Team 254 Library      wpilibj/src/main/java/edu/wpi/first/wpilibj/spline/SplineParameterizer.java
                       wpilibj/src/main/java/edu/wpi/first/wpilibj/trajectory/TrajectoryParameterizer.java
                       wpilibc/src/main/native/include/spline/SplineParameterizer.h
@@ -856,3 +860,84 @@ the extent permitted by applicable law. You can redistribute it
 and/or modify it under the terms of the Do What the **** You Want
 to Public License, Version 2, as published by the WTFPL Task Force.
 See http://www.wtfpl.net/ for more details.
+
+======================
+Boost Software License
+======================
+Boost Software License - Version 1.0 - August 17th, 2003
+
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+
+======
+fmtlib
+======
+Copyright (c) 2012 - present, Victor Zverovich
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+--- Optional exception to the license ---
+
+As an exception, if, as a result of your compiling your source code, portions
+of this Software are embedded into a machine-executable object form of such
+source code, you may redistribute such embedded portions in such object form
+without including the above copyright and permission notices.
+
+==============
+GHC filesystem
+==============
+Copyright (c) 2018, Steffen Schümann <s.schuemann@pobox.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

buildSrc/build.gradle

@@ -5,5 +5,5 @@ repositories {
     }
 }
 dependencies {
-    implementation "edu.wpi.first:native-utils:2021.1.1"
+    implementation "edu.wpi.first:native-utils:2022.0.2"
 }

cameraserver/.styleguide

@@ -12,6 +12,7 @@ repoRootNameOverride {
 }
 
 includeOtherLibs {
+  ^fmt/
   ^hal/
   ^networktables/
   ^opencv2/

cameraserver/multiCameraServer/src/main/java/edu/wpi/Main.java

@@ -10,8 +10,8 @@ import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
-import edu.wpi.cscore.VideoSource;
 import edu.wpi.first.cameraserver.CameraServer;
+import edu.wpi.first.cscore.VideoSource;
 import edu.wpi.first.networktables.NetworkTableInstance;
 import java.io.IOException;
 import java.nio.file.Files;
@@ -94,7 +94,6 @@ public final class Main {
   }
 
   /** Read configuration file. */
-  @SuppressWarnings("PMD.CyclomaticComplexity")
   public static boolean readConfig() {
     // parse file
     JsonElement top;
@@ -151,7 +150,7 @@ public final class Main {
   /** Start running the camera. */
   public static void startCamera(CameraConfig config) {
     System.out.println("Starting camera '" + config.name + "' on " + config.path);
-    VideoSource camera = CameraServer.getInstance().startAutomaticCapture(config.name, config.path);
+    VideoSource camera = CameraServer.startAutomaticCapture(config.name, config.path);
 
     Gson gson = new GsonBuilder().create();
 

cameraserver/multiCameraServer/src/main/native/cpp/main.cpp

@@ -4,10 +4,12 @@
 
 #include <cstdio>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <networktables/NetworkTableInstance.h>
-#include <wpi/StringRef.h>
+#include <wpi/StringExtras.h>
+#include <wpi/fmt/raw_ostream.h>
 #include <wpi/json.h>
 #include <wpi/raw_istream.h>
 #include <wpi/raw_ostream.h>
@@ -105,7 +107,7 @@ bool ReadConfig() {
   try {
     j = wpi::json::parse(is);
   } catch (const wpi::json::parse_error& e) {
-    ParseError() << "byte " << e.byte << ": " << e.what() << '\n';
+    fmt::print(ParseError(), "byte {}: {}\n", e.byte, e.what());
     return false;
   }
 
@@ -127,10 +129,9 @@ bool ReadConfig() {
   if (j.count("ntmode") != 0) {
     try {
       auto str = j.at("ntmode").get<std::string>();
-      wpi::StringRef s(str);
-      if (s.equals_lower("client")) {
+      if (wpi::equals_lower(str, "client")) {
         server = false;
-      } else if (s.equals_lower("server")) {
+      } else if (wpi::equals_lower(str, "server")) {
         server = true;
       } else {
         ParseError() << "could not understand ntmode value '" << str << "'\n";
@@ -156,10 +157,9 @@ bool ReadConfig() {
 }
 
 void StartCamera(const CameraConfig& config) {
-  wpi::outs() << "Starting camera '" << config.name << "' on " << config.path
-              << '\n';
-  auto camera = frc::CameraServer::GetInstance()->StartAutomaticCapture(
-      config.name, config.path);
+  fmt::print("Starting camera '{}' on {}\n", config.name, config.path);
+  auto camera =
+      frc::CameraServer::StartAutomaticCapture(config.name, config.path);
 
   camera.SetConfigJson(config.config);
 }
@@ -178,10 +178,10 @@ int main(int argc, char* argv[]) {
   // start NetworkTables
   auto ntinst = nt::NetworkTableInstance::GetDefault();
   if (server) {
-    wpi::outs() << "Setting up NetworkTables server\n";
+    std::puts("Setting up NetworkTables server");
     ntinst.StartServer();
   } else {
-    wpi::outs() << "Setting up NetworkTables client for team " << team << '\n';
+    fmt::print("Setting up NetworkTables client for team {}\n", team);
     ntinst.StartClientTeam(team);
   }
 

cameraserver/src/main/java/edu/wpi/first/cameraserver/CameraServer.java

@@ -4,20 +4,20 @@
 
 package edu.wpi.first.cameraserver;
 
-import edu.wpi.cscore.AxisCamera;
-import edu.wpi.cscore.CameraServerJNI;
-import edu.wpi.cscore.CvSink;
-import edu.wpi.cscore.CvSource;
-import edu.wpi.cscore.MjpegServer;
-import edu.wpi.cscore.UsbCamera;
-import edu.wpi.cscore.VideoEvent;
-import edu.wpi.cscore.VideoException;
-import edu.wpi.cscore.VideoListener;
-import edu.wpi.cscore.VideoMode;
-import edu.wpi.cscore.VideoMode.PixelFormat;
-import edu.wpi.cscore.VideoProperty;
-import edu.wpi.cscore.VideoSink;
-import edu.wpi.cscore.VideoSource;
+import edu.wpi.first.cscore.AxisCamera;
+import edu.wpi.first.cscore.CameraServerJNI;
+import edu.wpi.first.cscore.CvSink;
+import edu.wpi.first.cscore.CvSource;
+import edu.wpi.first.cscore.MjpegServer;
+import edu.wpi.first.cscore.UsbCamera;
+import edu.wpi.first.cscore.VideoEvent;
+import edu.wpi.first.cscore.VideoException;
+import edu.wpi.first.cscore.VideoListener;
+import edu.wpi.first.cscore.VideoMode;
+import edu.wpi.first.cscore.VideoMode.PixelFormat;
+import edu.wpi.first.cscore.VideoProperty;
+import edu.wpi.first.cscore.VideoSink;
+import edu.wpi.first.cscore.VideoSource;
 import edu.wpi.first.networktables.EntryListenerFlags;
 import edu.wpi.first.networktables.NetworkTable;
 import edu.wpi.first.networktables.NetworkTableEntry;
@@ -33,6 +33,7 @@ import java.util.concurrent.atomic.AtomicInteger;
  * Singleton class for creating and keeping camera servers. Also publishes camera information to
  * NetworkTables.
  */
+@SuppressWarnings("PMD.UnusedPrivateField")
 public final class CameraServer {
   public static final int kBasePort = 1181;
 
@@ -43,7 +44,12 @@ public final class CameraServer {
   private static final String kPublishName = "/CameraPublisher";
   private static CameraServer server;
 
-  /** Get the CameraServer instance. */
+  /**
+   * Get the CameraServer instance.
+   *
+   * @deprecated Use the static methods
+   */
+  @Deprecated
   public static synchronized CameraServer getInstance() {
     if (server == null) {
       server = new CameraServer();
@@ -51,18 +57,211 @@ public final class CameraServer {
     return server;
   }
 
-  private final AtomicInteger m_defaultUsbDevice;
-  private String m_primarySourceName;
-  private final Map<String, VideoSource> m_sources;
-  private final Map<String, VideoSink> m_sinks;
-  private final Map<Integer, NetworkTable> m_tables; // indexed by source handle
+  private static final AtomicInteger m_defaultUsbDevice = new AtomicInteger();
+  private static String m_primarySourceName;
+  private static final Map<String, VideoSource> m_sources = new HashMap<>();
+  private static final Map<String, VideoSink> m_sinks = new HashMap<>();
+  private static final Map<Integer, NetworkTable> m_tables =
+      new HashMap<>(); // indexed by source handle
   // source handle indexed by sink handle
-  private final Map<Integer, Integer> m_fixedSources;
-  private final NetworkTable m_publishTable;
-  private final VideoListener m_videoListener; // NOPMD
-  private final int m_tableListener; // NOPMD
-  private int m_nextPort;
-  private String[] m_addresses;
+  private static final Map<Integer, Integer> m_fixedSources = new HashMap<>();
+  private static final NetworkTable m_publishTable =
+      NetworkTableInstance.getDefault().getTable(kPublishName);
+
+  // We publish sources to NetworkTables using the following structure:
+  // "/CameraPublisher/{Source.Name}/" - root
+  // - "source" (string): Descriptive, prefixed with type (e.g. "usb:0")
+  // - "streams" (string array): URLs that can be used to stream data
+  // - "description" (string): Description of the source
+  // - "connected" (boolean): Whether source is connected
+  // - "mode" (string): Current video mode
+  // - "modes" (string array): Available video modes
+  // - "Property/{Property}" - Property values
+  // - "PropertyInfo/{Property}" - Property supporting information
+
+  // Listener for video events
+  private static final VideoListener m_videoListener =
+      new VideoListener(
+          event -> {
+            switch (event.kind) {
+              case kSourceCreated:
+                {
+                  // Create subtable for the camera
+                  NetworkTable table = m_publishTable.getSubTable(event.name);
+                  m_tables.put(event.sourceHandle, table);
+                  table.getEntry("source").setString(makeSourceValue(event.sourceHandle));
+                  table
+                      .getEntry("description")
+                      .setString(CameraServerJNI.getSourceDescription(event.sourceHandle));
+                  table
+                      .getEntry("connected")
+                      .setBoolean(CameraServerJNI.isSourceConnected(event.sourceHandle));
+                  table
+                      .getEntry("streams")
+                      .setStringArray(getSourceStreamValues(event.sourceHandle));
+                  try {
+                    VideoMode mode = CameraServerJNI.getSourceVideoMode(event.sourceHandle);
+                    table.getEntry("mode").setDefaultString(videoModeToString(mode));
+                    table.getEntry("modes").setStringArray(getSourceModeValues(event.sourceHandle));
+                  } catch (VideoException ignored) {
+                    // Do nothing. Let the other event handlers update this if there is an error.
+                  }
+                  break;
+                }
+              case kSourceDestroyed:
+                {
+                  NetworkTable table = m_tables.get(event.sourceHandle);
+                  if (table != null) {
+                    table.getEntry("source").setString("");
+                    table.getEntry("streams").setStringArray(new String[0]);
+                    table.getEntry("modes").setStringArray(new String[0]);
+                  }
+                  break;
+                }
+              case kSourceConnected:
+                {
+                  NetworkTable table = m_tables.get(event.sourceHandle);
+                  if (table != null) {
+                    // update the description too (as it may have changed)
+                    table
+                        .getEntry("description")
+                        .setString(CameraServerJNI.getSourceDescription(event.sourceHandle));
+                    table.getEntry("connected").setBoolean(true);
+                  }
+                  break;
+                }
+              case kSourceDisconnected:
+                {
+                  NetworkTable table = m_tables.get(event.sourceHandle);
+                  if (table != null) {
+                    table.getEntry("connected").setBoolean(false);
+                  }
+                  break;
+                }
+              case kSourceVideoModesUpdated:
+                {
+                  NetworkTable table = m_tables.get(event.sourceHandle);
+                  if (table != null) {
+                    table.getEntry("modes").setStringArray(getSourceModeValues(event.sourceHandle));
+                  }
+                  break;
+                }
+              case kSourceVideoModeChanged:
+                {
+                  NetworkTable table = m_tables.get(event.sourceHandle);
+                  if (table != null) {
+                    table.getEntry("mode").setString(videoModeToString(event.mode));
+                  }
+                  break;
+                }
+              case kSourcePropertyCreated:
+                {
+                  NetworkTable table = m_tables.get(event.sourceHandle);
+                  if (table != null) {
+                    putSourcePropertyValue(table, event, true);
+                  }
+                  break;
+                }
+              case kSourcePropertyValueUpdated:
+                {
+                  NetworkTable table = m_tables.get(event.sourceHandle);
+                  if (table != null) {
+                    putSourcePropertyValue(table, event, false);
+                  }
+                  break;
+                }
+              case kSourcePropertyChoicesUpdated:
+                {
+                  NetworkTable table = m_tables.get(event.sourceHandle);
+                  if (table != null) {
+                    try {
+                      String[] choices =
+                          CameraServerJNI.getEnumPropertyChoices(event.propertyHandle);
+                      table
+                          .getEntry("PropertyInfo/" + event.name + "/choices")
+                          .setStringArray(choices);
+                    } catch (VideoException ignored) {
+                      // ignore
+                    }
+                  }
+                  break;
+                }
+              case kSinkSourceChanged:
+              case kSinkCreated:
+              case kSinkDestroyed:
+              case kNetworkInterfacesChanged:
+                {
+                  m_addresses = CameraServerJNI.getNetworkInterfaces();
+                  updateStreamValues();
+                  break;
+                }
+              default:
+                break;
+            }
+          },
+          0x4fff,
+          true);
+
+  private static final int m_tableListener =
+      NetworkTableInstance.getDefault()
+          .addEntryListener(
+              kPublishName + "/",
+              event -> {
+                String relativeKey = event.name.substring(kPublishName.length() + 1);
+
+                // get source (sourceName/...)
+                int subKeyIndex = relativeKey.indexOf('/');
+                if (subKeyIndex == -1) {
+                  return;
+                }
+                String sourceName = relativeKey.substring(0, subKeyIndex);
+                VideoSource source = m_sources.get(sourceName);
+                if (source == null) {
+                  return;
+                }
+
+                // get subkey
+                relativeKey = relativeKey.substring(subKeyIndex + 1);
+
+                // handle standard names
+                String propName;
+                if ("mode".equals(relativeKey)) {
+                  // reset to current mode
+                  event.getEntry().setString(videoModeToString(source.getVideoMode()));
+                  return;
+                } else if (relativeKey.startsWith("Property/")) {
+                  propName = relativeKey.substring(9);
+                } else if (relativeKey.startsWith("RawProperty/")) {
+                  propName = relativeKey.substring(12);
+                } else {
+                  return; // ignore
+                }
+
+                // everything else is a property
+                VideoProperty property = source.getProperty(propName);
+                switch (property.getKind()) {
+                  case kNone:
+                    return;
+                  case kBoolean:
+                    // reset to current setting
+                    event.getEntry().setBoolean(property.get() != 0);
+                    return;
+                  case kInteger:
+                  case kEnum:
+                    // reset to current setting
+                    event.getEntry().setDouble(property.get());
+                    return;
+                  case kString:
+                    // reset to current setting
+                    event.getEntry().setString(property.getString());
+                    return;
+                  default:
+                    return;
+                }
+              },
+              EntryListenerFlags.kImmediate | EntryListenerFlags.kUpdate);
+  private static int m_nextPort = kBasePort;
+  private static String[] m_addresses = new String[0];
 
   @SuppressWarnings("MissingJavadocMethod")
   private static String makeSourceValue(int source) {
@@ -90,8 +289,8 @@ public final class CameraServer {
     return "mjpg:http://" + address + ":" + port + "/?action=stream";
   }
 
-  @SuppressWarnings({"MissingJavadocMethod", "PMD.AvoidUsingHardCodedIP"})
-  private synchronized String[] getSinkStreamValues(int sink) {
+  @SuppressWarnings("MissingJavadocMethod")
+  private static synchronized String[] getSinkStreamValues(int sink) {
     // Ignore all but MjpegServer
     if (VideoSink.getKindFromInt(CameraServerJNI.getSinkKind(sink)) != VideoSink.Kind.kMjpeg) {
       return new String[0];
@@ -120,8 +319,8 @@ public final class CameraServer {
     return values.toArray(new String[0]);
   }
 
-  @SuppressWarnings({"MissingJavadocMethod", "PMD.AvoidUsingHardCodedIP"})
-  private synchronized String[] getSourceStreamValues(int source) {
+  @SuppressWarnings("MissingJavadocMethod")
+  private static synchronized String[] getSourceStreamValues(int source) {
     // Ignore all but HttpCamera
     if (VideoSource.getKindFromInt(CameraServerJNI.getSourceKind(source))
         != VideoSource.Kind.kHttp) {
@@ -155,12 +354,8 @@ public final class CameraServer {
     return values;
   }
 
-  @SuppressWarnings({
-    "MissingJavadocMethod",
-    "PMD.AvoidUsingHardCodedIP",
-    "PMD.CyclomaticComplexity"
-  })
-  private synchronized void updateStreamValues() {
+  @SuppressWarnings("MissingJavadocMethod")
+  private static synchronized void updateStreamValues() {
     // Over all the sinks...
     for (VideoSink i : m_sinks.values()) {
       int sink = i.getHandle();
@@ -247,7 +442,7 @@ public final class CameraServer {
     return modeStrings;
   }
 
-  @SuppressWarnings({"MissingJavadocMethod", "PMD.CyclomaticComplexity"})
+  @SuppressWarnings("MissingJavadocMethod")
   private static void putSourcePropertyValue(NetworkTable table, VideoEvent event, boolean isNew) {
     String name;
     String infoName;
@@ -304,223 +499,7 @@ public final class CameraServer {
     }
   }
 
-  @SuppressWarnings({
-    "MissingJavadocMethod",
-    "PMD.UnusedLocalVariable",
-    "PMD.ExcessiveMethodLength",
-    "PMD.NPathComplexity"
-  })
-  private CameraServer() {
-    m_defaultUsbDevice = new AtomicInteger();
-    m_sources = new HashMap<>();
-    m_sinks = new HashMap<>();
-    m_fixedSources = new HashMap<>();
-    m_tables = new HashMap<>();
-    m_publishTable = NetworkTableInstance.getDefault().getTable(kPublishName);
-    m_nextPort = kBasePort;
-    m_addresses = new String[0];
-
-    // We publish sources to NetworkTables using the following structure:
-    // "/CameraPublisher/{Source.Name}/" - root
-    // - "source" (string): Descriptive, prefixed with type (e.g. "usb:0")
-    // - "streams" (string array): URLs that can be used to stream data
-    // - "description" (string): Description of the source
-    // - "connected" (boolean): Whether source is connected
-    // - "mode" (string): Current video mode
-    // - "modes" (string array): Available video modes
-    // - "Property/{Property}" - Property values
-    // - "PropertyInfo/{Property}" - Property supporting information
-
-    // Listener for video events
-    m_videoListener =
-        new VideoListener(
-            event -> {
-              switch (event.kind) {
-                case kSourceCreated:
-                  {
-                    // Create subtable for the camera
-                    NetworkTable table = m_publishTable.getSubTable(event.name);
-                    m_tables.put(event.sourceHandle, table);
-                    table.getEntry("source").setString(makeSourceValue(event.sourceHandle));
-                    table
-                        .getEntry("description")
-                        .setString(CameraServerJNI.getSourceDescription(event.sourceHandle));
-                    table
-                        .getEntry("connected")
-                        .setBoolean(CameraServerJNI.isSourceConnected(event.sourceHandle));
-                    table
-                        .getEntry("streams")
-                        .setStringArray(getSourceStreamValues(event.sourceHandle));
-                    try {
-                      VideoMode mode = CameraServerJNI.getSourceVideoMode(event.sourceHandle);
-                      table.getEntry("mode").setDefaultString(videoModeToString(mode));
-                      table
-                          .getEntry("modes")
-                          .setStringArray(getSourceModeValues(event.sourceHandle));
-                    } catch (VideoException ignored) {
-                      // Do nothing. Let the other event handlers update this if there is an error.
-                    }
-                    break;
-                  }
-                case kSourceDestroyed:
-                  {
-                    NetworkTable table = m_tables.get(event.sourceHandle);
-                    if (table != null) {
-                      table.getEntry("source").setString("");
-                      table.getEntry("streams").setStringArray(new String[0]);
-                      table.getEntry("modes").setStringArray(new String[0]);
-                    }
-                    break;
-                  }
-                case kSourceConnected:
-                  {
-                    NetworkTable table = m_tables.get(event.sourceHandle);
-                    if (table != null) {
-                      // update the description too (as it may have changed)
-                      table
-                          .getEntry("description")
-                          .setString(CameraServerJNI.getSourceDescription(event.sourceHandle));
-                      table.getEntry("connected").setBoolean(true);
-                    }
-                    break;
-                  }
-                case kSourceDisconnected:
-                  {
-                    NetworkTable table = m_tables.get(event.sourceHandle);
-                    if (table != null) {
-                      table.getEntry("connected").setBoolean(false);
-                    }
-                    break;
-                  }
-                case kSourceVideoModesUpdated:
-                  {
-                    NetworkTable table = m_tables.get(event.sourceHandle);
-                    if (table != null) {
-                      table
-                          .getEntry("modes")
-                          .setStringArray(getSourceModeValues(event.sourceHandle));
-                    }
-                    break;
-                  }
-                case kSourceVideoModeChanged:
-                  {
-                    NetworkTable table = m_tables.get(event.sourceHandle);
-                    if (table != null) {
-                      table.getEntry("mode").setString(videoModeToString(event.mode));
-                    }
-                    break;
-                  }
-                case kSourcePropertyCreated:
-                  {
-                    NetworkTable table = m_tables.get(event.sourceHandle);
-                    if (table != null) {
-                      putSourcePropertyValue(table, event, true);
-                    }
-                    break;
-                  }
-                case kSourcePropertyValueUpdated:
-                  {
-                    NetworkTable table = m_tables.get(event.sourceHandle);
-                    if (table != null) {
-                      putSourcePropertyValue(table, event, false);
-                    }
-                    break;
-                  }
-                case kSourcePropertyChoicesUpdated:
-                  {
-                    NetworkTable table = m_tables.get(event.sourceHandle);
-                    if (table != null) {
-                      try {
-                        String[] choices =
-                            CameraServerJNI.getEnumPropertyChoices(event.propertyHandle);
-                        table
-                            .getEntry("PropertyInfo/" + event.name + "/choices")
-                            .setStringArray(choices);
-                      } catch (VideoException ignored) {
-                        // ignore
-                      }
-                    }
-                    break;
-                  }
-                case kSinkSourceChanged:
-                case kSinkCreated:
-                case kSinkDestroyed:
-                case kNetworkInterfacesChanged:
-                  {
-                    m_addresses = CameraServerJNI.getNetworkInterfaces();
-                    updateStreamValues();
-                    break;
-                  }
-                default:
-                  break;
-              }
-            },
-            0x4fff,
-            true);
-
-    // Listener for NetworkTable events
-    // We don't currently support changing settings via NT due to
-    // synchronization issues, so just update to current setting if someone
-    // else tries to change it.
-    m_tableListener =
-        NetworkTableInstance.getDefault()
-            .addEntryListener(
-                kPublishName + "/",
-                event -> {
-                  String relativeKey = event.name.substring(kPublishName.length() + 1);
-
-                  // get source (sourceName/...)
-                  int subKeyIndex = relativeKey.indexOf('/');
-                  if (subKeyIndex == -1) {
-                    return;
-                  }
-                  String sourceName = relativeKey.substring(0, subKeyIndex);
-                  VideoSource source = m_sources.get(sourceName);
-                  if (source == null) {
-                    return;
-                  }
-
-                  // get subkey
-                  relativeKey = relativeKey.substring(subKeyIndex + 1);
-
-                  // handle standard names
-                  String propName;
-                  if ("mode".equals(relativeKey)) {
-                    // reset to current mode
-                    event.getEntry().setString(videoModeToString(source.getVideoMode()));
-                    return;
-                  } else if (relativeKey.startsWith("Property/")) {
-                    propName = relativeKey.substring(9);
-                  } else if (relativeKey.startsWith("RawProperty/")) {
-                    propName = relativeKey.substring(12);
-                  } else {
-                    return; // ignore
-                  }
-
-                  // everything else is a property
-                  VideoProperty property = source.getProperty(propName);
-                  switch (property.getKind()) {
-                    case kNone:
-                      return;
-                    case kBoolean:
-                      // reset to current setting
-                      event.getEntry().setBoolean(property.get() != 0);
-                      return;
-                    case kInteger:
-                    case kEnum:
-                      // reset to current setting
-                      event.getEntry().setDouble(property.get());
-                      return;
-                    case kString:
-                      // reset to current setting
-                      event.getEntry().setString(property.getString());
-                      return;
-                    default:
-                      return;
-                  }
-                },
-                EntryListenerFlags.kImmediate | EntryListenerFlags.kUpdate);
-  }
+  private CameraServer() {}
 
   /**
    * Start automatically capturing images to send to the dashboard.
@@ -531,8 +510,10 @@ public final class CameraServer {
    * <p>The first time this overload is called, it calls {@link #startAutomaticCapture(int)} with
    * device 0, creating a camera named "USB Camera 0". Subsequent calls increment the device number
    * (e.g. 1, 2, etc).
+   *
+   * @return The USB camera capturing images.
    */
-  public UsbCamera startAutomaticCapture() {
+  public static UsbCamera startAutomaticCapture() {
     UsbCamera camera = startAutomaticCapture(m_defaultUsbDevice.getAndIncrement());
     CameraServerSharedStore.getCameraServerShared().reportUsbCamera(camera.getHandle());
     return camera;
@@ -545,8 +526,9 @@ public final class CameraServer {
    * {dev}".
    *
    * @param dev The device number of the camera interface
+   * @return The USB camera capturing images.
    */
-  public UsbCamera startAutomaticCapture(int dev) {
+  public static UsbCamera startAutomaticCapture(int dev) {
     UsbCamera camera = new UsbCamera("USB Camera " + dev, dev);
     startAutomaticCapture(camera);
     CameraServerSharedStore.getCameraServerShared().reportUsbCamera(camera.getHandle());
@@ -558,8 +540,9 @@ public final class CameraServer {
    *
    * @param name The name to give the camera
    * @param dev The device number of the camera interface
+   * @return The USB camera capturing images.
    */
-  public UsbCamera startAutomaticCapture(String name, int dev) {
+  public static UsbCamera startAutomaticCapture(String name, int dev) {
     UsbCamera camera = new UsbCamera(name, dev);
     startAutomaticCapture(camera);
     CameraServerSharedStore.getCameraServerShared().reportUsbCamera(camera.getHandle());
@@ -571,8 +554,9 @@ public final class CameraServer {
    *
    * @param name The name to give the camera
    * @param path The device path (e.g. "/dev/video0") of the camera
+   * @return The USB camera capturing images.
    */
-  public UsbCamera startAutomaticCapture(String name, String path) {
+  public static UsbCamera startAutomaticCapture(String name, String path) {
     UsbCamera camera = new UsbCamera(name, path);
     startAutomaticCapture(camera);
     CameraServerSharedStore.getCameraServerShared().reportUsbCamera(camera.getHandle());
@@ -583,8 +567,9 @@ public final class CameraServer {
    * Start automatically capturing images to send to the dashboard from an existing camera.
    *
    * @param camera Camera
+   * @return The MJPEG server serving images from the given camera.
    */
-  public MjpegServer startAutomaticCapture(VideoSource camera) {
+  public static MjpegServer startAutomaticCapture(VideoSource camera) {
     addCamera(camera);
     MjpegServer server = addServer("serve_" + camera.getName());
     server.setSource(camera);
@@ -597,8 +582,9 @@ public final class CameraServer {
    * <p>This overload calls {@link #addAxisCamera(String, String)} with name "Axis Camera".
    *
    * @param host Camera host IP or DNS name (e.g. "10.x.y.11")
+   * @return The Axis camera capturing images.
    */
-  public AxisCamera addAxisCamera(String host) {
+  public static AxisCamera addAxisCamera(String host) {
     return addAxisCamera("Axis Camera", host);
   }
 
@@ -608,8 +594,9 @@ public final class CameraServer {
    * <p>This overload calls {@link #addAxisCamera(String, String[])} with name "Axis Camera".
    *
    * @param hosts Array of Camera host IPs/DNS names
+   * @return The Axis camera capturing images.
    */
-  public AxisCamera addAxisCamera(String[] hosts) {
+  public static AxisCamera addAxisCamera(String[] hosts) {
     return addAxisCamera("Axis Camera", hosts);
   }
 
@@ -618,8 +605,9 @@ public final class CameraServer {
    *
    * @param name The name to give the camera
    * @param host Camera host IP or DNS name (e.g. "10.x.y.11")
+   * @return The Axis camera capturing images.
    */
-  public AxisCamera addAxisCamera(String name, String host) {
+  public static AxisCamera addAxisCamera(String name, String host) {
     AxisCamera camera = new AxisCamera(name, host);
     // Create a passthrough MJPEG server for USB access
     startAutomaticCapture(camera);
@@ -632,8 +620,9 @@ public final class CameraServer {
    *
    * @param name The name to give the camera
    * @param hosts Array of Camera host IPs/DNS names
+   * @return The Axis camera capturing images.
    */
-  public AxisCamera addAxisCamera(String name, String[] hosts) {
+  public static AxisCamera addAxisCamera(String name, String[] hosts) {
     AxisCamera camera = new AxisCamera(name, hosts);
     // Create a passthrough MJPEG server for USB access
     startAutomaticCapture(camera);
@@ -645,12 +634,15 @@ public final class CameraServer {
    * Adds a virtual camera for switching between two streams. Unlike the other addCamera methods,
    * this returns a VideoSink rather than a VideoSource. Calling setSource() on the returned object
    * can be used to switch the actual source of the stream.
+   *
+   * @param name The name to give the camera
+   * @return The MJPEG server serving images from the given camera.
    */
-  public MjpegServer addSwitchedCamera(String name) {
+  public static MjpegServer addSwitchedCamera(String name) {
     // create a dummy CvSource
     CvSource source = new CvSource(name, VideoMode.PixelFormat.kMJPEG, 160, 120, 30);
     MjpegServer server = startAutomaticCapture(source);
-    synchronized (this) {
+    synchronized (CameraServer.class) {
       m_fixedSources.put(server.getHandle(), source.getHandle());
     }
 
@@ -663,10 +655,12 @@ public final class CameraServer {
    *
    * <p>This is only valid to call after a camera feed has been added with startAutomaticCapture()
    * or addServer().
+   *
+   * @return OpenCV sink for the primary camera feed
    */
-  public CvSink getVideo() {
+  public static CvSink getVideo() {
     VideoSource source;
-    synchronized (this) {
+    synchronized (CameraServer.class) {
       if (m_primarySourceName == null) {
         throw new VideoException("no camera available");
       }
@@ -683,11 +677,12 @@ public final class CameraServer {
    * image processing on the roboRIO.
    *
    * @param camera Camera (e.g. as returned by startAutomaticCapture).
+   * @return OpenCV sink for the specified camera
    */
-  public CvSink getVideo(VideoSource camera) {
+  public static CvSink getVideo(VideoSource camera) {
     String name = "opencv_" + camera.getName();
 
-    synchronized (this) {
+    synchronized (CameraServer.class) {
       VideoSink sink = m_sinks.get(name);
       if (sink != null) {
         VideoSink.Kind kind = sink.getKind();
@@ -709,10 +704,11 @@ public final class CameraServer {
    * image processing on the roboRIO.
    *
    * @param name Camera name
+   * @return OpenCV sink for the specified camera
    */
-  public CvSink getVideo(String name) {
+  public static CvSink getVideo(String name) {
     VideoSource source;
-    synchronized (this) {
+    synchronized (CameraServer.class) {
       source = m_sources.get(name);
       if (source == null) {
         throw new VideoException("could not find camera " + name);
@@ -728,8 +724,9 @@ public final class CameraServer {
    * @param name Name to give the stream
    * @param width Width of the image being sent
    * @param height Height of the image being sent
+   * @return OpenCV source for the MJPEG stream
    */
-  public CvSource putVideo(String name, int width, int height) {
+  public static CvSource putVideo(String name, int width, int height) {
     CvSource source = new CvSource(name, VideoMode.PixelFormat.kMJPEG, width, height, 30);
     startAutomaticCapture(source);
     return source;
@@ -739,10 +736,11 @@ public final class CameraServer {
    * Adds a MJPEG server at the next available port.
    *
    * @param name Server name
+   * @return The MJPEG server
    */
-  public MjpegServer addServer(String name) {
+  public static MjpegServer addServer(String name) {
     int port;
-    synchronized (this) {
+    synchronized (CameraServer.class) {
       port = m_nextPort;
       m_nextPort++;
     }
@@ -753,8 +751,10 @@ public final class CameraServer {
    * Adds a MJPEG server.
    *
    * @param name Server name
+   * @param port Server port
+   * @return The MJPEG server
    */
-  public MjpegServer addServer(String name, int port) {
+  public static MjpegServer addServer(String name, int port) {
     MjpegServer server = new MjpegServer(name, port);
     addServer(server);
     return server;
@@ -765,8 +765,8 @@ public final class CameraServer {
    *
    * @param server Server
    */
-  public void addServer(VideoSink server) {
-    synchronized (this) {
+  public static void addServer(VideoSink server) {
+    synchronized (CameraServer.class) {
       m_sinks.put(server.getName(), server);
     }
   }
@@ -776,8 +776,8 @@ public final class CameraServer {
    *
    * @param name Server name
    */
-  public void removeServer(String name) {
-    synchronized (this) {
+  public static void removeServer(String name) {
+    synchronized (CameraServer.class) {
       m_sinks.remove(name);
     }
   }
@@ -787,9 +787,11 @@ public final class CameraServer {
    *
    * <p>This is only valid to call after a camera feed has been added with startAutomaticCapture()
    * or addServer().
+   *
+   * @return The server for the primary camera feed
    */
-  public VideoSink getServer() {
-    synchronized (this) {
+  public static VideoSink getServer() {
+    synchronized (CameraServer.class) {
       if (m_primarySourceName == null) {
         throw new VideoException("no camera available");
       }
@@ -801,9 +803,10 @@ public final class CameraServer {
    * Gets a server by name.
    *
    * @param name Server name
+   * @return The server
    */
-  public VideoSink getServer(String name) {
-    synchronized (this) {
+  public static VideoSink getServer(String name) {
+    synchronized (CameraServer.class) {
       return m_sinks.get(name);
     }
   }
@@ -813,9 +816,9 @@ public final class CameraServer {
    *
    * @param camera Camera
    */
-  public void addCamera(VideoSource camera) {
+  public static void addCamera(VideoSource camera) {
     String name = camera.getName();
-    synchronized (this) {
+    synchronized (CameraServer.class) {
       if (m_primarySourceName == null) {
         m_primarySourceName = name;
       }
@@ -828,8 +831,8 @@ public final class CameraServer {
    *
    * @param name Camera name
    */
-  public void removeCamera(String name) {
-    synchronized (this) {
+  public static void removeCamera(String name) {
+    synchronized (CameraServer.class) {
       m_sources.remove(name);
     }
   }

cameraserver/src/main/java/edu/wpi/first/cameraserver/CameraServerSharedStore.java

@@ -9,7 +9,11 @@ public final class CameraServerSharedStore {
 
   private CameraServerSharedStore() {}
 
-  /** get the CameraServerShared object. */
+  /**
+   * Get the CameraServerShared object.
+   *
+   * @return The CameraServerSharedObject
+   */
   public static synchronized CameraServerShared getCameraServerShared() {
     if (cameraServerShared == null) {
       cameraServerShared =
@@ -36,7 +40,11 @@ public final class CameraServerSharedStore {
     return cameraServerShared;
   }
 
-  /** set the CameraServerShared object. */
+  /**
+   * Set the CameraServerShared object.
+   *
+   * @param shared The CameraServerShared object.
+   */
   public static synchronized void setCameraServerShared(CameraServerShared shared) {
     cameraServerShared = shared;
   }

cameraserver/src/main/java/edu/wpi/first/vision/VisionPipeline.java

@@ -17,6 +17,8 @@ public interface VisionPipeline {
   /**
    * Processes the image input and sets the result objects. Implementations should make these
    * objects accessible.
+   *
+   * @param image The image to process.
    */
   void process(Mat image);
 }

cameraserver/src/main/java/edu/wpi/first/vision/VisionRunner.java

@@ -4,9 +4,9 @@
 
 package edu.wpi.first.vision;
 
-import edu.wpi.cscore.CvSink;
-import edu.wpi.cscore.VideoSource;
 import edu.wpi.first.cameraserver.CameraServerSharedStore;
+import edu.wpi.first.cscore.CvSink;
+import edu.wpi.first.cscore.VideoSource;
 import org.opencv.core.Mat;
 
 /**

cameraserver/src/main/java/edu/wpi/first/vision/VisionThread.java

@@ -4,7 +4,7 @@
 
 package edu.wpi.first.vision;
 
-import edu.wpi.cscore.VideoSource;
+import edu.wpi.first.cscore.VideoSource;
 
 /**
  * A vision thread is a special thread that runs a vision pipeline. It is a <i>daemon</i> thread; it

cameraserver/src/main/java/edu/wpi/first/vision/package-info.java

@@ -13,7 +13,7 @@
  *     implements VisionRunner.Listener<MyFindTotePipeline> {
  *
  *      // A USB camera connected to the roboRIO.
- *      private {@link edu.wpi.cscore.VideoSource VideoSource} usbCamera;
+ *      private {@link edu.wpi.first.cscore.VideoSource VideoSource} usbCamera;
  *
  *      // A vision pipeline. This could be handwritten or generated by GRIP.
  *      // This has to implement {@link edu.wpi.first.vision.VisionPipeline}.
@@ -44,7 +44,7 @@
  *
  *     {@literal @}Override
  *      public void robotInit() {
- *          usbCamera = CameraServer.getInstance().startAutomaticCapture(0);
+ *          usbCamera = CameraServer.startAutomaticCapture(0);
  *          findTotePipeline = new MyFindTotePipeline();
  *          findToteThread = new VisionThread(usbCamera, findTotePipeline, this);
  *      }

cameraserver/src/main/native/cpp/cameraserver/CameraServer.cpp

@@ -7,14 +7,14 @@
 #include <atomic>
 #include <vector>
 
+#include <fmt/format.h>
 #include <networktables/NetworkTable.h>
 #include <networktables/NetworkTableInstance.h>
 #include <wpi/DenseMap.h>
-#include <wpi/ManagedStatic.h>
 #include <wpi/SmallString.h>
+#include <wpi/StringExtras.h>
 #include <wpi/StringMap.h>
 #include <wpi/mutex.h>
-#include <wpi/raw_ostream.h>
 
 #include "cameraserver/CameraServerShared.h"
 #include "ntcore_cpp.h"
@@ -23,8 +23,9 @@ using namespace frc;
 
 static constexpr char const* kPublishName = "/CameraPublisher";
 
-struct CameraServer::Impl {
-  Impl();
+namespace {
+struct Instance {
+  Instance();
   std::shared_ptr<nt::NetworkTable> GetSourceTable(CS_Source source);
   std::vector<std::string> GetSinkStreamValues(CS_Sink sink);
   std::vector<std::string> GetSourceStreamValues(CS_Source source);
@@ -41,35 +42,36 @@ struct CameraServer::Impl {
       nt::NetworkTableInstance::GetDefault().GetTable(kPublishName)};
   cs::VideoListener m_videoListener;
   int m_tableListener;
-  int m_nextPort;
+  int m_nextPort{CameraServer::kBasePort};
   std::vector<std::string> m_addresses;
 };
+}  // namespace
 
-CameraServer* CameraServer::GetInstance() {
-  struct Creator {
-    static void* call() { return new CameraServer{}; }
-  };
-  struct Deleter {
-    static void call(void* ptr) { delete static_cast<CameraServer*>(ptr); }
-  };
-  static wpi::ManagedStatic<CameraServer, Creator, Deleter> instance;
-  return &(*instance);
+static Instance& GetInstance() {
+  static Instance instance;
+  return instance;
 }
 
-static wpi::StringRef MakeSourceValue(CS_Source source,
-                                      wpi::SmallVectorImpl<char>& buf) {
+CameraServer* CameraServer::GetInstance() {
+  ::GetInstance();
+  static CameraServer instance;
+  return &instance;
+}
+
+static std::string_view MakeSourceValue(CS_Source source,
+                                        wpi::SmallVectorImpl<char>& buf) {
   CS_Status status = 0;
   buf.clear();
   switch (cs::GetSourceKind(source, &status)) {
     case CS_SOURCE_USB: {
-      wpi::StringRef prefix{"usb:"};
+      std::string_view prefix{"usb:"};
       buf.append(prefix.begin(), prefix.end());
       auto path = cs::GetUsbCameraPath(source, &status);
       buf.append(path.begin(), path.end());
       break;
     }
     case CS_SOURCE_HTTP: {
-      wpi::StringRef prefix{"ip:"};
+      std::string_view prefix{"ip:"};
       buf.append(prefix.begin(), prefix.end());
       auto urls = cs::GetHttpCameraUrls(source, &status);
       if (!urls.empty()) {
@@ -83,22 +85,19 @@ static wpi::StringRef MakeSourceValue(CS_Source source,
       return "unknown:";
   }
 
-  return wpi::StringRef{buf.begin(), buf.size()};
+  return {buf.begin(), buf.size()};
 }
 
-static std::string MakeStreamValue(const wpi::Twine& address, int port) {
-  return ("mjpg:http://" + address + wpi::Twine(':') + wpi::Twine(port) +
-          "/?action=stream")
-      .str();
+static std::string MakeStreamValue(std::string_view address, int port) {
+  return fmt::format("mjpg:http://{}:{}/?action=stream", address, port);
 }
 
-std::shared_ptr<nt::NetworkTable> CameraServer::Impl::GetSourceTable(
-    CS_Source source) {
+std::shared_ptr<nt::NetworkTable> Instance::GetSourceTable(CS_Source source) {
   std::scoped_lock lock(m_mutex);
   return m_tables.lookup(source);
 }
 
-std::vector<std::string> CameraServer::Impl::GetSinkStreamValues(CS_Sink sink) {
+std::vector<std::string> Instance::GetSinkStreamValues(CS_Sink sink) {
   CS_Status status = 0;
 
   // Ignore all but MjpegServer
@@ -130,8 +129,7 @@ std::vector<std::string> CameraServer::Impl::GetSinkStreamValues(CS_Sink sink) {
   return values;
 }
 
-std::vector<std::string> CameraServer::Impl::GetSourceStreamValues(
-    CS_Source source) {
+std::vector<std::string> Instance::GetSourceStreamValues(CS_Source source) {
   CS_Status status = 0;
 
   // Ignore all but HttpCamera
@@ -165,7 +163,7 @@ std::vector<std::string> CameraServer::Impl::GetSourceStreamValues(
   return values;
 }
 
-void CameraServer::Impl::UpdateStreamValues() {
+void Instance::UpdateStreamValues() {
   std::scoped_lock lock(m_mutex);
   // Over all the sinks...
   for (const auto& i : m_sinks) {
@@ -229,12 +227,8 @@ static std::string PixelFormatToString(int pixelFormat) {
 }
 
 static std::string VideoModeToString(const cs::VideoMode& mode) {
-  std::string rv;
-  wpi::raw_string_ostream oss{rv};
-  oss << mode.width << "x" << mode.height;
-  oss << " " << PixelFormatToString(mode.pixelFormat) << " ";
-  oss << mode.fps << " fps";
-  return oss.str();
+  return fmt::format("{}x{} {} {} fps", mode.width, mode.height,
+                     PixelFormatToString(mode.pixelFormat), mode.fps);
 }
 
 static std::vector<std::string> GetSourceModeValues(int source) {
@@ -248,23 +242,20 @@ static std::vector<std::string> GetSourceModeValues(int source) {
 
 static void PutSourcePropertyValue(nt::NetworkTable* table,
                                    const cs::VideoEvent& event, bool isNew) {
-  wpi::SmallString<64> name;
-  wpi::SmallString<64> infoName;
-  if (wpi::StringRef{event.name}.startswith("raw_")) {
-    name = "RawProperty/";
-    name += event.name;
-    infoName = "RawPropertyInfo/";
-    infoName += event.name;
+  std::string_view namePrefix;
+  std::string_view infoPrefix;
+  if (wpi::starts_with(event.name, "raw_")) {
+    namePrefix = "RawProperty";
+    infoPrefix = "RawPropertyInfo";
   } else {
-    name = "Property/";
-    name += event.name;
-    infoName = "PropertyInfo/";
-    infoName += event.name;
+    namePrefix = "Property";
+    infoPrefix = "PropertyInfo";
   }
 
   wpi::SmallString<64> buf;
   CS_Status status = 0;
-  nt::NetworkTableEntry entry = table->GetEntry(name);
+  nt::NetworkTableEntry entry =
+      table->GetEntry(fmt::format("{}/{}", namePrefix, event.name));
   switch (event.propertyKind) {
     case CS_PROP_BOOLEAN:
       if (isNew) {
@@ -277,13 +268,13 @@ static void PutSourcePropertyValue(nt::NetworkTable* table,
     case CS_PROP_ENUM:
       if (isNew) {
         entry.SetDefaultDouble(event.value);
-        table->GetEntry(infoName + "/min")
+        table->GetEntry(fmt::format("{}/{}/min", infoPrefix, event.name))
             .SetDouble(cs::GetPropertyMin(event.propertyHandle, &status));
-        table->GetEntry(infoName + "/max")
+        table->GetEntry(fmt::format("{}/{}/max", infoPrefix, event.name))
             .SetDouble(cs::GetPropertyMax(event.propertyHandle, &status));
-        table->GetEntry(infoName + "/step")
+        table->GetEntry(fmt::format("{}/{}/step", infoPrefix, event.name))
             .SetDouble(cs::GetPropertyStep(event.propertyHandle, &status));
-        table->GetEntry(infoName + "/default")
+        table->GetEntry(fmt::format("{}/{}/default", infoPrefix, event.name))
             .SetDouble(cs::GetPropertyDefault(event.propertyHandle, &status));
       } else {
         entry.SetDouble(event.value);
@@ -301,7 +292,7 @@ static void PutSourcePropertyValue(nt::NetworkTable* table,
   }
 }
 
-CameraServer::Impl::Impl() : m_nextPort(kBasePort) {
+Instance::Instance() {
   // We publish sources to NetworkTables using the following structure:
   // "/CameraPublisher/{Source.Name}/" - root
   // - "source" (string): Descriptive, prefixed with type (e.g. "usb:0")
@@ -404,12 +395,11 @@ CameraServer::Impl::Impl() : m_nextPort(kBasePort) {
           case cs::VideoEvent::kSourcePropertyChoicesUpdated: {
             auto table = GetSourceTable(event.sourceHandle);
             if (table) {
-              wpi::SmallString<64> name{"PropertyInfo/"};
-              name += event.name;
-              name += "/choices";
               auto choices =
                   cs::GetEnumPropertyChoices(event.propertyHandle, &status);
-              table->GetEntry(name).SetStringArray(choices);
+              table
+                  ->GetEntry(fmt::format("PropertyInfo/{}/choices", event.name))
+                  .SetStringArray(choices);
             }
             break;
           }
@@ -433,35 +423,35 @@ CameraServer::Impl::Impl() : m_nextPort(kBasePort) {
   // else tries to change it.
   wpi::SmallString<64> buf;
   m_tableListener = nt::NetworkTableInstance::GetDefault().AddEntryListener(
-      kPublishName + wpi::Twine('/'),
+      fmt::format("{}/", kPublishName),
       [=](const nt::EntryNotification& event) {
-        wpi::StringRef relativeKey =
-            event.name.substr(wpi::StringRef(kPublishName).size() + 1);
+        auto relativeKey = wpi::drop_front(
+            event.name, std::string_view{kPublishName}.size() + 1);
 
         // get source (sourceName/...)
         auto subKeyIndex = relativeKey.find('/');
-        if (subKeyIndex == wpi::StringRef::npos) {
+        if (subKeyIndex == std::string_view::npos) {
           return;
         }
-        wpi::StringRef sourceName = relativeKey.slice(0, subKeyIndex);
+        auto sourceName = wpi::slice(relativeKey, 0, subKeyIndex);
         auto sourceIt = m_sources.find(sourceName);
         if (sourceIt == m_sources.end()) {
           return;
         }
 
         // get subkey
-        relativeKey = relativeKey.substr(subKeyIndex + 1);
+        relativeKey.remove_prefix(subKeyIndex + 1);
 
         // handle standard names
-        wpi::StringRef propName;
+        std::string_view propName;
         nt::NetworkTableEntry entry{event.entry};
         if (relativeKey == "mode") {
           // reset to current mode
           entry.SetString(VideoModeToString(sourceIt->second.GetVideoMode()));
           return;
-        } else if (relativeKey.startswith("Property/")) {
+        } else if (wpi::starts_with(relativeKey, "Property/")) {
           propName = relativeKey.substr(9);
-        } else if (relativeKey.startswith("RawProperty/")) {
+        } else if (wpi::starts_with(relativeKey, "RawProperty/")) {
           propName = relativeKey.substr(12);
         } else {
           return;  // ignore
@@ -489,26 +479,23 @@ CameraServer::Impl::Impl() : m_nextPort(kBasePort) {
       NT_NOTIFY_IMMEDIATE | NT_NOTIFY_UPDATE);
 }
 
-CameraServer::CameraServer() : m_impl(new Impl) {}
-
-CameraServer::~CameraServer() = default;
-
 cs::UsbCamera CameraServer::StartAutomaticCapture() {
-  cs::UsbCamera camera = StartAutomaticCapture(m_impl->m_defaultUsbDevice++);
+  cs::UsbCamera camera =
+      StartAutomaticCapture(::GetInstance().m_defaultUsbDevice++);
   auto csShared = GetCameraServerShared();
   csShared->ReportUsbCamera(camera.GetHandle());
   return camera;
 }
 
 cs::UsbCamera CameraServer::StartAutomaticCapture(int dev) {
-  cs::UsbCamera camera{"USB Camera " + wpi::Twine(dev), dev};
+  cs::UsbCamera camera{fmt::format("USB Camera {}", dev), dev};
   StartAutomaticCapture(camera);
   auto csShared = GetCameraServerShared();
   csShared->ReportUsbCamera(camera.GetHandle());
   return camera;
 }
 
-cs::UsbCamera CameraServer::StartAutomaticCapture(const wpi::Twine& name,
+cs::UsbCamera CameraServer::StartAutomaticCapture(std::string_view name,
                                                   int dev) {
   cs::UsbCamera camera{name, dev};
   StartAutomaticCapture(camera);
@@ -517,8 +504,8 @@ cs::UsbCamera CameraServer::StartAutomaticCapture(const wpi::Twine& name,
   return camera;
 }
 
-cs::UsbCamera CameraServer::StartAutomaticCapture(const wpi::Twine& name,
-                                                  const wpi::Twine& path) {
+cs::UsbCamera CameraServer::StartAutomaticCapture(std::string_view name,
+                                                  std::string_view path) {
   cs::UsbCamera camera{name, path};
   StartAutomaticCapture(camera);
   auto csShared = GetCameraServerShared();
@@ -526,7 +513,7 @@ cs::UsbCamera CameraServer::StartAutomaticCapture(const wpi::Twine& name,
   return camera;
 }
 
-cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& host) {
+cs::AxisCamera CameraServer::AddAxisCamera(std::string_view host) {
   return AddAxisCamera("Axis Camera", host);
 }
 
@@ -538,12 +525,12 @@ cs::AxisCamera CameraServer::AddAxisCamera(const std::string& host) {
   return AddAxisCamera("Axis Camera", host);
 }
 
-cs::AxisCamera CameraServer::AddAxisCamera(wpi::ArrayRef<std::string> hosts) {
+cs::AxisCamera CameraServer::AddAxisCamera(wpi::span<const std::string> hosts) {
   return AddAxisCamera("Axis Camera", hosts);
 }
 
-cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& name,
-                                           const wpi::Twine& host) {
+cs::AxisCamera CameraServer::AddAxisCamera(std::string_view name,
+                                           std::string_view host) {
   cs::AxisCamera camera{name, host};
   StartAutomaticCapture(camera);
   auto csShared = GetCameraServerShared();
@@ -551,7 +538,7 @@ cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& name,
   return camera;
 }
 
-cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& name,
+cs::AxisCamera CameraServer::AddAxisCamera(std::string_view name,
                                            const char* host) {
   cs::AxisCamera camera{name, host};
   StartAutomaticCapture(camera);
@@ -560,7 +547,7 @@ cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& name,
   return camera;
 }
 
-cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& name,
+cs::AxisCamera CameraServer::AddAxisCamera(std::string_view name,
                                            const std::string& host) {
   cs::AxisCamera camera{name, host};
   StartAutomaticCapture(camera);
@@ -569,8 +556,8 @@ cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& name,
   return camera;
 }
 
-cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& name,
-                                           wpi::ArrayRef<std::string> hosts) {
+cs::AxisCamera CameraServer::AddAxisCamera(std::string_view name,
+                                           wpi::span<const std::string> hosts) {
   cs::AxisCamera camera{name, hosts};
   StartAutomaticCapture(camera);
   auto csShared = GetCameraServerShared();
@@ -578,11 +565,11 @@ cs::AxisCamera CameraServer::AddAxisCamera(const wpi::Twine& name,
   return camera;
 }
 
-cs::MjpegServer CameraServer::AddSwitchedCamera(const wpi::Twine& name) {
+cs::MjpegServer CameraServer::AddSwitchedCamera(std::string_view name) {
   // create a dummy CvSource
   cs::CvSource source{name, cs::VideoMode::PixelFormat::kMJPEG, 160, 120, 30};
   cs::MjpegServer server = StartAutomaticCapture(source);
-  m_impl->m_fixedSources[server.GetHandle()] = source.GetHandle();
+  ::GetInstance().m_fixedSources[server.GetHandle()] = source.GetHandle();
 
   return server;
 }
@@ -590,22 +577,23 @@ cs::MjpegServer CameraServer::AddSwitchedCamera(const wpi::Twine& name) {
 cs::MjpegServer CameraServer::StartAutomaticCapture(
     const cs::VideoSource& camera) {
   AddCamera(camera);
-  auto server = AddServer(wpi::Twine("serve_") + camera.GetName());
+  auto server = AddServer(fmt::format("serve_{}", camera.GetName()));
   server.SetSource(camera);
   return server;
 }
 
 cs::CvSink CameraServer::GetVideo() {
+  auto& inst = ::GetInstance();
   cs::VideoSource source;
   {
     auto csShared = GetCameraServerShared();
-    std::scoped_lock lock(m_impl->m_mutex);
-    if (m_impl->m_primarySourceName.empty()) {
+    std::scoped_lock lock(inst.m_mutex);
+    if (inst.m_primarySourceName.empty()) {
       csShared->SetCameraServerError("no camera available");
       return cs::CvSink{};
     }
-    auto it = m_impl->m_sources.find(m_impl->m_primarySourceName);
-    if (it == m_impl->m_sources.end()) {
+    auto it = inst.m_sources.find(inst.m_primarySourceName);
+    if (it == inst.m_sources.end()) {
       csShared->SetCameraServerError("no camera available");
       return cs::CvSink{};
     }
@@ -615,40 +603,40 @@ cs::CvSink CameraServer::GetVideo() {
 }
 
 cs::CvSink CameraServer::GetVideo(const cs::VideoSource& camera) {
+  auto& inst = ::GetInstance();
   wpi::SmallString<64> name{"opencv_"};
   name += camera.GetName();
 
   {
-    std::scoped_lock lock(m_impl->m_mutex);
-    auto it = m_impl->m_sinks.find(name);
-    if (it != m_impl->m_sinks.end()) {
+    std::scoped_lock lock(inst.m_mutex);
+    auto it = inst.m_sinks.find(name);
+    if (it != inst.m_sinks.end()) {
       auto kind = it->second.GetKind();
       if (kind != cs::VideoSink::kCv) {
         auto csShared = GetCameraServerShared();
-        csShared->SetCameraServerError("expected OpenCV sink, but got " +
-                                       wpi::Twine(kind));
+        csShared->SetCameraServerError("expected OpenCV sink, but got {}",
+                                       kind);
         return cs::CvSink{};
       }
       return *static_cast<cs::CvSink*>(&it->second);
     }
   }
 
-  cs::CvSink newsink{name};
+  cs::CvSink newsink{name.str()};
   newsink.SetSource(camera);
   AddServer(newsink);
   return newsink;
 }
 
-cs::CvSink CameraServer::GetVideo(const wpi::Twine& name) {
-  wpi::SmallString<64> nameBuf;
-  wpi::StringRef nameStr = name.toStringRef(nameBuf);
+cs::CvSink CameraServer::GetVideo(std::string_view name) {
+  auto& inst = ::GetInstance();
   cs::VideoSource source;
   {
-    std::scoped_lock lock(m_impl->m_mutex);
-    auto it = m_impl->m_sources.find(nameStr);
-    if (it == m_impl->m_sources.end()) {
+    std::scoped_lock lock(inst.m_mutex);
+    auto it = inst.m_sources.find(name);
+    if (it == inst.m_sources.end()) {
       auto csShared = GetCameraServerShared();
-      csShared->SetCameraServerError("could not find camera " + nameStr);
+      csShared->SetCameraServerError("could not find camera {}", name);
       return cs::CvSink{};
     }
     source = it->second;
@@ -656,89 +644,92 @@ cs::CvSink CameraServer::GetVideo(const wpi::Twine& name) {
   return GetVideo(source);
 }
 
-cs::CvSource CameraServer::PutVideo(const wpi::Twine& name, int width,
+cs::CvSource CameraServer::PutVideo(std::string_view name, int width,
                                     int height) {
   cs::CvSource source{name, cs::VideoMode::kMJPEG, width, height, 30};
   StartAutomaticCapture(source);
   return source;
 }
 
-cs::MjpegServer CameraServer::AddServer(const wpi::Twine& name) {
+cs::MjpegServer CameraServer::AddServer(std::string_view name) {
+  auto& inst = ::GetInstance();
   int port;
   {
-    std::scoped_lock lock(m_impl->m_mutex);
-    port = m_impl->m_nextPort++;
+    std::scoped_lock lock(inst.m_mutex);
+    port = inst.m_nextPort++;
   }
   return AddServer(name, port);
 }
 
-cs::MjpegServer CameraServer::AddServer(const wpi::Twine& name, int port) {
+cs::MjpegServer CameraServer::AddServer(std::string_view name, int port) {
   cs::MjpegServer server{name, port};
   AddServer(server);
   return server;
 }
 
 void CameraServer::AddServer(const cs::VideoSink& server) {
-  std::scoped_lock lock(m_impl->m_mutex);
-  m_impl->m_sinks.try_emplace(server.GetName(), server);
+  auto& inst = ::GetInstance();
+  std::scoped_lock lock(inst.m_mutex);
+  inst.m_sinks.try_emplace(server.GetName(), server);
 }
 
-void CameraServer::RemoveServer(const wpi::Twine& name) {
-  std::scoped_lock lock(m_impl->m_mutex);
-  wpi::SmallString<64> nameBuf;
-  m_impl->m_sinks.erase(name.toStringRef(nameBuf));
+void CameraServer::RemoveServer(std::string_view name) {
+  auto& inst = ::GetInstance();
+  std::scoped_lock lock(inst.m_mutex);
+  inst.m_sinks.erase(name);
 }
 
 cs::VideoSink CameraServer::GetServer() {
-  wpi::SmallString<64> name;
+  auto& inst = ::GetInstance();
+  std::string name;
   {
-    std::scoped_lock lock(m_impl->m_mutex);
-    if (m_impl->m_primarySourceName.empty()) {
+    std::scoped_lock lock(inst.m_mutex);
+    if (inst.m_primarySourceName.empty()) {
       auto csShared = GetCameraServerShared();
       csShared->SetCameraServerError("no camera available");
       return cs::VideoSink{};
     }
-    name = "serve_";
-    name += m_impl->m_primarySourceName;
+    name = fmt::format("serve_{}", inst.m_primarySourceName);
   }
   return GetServer(name);
 }
 
-cs::VideoSink CameraServer::GetServer(const wpi::Twine& name) {
-  wpi::SmallString<64> nameBuf;
-  wpi::StringRef nameStr = name.toStringRef(nameBuf);
-  std::scoped_lock lock(m_impl->m_mutex);
-  auto it = m_impl->m_sinks.find(nameStr);
-  if (it == m_impl->m_sinks.end()) {
+cs::VideoSink CameraServer::GetServer(std::string_view name) {
+  auto& inst = ::GetInstance();
+  std::scoped_lock lock(inst.m_mutex);
+  auto it = inst.m_sinks.find(name);
+  if (it == inst.m_sinks.end()) {
     auto csShared = GetCameraServerShared();
-    csShared->SetCameraServerError("could not find server " + nameStr);
+    csShared->SetCameraServerError("could not find server {}", name);
     return cs::VideoSink{};
   }
   return it->second;
 }
 
 void CameraServer::AddCamera(const cs::VideoSource& camera) {
+  auto& inst = ::GetInstance();
   std::string name = camera.GetName();
-  std::scoped_lock lock(m_impl->m_mutex);
-  if (m_impl->m_primarySourceName.empty()) {
-    m_impl->m_primarySourceName = name;
+  std::scoped_lock lock(inst.m_mutex);
+  if (inst.m_primarySourceName.empty()) {
+    inst.m_primarySourceName = name;
   }
-  m_impl->m_sources.try_emplace(name, camera);
+  inst.m_sources.try_emplace(name, camera);
 }
 
-void CameraServer::RemoveCamera(const wpi::Twine& name) {
-  std::scoped_lock lock(m_impl->m_mutex);
-  wpi::SmallString<64> nameBuf;
-  m_impl->m_sources.erase(name.toStringRef(nameBuf));
+void CameraServer::RemoveCamera(std::string_view name) {
+  auto& inst = ::GetInstance();
+  std::scoped_lock lock(inst.m_mutex);
+  inst.m_sources.erase(name);
 }
 
 void CameraServer::SetSize(int size) {
-  std::scoped_lock lock(m_impl->m_mutex);
-  if (m_impl->m_primarySourceName.empty()) {
+  auto& inst = ::GetInstance();
+  std::scoped_lock lock(inst.m_mutex);
+  if (inst.m_primarySourceName.empty()) {
     return;
   }
-  auto it = m_impl->m_sources.find(m_impl->m_primarySourceName);
-  if (it == m_impl->m_sources.end()) {
+  auto it = inst.m_sources.find(inst.m_primarySourceName);
+  if (it == inst.m_sources.end()) {
     return;
   }
   if (size == kSize160x120) {

cameraserver/src/main/native/cpp/cameraserver/CameraServerShared.cpp

@@ -12,9 +12,12 @@ class DefaultCameraServerShared : public frc::CameraServerShared {
   void ReportUsbCamera(int id) override {}
   void ReportAxisCamera(int id) override {}
   void ReportVideoServer(int id) override {}
-  void SetCameraServerError(const wpi::Twine& error) override {}
-  void SetVisionRunnerError(const wpi::Twine& error) override {}
-  void ReportDriverStationError(const wpi::Twine& error) override {}
+  void SetCameraServerErrorV(fmt::string_view format,
+                             fmt::format_args args) override {}
+  void SetVisionRunnerErrorV(fmt::string_view format,
+                             fmt::format_args args) override {}
+  void ReportDriverStationErrorV(fmt::string_view format,
+                                 fmt::format_args args) override {}
   std::pair<std::thread::id, bool> GetRobotMainThreadId() const override {
     return std::make_pair(std::thread::id(), false);
   }

cameraserver/src/main/native/cpp/vision/VisionRunner.cpp

@@ -33,7 +33,7 @@ void VisionRunnerBase::RunOnce() {
   auto frameTime = m_cvSink.GrabFrame(*m_image);
   if (frameTime == 0) {
     auto error = m_cvSink.GetError();
-    csShared->ReportDriverStationError(error);
+    csShared->ReportDriverStationError(error.c_str());
   } else {
     DoProcess(*m_image);
   }

cameraserver/src/main/native/include/cameraserver/CameraServer.h

@@ -6,11 +6,11 @@
 
 #include <stdint.h>
 
-#include <memory>
 #include <string>
+#include <string_view>
 
-#include <wpi/ArrayRef.h>
-#include <wpi/Twine.h>
+#include <wpi/deprecated.h>
+#include <wpi/span.h>
 
 #include "cscore.h"
 #include "cscore_cv.h"
@@ -31,7 +31,9 @@ class CameraServer {
 
   /**
    * Get the CameraServer instance.
+   * @deprecated Use the static methods
    */
+  WPI_DEPRECATED("Use static methods")
   static CameraServer* GetInstance();
 
   /**
@@ -45,7 +47,7 @@ class CameraServer {
    * with device 0, creating a camera named "USB Camera 0".  Subsequent calls
    * increment the device number (e.g. 1, 2, etc).
    */
-  cs::UsbCamera StartAutomaticCapture();
+  static cs::UsbCamera StartAutomaticCapture();
 
   /**
    * Start automatically capturing images to send to the dashboard.
@@ -55,7 +57,7 @@ class CameraServer {
    *
    * @param dev The device number of the camera interface
    */
-  cs::UsbCamera StartAutomaticCapture(int dev);
+  static cs::UsbCamera StartAutomaticCapture(int dev);
 
   /**
    * Start automatically capturing images to send to the dashboard.
@@ -63,7 +65,7 @@ class CameraServer {
    * @param name The name to give the camera
    * @param dev  The device number of the camera interface
    */
-  cs::UsbCamera StartAutomaticCapture(const wpi::Twine& name, int dev);
+  static cs::UsbCamera StartAutomaticCapture(std::string_view name, int dev);
 
   /**
    * Start automatically capturing images to send to the dashboard.
@@ -71,8 +73,8 @@ class CameraServer {
    * @param name The name to give the camera
    * @param path The device path (e.g. "/dev/video0") of the camera
    */
-  cs::UsbCamera StartAutomaticCapture(const wpi::Twine& name,
-                                      const wpi::Twine& path);
+  static cs::UsbCamera StartAutomaticCapture(std::string_view name,
+                                             std::string_view path);
 
   /**
    * Start automatically capturing images to send to the dashboard from
@@ -80,7 +82,7 @@ class CameraServer {
    *
    * @param camera Camera
    */
-  cs::MjpegServer StartAutomaticCapture(const cs::VideoSource& camera);
+  static cs::MjpegServer StartAutomaticCapture(const cs::VideoSource& camera);
 
   /**
    * Adds an Axis IP camera.
@@ -89,7 +91,7 @@ class CameraServer {
    *
    * @param host Camera host IP or DNS name (e.g. "10.x.y.11")
    */
-  cs::AxisCamera AddAxisCamera(const wpi::Twine& host);
+  static cs::AxisCamera AddAxisCamera(std::string_view host);
 
   /**
    * Adds an Axis IP camera.
@@ -98,7 +100,7 @@ class CameraServer {
    *
    * @param host Camera host IP or DNS name (e.g. "10.x.y.11")
    */
-  cs::AxisCamera AddAxisCamera(const char* host);
+  static cs::AxisCamera AddAxisCamera(const char* host);
 
   /**
    * Adds an Axis IP camera.
@@ -107,7 +109,7 @@ class CameraServer {
    *
    * @param host Camera host IP or DNS name (e.g. "10.x.y.11")
    */
-  cs::AxisCamera AddAxisCamera(const std::string& host);
+  static cs::AxisCamera AddAxisCamera(const std::string& host);
 
   /**
    * Adds an Axis IP camera.
@@ -116,7 +118,7 @@ class CameraServer {
    *
    * @param hosts Array of Camera host IPs/DNS names
    */
-  cs::AxisCamera AddAxisCamera(wpi::ArrayRef<std::string> hosts);
+  static cs::AxisCamera AddAxisCamera(wpi::span<const std::string> hosts);
 
   /**
    * Adds an Axis IP camera.
@@ -126,7 +128,7 @@ class CameraServer {
    * @param hosts Array of Camera host IPs/DNS names
    */
   template <typename T>
-  cs::AxisCamera AddAxisCamera(std::initializer_list<T> hosts);
+  static cs::AxisCamera AddAxisCamera(std::initializer_list<T> hosts);
 
   /**
    * Adds an Axis IP camera.
@@ -134,7 +136,8 @@ class CameraServer {
    * @param name The name to give the camera
    * @param host Camera host IP or DNS name (e.g. "10.x.y.11")
    */
-  cs::AxisCamera AddAxisCamera(const wpi::Twine& name, const wpi::Twine& host);
+  static cs::AxisCamera AddAxisCamera(std::string_view name,
+                                      std::string_view host);
 
   /**
    * Adds an Axis IP camera.
@@ -142,7 +145,7 @@ class CameraServer {
    * @param name The name to give the camera
    * @param host Camera host IP or DNS name (e.g. "10.x.y.11")
    */
-  cs::AxisCamera AddAxisCamera(const wpi::Twine& name, const char* host);
+  static cs::AxisCamera AddAxisCamera(std::string_view name, const char* host);
 
   /**
    * Adds an Axis IP camera.
@@ -150,7 +153,8 @@ class CameraServer {
    * @param name The name to give the camera
    * @param host Camera host IP or DNS name (e.g. "10.x.y.11")
    */
-  cs::AxisCamera AddAxisCamera(const wpi::Twine& name, const std::string& host);
+  static cs::AxisCamera AddAxisCamera(std::string_view name,
+                                      const std::string& host);
 
   /**
    * Adds an Axis IP camera.
@@ -158,8 +162,8 @@ class CameraServer {
    * @param name The name to give the camera
    * @param hosts Array of Camera host IPs/DNS names
    */
-  cs::AxisCamera AddAxisCamera(const wpi::Twine& name,
-                               wpi::ArrayRef<std::string> hosts);
+  static cs::AxisCamera AddAxisCamera(std::string_view name,
+                                      wpi::span<const std::string> hosts);
 
   /**
    * Adds an Axis IP camera.
@@ -168,8 +172,8 @@ class CameraServer {
    * @param hosts Array of Camera host IPs/DNS names
    */
   template <typename T>
-  cs::AxisCamera AddAxisCamera(const wpi::Twine& name,
-                               std::initializer_list<T> hosts);
+  static cs::AxisCamera AddAxisCamera(std::string_view name,
+                                      std::initializer_list<T> hosts);
 
   /**
    * Adds a virtual camera for switching between two streams.  Unlike the
@@ -177,7 +181,7 @@ class CameraServer {
    * VideoSource.  Calling SetSource() on the returned object can be used
    * to switch the actual source of the stream.
    */
-  cs::MjpegServer AddSwitchedCamera(const wpi::Twine& name);
+  static cs::MjpegServer AddSwitchedCamera(std::string_view name);
 
   /**
    * Get OpenCV access to the primary camera feed.  This allows you to
@@ -186,7 +190,7 @@ class CameraServer {
    * <p>This is only valid to call after a camera feed has been added
    * with startAutomaticCapture() or addServer().
    */
-  cs::CvSink GetVideo();
+  static cs::CvSink GetVideo();
 
   /**
    * Get OpenCV access to the specified camera.  This allows you to get
@@ -194,7 +198,7 @@ class CameraServer {
    *
    * @param camera Camera (e.g. as returned by startAutomaticCapture).
    */
-  cs::CvSink GetVideo(const cs::VideoSource& camera);
+  static cs::CvSink GetVideo(const cs::VideoSource& camera);
 
   /**
    * Get OpenCV access to the specified camera.  This allows you to get
@@ -202,7 +206,7 @@ class CameraServer {
    *
    * @param name Camera name
    */
-  cs::CvSink GetVideo(const wpi::Twine& name);
+  static cs::CvSink GetVideo(std::string_view name);
 
   /**
    * Create a MJPEG stream with OpenCV input. This can be called to pass custom
@@ -212,35 +216,35 @@ class CameraServer {
    * @param width Width of the image being sent
    * @param height Height of the image being sent
    */
-  cs::CvSource PutVideo(const wpi::Twine& name, int width, int height);
+  static cs::CvSource PutVideo(std::string_view name, int width, int height);
 
   /**
    * Adds a MJPEG server at the next available port.
    *
    * @param name Server name
    */
-  cs::MjpegServer AddServer(const wpi::Twine& name);
+  static cs::MjpegServer AddServer(std::string_view name);
 
   /**
    * Adds a MJPEG server.
    *
    * @param name Server name
    */
-  cs::MjpegServer AddServer(const wpi::Twine& name, int port);
+  static cs::MjpegServer AddServer(std::string_view name, int port);
 
   /**
    * Adds an already created server.
    *
    * @param server Server
    */
-  void AddServer(const cs::VideoSink& server);
+  static void AddServer(const cs::VideoSink& server);
 
   /**
    * Removes a server by name.
    *
    * @param name Server name
    */
-  void RemoveServer(const wpi::Twine& name);
+  static void RemoveServer(std::string_view name);
 
   /**
    * Get server for the primary camera feed.
@@ -248,28 +252,28 @@ class CameraServer {
    * This is only valid to call after a camera feed has been added with
    * StartAutomaticCapture() or AddServer().
    */
-  cs::VideoSink GetServer();
+  static cs::VideoSink GetServer();
 
   /**
    * Gets a server by name.
    *
    * @param name Server name
    */
-  cs::VideoSink GetServer(const wpi::Twine& name);
+  static cs::VideoSink GetServer(std::string_view name);
 
   /**
    * Adds an already created camera.
    *
    * @param camera Camera
    */
-  void AddCamera(const cs::VideoSource& camera);
+  static void AddCamera(const cs::VideoSource& camera);
 
   /**
    * Removes a camera by name.
    *
    * @param name Camera name
    */
-  void RemoveCamera(const wpi::Twine& name);
+  static void RemoveCamera(std::string_view name);
 
   /**
    * Sets the size of the image to use. Use the public kSize constants to set
@@ -280,14 +284,10 @@ class CameraServer {
    *             StartAutomaticCapture() instead.
    * @param size The size to use
    */
-  void SetSize(int size);
+  static void SetSize(int size);
 
  private:
-  CameraServer();
-  ~CameraServer();
-
-  struct Impl;
-  std::unique_ptr<Impl> m_impl;
+  CameraServer() = default;
 };
 
 }  // namespace frc

cameraserver/src/main/native/include/cameraserver/CameraServer.inc

@@ -19,7 +19,7 @@ inline cs::AxisCamera CameraServer::AddAxisCamera(
 
 template <typename T>
 inline cs::AxisCamera CameraServer::AddAxisCamera(
-    const wpi::Twine& name, std::initializer_list<T> hosts) {
+    std::string_view name, std::initializer_list<T> hosts) {
   std::vector<std::string> vec;
   vec.reserve(hosts.size());
   for (const auto& host : hosts) {

cameraserver/src/main/native/include/cameraserver/CameraServerShared.h

@@ -8,7 +8,7 @@
 #include <thread>
 #include <utility>
 
-#include <wpi/Twine.h>
+#include <fmt/format.h>
 
 namespace frc {
 class CameraServerShared {
@@ -17,10 +17,31 @@ class CameraServerShared {
   virtual void ReportUsbCamera(int id) = 0;
   virtual void ReportAxisCamera(int id) = 0;
   virtual void ReportVideoServer(int id) = 0;
-  virtual void SetCameraServerError(const wpi::Twine& error) = 0;
-  virtual void SetVisionRunnerError(const wpi::Twine& error) = 0;
-  virtual void ReportDriverStationError(const wpi::Twine& error) = 0;
+  virtual void SetCameraServerErrorV(fmt::string_view format,
+                                     fmt::format_args args) = 0;
+  virtual void SetVisionRunnerErrorV(fmt::string_view format,
+                                     fmt::format_args args) = 0;
+  virtual void ReportDriverStationErrorV(fmt::string_view format,
+                                         fmt::format_args args) = 0;
   virtual std::pair<std::thread::id, bool> GetRobotMainThreadId() const = 0;
+
+  template <typename S, typename... Args>
+  inline void SetCameraServerError(const S& format, Args&&... args) {
+    SetCameraServerErrorV(format,
+                          fmt::make_args_checked<Args...>(format, args...));
+  }
+
+  template <typename S, typename... Args>
+  inline void SetVisionRunnerError(const S& format, Args&&... args) {
+    SetVisionRunnerErrorV(format,
+                          fmt::make_args_checked<Args...>(format, args...));
+  }
+
+  template <typename S, typename... Args>
+  inline void ReportDriverStationError(const S& format, Args&&... args) {
+    ReportDriverStationErrorV(format,
+                              fmt::make_args_checked<Args...>(format, args...));
+  }
 };
 
 CameraServerShared* GetCameraServerShared();

cameraserver/src/main/native/include/vision/VisionRunner.h

@@ -49,9 +49,9 @@ class VisionRunnerBase {
   void RunOnce();
 
   /**
-   * A convenience method that calls {@link #runOnce()} in an infinite loop.
-   * This must be run in a dedicated thread, and cannot be used in the main
-   * robot thread because it will freeze the robot program.
+   * A convenience method that calls runOnce() in an infinite loop. This must be
+   * run in a dedicated thread, and cannot be used in the main robot thread
+   * because it will freeze the robot program.
    *
    * <strong>Do not call this method directly from the main thread.</strong>
    */

cmake/scripts/GenResource.cmake

@@ -7,7 +7,7 @@ GET_FILENAME_COMPONENT(inputBase ${input} NAME)
 STRING(REGEX REPLACE "[^a-zA-Z0-9]" "_" funcName "${inputBase}")
 SET(funcName "GetResource_${funcName}")
 
-FILE(WRITE "${output}" "#include <stddef.h>\n#include <wpi/StringRef.h>\nextern \"C\" {\nstatic const unsigned char contents[] = {")
+FILE(WRITE "${output}" "#include <stddef.h>\n#include <string_view>\nextern \"C\" {\nstatic const unsigned char contents[] = {")
 
 STRING(REGEX MATCHALL ".." outputData "${fileHex}")
 STRING(REGEX REPLACE ";" ", 0x" outputData "${outputData}")
@@ -17,7 +17,7 @@ FILE(APPEND "${output}" "const unsigned char* ${prefix}${funcName}(size_t* len)
 IF(NOT namespace STREQUAL "")
   FILE(APPEND "${output}" "namespace ${namespace} {\n")
 ENDIF()
-FILE(APPEND "${output}" "wpi::StringRef ${funcName}() {\n  return wpi::StringRef(reinterpret_cast<const char*>(contents), ${fileSize});\n}\n")
+FILE(APPEND "${output}" "std::string_view ${funcName}() {\n  return std::string_view(reinterpret_cast<const char*>(contents), ${fileSize});\n}\n")
 IF(NOT namespace STREQUAL "")
   FILE(APPEND "${output}" "}\n")
 ENDIF()

crossConnIntegrationTests/build.gradle

@@ -0,0 +1,118 @@
+import org.gradle.language.base.internal.ProjectLayout
+import jaci.gradle.toolchains.*
+import jaci.gradle.nativedeps.*
+import org.gradle.internal.os.OperatingSystem
+
+apply plugin: 'cpp'
+apply plugin: 'visual-studio'
+apply plugin: 'edu.wpi.first.NativeUtils'
+apply plugin: ExtraTasks
+
+apply plugin: 'edu.wpi.first.NativeUtils'
+apply plugin: 'jaci.gradle.EmbeddedTools'
+
+apply from: '../shared/config.gradle'
+
+ext {
+    sharedCvConfigs = [crossConnIntegrationTests: []]
+    staticCvConfigs = [:]
+    useJava = false
+    useCpp = true
+    staticGtestConfigs = [crossConnIntegrationTests: []]
+}
+
+apply from: "${rootDir}/shared/opencv.gradle"
+
+apply from: "${rootDir}/shared/googletest.gradle"
+
+model {
+    components {
+        crossConnIntegrationTests(NativeExecutableSpec) {
+            targetBuildTypes 'debug'
+            nativeUtils.useRequiredLibrary(it, 'googletest_static')
+            binaries.all { binary ->
+                if (binary.targetPlatform.name == nativeUtils.wpi.platforms.roborio) {
+                    binary.sources {
+                        athenaCpp(CppSourceSet) {
+                            source {
+                                srcDirs = ['src/main/native/cpp']
+                                includes = ['**/*.cpp']
+                            }
+                            exportedHeaders {
+                                srcDirs = ['src/main/native/include']
+                                includes = ['**/*.h']
+                            }
+                        }
+                    }
+                    binary.tasks.withType(CppCompile) {
+                        cppCompiler.args "-Wno-missing-field-initializers"
+                        cppCompiler.args "-Wno-unused-variable"
+                        cppCompiler.args "-Wno-error=deprecated-declarations"
+                    }
+                    project(':hal').addHalDependency(binary, 'shared')
+                    project(':hal').addHalJniDependency(binary)
+                    lib project: ':wpiutil', library: 'wpiutil', linkage: 'shared'
+                    if (binary.targetPlatform.name == nativeUtils.wpi.platforms.roborio) {
+                        nativeUtils.useRequiredLibrary(binary, 'netcomm_shared', 'chipobject_shared', 'visa_shared', 'ni_runtime_shared')
+                    }
+                } else {
+                    binary.sources {
+                        simCpp(CppSourceSet) {
+                            source {
+                                srcDirs 'src/main/native/dt'
+                                includes = ['**/*.cpp']
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+deploy {
+    targets {
+        target('roborio') {
+            directory = '/home/admin'
+            maxChannels = 4
+            locations {
+                ssh {
+                    address = "172.22.11.2"
+                    user = 'admin'
+                    password = ''
+                    ipv6 = false
+                }
+            }
+        }
+    }
+    artifacts {
+        all {
+            targets << 'roborio'
+            predeploy << { ctx ->
+                ctx.execute('/usr/local/frc/bin/frcKillRobot.sh -t')
+            }
+            postdeploy << { ctx ->
+                ctx.execute("sync")
+                ctx.execute("ldconfig")
+            }
+        }
+
+        nativeArtifact('crossConnIntegrationTests') {
+            component = 'crossConnIntegrationTests'
+            targetPlatform = nativeUtils.wpi.platforms.roborio
+            libraryDirectory = '/usr/local/frc/third-party/lib'
+            buildType = 'debug'
+            postdeploy << { ctx ->
+                ctx.execute('chmod +x crossConnIntegrationTests')
+            }
+        }
+    }
+}
+
+tasks.register('deployTests') {
+    try {
+        dependsOn tasks.named('deployCrossConnIntegrationTestsLibrariesRoborio')
+        dependsOn tasks.named('deployCrossConnIntegrationTestsRoborio')
+    } catch (ignored) {
+    }
+}

crossConnIntegrationTests/src/main/native/cpp/AnalogTests.cpp

@@ -0,0 +1,112 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <hal/AnalogInput.h>
+#include <hal/AnalogOutput.h>
+#include <wpi/SmallVector.h>
+
+#include "CrossConnects.h"
+#include "LifetimeWrappers.h"
+#include "gtest/gtest.h"
+
+using namespace hlt;
+
+class AnalogCrossTest : public ::testing::TestWithParam<std::pair<int, int>> {};
+
+TEST_P(AnalogCrossTest, TestAnalogCross) {
+  auto param = GetParam();
+
+  int32_t status = 0;
+  AnalogInputHandle input{param.first, &status};
+  ASSERT_EQ(0, status);
+  AnalogOutputHandle output{param.second, &status};
+  ASSERT_EQ(0, status);
+
+  for (double i = 0; i < 5; i += 0.1) {
+    HAL_SetAnalogOutput(output, i, &status);
+    ASSERT_EQ(0, status);
+    usleep(1000);
+    ASSERT_NEAR(i, HAL_GetAnalogVoltage(input, &status), 0.01);
+    ASSERT_EQ(0, status);
+  }
+
+  for (double i = 5; i > 0; i -= 0.1) {
+    HAL_SetAnalogOutput(output, i, &status);
+    ASSERT_EQ(0, status);
+    usleep(1000);
+    ASSERT_NEAR(i, HAL_GetAnalogVoltage(input, &status), 0.01);
+    ASSERT_EQ(0, status);
+  }
+}
+
+TEST(AnalogInputTest, TestAllocateAll) {
+  wpi::SmallVector<AnalogInputHandle, 21> analogHandles;
+  for (int i = 0; i < HAL_GetNumAnalogInputs(); i++) {
+    int32_t status = 0;
+    analogHandles.emplace_back(AnalogInputHandle(i, &status));
+    ASSERT_EQ(status, 0);
+  }
+}
+
+TEST(AnalogInputTest, TestMultipleAllocateFails) {
+  int32_t status = 0;
+  AnalogInputHandle handle(0, &status);
+  ASSERT_NE(handle, HAL_kInvalidHandle);
+  ASSERT_EQ(status, 0);
+
+  AnalogInputHandle handle2(0, &status);
+  ASSERT_EQ(handle2, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_IS_ALLOCATED);
+}
+
+TEST(AnalogInputTest, TestOverAllocateFails) {
+  int32_t status = 0;
+  AnalogInputHandle handle(HAL_GetNumAnalogInputs(), &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+TEST(AnalogInputTest, TestUnderAllocateFails) {
+  int32_t status = 0;
+  AnalogInputHandle handle(-1, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+TEST(AnalogOutputTest, TestAllocateAll) {
+  wpi::SmallVector<AnalogOutputHandle, 21> analogHandles;
+  for (int i = 0; i < HAL_GetNumAnalogOutputs(); i++) {
+    int32_t status = 0;
+    analogHandles.emplace_back(AnalogOutputHandle(i, &status));
+    ASSERT_EQ(status, 0);
+  }
+}
+
+TEST(AnalogOutputTest, TestMultipleAllocateFails) {
+  int32_t status = 0;
+  AnalogOutputHandle handle(0, &status);
+  ASSERT_NE(handle, HAL_kInvalidHandle);
+  ASSERT_EQ(status, 0);
+
+  AnalogOutputHandle handle2(0, &status);
+  ASSERT_EQ(handle2, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_IS_ALLOCATED);
+}
+
+TEST(AnalogOutputTest, TestOverAllocateFails) {
+  int32_t status = 0;
+  AnalogOutputHandle handle(HAL_GetNumAnalogOutputs(), &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+TEST(AnalogOutputTest, TestUnderAllocateFails) {
+  int32_t status = 0;
+  AnalogOutputHandle handle(-1, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+INSTANTIATE_TEST_SUITE_P(AnalogCrossConnectsTest, AnalogCrossTest,
+                         ::testing::ValuesIn(AnalogCrossConnects));

crossConnIntegrationTests/src/main/native/cpp/DIOTests.cpp

@@ -0,0 +1,101 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <hal/DIO.h>
+#include <wpi/SmallVector.h>
+
+#include "CrossConnects.h"
+#include "LifetimeWrappers.h"
+#include "gtest/gtest.h"
+
+using namespace hlt;
+
+class DIOTest : public ::testing::TestWithParam<std::pair<int, int>> {};
+
+TEST_P(DIOTest, TestDIOCross) {
+  auto param = GetParam();
+  int32_t status = 0;
+  DIOHandle first{param.first, false, &status};
+  ASSERT_EQ(0, status);
+  DIOHandle second{param.second, true, &status};
+  ASSERT_EQ(0, status);
+
+  HAL_SetDIO(first, false, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_FALSE(HAL_GetDIO(first, &status));
+  ASSERT_EQ(0, status);
+  ASSERT_FALSE(HAL_GetDIO(second, &status));
+  ASSERT_EQ(0, status);
+
+  HAL_SetDIO(first, true, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_TRUE(HAL_GetDIO(second, &status));
+  ASSERT_EQ(0, status);
+
+  HAL_SetDIODirection(first, true, &status);
+  ASSERT_EQ(0, status);
+  HAL_SetDIODirection(second, false, &status);
+  ASSERT_EQ(0, status);
+
+  HAL_SetDIO(second, false, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_FALSE(HAL_GetDIO(first, &status));
+  ASSERT_EQ(0, status);
+
+  HAL_SetDIO(second, true, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_TRUE(HAL_GetDIO(first, &status));
+  ASSERT_EQ(0, status);
+}
+
+TEST(DIOTest, TestAllocateAll) {
+  wpi::SmallVector<DIOHandle, 32> dioHandles;
+  for (int i = 0; i < HAL_GetNumDigitalChannels(); i++) {
+    int32_t status = 0;
+    dioHandles.emplace_back(i, true, &status);
+    ASSERT_EQ(status, 0);
+  }
+}
+
+TEST(DIOTest, TestMultipleAllocateFails) {
+  int32_t status = 0;
+  DIOHandle handle(0, true, &status);
+  ASSERT_NE(handle, HAL_kInvalidHandle);
+  ASSERT_EQ(status, 0);
+
+  DIOHandle handle2(0, true, &status);
+  ASSERT_EQ(handle2, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_IS_ALLOCATED);
+}
+
+TEST(DIOTest, TestOverAllocateFails) {
+  int32_t status = 0;
+  DIOHandle handle(HAL_GetNumDigitalChannels(), true, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+TEST(DIOTest, TestUnderAllocateFails) {
+  int32_t status = 0;
+  DIOHandle handle(-1, true, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+TEST(DIOTest, TestCrossAllocationFails) {
+  int32_t status = 0;
+  PWMHandle pwmHandle(10, &status);
+  ASSERT_NE(pwmHandle, HAL_kInvalidHandle);
+  ASSERT_EQ(status, 0);
+  DIOHandle handle(10, true, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_IS_ALLOCATED);
+}
+
+INSTANTIATE_TEST_SUITE_P(DIOCrossConnectsTest, DIOTest,
+                         ::testing::ValuesIn(DIOCrossConnects));

crossConnIntegrationTests/src/main/native/cpp/DutyCycleTests.cpp

@@ -0,0 +1,51 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <hal/HAL.h>
+
+#include "CrossConnects.h"
+#include "LifetimeWrappers.h"
+#include "gtest/gtest.h"
+
+using namespace hlt;
+
+class DutyCycleTest : public ::testing::TestWithParam<std::pair<int, int>> {};
+
+TEST_P(DutyCycleTest, TestDutyCycle) {
+  auto param = GetParam();
+
+  int32_t status = 0;
+  PWMHandle pwmHandle(param.first, &status);
+  ASSERT_NE(pwmHandle, HAL_kInvalidHandle);
+  ASSERT_EQ(0, status);
+
+  // Ensure our PWM is disabled, and set up properly
+  HAL_SetPWMRaw(pwmHandle, 0, &status);
+  ASSERT_EQ(0, status);
+  HAL_SetPWMConfig(pwmHandle, 2.0, 1.0, 1.0, 0, 0, &status);
+  HAL_SetPWMConfig(pwmHandle, 5.05, 2.525, 2.525, 2.525, 0, &status);
+  ASSERT_EQ(0, status);
+  HAL_SetPWMPeriodScale(pwmHandle, 0, &status);
+  ASSERT_EQ(0, status);
+
+  DIOHandle dioHandle{param.second, true, &status};
+  ASSERT_EQ(0, status);
+
+  DutyCycleHandle dutyCycle{dioHandle, &status};
+  ASSERT_EQ(0, status);
+
+  HAL_SetPWMSpeed(pwmHandle, 0.5, &status);
+  ASSERT_EQ(0, status);
+
+  // Sleep enough time for the frequency to converge
+  usleep(3500000);
+
+  ASSERT_NEAR(1000 / 5.05,
+              (double)HAL_GetDutyCycleFrequency(dutyCycle, &status), 1);
+
+  // TODO measure output
+}
+
+INSTANTIATE_TEST_SUITE_P(DutyCycleCrossConnTest, DutyCycleTest,
+                         ::testing::ValuesIn(PWMCrossConnects));

crossConnIntegrationTests/src/main/native/cpp/Main.cpp

@@ -5,7 +5,6 @@
 #include "gtest/gtest.h"
 
 int main(int argc, char** argv) {
-  ::testing::InitGoogleTest(&argc, argv);
-  int ret = RUN_ALL_TESTS();
-  return ret;
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
 }

crossConnIntegrationTests/src/main/native/cpp/PWMTests.cpp

@@ -0,0 +1,357 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <atomic>
+#include <thread>
+
+#include <hal/DMA.h>
+#include <hal/HAL.h>
+#include <wpi/SmallVector.h>
+#include <wpi/condition_variable.h>
+#include <wpi/priority_mutex.h>
+
+#include "CrossConnects.h"
+#include "LifetimeWrappers.h"
+#include "gtest/gtest.h"
+
+using namespace hlt;
+
+class PWMTest : public ::testing::TestWithParam<std::pair<int, int>> {};
+
+void TestTimingDMA(int squelch, std::pair<int, int> param) {
+  // Initialize DMA
+  int32_t status = 0;
+  DMAHandle dmaHandle(&status);
+  ASSERT_NE(dmaHandle, HAL_kInvalidHandle);
+  ASSERT_EQ(0, status);
+
+  status = 0;
+  PWMHandle pwmHandle(param.first, &status);
+  ASSERT_NE(pwmHandle, HAL_kInvalidHandle);
+  ASSERT_EQ(0, status);
+
+  // Ensure our PWM is disabled, and set up properly
+  HAL_SetPWMRaw(pwmHandle, 0, &status);
+  HAL_SetPWMConfig(pwmHandle, 2.0, 1.0, 1.0, 0, 0, &status);
+  HAL_SetPWMPeriodScale(pwmHandle, squelch, &status);
+
+  unsigned int checkPeriod = 0;
+  switch (squelch) {
+    case (0):
+      checkPeriod = 5050;
+      break;
+    case (1):
+      checkPeriod = 10100;
+      break;
+    case (3):
+      checkPeriod = 20200;
+      break;
+  }
+
+  status = 0;
+  DIOHandle dioHandle(param.second, true, &status);
+  ASSERT_NE(dioHandle, HAL_kInvalidHandle);
+
+  HAL_AddDMADigitalSource(dmaHandle, dioHandle, &status);
+  ASSERT_EQ(0, status);
+
+  HAL_SetDMAExternalTrigger(dmaHandle, dioHandle,
+                            HAL_AnalogTriggerType::HAL_Trigger_kInWindow, true,
+                            true, &status);
+  ASSERT_EQ(0, status);
+
+  // Loop to test 5 speeds
+  for (unsigned int testWidth = 1000; testWidth < 2100; testWidth += 250) {
+    HAL_StartDMA(dmaHandle, 1024, &status);
+    ASSERT_EQ(0, status);
+
+    while (true) {
+      int32_t remaining = 0;
+      HAL_DMASample testSample;
+      HAL_ReadDMA(dmaHandle, &testSample, 0.01, &remaining, &status);
+      if (remaining == 0) {
+        break;
+      }
+    }
+
+    HAL_SetPWMSpeed(pwmHandle, (testWidth - 1000) / 1000.0, &status);
+
+    constexpr const int kSampleCount = 15;
+    HAL_DMASample dmaSamples[kSampleCount];
+    int readCount = 0;
+    while (readCount < kSampleCount) {
+      status = 0;
+      int32_t remaining = 0;
+      HAL_DMAReadStatus readStatus = HAL_ReadDMA(
+          dmaHandle, &dmaSamples[readCount], 1.0, &remaining, &status);
+      ASSERT_EQ(0, status);
+      ASSERT_EQ(HAL_DMAReadStatus::HAL_DMA_OK, readStatus);
+      readCount++;
+    }
+
+    HAL_SetPWMSpeed(pwmHandle, 0, &status);
+    HAL_StopDMA(dmaHandle, &status);
+
+    // Find first rising edge
+    int startIndex = 4;
+    while (startIndex < 6) {
+      status = 0;
+      auto value = HAL_GetDMASampleDigitalSource(&dmaSamples[startIndex],
+                                                 dioHandle, &status);
+      ASSERT_EQ(0, status);
+      if (value)
+        break;
+      startIndex++;
+    }
+    ASSERT_LT(startIndex, 6);
+
+    // Check that samples alternate
+    bool previous = false;
+    int iterationCount = 0;
+    for (int i = startIndex; i < startIndex + 8; i++) {
+      auto value =
+          HAL_GetDMASampleDigitalSource(&dmaSamples[i], dioHandle, &status);
+      ASSERT_EQ(0, status);
+      ASSERT_NE(previous, value);
+      previous = !previous;
+      iterationCount++;
+    }
+    ASSERT_EQ(iterationCount, 8);
+    iterationCount = 0;
+
+    // Check width between samples
+    for (int i = startIndex; i < startIndex + 8; i += 2) {
+      auto width = HAL_GetDMASampleTime(&dmaSamples[i + 1], &status) -
+                   HAL_GetDMASampleTime(&dmaSamples[i], &status);
+      ASSERT_NEAR(testWidth, width, 10);
+      iterationCount++;
+    }
+    ASSERT_EQ(iterationCount, 4);
+    iterationCount = 0;
+
+    // Check period between samples
+    for (int i = startIndex; i < startIndex + 6; i += 2) {
+      auto period = HAL_GetDMASampleTime(&dmaSamples[i + 2], &status) -
+                    HAL_GetDMASampleTime(&dmaSamples[i], &status);
+      ASSERT_NEAR(checkPeriod, period, 10);
+      iterationCount++;
+    }
+    ASSERT_EQ(iterationCount, 3);
+  }
+}
+
+struct InterruptCheckData {
+  wpi::SmallVector<uint64_t, 8> risingStamps;
+  wpi::SmallVector<uint64_t, 8> fallingStamps;
+  wpi::priority_mutex mutex;
+  wpi::condition_variable cond;
+  HAL_InterruptHandle handle;
+};
+
+// TODO switch this to DMA
+void TestTiming(int squelch, std::pair<int, int> param) {
+  // Initialize interrupt
+  int32_t status = 0;
+  InterruptHandle interruptHandle(&status);
+  // Ensure we have a valid interrupt handle
+  ASSERT_NE(interruptHandle, HAL_kInvalidHandle);
+
+  status = 0;
+  PWMHandle pwmHandle(param.first, &status);
+  ASSERT_NE(pwmHandle, HAL_kInvalidHandle);
+
+  // Ensure our PWM is disabled, and set up properly
+  HAL_SetPWMRaw(pwmHandle, 0, &status);
+  HAL_SetPWMConfig(pwmHandle, 2.0, 1.0, 1.0, 0, 0, &status);
+  HAL_SetPWMPeriodScale(pwmHandle, squelch, &status);
+
+  unsigned int checkPeriod = 0;
+  switch (squelch) {
+    case (0):
+      checkPeriod = 5050;
+      break;
+    case (1):
+      checkPeriod = 10100;
+      break;
+    case (3):
+      checkPeriod = 20200;
+      break;
+  }
+
+  status = 0;
+  DIOHandle dioHandle(param.second, true, &status);
+  ASSERT_NE(dioHandle, HAL_kInvalidHandle);
+
+  InterruptCheckData interruptData;
+  interruptData.handle = interruptHandle;
+
+  // Can use any type for the interrupt handle
+  HAL_RequestInterrupts(interruptHandle, dioHandle,
+                        HAL_AnalogTriggerType::HAL_Trigger_kInWindow, &status);
+
+  HAL_SetInterruptUpSourceEdge(interruptHandle, true, true, &status);
+
+  // Loop to test 5 speeds
+  for (unsigned int i = 1000; i < 2100; i += 250) {
+    interruptData.risingStamps.clear();
+    interruptData.fallingStamps.clear();
+
+    std::atomic_bool runThread{true};
+
+    status = 0;
+    std::thread interruptThread([&]() {
+      while (runThread) {
+        int32_t threadStatus = 0;
+        auto mask =
+            HAL_WaitForInterrupt(interruptHandle, 5, true, &threadStatus);
+
+        if ((mask & 0x100) == 0x100 && interruptData.risingStamps.size() == 0 &&
+            interruptData.fallingStamps.size() == 0) {
+          // Falling edge at start of tracking. Skip
+          continue;
+        }
+
+        int32_t status = 0;
+        if ((mask & 0x1) == 0x1) {
+          auto ts = HAL_ReadInterruptRisingTimestamp(interruptHandle, &status);
+          // Rising Edge
+          interruptData.risingStamps.push_back(ts);
+        } else if ((mask & 0x100) == 0x100) {
+          auto ts = HAL_ReadInterruptFallingTimestamp(interruptHandle, &status);
+          // Falling Edge
+          interruptData.fallingStamps.push_back(ts);
+        }
+
+        if (interruptData.risingStamps.size() >= 4 &&
+            interruptData.fallingStamps.size() >= 4) {
+          interruptData.cond.notify_all();
+          runThread = false;
+          break;
+        }
+      }
+    });
+
+    // Ensure our interrupt actually got created correctly.
+    ASSERT_EQ(status, 0);
+    HAL_SetPWMSpeed(pwmHandle, (i - 1000) / 1000.0, &status);
+    ASSERT_EQ(status, 0);
+    {
+      std::unique_lock<wpi::priority_mutex> lock(interruptData.mutex);
+      // Wait for lock
+      // TODO: Add Timeout
+      auto timeout = interruptData.cond.wait_for(lock, std::chrono::seconds(2));
+      if (timeout == std::cv_status::timeout) {
+        runThread = false;
+        if (interruptThread.joinable()) {
+          interruptThread.join();
+        }
+        ASSERT_TRUE(false);  // Exit test as failure on timeout
+      }
+    }
+
+    HAL_SetPWMRaw(pwmHandle, 0, &status);
+
+    // Ensure our interrupts have the proper counts
+    ASSERT_EQ(interruptData.risingStamps.size(),
+              interruptData.fallingStamps.size());
+
+    ASSERT_GT(interruptData.risingStamps.size(), 0u);
+
+    ASSERT_EQ(interruptData.risingStamps.size() % 2, 0u);
+    ASSERT_EQ(interruptData.fallingStamps.size() % 2, 0u);
+
+    for (size_t j = 0; j < interruptData.risingStamps.size(); j++) {
+      uint64_t width =
+          interruptData.fallingStamps[j] - interruptData.risingStamps[j];
+      ASSERT_NEAR(width, i, 10);
+    }
+
+    for (unsigned int j = 0; j < interruptData.risingStamps.size() - 1; j++) {
+      uint64_t period =
+          interruptData.risingStamps[j + 1] - interruptData.risingStamps[j];
+      ASSERT_NEAR(period, checkPeriod, 10);
+    }
+    runThread = false;
+    if (interruptThread.joinable()) {
+      interruptThread.join();
+    }
+  }
+}
+
+TEST_P(PWMTest, TestTiming4x) {
+  auto param = GetParam();
+  TestTiming(3, param);
+}
+
+TEST_P(PWMTest, TestTiming2x) {
+  auto param = GetParam();
+  TestTiming(1, param);
+}
+
+TEST_P(PWMTest, TestTiming1x) {
+  auto param = GetParam();
+  TestTiming(0, param);
+}
+
+TEST_P(PWMTest, TestTimingDMA4x) {
+  auto param = GetParam();
+  TestTimingDMA(3, param);
+}
+
+TEST_P(PWMTest, TestTimingDMA2x) {
+  auto param = GetParam();
+  TestTimingDMA(1, param);
+}
+
+TEST_P(PWMTest, TestTimingDMA1x) {
+  auto param = GetParam();
+  TestTimingDMA(0, param);
+}
+
+TEST(PWMTest, TestAllocateAll) {
+  wpi::SmallVector<PWMHandle, 21> pwmHandles;
+  for (int i = 0; i < HAL_GetNumPWMChannels(); i++) {
+    int32_t status = 0;
+    pwmHandles.emplace_back(PWMHandle(i, &status));
+    ASSERT_EQ(status, 0);
+  }
+}
+
+TEST(PWMTest, TestMultipleAllocateFails) {
+  int32_t status = 0;
+  PWMHandle handle(0, &status);
+  ASSERT_NE(handle, HAL_kInvalidHandle);
+  ASSERT_EQ(status, 0);
+
+  PWMHandle handle2(0, &status);
+  ASSERT_EQ(handle2, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_IS_ALLOCATED);
+}
+
+TEST(PWMTest, TestOverAllocateFails) {
+  int32_t status = 0;
+  PWMHandle handle(HAL_GetNumPWMChannels(), &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+TEST(PWMTest, TestUnderAllocateFails) {
+  int32_t status = 0;
+  PWMHandle handle(-1, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+TEST(PWMTest, TestCrossAllocationFails) {
+  int32_t status = 0;
+  DIOHandle dioHandle(10, true, &status);
+  ASSERT_NE(dioHandle, HAL_kInvalidHandle);
+  ASSERT_EQ(status, 0);
+  PWMHandle handle(10, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_IS_ALLOCATED);
+}
+
+INSTANTIATE_TEST_SUITE_P(PWMCrossConnectTests, PWMTest,
+                         ::testing::ValuesIn(PWMCrossConnects));

crossConnIntegrationTests/src/main/native/cpp/RelayAnalogTests.cpp

@@ -0,0 +1,50 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <hal/AnalogInput.h>
+#include <hal/Relay.h>
+#include <wpi/SmallVector.h>
+
+#include "CrossConnects.h"
+#include "LifetimeWrappers.h"
+#include "gtest/gtest.h"
+
+using namespace hlt;
+
+class RelayAnalogTest : public ::testing::TestWithParam<std::pair<int, int>> {};
+
+TEST_P(RelayAnalogTest, TestRelayAnalogCross) {
+  auto param = GetParam();
+
+  int32_t status = 0;
+  RelayHandle relay{param.first, true, &status};
+  ASSERT_EQ(0, status);
+  AnalogInputHandle analog{param.second, &status};
+  ASSERT_EQ(0, status);
+  AnalogTriggerHandle trigger{analog, &status};
+  ASSERT_EQ(0, status);
+  HAL_SetAnalogTriggerLimitsVoltage(trigger, 1.5, 3.0, &status);
+  ASSERT_EQ(0, status);
+
+  HAL_SetRelay(relay, false, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_FALSE(HAL_GetAnalogTriggerTriggerState(trigger, &status));
+  ASSERT_EQ(0, status);
+
+  HAL_SetRelay(relay, true, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_TRUE(HAL_GetAnalogTriggerTriggerState(trigger, &status));
+  ASSERT_EQ(0, status);
+
+  HAL_SetRelay(relay, false, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_FALSE(HAL_GetAnalogTriggerTriggerState(trigger, &status));
+  ASSERT_EQ(0, status);
+}
+
+INSTANTIATE_TEST_SUITE_P(RelayAnalogCrossConnectsTest, RelayAnalogTest,
+                         ::testing::ValuesIn(RelayAnalogCrossConnects));

crossConnIntegrationTests/src/main/native/cpp/RelayDigitalTests.cpp

@@ -0,0 +1,104 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <hal/Relay.h>
+#include <wpi/SmallVector.h>
+
+#include "CrossConnects.h"
+#include "LifetimeWrappers.h"
+#include "gtest/gtest.h"
+
+using namespace hlt;
+
+class RelayDigitalTest : public ::testing::TestWithParam<RelayCross> {};
+
+TEST_P(RelayDigitalTest, TestRelayCross) {
+  auto param = GetParam();
+  int32_t status = 0;
+  RelayHandle fwd{param.Relay, true, &status};
+  ASSERT_EQ(0, status);
+  RelayHandle rev{param.Relay, false, &status};
+  ASSERT_EQ(0, status);
+  DIOHandle fwdInput{param.FwdDio, true, &status};
+  ASSERT_EQ(0, status);
+  DIOHandle revInput{param.RevDio, true, &status};
+  ASSERT_EQ(0, status);
+
+  HAL_SetRelay(fwd, false, &status);
+  ASSERT_EQ(0, status);
+  HAL_SetRelay(rev, false, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_FALSE(HAL_GetDIO(fwdInput, &status));
+  ASSERT_EQ(0, status);
+  ASSERT_FALSE(HAL_GetDIO(revInput, &status));
+  ASSERT_EQ(0, status);
+
+  HAL_SetRelay(fwd, false, &status);
+  ASSERT_EQ(0, status);
+  HAL_SetRelay(rev, true, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_FALSE(HAL_GetDIO(fwdInput, &status));
+  ASSERT_EQ(0, status);
+  ASSERT_TRUE(HAL_GetDIO(revInput, &status));
+  ASSERT_EQ(0, status);
+
+  HAL_SetRelay(fwd, true, &status);
+  ASSERT_EQ(0, status);
+  HAL_SetRelay(rev, false, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_TRUE(HAL_GetDIO(fwdInput, &status));
+  ASSERT_EQ(0, status);
+  ASSERT_FALSE(HAL_GetDIO(revInput, &status));
+  ASSERT_EQ(0, status);
+
+  HAL_SetRelay(fwd, true, &status);
+  ASSERT_EQ(0, status);
+  HAL_SetRelay(rev, true, &status);
+  ASSERT_EQ(0, status);
+  usleep(1000);
+  ASSERT_TRUE(HAL_GetDIO(fwdInput, &status));
+  ASSERT_EQ(0, status);
+  ASSERT_TRUE(HAL_GetDIO(revInput, &status));
+  ASSERT_EQ(0, status);
+}
+
+TEST(RelayDigitalTest, TestAllocateAll) {
+  wpi::SmallVector<RelayHandle, 32> relayHandles;
+  for (int i = 0; i < HAL_GetNumRelayChannels(); i++) {
+    int32_t status = 0;
+    relayHandles.emplace_back(i / 2, i % 2, &status);
+    ASSERT_EQ(status, 0);
+  }
+}
+
+TEST(RelayDigitalTest, TestMultipleAllocateFails) {
+  int32_t status = 0;
+  RelayHandle handle(0, true, &status);
+  ASSERT_NE(handle, HAL_kInvalidHandle);
+  ASSERT_EQ(status, 0);
+
+  RelayHandle handle2(0, true, &status);
+  ASSERT_EQ(handle2, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_IS_ALLOCATED);
+}
+
+TEST(RelayDigitalTest, TestOverAllocateFails) {
+  int32_t status = 0;
+  RelayHandle handle(HAL_GetNumRelayChannels(), true, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+TEST(RelayDigitalTest, TestUnderAllocateFails) {
+  int32_t status = 0;
+  RelayHandle handle(-1, true, &status);
+  ASSERT_EQ(handle, HAL_kInvalidHandle);
+  ASSERT_LAST_ERROR_STATUS(status, RESOURCE_OUT_OF_RANGE);
+}
+
+INSTANTIATE_TEST_SUITE_P(RelayDigitalCrossConnectsTest, RelayDigitalTest,
+                         ::testing::ValuesIn(RelayCrossConnects));

crossConnIntegrationTests/src/main/native/cpp/TestEnvironment.cpp

@@ -0,0 +1,71 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <cstdlib>
+#include <thread>
+
+#include <fmt/core.h>
+#include <hal/HAL.h>
+
+#include "gtest/gtest.h"
+#include "mockds/MockDS.h"
+
+using namespace std::chrono_literals;
+
+class TestEnvironment : public testing::Environment {
+  bool m_alreadySetUp = false;
+  MockDS m_mockDS;
+
+ public:
+  TestEnvironment() {
+    // Only set up once. This allows gtest_repeat to be used to automatically
+    // repeat tests.
+    if (m_alreadySetUp) {
+      return;
+    }
+    m_alreadySetUp = true;
+
+    if (!HAL_Initialize(500, 0)) {
+      fmt::print(stderr, "FATAL ERROR: HAL could not be initialized\n");
+      std::exit(-1);
+    }
+
+    m_mockDS.Start();
+
+    // This sets up the network communications library to enable the driver
+    // station. After starting network coms, it will loop until the driver
+    // station returns that the robot is enabled, to ensure that tests will be
+    // able to run on the hardware.
+    HAL_ObserveUserProgramStarting();
+
+    fmt::print("Started coms\n");
+
+    int enableCounter = 0;
+
+    auto checkEnabled = []() {
+      HAL_ControlWord controlWord;
+      std::memset(&controlWord, 0, sizeof(controlWord));
+      HAL_GetControlWord(&controlWord);
+      return controlWord.enabled && controlWord.dsAttached;
+    };
+    while (!checkEnabled()) {
+      if (enableCounter > 50) {
+        // Robot did not enable properly after 5 seconds.
+        // Force exit
+        fmt::print(stderr, " Failed to enable. Aborting\n");
+        std::terminate();
+      }
+
+      std::this_thread::sleep_for(100ms);
+
+      fmt::print("Waiting for enable: {}\n", enableCounter++);
+    }
+    std::this_thread::sleep_for(500ms);
+  }
+
+  ~TestEnvironment() override { m_mockDS.Stop(); }
+};
+
+testing::Environment* const environment =
+    testing::AddGlobalTestEnvironment(new TestEnvironment);

crossConnIntegrationTests/src/main/native/cpp/mockds/MockDS.cpp

@@ -0,0 +1,86 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "MockDS.h"
+
+#include <stdint.h>
+
+#include <string_view>
+
+#include <fmt/core.h>
+#include <hal/cpp/fpga_clock.h>
+#include <wpi/Logger.h>
+#include <wpi/SmallVector.h>
+#include <wpi/UDPClient.h>
+
+static void LoggerFunc(unsigned int level, const char* file, unsigned int line,
+                       const char* msg) {
+  if (level == 20) {
+    fmt::print(stderr, "DS: {}\n", msg);
+    return;
+  }
+
+  std::string_view levelmsg;
+  if (level >= 50) {
+    levelmsg = "CRITICAL";
+  } else if (level >= 40) {
+    levelmsg = "ERROR";
+  } else if (level >= 30) {
+    levelmsg = "WARNING";
+  } else {
+    return;
+  }
+  fmt::print(stderr, "DS: {}: {} ({}:{})\n", levelmsg, msg, file, line);
+}
+
+static void generateEnabledDsPacket(wpi::SmallVectorImpl<uint8_t>& data,
+                                    uint16_t sendCount) {
+  data.clear();
+  data.push_back(sendCount >> 8);
+  data.push_back(sendCount);
+  data.push_back(0x01);  // general data tag
+  data.push_back(0x04);  // teleop enabled
+  data.push_back(0x10);  // normal data request
+  data.push_back(0x00);  // red 1 station
+}
+
+void MockDS::Start() {
+  if (m_active) {
+    return;
+  }
+  m_active = true;
+  m_thread = std::thread([&]() {
+    wpi::Logger logger(LoggerFunc);
+    wpi::UDPClient client(logger);
+    client.start();
+    auto timeout_time = hal::fpga_clock::now();
+    int initCount = 0;
+    uint16_t sendCount = 0;
+    wpi::SmallVector<uint8_t, 8> data;
+    while (m_active) {
+      // Keep 20ms intervals, and increase time to next interval
+      auto current = hal::fpga_clock::now();
+      while (timeout_time <= current) {
+        timeout_time += std::chrono::milliseconds(20);
+      }
+      std::this_thread::sleep_until(timeout_time);
+      generateEnabledDsPacket(data, sendCount++);
+      // ~10 disabled packets are required to make the robot actually enable
+      // 1 is definitely not enough.
+      if (initCount < 10) {
+        initCount++;
+        data[3] = 0;
+      }
+      client.send(data, "127.0.0.1", 1110);
+    }
+    client.shutdown();
+  });
+}
+
+void MockDS::Stop() {
+  m_active = false;
+  if (m_thread.joinable()) {
+    m_thread.join();
+  }
+}

crossConnIntegrationTests/src/main/native/cpp/mockds/MockDS.h

@@ -0,0 +1,23 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include <atomic>
+#include <thread>
+
+class MockDS {
+ public:
+  MockDS() = default;
+  ~MockDS() { Stop(); }
+  MockDS(const MockDS& other) = delete;
+  MockDS& operator=(const MockDS& other) = delete;
+
+  void Start();
+  void Stop();
+
+ private:
+  std::thread m_thread;
+  std::atomic_bool m_active{false};
+};

crossConnIntegrationTests/src/main/native/include/CrossConnects.h

@@ -0,0 +1,62 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include <array>
+#include <utility>
+
+namespace hlt {
+
+constexpr static std::array<std::pair<int, int>, 22> DIOCrossConnects{
+    std::pair{20, 25},
+    std::pair{19, 24},
+    std::pair{17, 13},
+    std::pair{16, 12},
+    std::pair{15, 11},
+    std::pair{14, 10},
+    std::pair{26, 2},
+    std::pair{27, 1},
+    std::pair{28, 0},
+    std::pair{29, 3},
+    std::pair{30, 4},
+
+    // Opposite direction
+    std::pair{25, 20},
+    std::pair{24, 19},
+    std::pair{13, 17},
+    std::pair{12, 16},
+    std::pair{11, 15},
+    std::pair{10, 14},
+    std::pair{2, 26},
+    std::pair{1, 27},
+    std::pair{0, 28},
+    std::pair{3, 29},
+    std::pair{4, 30},
+};
+
+// PWM on left, DIO on right
+constexpr static std::array<std::pair<int, int>, 2> PWMCrossConnects{
+    std::pair{0, 18},
+    std::pair{16, 25},
+};
+
+// FWD only, relay on left
+constexpr static std::array<std::pair<int, int>, 2> RelayAnalogCrossConnects{
+    std::pair{2, 0}, std::pair{3, 1}};
+
+struct RelayCross {
+  int Relay;
+  int FwdDio;
+  int RevDio;
+};
+
+constexpr static std::array<RelayCross, 1> RelayCrossConnects{
+    RelayCross{0, 23, 22}};
+
+// input on left
+constexpr static std::array<std::pair<int, int>, 2> AnalogCrossConnects{
+    std::pair{2, 0}, std::pair{4, 1}};
+
+}  // namespace hlt

crossConnIntegrationTests/src/main/native/include/LifetimeWrappers.h

@@ -0,0 +1,200 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include <hal/DMA.h>
+#include <hal/DutyCycle.h>
+#include <hal/HAL.h>
+
+namespace hlt {
+
+struct InterruptHandle {
+ public:
+  explicit InterruptHandle(int32_t* status) {
+    handle = HAL_InitializeInterrupts(status);
+  }
+  InterruptHandle(const InterruptHandle&) = delete;
+  InterruptHandle operator=(const InterruptHandle&) = delete;
+
+  InterruptHandle(InterruptHandle&&) = default;
+  InterruptHandle& operator=(InterruptHandle&&) = default;
+
+  ~InterruptHandle() { HAL_CleanInterrupts(handle); }
+
+  operator HAL_InterruptHandle() const { return handle; }
+
+ private:
+  HAL_InterruptHandle handle = 0;
+};
+
+struct DMAHandle {
+ public:
+  explicit DMAHandle(int32_t* status) { handle = HAL_InitializeDMA(status); }
+  DMAHandle(const DMAHandle&) = delete;
+  DMAHandle operator=(const DMAHandle&) = delete;
+
+  DMAHandle(DMAHandle&&) = default;
+  DMAHandle& operator=(DMAHandle&&) = default;
+
+  ~DMAHandle() { HAL_FreeDMA(handle); }
+
+  operator HAL_DMAHandle() const { return handle; }
+
+ private:
+  HAL_DMAHandle handle = 0;
+};
+
+struct AnalogInputHandle {
+ public:
+  AnalogInputHandle(int32_t port, int32_t* status) {
+    handle = HAL_InitializeAnalogInputPort(HAL_GetPort(port), nullptr, status);
+  }
+  AnalogInputHandle(const AnalogInputHandle&) = delete;
+  AnalogInputHandle operator=(const AnalogInputHandle&) = delete;
+
+  AnalogInputHandle(AnalogInputHandle&&) = default;
+  AnalogInputHandle& operator=(AnalogInputHandle&&) = default;
+
+  ~AnalogInputHandle() { HAL_FreeAnalogInputPort(handle); }
+
+  operator HAL_AnalogInputHandle() const { return handle; }
+
+ private:
+  HAL_AnalogInputHandle handle = 0;
+};
+
+struct AnalogOutputHandle {
+ public:
+  AnalogOutputHandle(int32_t port, int32_t* status) {
+    handle = HAL_InitializeAnalogOutputPort(HAL_GetPort(port), nullptr, status);
+  }
+  AnalogOutputHandle(const AnalogOutputHandle&) = delete;
+  AnalogOutputHandle operator=(const AnalogOutputHandle&) = delete;
+
+  AnalogOutputHandle(AnalogOutputHandle&&) = default;
+  AnalogOutputHandle& operator=(AnalogOutputHandle&&) = default;
+
+  ~AnalogOutputHandle() { HAL_FreeAnalogOutputPort(handle); }
+
+  operator HAL_AnalogOutputHandle() const { return handle; }
+
+ private:
+  HAL_AnalogOutputHandle handle = 0;
+};
+
+struct AnalogTriggerHandle {
+ public:
+  explicit AnalogTriggerHandle(HAL_AnalogInputHandle port, int32_t* status) {
+    handle = HAL_InitializeAnalogTrigger(port, status);
+  }
+  AnalogTriggerHandle(const AnalogTriggerHandle&) = delete;
+  AnalogTriggerHandle operator=(const AnalogTriggerHandle&) = delete;
+
+  AnalogTriggerHandle(AnalogTriggerHandle&&) = default;
+  AnalogTriggerHandle& operator=(AnalogTriggerHandle&&) = default;
+
+  ~AnalogTriggerHandle() {
+    int32_t status = 0;
+    HAL_CleanAnalogTrigger(handle, &status);
+  }
+
+  operator HAL_AnalogTriggerHandle() const { return handle; }
+
+ private:
+  HAL_AnalogTriggerHandle handle = 0;
+};
+
+struct DutyCycleHandle {
+ public:
+  DutyCycleHandle(HAL_DigitalHandle port, int32_t* status) {
+    handle = HAL_InitializeDutyCycle(
+        port, HAL_AnalogTriggerType::HAL_Trigger_kInWindow, status);
+  }
+  DutyCycleHandle(const DutyCycleHandle&) = delete;
+  DutyCycleHandle operator=(const DutyCycleHandle&) = delete;
+
+  DutyCycleHandle(DutyCycleHandle&&) = default;
+  DutyCycleHandle& operator=(DutyCycleHandle&&) = default;
+
+  ~DutyCycleHandle() { HAL_FreeDutyCycle(handle); }
+
+  operator HAL_DutyCycleHandle() const { return handle; }
+
+ private:
+  HAL_DutyCycleHandle handle = 0;
+};
+
+struct DIOHandle {
+ public:
+  DIOHandle() {}
+  DIOHandle(const DIOHandle&) = delete;
+  DIOHandle operator=(const DIOHandle&) = delete;
+
+  DIOHandle(DIOHandle&&) = default;
+  DIOHandle& operator=(DIOHandle&&) = default;
+
+  DIOHandle(int32_t port, HAL_Bool input, int32_t* status) {
+    handle = HAL_InitializeDIOPort(HAL_GetPort(port), input, nullptr, status);
+  }
+
+  ~DIOHandle() { HAL_FreeDIOPort(handle); }
+
+  operator HAL_DigitalHandle() const { return handle; }
+
+ private:
+  HAL_DigitalHandle handle = 0;
+};
+
+struct PWMHandle {
+ public:
+  PWMHandle() {}
+  PWMHandle(const PWMHandle&) = delete;
+  PWMHandle operator=(const PWMHandle&) = delete;
+
+  PWMHandle(PWMHandle&&) = default;
+  PWMHandle& operator=(PWMHandle&&) = default;
+
+  PWMHandle(int32_t port, int32_t* status) {
+    handle = HAL_InitializePWMPort(HAL_GetPort(port), nullptr, status);
+  }
+
+  ~PWMHandle() {
+    int32_t status = 0;
+    HAL_FreePWMPort(handle, &status);
+  }
+
+  operator HAL_DigitalHandle() const { return handle; }
+
+ private:
+  HAL_DigitalHandle handle = 0;
+};
+
+struct RelayHandle {
+ public:
+  RelayHandle(int32_t port, HAL_Bool fwd, int32_t* status) {
+    handle = HAL_InitializeRelayPort(HAL_GetPort(port), fwd, nullptr, status);
+  }
+  RelayHandle(const RelayHandle&) = delete;
+  RelayHandle operator=(const RelayHandle&) = delete;
+
+  RelayHandle(RelayHandle&&) = default;
+  RelayHandle& operator=(RelayHandle&&) = default;
+
+  ~RelayHandle() { HAL_FreeRelayPort(handle); }
+
+  operator HAL_RelayHandle() const { return handle; }
+
+ private:
+  HAL_RelayHandle handle = 0;
+};
+
+#define ASSERT_LAST_ERROR_STATUS(status, x)                          \
+  do {                                                               \
+    ASSERT_EQ(status, HAL_USE_LAST_ERROR);                           \
+    const char* lastErrorMessageInMacro = HAL_GetLastError(&status); \
+    ASSERT_EQ(status, x);                                            \
+  } while (0)
+
+}  // namespace hlt

cscore/.styleguide

@@ -31,6 +31,7 @@ repoRootNameOverride {
 }
 
 includeOtherLibs {
+  ^fmt/
   ^opencv2/
   ^support/
   ^tcpsockets/

cscore/examples/enum_usb/enum_usb.cpp

@@ -2,83 +2,77 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-#include <wpi/SmallString.h>
-#include <wpi/raw_ostream.h>
+#include <cstdio>
+
+#include <fmt/format.h>
 
 #include "cscore.h"
 
 int main() {
   CS_Status status = 0;
-  wpi::SmallString<64> buf;
 
   for (const auto& caminfo : cs::EnumerateUsbCameras(&status)) {
-    wpi::outs() << caminfo.dev << ": " << caminfo.path << " (" << caminfo.name
-                << ")\n";
+    fmt::print("{}: {} ({})\n", caminfo.dev, caminfo.path, caminfo.name);
     if (!caminfo.otherPaths.empty()) {
-      wpi::outs() << "Other device paths:\n";
+      std::puts("Other device paths:");
       for (auto&& path : caminfo.otherPaths) {
-        wpi::outs() << "  " << path << '\n';
+        fmt::print("  {}\n", path);
       }
     }
 
     cs::UsbCamera camera{"usbcam", caminfo.dev};
 
-    wpi::outs() << "Properties:\n";
+    std::puts("Properties:");
     for (const auto& prop : camera.EnumerateProperties()) {
-      wpi::outs() << "  " << prop.GetName();
+      fmt::print("  {}", prop.GetName());
       switch (prop.GetKind()) {
         case cs::VideoProperty::kBoolean:
-          wpi::outs() << " (bool): "
-                      << "value=" << prop.Get()
-                      << " default=" << prop.GetDefault();
+          fmt::print(" (bool): value={} default={}", prop.Get(),
+                     prop.GetDefault());
           break;
         case cs::VideoProperty::kInteger:
-          wpi::outs() << " (int): "
-                      << "value=" << prop.Get() << " min=" << prop.GetMin()
-                      << " max=" << prop.GetMax() << " step=" << prop.GetStep()
-                      << " default=" << prop.GetDefault();
+          fmt::print(" (int): value={} min={} max={} step={} default={}",
+                     prop.Get(), prop.GetMin(), prop.GetMax(), prop.GetStep(),
+                     prop.GetDefault());
           break;
         case cs::VideoProperty::kString:
-          wpi::outs() << " (string): " << prop.GetString(buf);
+          fmt::print(" (string): {}", prop.GetString());
           break;
         case cs::VideoProperty::kEnum: {
-          wpi::outs() << " (enum): "
-                      << "value=" << prop.Get();
+          fmt::print(" (enum): value={}", prop.Get());
           auto choices = prop.GetChoices();
           for (size_t i = 0; i < choices.size(); ++i) {
-            if (choices[i].empty()) {
-              continue;
+            if (!choices[i].empty()) {
+              fmt::print("\n    {}: {}", i, choices[i]);
             }
-            wpi::outs() << "\n    " << i << ": " << choices[i];
           }
           break;
         }
         default:
           break;
       }
-      wpi::outs() << '\n';
+      std::fputc('\n', stdout);
     }
 
-    wpi::outs() << "Video Modes:\n";
+    std::puts("Video Modes:");
     for (const auto& mode : camera.EnumerateVideoModes()) {
-      wpi::outs() << "  PixelFormat:";
+      const char* pixelFormat;
       switch (mode.pixelFormat) {
         case cs::VideoMode::kMJPEG:
-          wpi::outs() << "MJPEG";
+          pixelFormat = "MJPEG";
           break;
         case cs::VideoMode::kYUYV:
-          wpi::outs() << "YUYV";
+          pixelFormat = "YUYV";
           break;
         case cs::VideoMode::kRGB565:
-          wpi::outs() << "RGB565";
+          pixelFormat = "RGB565";
           break;
         default:
-          wpi::outs() << "Unknown";
+          pixelFormat = "Unknown";
           break;
       }
-      wpi::outs() << " Width:" << mode.width;
-      wpi::outs() << " Height:" << mode.height;
-      wpi::outs() << " FPS:" << mode.fps << '\n';
+      fmt::print("  PixelFormat:{} Width:{} Height:{} FPS:{}\n", pixelFormat,
+                 mode.width, mode.height, mode.fps);
     }
   }
 }

cscore/examples/settings/settings.cpp

@@ -3,23 +3,27 @@
 // the WPILib BSD license file in the root directory of this project.
 
 #include <chrono>
+#include <cstdio>
 #include <thread>
 
-#include <wpi/SmallString.h>
-#include <wpi/raw_ostream.h>
+#include <fmt/format.h>
+#include <wpi/StringExtras.h>
 
 #include "cscore.h"
 
 int main(int argc, char** argv) {
   if (argc < 2) {
-    wpi::errs() << "Usage: settings camera [prop val] ... -- [prop val]...\n";
-    wpi::errs() << "  Example: settings 1 brightness 30 raw_contrast 10\n";
+    std::fputs("Usage: settings camera [prop val] ... -- [prop val]...\n",
+               stderr);
+    std::fputs("  Example: settings 1 brightness 30 raw_contrast 10\n", stderr);
     return 1;
   }
 
   int id;
-  if (wpi::StringRef{argv[1]}.getAsInteger(10, id)) {
-    wpi::errs() << "Expected number for camera\n";
+  if (auto v = wpi::parse_integer<int>(argv[1], 10)) {
+    id = v.value();
+  } else {
+    std::fputs("Expected number for camera\n", stderr);
     return 2;
   }
 
@@ -27,22 +31,21 @@ int main(int argc, char** argv) {
 
   // Set prior to connect
   int arg = 2;
-  wpi::StringRef propName;
-  for (; arg < argc && wpi::StringRef{argv[arg]} != "--"; ++arg) {
+  std::string_view propName;
+  for (; arg < argc && std::string_view{argv[arg]} != "--"; ++arg) {
     if (propName.empty()) {
       propName = argv[arg];
     } else {
-      wpi::StringRef propVal{argv[arg]};
-      int intVal;
-      if (propVal.getAsInteger(10, intVal)) {
-        camera.GetProperty(propName).SetString(propVal);
+      std::string_view propVal{argv[arg]};
+      if (auto v = wpi::parse_integer<int>(propVal, 10)) {
+        camera.GetProperty(propName).Set(v.value());
       } else {
-        camera.GetProperty(propName).Set(intVal);
+        camera.GetProperty(propName).SetString(propVal);
       }
-      propName = wpi::StringRef{};
+      propName = {};
     }
   }
-  if (arg < argc && wpi::StringRef{argv[arg]} == "--") {
+  if (arg < argc && std::string_view{argv[arg]} == "--") {
     ++arg;
   }
 
@@ -52,57 +55,51 @@ int main(int argc, char** argv) {
   }
 
   // Set rest
-  propName = wpi::StringRef{};
+  propName = {};
   for (; arg < argc; ++arg) {
     if (propName.empty()) {
       propName = argv[arg];
     } else {
-      wpi::StringRef propVal{argv[arg]};
-      int intVal;
-      if (propVal.getAsInteger(10, intVal)) {
-        camera.GetProperty(propName).SetString(propVal);
+      std::string_view propVal{argv[arg]};
+      if (auto v = wpi::parse_integer<int>(propVal, 10)) {
+        camera.GetProperty(propName).Set(v.value());
       } else {
-        camera.GetProperty(propName).Set(intVal);
+        camera.GetProperty(propName).SetString(propVal);
       }
-      propName = wpi::StringRef{};
+      propName = {};
     }
   }
 
   // Print settings
-  wpi::SmallString<64> buf;
-  wpi::outs() << "Properties:\n";
+  std::puts("Properties:");
   for (const auto& prop : camera.EnumerateProperties()) {
-    wpi::outs() << "  " << prop.GetName();
+    fmt::print("  {}", prop.GetName());
     switch (prop.GetKind()) {
       case cs::VideoProperty::kBoolean:
-        wpi::outs() << " (bool): "
-                    << "value=" << prop.Get()
-                    << " default=" << prop.GetDefault();
+        fmt::print(" (bool): value={} default={}", prop.Get(),
+                   prop.GetDefault());
         break;
       case cs::VideoProperty::kInteger:
-        wpi::outs() << " (int): "
-                    << "value=" << prop.Get() << " min=" << prop.GetMin()
-                    << " max=" << prop.GetMax() << " step=" << prop.GetStep()
-                    << " default=" << prop.GetDefault();
+        fmt::print(" (int): value={} min={} max={} step={} default={}",
+                   prop.Get(), prop.GetMin(), prop.GetMax(), prop.GetStep(),
+                   prop.GetDefault());
         break;
       case cs::VideoProperty::kString:
-        wpi::outs() << " (string): " << prop.GetString(buf);
+        fmt::print(" (string): {}", prop.GetString());
         break;
       case cs::VideoProperty::kEnum: {
-        wpi::outs() << " (enum): "
-                    << "value=" << prop.Get();
+        fmt::print(" (enum): value={}", prop.Get());
         auto choices = prop.GetChoices();
         for (size_t i = 0; i < choices.size(); ++i) {
-          if (choices[i].empty()) {
-            continue;
+          if (!choices[i].empty()) {
+            fmt::print("\n    {}: {}", i, choices[i]);
           }
-          wpi::outs() << "\n    " << i << ": " << choices[i];
         }
         break;
       }
       default:
         break;
     }
-    wpi::outs() << '\n';
+    std::fputc('\n', stdout);
   }
 }

cscore/examples/usbstream/usbstream.cpp

@@ -4,15 +4,15 @@
 
 #include <cstdio>
 
-#include <wpi/raw_ostream.h>
+#include <fmt/format.h>
 
 #include "cscore.h"
 
 int main() {
-  wpi::outs() << "hostname: " << cs::GetHostname() << '\n';
-  wpi::outs() << "IPv4 network addresses:\n";
+  fmt::print("hostname: {}\n", cs::GetHostname());
+  std::puts("IPv4 network addresses:");
   for (const auto& addr : cs::GetNetworkInterfaces()) {
-    wpi::outs() << "  " << addr << '\n';
+    fmt::print("  {}\n", addr);
   }
   cs::UsbCamera camera{"usbcam", 0};
   camera.SetVideoMode(cs::VideoMode::kMJPEG, 320, 240, 30);
@@ -22,9 +22,8 @@ int main() {
   CS_Status status = 0;
   cs::AddListener(
       [&](const cs::RawEvent& event) {
-        wpi::outs() << "FPS=" << camera.GetActualFPS()
-                    << " MBPS=" << (camera.GetActualDataRate() / 1000000.0)
-                    << '\n';
+        fmt::print("FPS={} MBPS={}\n", camera.GetActualFPS(),
+                   (camera.GetActualDataRate() / 1000000.0));
       },
       cs::RawEvent::kTelemetryUpdated, false, &status);
   cs::SetTelemetryPeriod(1.0);

cscore/examples/usbviewer/usbviewer.cpp

@@ -6,12 +6,13 @@
 #include <thread>
 #include <vector>
 
+#include <fmt/format.h>
+
 #define IMGUI_DEFINE_MATH_OPERATORS
 #include <imgui.h>
 #include <imgui_internal.h>
 #include <opencv2/core/core.hpp>
 #include <opencv2/imgproc.hpp>
-#include <wpi/raw_ostream.h>
 #include <wpi/spinlock.h>
 #include <wpigui.h>
 
@@ -38,7 +39,7 @@ int main() {
       // get frame from camera
       uint64_t time = cvsink.GrabFrame(frame);
       if (time == 0) {
-        wpi::outs() << "error: " << cvsink.GetError() << '\n';
+        fmt::print("error: {}\n", cvsink.GetError());
         continue;
       }
 

cscore/src/dev/java/edu/wpi/first/cscore/DevMain.java

@@ -2,9 +2,9 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
-import edu.wpi.first.wpiutil.RuntimeDetector;
+import edu.wpi.first.util.RuntimeDetector;
 
 public final class DevMain {
   /** Main method. */

cscore/src/main/java/edu/wpi/first/cscore/AxisCamera.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** A source that represents an Axis IP camera. */
 public class AxisCamera extends HttpCamera {

cscore/src/main/java/edu/wpi/first/cscore/CameraServerCvJNI.java

@@ -2,9 +2,9 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
-import edu.wpi.first.wpiutil.RuntimeLoader;
+import edu.wpi.first.util.RuntimeLoader;
 import java.io.IOException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import org.opencv.core.Core;
@@ -42,7 +42,11 @@ public class CameraServerCvJNI {
     }
   }
 
-  /** Force load the library. */
+  /**
+   * Force load the library.
+   *
+   * @throws IOException if library load failed
+   */
   public static synchronized void forceLoad() throws IOException {
     if (libraryLoaded) {
       return;

cscore/src/main/java/edu/wpi/first/cscore/CameraServerJNI.java

@@ -2,10 +2,10 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
-import edu.wpi.cscore.raw.RawFrame;
-import edu.wpi.first.wpiutil.RuntimeLoader;
+import edu.wpi.first.cscore.raw.RawFrame;
+import edu.wpi.first.util.RuntimeLoader;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -43,7 +43,11 @@ public class CameraServerJNI {
     }
   }
 
-  /** Force load the library. */
+  /**
+   * Force load the library.
+   *
+   * @throws IOException if library load failed
+   */
   public static synchronized void forceLoad() throws IOException {
     if (libraryLoaded) {
       return;

cscore/src/main/java/edu/wpi/first/cscore/CvSink.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 import org.opencv.core.Mat;
 
@@ -38,6 +38,7 @@ public class CvSink extends ImageSink {
    * Wait for the next frame and get the image. Times out (returning 0) after 0.225 seconds. The
    * provided image will have three 3-bit channels stored in BGR order.
    *
+   * @param image Where to store the image.
    * @return Frame time, or 0 on error (call GetError() to obtain the error message)
    */
   public long grabFrame(Mat image) {
@@ -48,6 +49,8 @@ public class CvSink extends ImageSink {
    * Wait for the next frame and get the image. Times out (returning 0) after timeout seconds. The
    * provided image will have three 3-bit channels stored in BGR order.
    *
+   * @param image Where to store the image.
+   * @param timeout Retrieval timeout in seconds.
    * @return Frame time, or 0 on error (call GetError() to obtain the error message); the frame time
    *     is in 1 us increments.
    */
@@ -59,6 +62,7 @@ public class CvSink extends ImageSink {
    * Wait for the next frame and get the image. May block forever. The provided image will have
    * three 3-bit channels stored in BGR order.
    *
+   * @param image Where to store the image.
    * @return Frame time, or 0 on error (call GetError() to obtain the error message); the frame time
    *     is in 1 us increments.
    */

cscore/src/main/java/edu/wpi/first/cscore/CvSource.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 import org.opencv.core.Mat;
 

cscore/src/main/java/edu/wpi/first/cscore/HttpCamera.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** A source that represents a MJPEG-over-HTTP (IP) camera. */
 public class HttpCamera extends VideoCamera {
@@ -88,17 +88,27 @@ public class HttpCamera extends VideoCamera {
    * Get the kind of HTTP camera.
    *
    * <p>Autodetection can result in returning a different value than the camera was created with.
+   *
+   * @return The kind of HTTP camera.
    */
   public HttpCameraKind getHttpCameraKind() {
     return getHttpCameraKindFromInt(CameraServerJNI.getHttpCameraKind(m_handle));
   }
 
-  /** Change the URLs used to connect to the camera. */
+  /**
+   * Change the URLs used to connect to the camera.
+   *
+   * @param urls Array of Camera URLs
+   */
   public void setUrls(String[] urls) {
     CameraServerJNI.setHttpCameraUrls(m_handle, urls);
   }
 
-  /** Get the URLs used to connect to the camera. */
+  /**
+   * Get the URLs used to connect to the camera.
+   *
+   * @return Array of camera URLs.
+   */
   public String[] getUrls() {
     return CameraServerJNI.getHttpCameraUrls(m_handle);
   }

cscore/src/main/java/edu/wpi/first/cscore/ImageSink.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 public abstract class ImageSink extends VideoSink {
   protected ImageSink(int handle) {
@@ -18,7 +18,11 @@ public abstract class ImageSink extends VideoSink {
     CameraServerJNI.setSinkDescription(m_handle, description);
   }
 
-  /** Get error string. Call this if WaitForFrame() returns 0 to determine what the error is. */
+  /**
+   * Get error string. Call this if WaitForFrame() returns 0 to determine what the error is.
+   *
+   * @return Error string.
+   */
   public String getError() {
     return CameraServerJNI.getSinkError(m_handle);
   }
@@ -27,6 +31,8 @@ public abstract class ImageSink extends VideoSink {
    * Enable or disable getting new frames. Disabling will cause processFrame (for callback-based
    * CvSinks) to not be called and WaitForFrame() to not return. This can be used to save processor
    * resources when frames are not needed.
+   *
+   * @param enabled Enable to get new frames.
    */
   public void setEnabled(boolean enabled) {
     CameraServerJNI.setSinkEnabled(m_handle, enabled);

cscore/src/main/java/edu/wpi/first/cscore/ImageSource.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 public abstract class ImageSource extends VideoSource {
   protected ImageSource(int handle) {
@@ -12,6 +12,8 @@ public abstract class ImageSource extends VideoSource {
   /**
    * Signal sinks that an error has occurred. This should be called instead of NotifyFrame when an
    * error occurs.
+   *
+   * @param msg Error message.
    */
   public void notifyError(String msg) {
     CameraServerJNI.notifySourceError(m_handle, msg);

cscore/src/main/java/edu/wpi/first/cscore/MjpegServer.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** A sink that acts as a MJPEG-over-HTTP network server. */
 public class MjpegServer extends VideoSink {
@@ -27,12 +27,20 @@ public class MjpegServer extends VideoSink {
     this(name, "", port);
   }
 
-  /** Get the listen address of the server. */
+  /**
+   * Get the listen address of the server.
+   *
+   * @return The listen address.
+   */
   public String getListenAddress() {
     return CameraServerJNI.getMjpegServerListenAddress(m_handle);
   }
 
-  /** Get the port number of the server. */
+  /**
+   * Get the port number of the server.
+   *
+   * @return The port number.
+   */
   public int getPort() {
     return CameraServerJNI.getMjpegServerPort(m_handle);
   }

cscore/src/main/java/edu/wpi/first/cscore/UsbCamera.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** A source that represents a USB camera. */
 public class UsbCamera extends VideoCamera {
@@ -35,17 +35,29 @@ public class UsbCamera extends VideoCamera {
     return CameraServerJNI.enumerateUsbCameras();
   }
 
-  /** Change the path to the device. */
+  /**
+   * Change the path to the device.
+   *
+   * @param path New device path.
+   */
   void setPath(String path) {
     CameraServerJNI.setUsbCameraPath(m_handle, path);
   }
 
-  /** Get the path to the device. */
+  /**
+   * Get the path to the device.
+   *
+   * @return The device path.
+   */
   public String getPath() {
     return CameraServerJNI.getUsbCameraPath(m_handle);
   }
 
-  /** Get the full camera information for the device. */
+  /**
+   * Get the full camera information for the device.
+   *
+   * @return The camera information.
+   */
   public UsbCameraInfo getInfo() {
     return CameraServerJNI.getUsbCameraInfo(m_handle);
   }

cscore/src/main/java/edu/wpi/first/cscore/UsbCameraInfo.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** USB camera information. */
 public class UsbCameraInfo {

cscore/src/main/java/edu/wpi/first/cscore/VideoCamera.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** A source that represents a video camera. */
 public class VideoCamera extends VideoSource {
@@ -18,12 +18,20 @@ public class VideoCamera extends VideoSource {
     super(handle);
   }
 
-  /** Set the brightness, as a percentage (0-100). */
+  /**
+   * Set the brightness, as a percentage (0-100).
+   *
+   * @param brightness Brightness as a percentage (0-100).
+   */
   public synchronized void setBrightness(int brightness) {
     CameraServerJNI.setCameraBrightness(m_handle, brightness);
   }
 
-  /** Get the brightness, as a percentage (0-100). */
+  /**
+   * Get the brightness, as a percentage (0-100).
+   *
+   * @return The brightness as a percentage (0-100).
+   */
   public synchronized int getBrightness() {
     return CameraServerJNI.getCameraBrightness(m_handle);
   }
@@ -38,7 +46,11 @@ public class VideoCamera extends VideoSource {
     CameraServerJNI.setCameraWhiteBalanceHoldCurrent(m_handle);
   }
 
-  /** Set the white balance to manual, with specified color temperature. */
+  /**
+   * Set the white balance to manual, with specified color temperature.
+   *
+   * @param value The specified color temperature.
+   */
   public synchronized void setWhiteBalanceManual(int value) {
     CameraServerJNI.setCameraWhiteBalanceManual(m_handle, value);
   }
@@ -53,7 +65,11 @@ public class VideoCamera extends VideoSource {
     CameraServerJNI.setCameraExposureHoldCurrent(m_handle);
   }
 
-  /** Set the exposure to manual, as a percentage (0-100). */
+  /**
+   * Set the exposure to manual, as a percentage (0-100).
+   *
+   * @param value The exposure as a percentage (0-100).
+   */
   public synchronized void setExposureManual(int value) {
     CameraServerJNI.setCameraExposureManual(m_handle, value);
   }

cscore/src/main/java/edu/wpi/first/cscore/VideoEvent.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** Video event. */
 public class VideoEvent {
@@ -46,7 +46,6 @@ public class VideoEvent {
    * @param kind The numerical representation of kind
    * @return The kind
    */
-  @SuppressWarnings("PMD.CyclomaticComplexity")
   public static Kind getKindFromInt(int kind) {
     switch (kind) {
       case 0x0001:
@@ -92,7 +91,6 @@ public class VideoEvent {
     }
   }
 
-  @SuppressWarnings("PMD.ExcessiveParameterList")
   VideoEvent(
       int kind,
       int source,

cscore/src/main/java/edu/wpi/first/cscore/VideoException.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** An exception raised by the camera server. */
 public class VideoException extends RuntimeException {

cscore/src/main/java/edu/wpi/first/cscore/VideoListener.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 import java.util.HashMap;
 import java.util.Map;

cscore/src/main/java/edu/wpi/first/cscore/VideoMode.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** Video mode. */
 public class VideoMode {
@@ -31,7 +31,14 @@ public class VideoMode {
     return m_pixelFormatValues[pixelFormat];
   }
 
-  /** Create a new video mode. */
+  /**
+   * Create a new video mode.
+   *
+   * @param pixelFormat The pixel format enum as an integer.
+   * @param width The image width in pixels.
+   * @param height The image height in pixels.
+   * @param fps The camera's frames per second.
+   */
   public VideoMode(int pixelFormat, int width, int height, int fps) {
     this.pixelFormat = getPixelFormatFromInt(pixelFormat);
     this.width = width;
@@ -39,7 +46,14 @@ public class VideoMode {
     this.fps = fps;
   }
 
-  /** Create a new video mode. */
+  /**
+   * Create a new video mode.
+   *
+   * @param pixelFormat The pixel format.
+   * @param width The image width in pixels.
+   * @param height The image height in pixels.
+   * @param fps The camera's frames per second.
+   */
   public VideoMode(PixelFormat pixelFormat, int width, int height, int fps) {
     this.pixelFormat = pixelFormat;
     this.width = width;

cscore/src/main/java/edu/wpi/first/cscore/VideoProperty.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /** A source or sink property. */
 public class VideoProperty {

cscore/src/main/java/edu/wpi/first/cscore/VideoSink.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /**
  * A source for video that provides a sequence of frames. Each frame may consist of multiple images
@@ -83,7 +83,11 @@ public class VideoSink implements AutoCloseable {
     return m_handle;
   }
 
-  /** Get the kind of the sink. */
+  /**
+   * Get the kind of the sink.
+   *
+   * @return The kind of the sink.
+   */
   public Kind getKind() {
     return getKindFromInt(CameraServerJNI.getSinkKind(m_handle));
   }
@@ -91,12 +95,18 @@ public class VideoSink implements AutoCloseable {
   /**
    * Get the name of the sink. The name is an arbitrary identifier provided when the sink is
    * created, and should be unique.
+   *
+   * @return The name of the sink.
    */
   public String getName() {
     return CameraServerJNI.getSinkName(m_handle);
   }
 
-  /** Get the sink description. This is sink-kind specific. */
+  /**
+   * Get the sink description. This is sink-kind specific.
+   *
+   * @return The sink description.
+   */
   public String getDescription() {
     return CameraServerJNI.getSinkDescription(m_handle);
   }
@@ -111,8 +121,11 @@ public class VideoSink implements AutoCloseable {
     return new VideoProperty(CameraServerJNI.getSinkProperty(m_handle, name));
   }
 
-  /** Enumerate all properties of this sink. */
-  @SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops")
+  /**
+   * Enumerate all properties of this sink.
+   *
+   * @return List of properties.
+   */
   public VideoProperty[] enumerateProperties() {
     int[] handles = CameraServerJNI.enumerateSinkProperties(m_handle);
     VideoProperty[] rv = new VideoProperty[handles.length];
@@ -195,7 +208,6 @@ public class VideoSink implements AutoCloseable {
    *
    * @return Vector of sinks.
    */
-  @SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops")
   public static VideoSink[] enumerateSinks() {
     int[] handles = CameraServerJNI.enumerateSinks();
     VideoSink[] rv = new VideoSink[handles.length];

cscore/src/main/java/edu/wpi/first/cscore/VideoSource.java

@@ -2,7 +2,7 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore;
+package edu.wpi.first.cscore;
 
 /**
  * A source for video that provides a sequence of frames. Each frame may consist of multiple images
@@ -113,7 +113,11 @@ public class VideoSource implements AutoCloseable {
     return m_handle;
   }
 
-  /** Get the kind of the source. */
+  /**
+   * Get the kind of the source.
+   *
+   * @return The kind of the source.
+   */
   public Kind getKind() {
     return getKindFromInt(CameraServerJNI.getSourceKind(m_handle));
   }
@@ -121,12 +125,18 @@ public class VideoSource implements AutoCloseable {
   /**
    * Get the name of the source. The name is an arbitrary identifier provided when the source is
    * created, and should be unique.
+   *
+   * @return The name of the source.
    */
   public String getName() {
     return CameraServerJNI.getSourceName(m_handle);
   }
 
-  /** Get the source description. This is source-kind specific. */
+  /**
+   * Get the source description. This is source-kind specific.
+   *
+   * @return The source description.
+   */
   public String getDescription() {
     return CameraServerJNI.getSourceDescription(m_handle);
   }
@@ -153,7 +163,11 @@ public class VideoSource implements AutoCloseable {
     CameraServerJNI.setSourceConnectionStrategy(m_handle, strategy.getValue());
   }
 
-  /** Returns if the source currently connected to whatever is providing the images. */
+  /**
+   * Returns true if the source currently connected to whatever is providing the images.
+   *
+   * @return True if the source currently connected to whatever is providing the images.
+   */
   public boolean isConnected() {
     return CameraServerJNI.isSourceConnected(m_handle);
   }
@@ -178,8 +192,11 @@ public class VideoSource implements AutoCloseable {
     return new VideoProperty(CameraServerJNI.getSourceProperty(m_handle, name));
   }
 
-  /** Enumerate all properties of this source. */
-  @SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops")
+  /**
+   * Enumerate all properties of this source.
+   *
+   * @return Array of video properties.
+   */
   public VideoProperty[] enumerateProperties() {
     int[] handles = CameraServerJNI.enumerateSourceProperties(m_handle);
     VideoProperty[] rv = new VideoProperty[handles.length];
@@ -189,7 +206,11 @@ public class VideoSource implements AutoCloseable {
     return rv;
   }
 
-  /** Get the current video mode. */
+  /**
+   * Get the current video mode.
+   *
+   * @return The current video mode.
+   */
   public VideoMode getVideoMode() {
     return CameraServerJNI.getSourceVideoMode(m_handle);
   }
@@ -198,6 +219,7 @@ public class VideoSource implements AutoCloseable {
    * Set the video mode.
    *
    * @param mode Video mode
+   * @return True if set successfully.
    */
   public boolean setVideoMode(VideoMode mode) {
     return CameraServerJNI.setSourceVideoMode(
@@ -313,7 +335,11 @@ public class VideoSource implements AutoCloseable {
         m_handle, CameraServerJNI.TelemetryKind.kSourceBytesReceived);
   }
 
-  /** Enumerate all known video modes for this source. */
+  /**
+   * Enumerate all known video modes for this source.
+   *
+   * @return Vector of video modes.
+   */
   public VideoMode[] enumerateVideoModes() {
     return CameraServerJNI.enumerateSourceVideoModes(m_handle);
   }
@@ -323,7 +349,6 @@ public class VideoSource implements AutoCloseable {
    *
    * @return Vector of sinks.
    */
-  @SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops")
   public VideoSink[] enumerateSinks() {
     int[] handles = CameraServerJNI.enumerateSourceSinks(m_handle);
     VideoSink[] rv = new VideoSink[handles.length];
@@ -338,7 +363,6 @@ public class VideoSource implements AutoCloseable {
    *
    * @return Vector of sources.
    */
-  @SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops")
   public static VideoSource[] enumerateSources() {
     int[] handles = CameraServerJNI.enumerateSources();
     VideoSource[] rv = new VideoSource[handles.length];

cscore/src/main/java/edu/wpi/first/cscore/raw/RawFrame.java

@@ -2,9 +2,9 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore.raw;
+package edu.wpi.first.cscore.raw;
 
-import edu.wpi.cscore.CameraServerJNI;
+import edu.wpi.first.cscore.CameraServerJNI;
 import java.nio.ByteBuffer;
 
 /**
@@ -35,7 +35,16 @@ public class RawFrame implements AutoCloseable {
     CameraServerJNI.freeRawFrame(m_framePtr);
   }
 
-  /** Called from JNI to set data in class. */
+  /**
+   * Called from JNI to set data in class.
+   *
+   * @param dataByteBuffer A ByteBuffer pointing to the frame data.
+   * @param dataPtr A long (a char* in native code) pointing to the frame data.
+   * @param totalData The total length of the data stored in the frame.
+   * @param width The width of the frame.
+   * @param height The height of the frame.
+   * @param pixelFormat The PixelFormat of the frame.
+   */
   public void setData(
       ByteBuffer dataByteBuffer,
       long dataPtr,
@@ -51,7 +60,11 @@ public class RawFrame implements AutoCloseable {
     m_pixelFormat = pixelFormat;
   }
 
-  /** Get the pointer to native representation of this frame. */
+  /**
+   * Get the pointer to native representation of this frame.
+   *
+   * @return The pointer to native representation of this frame.
+   */
   public long getFramePtr() {
     return m_framePtr;
   }
@@ -60,6 +73,8 @@ public class RawFrame implements AutoCloseable {
    * Get a ByteBuffer pointing to the frame data. This ByteBuffer is backed by the frame directly.
    * Its lifetime is controlled by the frame. If a new frame gets read, it will overwrite the
    * current one.
+   *
+   * @return A ByteBuffer pointing to the frame data.
    */
   public ByteBuffer getDataByteBuffer() {
     return m_dataByteBuffer;
@@ -69,42 +84,72 @@ public class RawFrame implements AutoCloseable {
    * Get a long (is a char* in native code) pointing to the frame data. This pointer is backed by
    * the frame directly. Its lifetime is controlled by the frame. If a new frame gets read, it will
    * overwrite the current one.
+   *
+   * @return A long pointing to the frame data.
    */
   public long getDataPtr() {
     return m_dataPtr;
   }
 
-  /** Get the total length of the data stored in the frame. */
+  /**
+   * Get the total length of the data stored in the frame.
+   *
+   * @return The total length of the data stored in the frame.
+   */
   public int getTotalData() {
     return m_totalData;
   }
 
-  /** Get the width of the frame. */
+  /**
+   * Get the width of the frame.
+   *
+   * @return The width of the frame.
+   */
   public int getWidth() {
     return m_width;
   }
 
-  /** Set the width of the frame. */
+  /**
+   * Set the width of the frame.
+   *
+   * @param width The width of the frame.
+   */
   public void setWidth(int width) {
     this.m_width = width;
   }
 
-  /** Get the height of the frame. */
+  /**
+   * Get the height of the frame.
+   *
+   * @return The height of the frame.
+   */
   public int getHeight() {
     return m_height;
   }
 
-  /** Set the height of the frame. */
+  /**
+   * Set the height of the frame.
+   *
+   * @param height The height of the frame.
+   */
   public void setHeight(int height) {
     this.m_height = height;
   }
 
-  /** Get the PixelFormat of the frame. */
+  /**
+   * Get the PixelFormat of the frame.
+   *
+   * @return The PixelFormat of the frame.
+   */
   public int getPixelFormat() {
     return m_pixelFormat;
   }
 
-  /** Set the PixelFormat of the frame. */
+  /**
+   * Set the PixelFormat of the frame.
+   *
+   * @param pixelFormat The PixelFormat of the frame.
+   */
   public void setPixelFormat(int pixelFormat) {
     this.m_pixelFormat = pixelFormat;
   }

cscore/src/main/java/edu/wpi/first/cscore/raw/RawSink.java

@@ -2,10 +2,10 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore.raw;
+package edu.wpi.first.cscore.raw;
 
-import edu.wpi.cscore.CameraServerJNI;
-import edu.wpi.cscore.ImageSink;
+import edu.wpi.first.cscore.CameraServerJNI;
+import edu.wpi.first.cscore.ImageSink;
 
 /**
  * A sink for user code to accept video frames as raw bytes.
@@ -28,6 +28,7 @@ public class RawSink extends ImageSink {
    * Wait for the next frame and get the image. Times out (returning 0) after 0.225 seconds. The
    * provided image will have three 8-bit channels stored in BGR order.
    *
+   * @param frame The frame object in which to store the image.
    * @return Frame time, or 0 on error (call getError() to obtain the error message); the frame time
    *     is in the same time base as wpi::Now(), and is in 1 us increments.
    */
@@ -39,6 +40,8 @@ public class RawSink extends ImageSink {
    * Wait for the next frame and get the image. Times out (returning 0) after timeout seconds. The
    * provided image will have three 8-bit channels stored in BGR order.
    *
+   * @param frame The frame object in which to store the image.
+   * @param timeout The frame timeout in seconds.
    * @return Frame time, or 0 on error (call getError() to obtain the error message); the frame time
    *     is in the same time base as wpi::Now(), and is in 1 us increments.
    */
@@ -50,6 +53,7 @@ public class RawSink extends ImageSink {
    * Wait for the next frame and get the image. May block forever. The provided image will have
    * three 8-bit channels stored in BGR order.
    *
+   * @param frame The frame object in which to store the image.
    * @return Frame time, or 0 on error (call getError() to obtain the error message); the frame time
    *     is in the same time base as wpi::Now(), and is in 1 us increments.
    */

cscore/src/main/java/edu/wpi/first/cscore/raw/RawSource.java

@@ -2,11 +2,11 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-package edu.wpi.cscore.raw;
+package edu.wpi.first.cscore.raw;
 
-import edu.wpi.cscore.CameraServerJNI;
-import edu.wpi.cscore.ImageSource;
-import edu.wpi.cscore.VideoMode;
+import edu.wpi.first.cscore.CameraServerJNI;
+import edu.wpi.first.cscore.ImageSource;
+import edu.wpi.first.cscore.VideoMode;
 
 /**
  * A source for user code to provide video frames as raw bytes.

cscore/src/main/native/cpp/ConfigurableSourceImpl.cpp

@@ -13,7 +13,7 @@
 
 using namespace cs;
 
-ConfigurableSourceImpl::ConfigurableSourceImpl(const wpi::Twine& name,
+ConfigurableSourceImpl::ConfigurableSourceImpl(std::string_view name,
                                                wpi::Logger& logger,
                                                Notifier& notifier,
                                                Telemetry& telemetry,
@@ -50,11 +50,11 @@ void ConfigurableSourceImpl::NumSinksEnabledChanged() {
   // ignore
 }
 
-void ConfigurableSourceImpl::NotifyError(const wpi::Twine& msg) {
+void ConfigurableSourceImpl::NotifyError(std::string_view msg) {
   PutError(msg, wpi::Now());
 }
 
-int ConfigurableSourceImpl::CreateProperty(const wpi::Twine& name,
+int ConfigurableSourceImpl::CreateProperty(std::string_view name,
                                            CS_PropertyKind kind, int minimum,
                                            int maximum, int step,
                                            int defaultValue, int value) {
@@ -75,12 +75,12 @@ int ConfigurableSourceImpl::CreateProperty(const wpi::Twine& name,
         value = prop.value;
       });
   m_notifier.NotifySourceProperty(*this, CS_SOURCE_PROPERTY_CREATED, name, ndx,
-                                  kind, value, wpi::Twine{});
+                                  kind, value, {});
   return ndx;
 }
 
 int ConfigurableSourceImpl::CreateProperty(
-    const wpi::Twine& name, CS_PropertyKind kind, int minimum, int maximum,
+    std::string_view name, CS_PropertyKind kind, int minimum, int maximum,
     int step, int defaultValue, int value,
     std::function<void(CS_Property property)> onChange) {
   // TODO
@@ -88,7 +88,7 @@ int ConfigurableSourceImpl::CreateProperty(
 }
 
 void ConfigurableSourceImpl::SetEnumPropertyChoices(
-    int property, wpi::ArrayRef<std::string> choices, CS_Status* status) {
+    int property, wpi::span<const std::string> choices, CS_Status* status) {
   std::scoped_lock lock(m_mutex);
   auto prop = GetProperty(property);
   if (!prop) {
@@ -99,8 +99,8 @@ void ConfigurableSourceImpl::SetEnumPropertyChoices(
     *status = CS_WRONG_PROPERTY_TYPE;
     return;
   }
-  prop->enumChoices = choices;
+  prop->enumChoices.assign(choices.begin(), choices.end());
   m_notifier.NotifySourceProperty(*this, CS_SOURCE_PROPERTY_CHOICES_UPDATED,
                                   prop->name, property, CS_PROP_ENUM,
-                                  prop->value, wpi::Twine{});
+                                  prop->value, {});
 }

cscore/src/main/native/cpp/ConfigurableSourceImpl.h

@@ -9,10 +9,10 @@
 #include <functional>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <vector>
 
-#include <wpi/ArrayRef.h>
-#include <wpi/Twine.h>
+#include <wpi/span.h>
 
 #include "SourceImpl.h"
 
@@ -20,7 +20,7 @@ namespace cs {
 
 class ConfigurableSourceImpl : public SourceImpl {
  protected:
-  ConfigurableSourceImpl(const wpi::Twine& name, wpi::Logger& logger,
+  ConfigurableSourceImpl(std::string_view name, wpi::Logger& logger,
                          Notifier& notifier, Telemetry& telemetry,
                          const VideoMode& mode);
 
@@ -35,13 +35,14 @@ class ConfigurableSourceImpl : public SourceImpl {
   void NumSinksEnabledChanged() override;
 
   // OpenCV-specific functions
-  void NotifyError(const wpi::Twine& msg);
-  int CreateProperty(const wpi::Twine& name, CS_PropertyKind kind, int minimum,
+  void NotifyError(std::string_view msg);
+  int CreateProperty(std::string_view name, CS_PropertyKind kind, int minimum,
                      int maximum, int step, int defaultValue, int value);
-  int CreateProperty(const wpi::Twine& name, CS_PropertyKind kind, int minimum,
+  int CreateProperty(std::string_view name, CS_PropertyKind kind, int minimum,
                      int maximum, int step, int defaultValue, int value,
                      std::function<void(CS_Property property)> onChange);
-  void SetEnumPropertyChoices(int property, wpi::ArrayRef<std::string> choices,
+  void SetEnumPropertyChoices(int property,
+                              wpi::span<const std::string> choices,
                               CS_Status* status);
 
  private:

cscore/src/main/native/cpp/CvSinkImpl.cpp

@@ -18,14 +18,14 @@
 
 using namespace cs;
 
-CvSinkImpl::CvSinkImpl(const wpi::Twine& name, wpi::Logger& logger,
+CvSinkImpl::CvSinkImpl(std::string_view name, wpi::Logger& logger,
                        Notifier& notifier, Telemetry& telemetry)
     : SinkImpl{name, logger, notifier, telemetry} {
   m_active = true;
   // m_thread = std::thread(&CvSinkImpl::ThreadMain, this);
 }
 
-CvSinkImpl::CvSinkImpl(const wpi::Twine& name, wpi::Logger& logger,
+CvSinkImpl::CvSinkImpl(std::string_view name, wpi::Logger& logger,
                        Notifier& notifier, Telemetry& telemetry,
                        std::function<void(uint64_t time)> processFrame)
     : SinkImpl{name, logger, notifier, telemetry} {}
@@ -110,7 +110,7 @@ void CvSinkImpl::ThreadMain() {
       std::this_thread::sleep_for(std::chrono::seconds(1));
       continue;
     }
-    SDEBUG4("waiting for frame");
+    SDEBUG4("{}", "waiting for frame");
     Frame frame = source->GetNextFrame();  // blocks
     if (!m_active) {
       break;
@@ -127,14 +127,14 @@ void CvSinkImpl::ThreadMain() {
 
 namespace cs {
 
-CS_Sink CreateCvSink(const wpi::Twine& name, CS_Status* status) {
+CS_Sink CreateCvSink(std::string_view name, CS_Status* status) {
   auto& inst = Instance::GetInstance();
   return inst.CreateSink(
       CS_SINK_CV, std::make_shared<CvSinkImpl>(name, inst.logger, inst.notifier,
                                                inst.telemetry));
 }
 
-CS_Sink CreateCvSinkCallback(const wpi::Twine& name,
+CS_Sink CreateCvSinkCallback(std::string_view name,
                              std::function<void(uint64_t time)> processFrame,
                              CS_Status* status) {
   auto& inst = Instance::GetInstance();
@@ -145,7 +145,7 @@ CS_Sink CreateCvSinkCallback(const wpi::Twine& name,
 
 static constexpr unsigned SinkMask = CS_SINK_CV | CS_SINK_RAW;
 
-void SetSinkDescription(CS_Sink sink, const wpi::Twine& description,
+void SetSinkDescription(CS_Sink sink, std::string_view description,
                         CS_Status* status) {
   auto data = Instance::GetInstance().GetSink(sink);
   if (!data || (data->kind & SinkMask) == 0) {
@@ -183,12 +183,12 @@ std::string GetSinkError(CS_Sink sink, CS_Status* status) {
   return static_cast<CvSinkImpl&>(*data->sink).GetError();
 }
 
-wpi::StringRef GetSinkError(CS_Sink sink, wpi::SmallVectorImpl<char>& buf,
-                            CS_Status* status) {
+std::string_view GetSinkError(CS_Sink sink, wpi::SmallVectorImpl<char>& buf,
+                              CS_Status* status) {
   auto data = Instance::GetInstance().GetSink(sink);
   if (!data || (data->kind & SinkMask) == 0) {
     *status = CS_INVALID_HANDLE;
-    return wpi::StringRef{};
+    return {};
   }
   return static_cast<CvSinkImpl&>(*data->sink).GetError(buf);
 }

cscore/src/main/native/cpp/CvSinkImpl.h

@@ -9,10 +9,10 @@
 
 #include <atomic>
 #include <functional>
+#include <string_view>
 #include <thread>
 
 #include <opencv2/core/core.hpp>
-#include <wpi/Twine.h>
 #include <wpi/condition_variable.h>
 
 #include "Frame.h"
@@ -24,9 +24,9 @@ class SourceImpl;
 
 class CvSinkImpl : public SinkImpl {
  public:
-  CvSinkImpl(const wpi::Twine& name, wpi::Logger& logger, Notifier& notifier,
+  CvSinkImpl(std::string_view name, wpi::Logger& logger, Notifier& notifier,
              Telemetry& telemetry);
-  CvSinkImpl(const wpi::Twine& name, wpi::Logger& logger, Notifier& notifier,
+  CvSinkImpl(std::string_view name, wpi::Logger& logger, Notifier& notifier,
              Telemetry& telemetry,
              std::function<void(uint64_t time)> processFrame);
   ~CvSinkImpl() override;

cscore/src/main/native/cpp/CvSourceImpl.cpp

@@ -7,7 +7,6 @@
 #include <opencv2/core/core.hpp>
 #include <opencv2/highgui/highgui.hpp>
 #include <opencv2/imgproc/imgproc.hpp>
-#include <wpi/STLExtras.h>
 #include <wpi/timestamp.h>
 
 #include "Handle.h"
@@ -19,7 +18,7 @@
 
 using namespace cs;
 
-CvSourceImpl::CvSourceImpl(const wpi::Twine& name, wpi::Logger& logger,
+CvSourceImpl::CvSourceImpl(std::string_view name, wpi::Logger& logger,
                            Notifier& notifier, Telemetry& telemetry,
                            const VideoMode& mode)
     : ConfigurableSourceImpl{name, logger, notifier, telemetry, mode} {}
@@ -53,8 +52,7 @@ void CvSourceImpl::PutFrame(cv::Mat& image) {
       cv::cvtColor(finalImage, dest->AsMat(), cv::COLOR_BGRA2BGR);
       break;
     default:
-      SERROR("PutFrame: " << image.channels()
-                          << "-channel images not supported");
+      SERROR("PutFrame: {}-channel images not supported", image.channels());
       return;
   }
   SourceImpl::PutFrame(std::move(dest), wpi::Now());
@@ -62,7 +60,7 @@ void CvSourceImpl::PutFrame(cv::Mat& image) {
 
 namespace cs {
 
-CS_Source CreateCvSource(const wpi::Twine& name, const VideoMode& mode,
+CS_Source CreateCvSource(std::string_view name, const VideoMode& mode,
                          CS_Status* status) {
   auto& inst = Instance::GetInstance();
   return inst.CreateSource(CS_SOURCE_CV, std::make_shared<CvSourceImpl>(
@@ -81,7 +79,7 @@ void PutSourceFrame(CS_Source source, cv::Mat& image, CS_Status* status) {
 
 static constexpr unsigned SourceMask = CS_SINK_CV | CS_SINK_RAW;
 
-void NotifySourceError(CS_Source source, const wpi::Twine& msg,
+void NotifySourceError(CS_Source source, std::string_view msg,
                        CS_Status* status) {
   auto data = Instance::GetInstance().GetSource(source);
   if (!data || (data->kind & SourceMask) == 0) {
@@ -100,7 +98,7 @@ void SetSourceConnected(CS_Source source, bool connected, CS_Status* status) {
   static_cast<CvSourceImpl&>(*data->source).SetConnected(connected);
 }
 
-void SetSourceDescription(CS_Source source, const wpi::Twine& description,
+void SetSourceDescription(CS_Source source, std::string_view description,
                           CS_Status* status) {
   auto data = Instance::GetInstance().GetSource(source);
   if (!data || (data->kind & SourceMask) == 0) {
@@ -110,7 +108,7 @@ void SetSourceDescription(CS_Source source, const wpi::Twine& description,
   static_cast<CvSourceImpl&>(*data->source).SetDescription(description);
 }
 
-CS_Property CreateSourceProperty(CS_Source source, const wpi::Twine& name,
+CS_Property CreateSourceProperty(CS_Source source, std::string_view name,
                                  CS_PropertyKind kind, int minimum, int maximum,
                                  int step, int defaultValue, int value,
                                  CS_Status* status) {
@@ -126,7 +124,7 @@ CS_Property CreateSourceProperty(CS_Source source, const wpi::Twine& name,
 }
 
 CS_Property CreateSourcePropertyCallback(
-    CS_Source source, const wpi::Twine& name, CS_PropertyKind kind, int minimum,
+    CS_Source source, std::string_view name, CS_PropertyKind kind, int minimum,
     int maximum, int step, int defaultValue, int value,
     std::function<void(CS_Property property)> onChange, CS_Status* status) {
   auto data = Instance::GetInstance().GetSource(source);
@@ -141,7 +139,7 @@ CS_Property CreateSourcePropertyCallback(
 }
 
 void SetSourceEnumPropertyChoices(CS_Source source, CS_Property property,
-                                  wpi::ArrayRef<std::string> choices,
+                                  wpi::span<const std::string> choices,
                                   CS_Status* status) {
   auto data = Instance::GetInstance().GetSource(source);
   if (!data || (data->kind & SourceMask) == 0) {

cscore/src/main/native/cpp/CvSourceImpl.h

@@ -9,11 +9,10 @@
 #include <functional>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <opencv2/core/core.hpp>
-#include <wpi/ArrayRef.h>
-#include <wpi/Twine.h>
 
 #include "ConfigurableSourceImpl.h"
 #include "SourceImpl.h"
@@ -22,7 +21,7 @@ namespace cs {
 
 class CvSourceImpl : public ConfigurableSourceImpl {
  public:
-  CvSourceImpl(const wpi::Twine& name, wpi::Logger& logger, Notifier& notifier,
+  CvSourceImpl(std::string_view name, wpi::Logger& logger, Notifier& notifier,
                Telemetry& telemetry, const VideoMode& mode);
   ~CvSourceImpl() override;
 

cscore/src/main/native/cpp/Frame.cpp

@@ -16,10 +16,10 @@
 
 using namespace cs;
 
-Frame::Frame(SourceImpl& source, const wpi::Twine& error, Time time)
+Frame::Frame(SourceImpl& source, std::string_view error, Time time)
     : m_impl{source.AllocFrameImpl().release()} {
   m_impl->refcount = 1;
-  m_impl->error = error.str();
+  m_impl->error = error;
   m_impl->time = time;
 }
 
@@ -522,10 +522,8 @@ Image* Frame::GetImageImpl(int width, int height,
   }
 
   WPI_DEBUG4(Instance::GetInstance().logger,
-             "converting image from " << cur->width << "x" << cur->height
-                                      << " type " << cur->pixelFormat << " to "
-                                      << width << "x" << height << " type "
-                                      << pixelFormat);
+             "converting image from {}x{} type {} to {}x{} type {}", cur->width,
+             cur->height, cur->pixelFormat, width, height, pixelFormat);
 
   // If the source image is a JPEG, we need to decode it before we can do
   // anything else with it.  Note that if the destination format is JPEG, we

cscore/src/main/native/cpp/Frame.h

@@ -8,11 +8,11 @@
 #include <atomic>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <utility>
 #include <vector>
 
 #include <wpi/SmallVector.h>
-#include <wpi/Twine.h>
 #include <wpi/mutex.h>
 
 #include "Image.h"
@@ -44,7 +44,7 @@ class Frame {
  public:
   Frame() noexcept = default;
 
-  Frame(SourceImpl& source, const wpi::Twine& error, Time time);
+  Frame(SourceImpl& source, std::string_view error, Time time);
 
   Frame(SourceImpl& source, std::unique_ptr<Image> image, Time time);
 
@@ -72,7 +72,7 @@ class Frame {
 
   Time GetTime() const { return m_impl ? m_impl->time : 0; }
 
-  wpi::StringRef GetError() const {
+  std::string_view GetError() const {
     if (!m_impl) {
       return {};
     }

cscore/src/main/native/cpp/HttpCameraImpl.cpp

@@ -5,6 +5,7 @@
 #include "HttpCameraImpl.h"
 
 #include <wpi/MemAlloc.h>
+#include <wpi/StringExtras.h>
 #include <wpi/TCPConnector.h>
 #include <wpi/timestamp.h>
 
@@ -18,7 +19,7 @@
 
 using namespace cs;
 
-HttpCameraImpl::HttpCameraImpl(const wpi::Twine& name, CS_HttpCameraKind kind,
+HttpCameraImpl::HttpCameraImpl(std::string_view name, CS_HttpCameraKind kind,
                                wpi::Logger& logger, Notifier& notifier,
                                Telemetry& telemetry)
     : SourceImpl{name, logger, notifier, telemetry}, m_kind{kind} {}
@@ -84,7 +85,7 @@ void HttpCameraImpl::MonitorThreadMain() {
     // (this will result in an error at the read point, and ultimately
     // a reconnect attempt)
     if (m_streamConn && m_frameCount == 0) {
-      SWARNING("Monitor detected stream hung, disconnecting");
+      SWARNING("{}", "Monitor detected stream hung, disconnecting");
       m_streamConn->stream->close();
     }
 
@@ -92,7 +93,7 @@ void HttpCameraImpl::MonitorThreadMain() {
     m_frameCount = 0;
   }
 
-  SDEBUG("Monitor Thread exiting");
+  SDEBUG("{}", "Monitor Thread exiting");
 }
 
 void HttpCameraImpl::StreamThreadMain() {
@@ -132,14 +133,14 @@ void HttpCameraImpl::StreamThreadMain() {
     SetConnected(true);
 
     // stream
-    DeviceStream(conn->is, boundary);
+    DeviceStream(conn->is, boundary.str());
     {
       std::unique_lock lock(m_mutex);
       m_streamConn = nullptr;
     }
   }
 
-  SDEBUG("Camera Thread exiting");
+  SDEBUG("{}", "Camera Thread exiting");
   SetConnected(false);
 }
 
@@ -150,7 +151,7 @@ wpi::HttpConnection* HttpCameraImpl::DeviceStreamConnect(
   {
     std::scoped_lock lock(m_mutex);
     if (m_locations.empty()) {
-      SERROR("locations array is empty!?");
+      SERROR("{}", "locations array is empty!?");
       std::this_thread::sleep_for(std::chrono::seconds(1));
       return nullptr;
     }
@@ -181,19 +182,17 @@ wpi::HttpConnection* HttpCameraImpl::DeviceStreamConnect(
 
   std::string warn;
   if (!conn->Handshake(req, &warn)) {
-    SWARNING(GetName() << ": " << warn);
+    SWARNING("{}", warn);
     std::scoped_lock lock(m_mutex);
     m_streamConn = nullptr;
     return nullptr;
   }
 
   // Parse Content-Type header to get the boundary
-  wpi::StringRef mediaType, contentType;
-  std::tie(mediaType, contentType) = conn->contentType.str().split(';');
-  mediaType = mediaType.trim();
+  auto [mediaType, contentType] = wpi::split(conn->contentType.str(), ';');
+  mediaType = wpi::trim(mediaType);
   if (mediaType != "multipart/x-mixed-replace") {
-    SWARNING("\"" << req.host << "\": unrecognized Content-Type \"" << mediaType
-                  << "\"");
+    SWARNING("\"{}\": unrecognized Content-Type \"{}\"", req.host, mediaType);
     std::scoped_lock lock(m_mutex);
     m_streamConn = nullptr;
     return nullptr;
@@ -202,14 +201,13 @@ wpi::HttpConnection* HttpCameraImpl::DeviceStreamConnect(
   // media parameters
   boundary.clear();
   while (!contentType.empty()) {
-    wpi::StringRef keyvalue;
-    std::tie(keyvalue, contentType) = contentType.split(';');
-    contentType = contentType.ltrim();
-    wpi::StringRef key, value;
-    std::tie(key, value) = keyvalue.split('=');
-    if (key.trim() == "boundary") {
-      value = value.trim().trim('"');  // value may be quoted
-      if (value.startswith("--")) {
+    std::string_view keyvalue;
+    std::tie(keyvalue, contentType) = wpi::split(contentType, ';');
+    contentType = wpi::ltrim(contentType);
+    auto [key, value] = wpi::split(keyvalue, '=');
+    if (wpi::trim(key) == "boundary") {
+      value = wpi::trim(wpi::trim(value), '"');  // value may be quoted
+      if (wpi::starts_with(value, "--")) {
         value = value.substr(2);
       }
       boundary.append(value.begin(), value.end());
@@ -217,8 +215,7 @@ wpi::HttpConnection* HttpCameraImpl::DeviceStreamConnect(
   }
 
   if (boundary.empty()) {
-    SWARNING("\"" << req.host
-                  << "\": empty multi-part boundary or no Content-Type");
+    SWARNING("\"{}\": empty multi-part boundary or no Content-Type", req.host);
     std::scoped_lock lock(m_mutex);
     m_streamConn = nullptr;
     return nullptr;
@@ -228,7 +225,7 @@ wpi::HttpConnection* HttpCameraImpl::DeviceStreamConnect(
 }
 
 void HttpCameraImpl::DeviceStream(wpi::raw_istream& is,
-                                  wpi::StringRef boundary) {
+                                  std::string_view boundary) {
   // Stored here so we reuse it from frame to frame
   std::string imageBuf;
 
@@ -275,28 +272,29 @@ bool HttpCameraImpl::DeviceStreamFrame(wpi::raw_istream& is,
   wpi::SmallString<64> contentTypeBuf;
   wpi::SmallString<64> contentLengthBuf;
   if (!ParseHttpHeaders(is, &contentTypeBuf, &contentLengthBuf)) {
-    SWARNING("disconnected during headers");
+    SWARNING("{}", "disconnected during headers");
     PutError("disconnected during headers", wpi::Now());
     return false;
   }
 
   // Check the content type (if present)
   if (!contentTypeBuf.str().empty() &&
-      !contentTypeBuf.str().startswith("image/jpeg")) {
-    wpi::SmallString<64> errBuf;
-    wpi::raw_svector_ostream errMsg{errBuf};
-    errMsg << "received unknown Content-Type \"" << contentTypeBuf << "\"";
-    SWARNING(errMsg.str());
-    PutError(errMsg.str(), wpi::Now());
+      !wpi::starts_with(contentTypeBuf, "image/jpeg")) {
+    auto errMsg =
+        fmt::format("received unknown Content-Type \"{}\"", contentTypeBuf);
+    SWARNING("{}", errMsg);
+    PutError(errMsg, wpi::Now());
     return false;
   }
 
   unsigned int contentLength = 0;
-  if (contentLengthBuf.str().getAsInteger(10, contentLength)) {
+  if (auto v = wpi::parse_integer<unsigned int>(contentLengthBuf, 10)) {
+    contentLength = v.value();
+  } else {
     // Ugh, no Content-Length?  Read the blocks of the JPEG file.
     int width, height;
     if (!ReadJpeg(is, imageBuf, &width, &height)) {
-      SWARNING("did not receive a JPEG image");
+      SWARNING("{}", "did not receive a JPEG image");
       PutError("did not receive a JPEG image", wpi::Now());
       return false;
     }
@@ -315,7 +313,7 @@ bool HttpCameraImpl::DeviceStreamFrame(wpi::raw_istream& is,
   }
   int width, height;
   if (!GetJpegSize(image->str(), &width, &height)) {
-    SWARNING("did not receive a JPEG image");
+    SWARNING("{}", "did not receive a JPEG image");
     PutError("did not receive a JPEG image", wpi::Now());
     return false;
   }
@@ -345,7 +343,7 @@ void HttpCameraImpl::SettingsThreadMain() {
     DeviceSendSettings(req);
   }
 
-  SDEBUG("Settings Thread exiting");
+  SDEBUG("{}", "Settings Thread exiting");
 }
 
 void HttpCameraImpl::DeviceSendSettings(wpi::HttpRequest& req) {
@@ -369,7 +367,7 @@ void HttpCameraImpl::DeviceSendSettings(wpi::HttpRequest& req) {
   // Just need a handshake as settings are sent via GET parameters
   std::string warn;
   if (!conn->Handshake(req, &warn)) {
-    SWARNING(GetName() << ": " << warn);
+    SWARNING("{}", warn);
   }
 
   conn->stream->close();
@@ -380,7 +378,7 @@ CS_HttpCameraKind HttpCameraImpl::GetKind() const {
   return m_kind;
 }
 
-bool HttpCameraImpl::SetUrls(wpi::ArrayRef<std::string> urls,
+bool HttpCameraImpl::SetUrls(wpi::span<const std::string> urls,
                              CS_Status* status) {
   std::vector<wpi::HttpLocation> locations;
   for (const auto& url : urls) {
@@ -388,7 +386,7 @@ bool HttpCameraImpl::SetUrls(wpi::ArrayRef<std::string> urls,
     std::string errorMsg;
     locations.emplace_back(url, &error, &errorMsg);
     if (error) {
-      SERROR(GetName() << ": " << errorMsg);
+      SERROR("{}", errorMsg);
       *status = CS_BAD_URL;
       return false;
     }
@@ -410,8 +408,8 @@ std::vector<std::string> HttpCameraImpl::GetUrls() const {
   return urls;
 }
 
-void HttpCameraImpl::CreateProperty(const wpi::Twine& name,
-                                    const wpi::Twine& httpParam,
+void HttpCameraImpl::CreateProperty(std::string_view name,
+                                    std::string_view httpParam,
                                     bool viaSettings, CS_PropertyKind kind,
                                     int minimum, int maximum, int step,
                                     int defaultValue, int value) const {
@@ -421,13 +419,12 @@ void HttpCameraImpl::CreateProperty(const wpi::Twine& name,
       value));
 
   m_notifier.NotifySourceProperty(*this, CS_SOURCE_PROPERTY_CREATED, name,
-                                  m_propertyData.size() + 1, kind, value,
-                                  wpi::Twine{});
+                                  m_propertyData.size() + 1, kind, value, {});
 }
 
 template <typename T>
 void HttpCameraImpl::CreateEnumProperty(
-    const wpi::Twine& name, const wpi::Twine& httpParam, bool viaSettings,
+    std::string_view name, std::string_view httpParam, bool viaSettings,
     int defaultValue, int value, std::initializer_list<T> choices) const {
   std::scoped_lock lock(m_mutex);
   m_propertyData.emplace_back(std::make_unique<PropertyData>(
@@ -442,14 +439,14 @@ void HttpCameraImpl::CreateEnumProperty(
 
   m_notifier.NotifySourceProperty(*this, CS_SOURCE_PROPERTY_CREATED, name,
                                   m_propertyData.size() + 1, CS_PROP_ENUM,
-                                  value, wpi::Twine{});
+                                  value, {});
   m_notifier.NotifySourceProperty(*this, CS_SOURCE_PROPERTY_CHOICES_UPDATED,
                                   name, m_propertyData.size() + 1, CS_PROP_ENUM,
-                                  value, wpi::Twine{});
+                                  value, {});
 }
 
 std::unique_ptr<PropertyImpl> HttpCameraImpl::CreateEmptyProperty(
-    const wpi::Twine& name) const {
+    std::string_view name) const {
   return std::make_unique<PropertyData>(name);
 }
 
@@ -474,7 +471,7 @@ void HttpCameraImpl::SetProperty(int property, int value, CS_Status* status) {
   // TODO
 }
 
-void HttpCameraImpl::SetStringProperty(int property, const wpi::Twine& value,
+void HttpCameraImpl::SetStringProperty(int property, std::string_view value,
                                        CS_Status* status) {
   // TODO
 }
@@ -560,7 +557,7 @@ bool AxisCameraImpl::CacheProperties(CS_Status* status) const {
 
 namespace cs {
 
-CS_Source CreateHttpCamera(const wpi::Twine& name, const wpi::Twine& url,
+CS_Source CreateHttpCamera(std::string_view name, std::string_view url,
                            CS_HttpCameraKind kind, CS_Status* status) {
   auto& inst = Instance::GetInstance();
   std::shared_ptr<HttpCameraImpl> source;
@@ -574,14 +571,15 @@ CS_Source CreateHttpCamera(const wpi::Twine& name, const wpi::Twine& url,
                                                 inst.notifier, inst.telemetry);
       break;
   }
-  if (!source->SetUrls(url.str(), status)) {
+  std::string urlStr{url};
+  if (!source->SetUrls(wpi::span{&urlStr, 1}, status)) {
     return 0;
   }
   return inst.CreateSource(CS_SOURCE_HTTP, source);
 }
 
-CS_Source CreateHttpCamera(const wpi::Twine& name,
-                           wpi::ArrayRef<std::string> urls,
+CS_Source CreateHttpCamera(std::string_view name,
+                           wpi::span<const std::string> urls,
                            CS_HttpCameraKind kind, CS_Status* status) {
   auto& inst = Instance::GetInstance();
   if (urls.empty()) {
@@ -605,7 +603,7 @@ CS_HttpCameraKind GetHttpCameraKind(CS_Source source, CS_Status* status) {
   return static_cast<HttpCameraImpl&>(*data->source).GetKind();
 }
 
-void SetHttpCameraUrls(CS_Source source, wpi::ArrayRef<std::string> urls,
+void SetHttpCameraUrls(CS_Source source, wpi::span<const std::string> urls,
                        CS_Status* status) {
   if (urls.empty()) {
     *status = CS_EMPTY_VALUE;

cscore/src/main/native/cpp/HttpCameraImpl.h

@@ -10,15 +10,16 @@
 #include <initializer_list>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <thread>
 #include <vector>
 
 #include <wpi/HttpUtil.h>
 #include <wpi/SmallString.h>
 #include <wpi/StringMap.h>
-#include <wpi/Twine.h>
 #include <wpi/condition_variable.h>
 #include <wpi/raw_istream.h>
+#include <wpi/span.h>
 
 #include "SourceImpl.h"
 #include "cscore_cpp.h"
@@ -27,7 +28,7 @@ namespace cs {
 
 class HttpCameraImpl : public SourceImpl {
  public:
-  HttpCameraImpl(const wpi::Twine& name, CS_HttpCameraKind kind,
+  HttpCameraImpl(std::string_view name, CS_HttpCameraKind kind,
                  wpi::Logger& logger, Notifier& notifier, Telemetry& telemetry);
   ~HttpCameraImpl() override;
 
@@ -35,7 +36,7 @@ class HttpCameraImpl : public SourceImpl {
 
   // Property functions
   void SetProperty(int property, int value, CS_Status* status) override;
-  void SetStringProperty(int property, const wpi::Twine& value,
+  void SetStringProperty(int property, std::string_view value,
                          CS_Status* status) override;
 
   // Standard common camera properties
@@ -54,20 +55,20 @@ class HttpCameraImpl : public SourceImpl {
   void NumSinksEnabledChanged() override;
 
   CS_HttpCameraKind GetKind() const;
-  bool SetUrls(wpi::ArrayRef<std::string> urls, CS_Status* status);
+  bool SetUrls(wpi::span<const std::string> urls, CS_Status* status);
   std::vector<std::string> GetUrls() const;
 
   // Property data
   class PropertyData : public PropertyImpl {
    public:
     PropertyData() = default;
-    explicit PropertyData(const wpi::Twine& name_) : PropertyImpl{name_} {}
-    PropertyData(const wpi::Twine& name_, const wpi::Twine& httpParam_,
+    explicit PropertyData(std::string_view name_) : PropertyImpl{name_} {}
+    PropertyData(std::string_view name_, std::string_view httpParam_,
                  bool viaSettings_, CS_PropertyKind kind_, int minimum_,
                  int maximum_, int step_, int defaultValue_, int value_)
         : PropertyImpl(name_, kind_, step_, defaultValue_, value_),
           viaSettings(viaSettings_),
-          httpParam(httpParam_.str()) {
+          httpParam(httpParam_) {
       hasMinimum = true;
       minimum = minimum_;
       hasMaximum = true;
@@ -81,16 +82,16 @@ class HttpCameraImpl : public SourceImpl {
 
  protected:
   std::unique_ptr<PropertyImpl> CreateEmptyProperty(
-      const wpi::Twine& name) const override;
+      std::string_view name) const override;
 
   bool CacheProperties(CS_Status* status) const override;
 
-  void CreateProperty(const wpi::Twine& name, const wpi::Twine& httpParam,
+  void CreateProperty(std::string_view name, std::string_view httpParam,
                       bool viaSettings, CS_PropertyKind kind, int minimum,
                       int maximum, int step, int defaultValue, int value) const;
 
   template <typename T>
-  void CreateEnumProperty(const wpi::Twine& name, const wpi::Twine& httpParam,
+  void CreateEnumProperty(std::string_view name, std::string_view httpParam,
                           bool viaSettings, int defaultValue, int value,
                           std::initializer_list<T> choices) const;
 
@@ -101,7 +102,7 @@ class HttpCameraImpl : public SourceImpl {
   // Functions used by StreamThreadMain()
   wpi::HttpConnection* DeviceStreamConnect(
       wpi::SmallVectorImpl<char>& boundary);
-  void DeviceStream(wpi::raw_istream& is, wpi::StringRef boundary);
+  void DeviceStream(wpi::raw_istream& is, std::string_view boundary);
   bool DeviceStreamFrame(wpi::raw_istream& is, std::string& imageBuf);
 
   // The camera settings thread
@@ -146,12 +147,12 @@ class HttpCameraImpl : public SourceImpl {
 
 class AxisCameraImpl : public HttpCameraImpl {
  public:
-  AxisCameraImpl(const wpi::Twine& name, wpi::Logger& logger,
-                 Notifier& notifier, Telemetry& telemetry)
+  AxisCameraImpl(std::string_view name, wpi::Logger& logger, Notifier& notifier,
+                 Telemetry& telemetry)
       : HttpCameraImpl{name, CS_HTTP_AXIS, logger, notifier, telemetry} {}
 #if 0
   void SetProperty(int property, int value, CS_Status* status) override;
-  void SetStringProperty(int property, const wpi::Twine& value,
+  void SetStringProperty(int property, std::string_view value,
                          CS_Status* status) override;
 #endif
  protected:

cscore/src/main/native/cpp/Image.h

@@ -5,10 +5,10 @@
 #ifndef CSCORE_IMAGE_H_
 #define CSCORE_IMAGE_H_
 
+#include <string_view>
 #include <vector>
 
 #include <opencv2/core/core.hpp>
-#include <wpi/StringRef.h>
 
 #include "cscore_cpp.h"
 #include "default_init_allocator.h"
@@ -34,8 +34,8 @@ class Image {
   Image& operator=(const Image&) = delete;
 
   // Getters
-  operator wpi::StringRef() const { return str(); }  // NOLINT
-  wpi::StringRef str() const { return wpi::StringRef(data(), size()); }
+  operator std::string_view() const { return str(); }  // NOLINT
+  std::string_view str() const { return {data(), size()}; }
   size_t capacity() const { return m_data.capacity(); }
   const char* data() const {
     return reinterpret_cast<const char*>(m_data.data());

cscore/src/main/native/cpp/Instance.cpp

@@ -4,36 +4,32 @@
 
 #include "Instance.h"
 
-#include <wpi/Path.h>
-#include <wpi/SmallString.h>
-#include <wpi/StringRef.h>
-#include <wpi/raw_ostream.h>
+#include <string_view>
+
+#include <fmt/format.h>
+#include <wpi/fs.h>
 
 using namespace cs;
 
 static void def_log_func(unsigned int level, const char* file,
                          unsigned int line, const char* msg) {
-  wpi::SmallString<128> buf;
-  wpi::raw_svector_ostream oss(buf);
   if (level == 20) {
-    oss << "CS: " << msg << '\n';
-    wpi::errs() << oss.str();
+    fmt::print(stderr, "CS: {}\n", msg);
     return;
   }
 
-  wpi::StringRef levelmsg;
+  std::string_view levelmsg;
   if (level >= 50) {
-    levelmsg = "CRITICAL: ";
+    levelmsg = "CRITICAL";
   } else if (level >= 40) {
-    levelmsg = "ERROR: ";
+    levelmsg = "ERROR";
   } else if (level >= 30) {
-    levelmsg = "WARNING: ";
+    levelmsg = "WARNING";
   } else {
     return;
   }
-  oss << "CS: " << levelmsg << msg << " (" << wpi::sys::path::filename(file)
-      << ':' << line << ")\n";
-  wpi::errs() << oss.str();
+  fmt::print(stderr, "CS: {}: {} ({}:{})\n", levelmsg, msg,
+             fs::path{file}.filename().string(), line);
 }
 
 Instance::Instance()

cscore/src/main/native/cpp/Instance.h

@@ -86,18 +86,17 @@ class Instance {
   void DestroySource(CS_Source handle);
   void DestroySink(CS_Sink handle);
 
-  wpi::ArrayRef<CS_Source> EnumerateSourceHandles(
+  wpi::span<CS_Source> EnumerateSourceHandles(
       wpi::SmallVectorImpl<CS_Source>& vec) {
     return m_sources.GetAll(vec);
   }
 
-  wpi::ArrayRef<CS_Sink> EnumerateSinkHandles(
-      wpi::SmallVectorImpl<CS_Sink>& vec) {
+  wpi::span<CS_Sink> EnumerateSinkHandles(wpi::SmallVectorImpl<CS_Sink>& vec) {
     return m_sinks.GetAll(vec);
   }
 
-  wpi::ArrayRef<CS_Sink> EnumerateSourceSinks(
-      CS_Source source, wpi::SmallVectorImpl<CS_Sink>& vec) {
+  wpi::span<CS_Sink> EnumerateSourceSinks(CS_Source source,
+                                          wpi::SmallVectorImpl<CS_Sink>& vec) {
     vec.clear();
     m_sinks.ForEach([&](CS_Sink sinkHandle, const SinkData& data) {
       if (source == data.sourceHandle.load()) {

cscore/src/main/native/cpp/JpegUtil.cpp

@@ -46,20 +46,20 @@ static const unsigned char dhtData[] = {
     0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
     0xe8, 0xe9, 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa};
 
-bool IsJpeg(wpi::StringRef data) {
+bool IsJpeg(std::string_view data) {
   if (data.size() < 11) {
     return false;
   }
 
   // Check for valid SOI
-  auto bytes = data.bytes_begin();
+  auto bytes = reinterpret_cast<const unsigned char*>(data.data());
   if (bytes[0] != 0xff || bytes[1] != 0xd8) {
     return false;
   }
   return true;
 }
 
-bool GetJpegSize(wpi::StringRef data, int* width, int* height) {
+bool GetJpegSize(std::string_view data, int* width, int* height) {
   if (!IsJpeg(data)) {
     return false;
   }
@@ -69,7 +69,7 @@ bool GetJpegSize(wpi::StringRef data, int* width, int* height) {
     if (data.size() < 4) {
       return false;  // EOF
     }
-    auto bytes = data.bytes_begin();
+    auto bytes = reinterpret_cast<const unsigned char*>(data.data());
     if (bytes[0] != 0xff) {
       return false;  // not a tag
     }
@@ -94,7 +94,7 @@ bool GetJpegSize(wpi::StringRef data, int* width, int* height) {
 }
 
 bool JpegNeedsDHT(const char* data, size_t* size, size_t* locSOF) {
-  wpi::StringRef sdata(data, *size);
+  std::string_view sdata(data, *size);
   if (!IsJpeg(sdata)) {
     return false;
   }
@@ -107,7 +107,7 @@ bool JpegNeedsDHT(const char* data, size_t* size, size_t* locSOF) {
     if (sdata.size() < 4) {
       return false;  // EOF
     }
-    auto bytes = sdata.bytes_begin();
+    auto bytes = reinterpret_cast<const unsigned char*>(sdata.data());
     if (bytes[0] != 0xff) {
       return false;  // not a tag
     }
@@ -132,9 +132,8 @@ bool JpegNeedsDHT(const char* data, size_t* size, size_t* locSOF) {
   return false;
 }
 
-wpi::StringRef JpegGetDHT() {
-  return wpi::StringRef(reinterpret_cast<const char*>(dhtData),
-                        sizeof(dhtData));
+std::string_view JpegGetDHT() {
+  return {reinterpret_cast<const char*>(dhtData), sizeof(dhtData)};
 }
 
 static inline void ReadInto(wpi::raw_istream& is, std::string& buf,

cscore/src/main/native/cpp/JpegUtil.h

@@ -6,8 +6,7 @@
 #define CSCORE_JPEGUTIL_H_
 
 #include <string>
-
-#include <wpi/StringRef.h>
+#include <string_view>
 
 namespace wpi {
 class raw_istream;
@@ -15,13 +14,13 @@ class raw_istream;
 
 namespace cs {
 
-bool IsJpeg(wpi::StringRef data);
+bool IsJpeg(std::string_view data);
 
-bool GetJpegSize(wpi::StringRef data, int* width, int* height);
+bool GetJpegSize(std::string_view data, int* width, int* height);
 
 bool JpegNeedsDHT(const char* data, size_t* size, size_t* locSOF);
 
-wpi::StringRef JpegGetDHT();
+std::string_view JpegGetDHT();
 
 bool ReadJpeg(wpi::raw_istream& is, std::string& buf, int* width, int* height);
 

cscore/src/main/native/cpp/Log.cpp

@@ -0,0 +1,15 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "Log.h"
+
+void cs::NamedLogV(wpi::Logger& logger, unsigned int level, const char* file,
+                   unsigned int line, std::string_view name,
+                   fmt::string_view format, fmt::format_args args) {
+  fmt::memory_buffer out;
+  fmt::format_to(fmt::appender{out}, "{}: ", name);
+  fmt::vformat_to(fmt::appender{out}, format, args);
+  out.push_back('\0');
+  logger.DoLog(level, file, line, out.data());
+}

cscore/src/main/native/cpp/Log.h

@@ -5,29 +5,71 @@
 #ifndef CSCORE_LOG_H_
 #define CSCORE_LOG_H_
 
+#include <string_view>
+
 #include <wpi/Logger.h>
 
-#define LOG(level, x) WPI_LOG(m_logger, level, x)
+namespace cs {
+
+void NamedLogV(wpi::Logger& logger, unsigned int level, const char* file,
+               unsigned int line, std::string_view name,
+               fmt::string_view format, fmt::format_args args);
+
+template <typename S, typename... Args>
+inline void NamedLog(wpi::Logger& logger, unsigned int level, const char* file,
+                     unsigned int line, std::string_view name, const S& format,
+                     Args&&... args) {
+  if (logger.HasLogger() && level >= logger.min_level()) {
+    NamedLogV(logger, level, file, line, name, format,
+              fmt::make_args_checked<Args...>(format, args...));
+  }
+}
+
+}  // namespace cs
+
+#define LOG(level, format, ...) WPI_LOG(m_logger, level, format, __VA_ARGS__)
 
 #undef ERROR
-#define ERROR(x) WPI_ERROR(m_logger, x)
-#define WARNING(x) WPI_WARNING(m_logger, x)
-#define INFO(x) WPI_INFO(m_logger, x)
+#define ERROR(format, ...) WPI_ERROR(m_logger, format, __VA_ARGS__)
+#define WARNING(format, ...) WPI_WARNING(m_logger, format, __VA_ARGS__)
+#define INFO(format, ...) WPI_INFO(m_logger, format, __VA_ARGS__)
 
-#define DEBUG0(x) WPI_DEBUG(m_logger, x)
-#define DEBUG1(x) WPI_DEBUG1(m_logger, x)
-#define DEBUG2(x) WPI_DEBUG2(m_logger, x)
-#define DEBUG3(x) WPI_DEBUG3(m_logger, x)
-#define DEBUG4(x) WPI_DEBUG4(m_logger, x)
+#define DEBUG0(format, ...) WPI_DEBUG(m_logger, format, __VA_ARGS__)
+#define DEBUG1(format, ...) WPI_DEBUG1(m_logger, format, __VA_ARGS__)
+#define DEBUG2(format, ...) WPI_DEBUG2(m_logger, format, __VA_ARGS__)
+#define DEBUG3(format, ...) WPI_DEBUG3(m_logger, format, __VA_ARGS__)
+#define DEBUG4(format, ...) WPI_DEBUG4(m_logger, format, __VA_ARGS__)
 
-#define SERROR(x) ERROR(GetName() << ": " << x)
-#define SWARNING(x) WARNING(GetName() << ": " << x)
-#define SINFO(x) INFO(GetName() << ": " << x)
+#define SLOG(level, format, ...)                                               \
+  NamedLog(m_logger, level, __FILE__, __LINE__, GetName(), FMT_STRING(format), \
+           __VA_ARGS__)
 
-#define SDEBUG(x) DEBUG0(GetName() << ": " << x)
-#define SDEBUG1(x) DEBUG1(GetName() << ": " << x)
-#define SDEBUG2(x) DEBUG2(GetName() << ": " << x)
-#define SDEBUG3(x) DEBUG3(GetName() << ": " << x)
-#define SDEBUG4(x) DEBUG4(GetName() << ": " << x)
+#define SERROR(format, ...) SLOG(::wpi::WPI_LOG_ERROR, format, __VA_ARGS__)
+#define SWARNING(format, ...) SLOG(::wpi::WPI_LOG_WARNING, format, __VA_ARGS__)
+#define SINFO(format, ...) SLOG(::wpi::WPI_LOG_INFO, format, __VA_ARGS__)
+
+#ifdef NDEBUG
+#define SDEBUG(format, ...) \
+  do {                      \
+  } while (0)
+#define SDEBUG1(format, ...) \
+  do {                       \
+  } while (0)
+#define SDEBUG2(format, ...) \
+  do {                       \
+  } while (0)
+#define SDEBUG3(format, ...) \
+  do {                       \
+  } while (0)
+#define SDEBUG4(format, ...) \
+  do {                       \
+  } while (0)
+#else
+#define SDEBUG(format, ...) SLOG(::wpi::WPI_LOG_DEBUG, format, __VA_ARGS__)
+#define SDEBUG1(format, ...) SLOG(::wpi::WPI_LOG_DEBUG1, format, __VA_ARGS__)
+#define SDEBUG2(format, ...) SLOG(::wpi::WPI_LOG_DEBUG2, format, __VA_ARGS__)
+#define SDEBUG3(format, ...) SLOG(::wpi::WPI_LOG_DEBUG3, format, __VA_ARGS__)
+#define SDEBUG4(format, ...) SLOG(::wpi::WPI_LOG_DEBUG4, format, __VA_ARGS__)
+#endif
 
 #endif  // CSCORE_LOG_H_

cscore/src/main/native/cpp/MjpegServerImpl.cpp

@@ -6,9 +6,12 @@
 
 #include <chrono>
 
+#include <fmt/format.h>
 #include <wpi/HttpUtil.h>
 #include <wpi/SmallString.h>
+#include <wpi/StringExtras.h>
 #include <wpi/TCPAcceptor.h>
+#include <wpi/fmt/raw_ostream.h>
 #include <wpi/raw_socket_istream.h>
 #include <wpi/raw_socket_ostream.h>
 
@@ -72,13 +75,13 @@ static const char* endRootPage = "</div></body></html>";
 
 class MjpegServerImpl::ConnThread : public wpi::SafeThread {
  public:
-  explicit ConnThread(const wpi::Twine& name, wpi::Logger& logger)
-      : m_name(name.str()), m_logger(logger) {}
+  explicit ConnThread(std::string_view name, wpi::Logger& logger)
+      : m_name(name), m_logger(logger) {}
 
   void Main() override;
 
   bool ProcessCommand(wpi::raw_ostream& os, SourceImpl& source,
-                      wpi::StringRef parameters, bool respond);
+                      std::string_view parameters, bool respond);
   void SendJSON(wpi::raw_ostream& os, SourceImpl& source, bool header);
   void SendHTMLHeadTitle(wpi::raw_ostream& os) const;
   void SendHTML(wpi::raw_ostream& os, SourceImpl& source, bool header);
@@ -99,7 +102,7 @@ class MjpegServerImpl::ConnThread : public wpi::SafeThread {
   std::string m_name;
   wpi::Logger& m_logger;
 
-  wpi::StringRef GetName() { return m_name; }
+  std::string_view GetName() { return m_name; }
 
   std::shared_ptr<SourceImpl> GetSource() {
     std::scoped_lock lock(m_mutex);
@@ -130,10 +133,9 @@ class MjpegServerImpl::ConnThread : public wpi::SafeThread {
 // Using cached pictures would lead to showing old/outdated pictures.
 // Many browsers seem to ignore, or at least not always obey, those headers.
 static void SendHeader(wpi::raw_ostream& os, int code,
-                       const wpi::Twine& codeText,
-                       const wpi::Twine& contentType,
-                       const wpi::Twine& extra = wpi::Twine{}) {
-  os << "HTTP/1.0 " << code << ' ' << codeText << "\r\n";
+                       std::string_view codeText, std::string_view contentType,
+                       std::string_view extra = {}) {
+  fmt::print(os, "HTTP/1.0 {} {}\r\n", code, codeText);
   os << "Connection: close\r\n"
         "Server: CameraServer/1.0\r\n"
         "Cache-Control: no-store, no-cache, must-revalidate, pre-check=0, "
@@ -142,10 +144,8 @@ static void SendHeader(wpi::raw_ostream& os, int code,
         "Expires: Mon, 3 Jan 2000 12:34:56 GMT\r\n";
   os << "Content-Type: " << contentType << "\r\n";
   os << "Access-Control-Allow-Origin: *\r\nAccess-Control-Allow-Methods: *\r\n";
-  wpi::SmallString<128> extraBuf;
-  wpi::StringRef extraStr = extra.toStringRef(extraBuf);
-  if (!extraStr.empty()) {
-    os << extraStr << "\r\n";
+  if (!extra.empty()) {
+    os << extra << "\r\n";
   }
   os << "\r\n";  // header ends with a blank line
 }
@@ -154,8 +154,8 @@ static void SendHeader(wpi::raw_ostream& os, int code,
 // @param code HTTP error code (e.g. 404)
 // @param message Additional message text
 static void SendError(wpi::raw_ostream& os, int code,
-                      const wpi::Twine& message) {
-  wpi::StringRef codeText, extra, baseMessage;
+                      std::string_view message) {
+  std::string_view codeText, extra, baseMessage;
   switch (code) {
     case 401:
       codeText = "Unauthorized";
@@ -195,66 +195,61 @@ static void SendError(wpi::raw_ostream& os, int code,
 // Perform a command specified by HTTP GET parameters.
 bool MjpegServerImpl::ConnThread::ProcessCommand(wpi::raw_ostream& os,
                                                  SourceImpl& source,
-                                                 wpi::StringRef parameters,
+                                                 std::string_view parameters,
                                                  bool respond) {
   wpi::SmallString<256> responseBuf;
   wpi::raw_svector_ostream response{responseBuf};
   // command format: param1=value1&param2=value2...
   while (!parameters.empty()) {
     // split out next param and value
-    wpi::StringRef rawParam, rawValue;
-    std::tie(rawParam, parameters) = parameters.split('&');
+    std::string_view rawParam, rawValue;
+    std::tie(rawParam, parameters) = wpi::split(parameters, '&');
     if (rawParam.empty()) {
       continue;  // ignore "&&"
     }
-    std::tie(rawParam, rawValue) = rawParam.split('=');
+    std::tie(rawParam, rawValue) = wpi::split(rawParam, '=');
     if (rawParam.empty() || rawValue.empty()) {
       continue;  // ignore "param="
     }
-    SDEBUG4("HTTP parameter \"" << rawParam << "\" value \"" << rawValue
-                                << "\"");
+    SDEBUG4("HTTP parameter \"{}\" value \"{}\"", rawParam, rawValue);
 
     // unescape param
     bool error = false;
     wpi::SmallString<64> paramBuf;
-    wpi::StringRef param = wpi::UnescapeURI(rawParam, paramBuf, &error);
+    std::string_view param = wpi::UnescapeURI(rawParam, paramBuf, &error);
     if (error) {
-      wpi::SmallString<128> error;
-      wpi::raw_svector_ostream oss{error};
-      oss << "could not unescape parameter \"" << rawParam << "\"";
-      SendError(os, 500, error.str());
-      SDEBUG(error.str());
+      auto estr = fmt::format("could not unescape parameter \"{}\"", rawParam);
+      SendError(os, 500, estr);
+      SDEBUG("{}", estr);
       return false;
     }
 
     // unescape value
     wpi::SmallString<64> valueBuf;
-    wpi::StringRef value = wpi::UnescapeURI(rawValue, valueBuf, &error);
+    std::string_view value = wpi::UnescapeURI(rawValue, valueBuf, &error);
     if (error) {
-      wpi::SmallString<128> error;
-      wpi::raw_svector_ostream oss{error};
-      oss << "could not unescape value \"" << rawValue << "\"";
-      SendError(os, 500, error.str());
-      SDEBUG(error.str());
+      auto estr = fmt::format("could not unescape value \"{}\"", rawValue);
+      SendError(os, 500, estr);
+      SDEBUG("{}", estr);
       return false;
     }
 
     // Handle resolution, compression, and FPS.  These are handled locally
     // rather than passed to the source.
     if (param == "resolution") {
-      wpi::StringRef widthStr, heightStr;
-      std::tie(widthStr, heightStr) = value.split('x');
-      int width, height;
-      if (widthStr.getAsInteger(10, width)) {
+      auto [widthStr, heightStr] = wpi::split(value, 'x');
+      int width = wpi::parse_integer<int>(widthStr, 10).value_or(-1);
+      int height = wpi::parse_integer<int>(heightStr, 10).value_or(-1);
+      if (width < 0) {
         response << param << ": \"width is not an integer\"\r\n";
-        SWARNING("HTTP parameter \"" << param << "\" width \"" << widthStr
-                                     << "\" is not an integer");
+        SWARNING("HTTP parameter \"{}\" width \"{}\" is not an integer", param,
+                 widthStr);
         continue;
       }
-      if (heightStr.getAsInteger(10, height)) {
+      if (height < 0) {
         response << param << ": \"height is not an integer\"\r\n";
-        SWARNING("HTTP parameter \"" << param << "\" height \"" << heightStr
-                                     << "\" is not an integer");
+        SWARNING("HTTP parameter \"{}\" height \"{}\" is not an integer", param,
+                 heightStr);
         continue;
       }
       m_width = width;
@@ -264,29 +259,25 @@ bool MjpegServerImpl::ConnThread::ProcessCommand(wpi::raw_ostream& os,
     }
 
     if (param == "fps") {
-      int fps;
-      if (value.getAsInteger(10, fps)) {
-        response << param << ": \"invalid integer\"\r\n";
-        SWARNING("HTTP parameter \"" << param << "\" value \"" << value
-                                     << "\" is not an integer");
-        continue;
-      } else {
-        m_fps = fps;
+      if (auto v = wpi::parse_integer<int>(value, 10)) {
+        m_fps = v.value();
         response << param << ": \"ok\"\r\n";
+      } else {
+        response << param << ": \"invalid integer\"\r\n";
+        SWARNING("HTTP parameter \"{}\" value \"{}\" is not an integer", param,
+                 value);
       }
       continue;
     }
 
     if (param == "compression") {
-      int compression;
-      if (value.getAsInteger(10, compression)) {
-        response << param << ": \"invalid integer\"\r\n";
-        SWARNING("HTTP parameter \"" << param << "\" value \"" << value
-                                     << "\" is not an integer");
-        continue;
-      } else {
-        m_compression = compression;
+      if (auto v = wpi::parse_integer<int>(value, 10)) {
+        m_compression = v.value();
         response << param << ": \"ok\"\r\n";
+      } else {
+        response << param << ": \"invalid integer\"\r\n";
+        SWARNING("HTTP parameter \"{}\" value \"{}\" is not an integer", param,
+                 value);
       }
       continue;
     }
@@ -300,7 +291,7 @@ bool MjpegServerImpl::ConnThread::ProcessCommand(wpi::raw_ostream& os,
     auto prop = source.GetPropertyIndex(param);
     if (!prop) {
       response << param << ": \"ignored\"\r\n";
-      SWARNING("ignoring HTTP parameter \"" << param << "\"");
+      SWARNING("ignoring HTTP parameter \"{}\"", param);
       continue;
     }
 
@@ -310,21 +301,20 @@ bool MjpegServerImpl::ConnThread::ProcessCommand(wpi::raw_ostream& os,
       case CS_PROP_BOOLEAN:
       case CS_PROP_INTEGER:
       case CS_PROP_ENUM: {
-        int val = 0;
-        if (value.getAsInteger(10, val)) {
-          response << param << ": \"invalid integer\"\r\n";
-          SWARNING("HTTP parameter \"" << param << "\" value \"" << value
-                                       << "\" is not an integer");
+        if (auto v = wpi::parse_integer<int>(value, 10)) {
+          fmt::print(response, "{}: {}\r\n", param, v.value());
+          SDEBUG4("HTTP parameter \"{}\" value {}", param, value);
+          source.SetProperty(prop, v.value(), &status);
         } else {
-          response << param << ": " << val << "\r\n";
-          SDEBUG4("HTTP parameter \"" << param << "\" value " << value);
-          source.SetProperty(prop, val, &status);
+          response << param << ": \"invalid integer\"\r\n";
+          SWARNING("HTTP parameter \"{}\" value \"{}\" is not an integer",
+                   param, value);
         }
         break;
       }
       case CS_PROP_STRING: {
         response << param << ": \"ok\"\r\n";
-        SDEBUG4("HTTP parameter \"" << param << "\" value \"" << value << "\"");
+        SDEBUG4("HTTP parameter \"{}\" value \"{}\"", param, value);
         source.SetStringProperty(prop, value, &status);
         break;
       }
@@ -362,17 +352,17 @@ void MjpegServerImpl::ConnThread::SendHTML(wpi::raw_ostream& os,
   for (auto prop : source.EnumerateProperties(properties_vec, &status)) {
     wpi::SmallString<128> name_buf;
     auto name = source.GetPropertyName(prop, name_buf, &status);
-    if (name.startswith("raw_")) {
+    if (wpi::starts_with(name, "raw_")) {
       continue;
     }
     auto kind = source.GetPropertyKind(prop);
-    os << "<p />"
-       << "<label for=\"" << name << "\">" << name << "</label>\n";
+    fmt::print(os, "<p /><label for=\"{0}\">{0}</label>\n", name);
     switch (kind) {
       case CS_PROP_BOOLEAN:
-        os << "<input id=\"" << name
-           << "\" type=\"checkbox\" onclick=\"update('" << name
-           << "', this.checked ? 1 : 0)\" ";
+        fmt::print(os,
+                   "<input id=\"{0}\" type=\"checkbox\" "
+                   "onclick=\"update('{0}', this.checked ? 1 : 0)\" ",
+                   name);
         if (source.GetProperty(prop, &status) != 0) {
           os << "checked />\n";
         } else {
@@ -384,12 +374,13 @@ void MjpegServerImpl::ConnThread::SendHTML(wpi::raw_ostream& os,
         auto min = source.GetPropertyMin(prop, &status);
         auto max = source.GetPropertyMax(prop, &status);
         auto step = source.GetPropertyStep(prop, &status);
-        os << "<input type=\"range\" min=\"" << min << "\" max=\"" << max
-           << "\" value=\"" << valI << "\" id=\"" << name << "\" step=\""
-           << step << "\" oninput=\"updateInt('#" << name << "op', '" << name
-           << "', value)\" />\n";
-        os << "<output for=\"" << name << "\" id=\"" << name << "op\">" << valI
-           << "</output>\n";
+        fmt::print(os,
+                   "<input type=\"range\" min=\"{1}\" max=\"{2}\" "
+                   "value=\"{3}\" id=\"{0}\" step=\"{4}\" "
+                   "oninput=\"updateInt('#{0}op', '{0}', value)\" />\n",
+                   name, min, max, valI, step);
+        fmt::print(os, "<output for=\"{0}\" id=\"{0}op\">{1}</output>\n", name,
+                   valI);
         break;
       }
       case CS_PROP_ENUM: {
@@ -404,26 +395,30 @@ void MjpegServerImpl::ConnThread::SendHTML(wpi::raw_ostream& os,
           // replace any non-printable characters in name with spaces
           wpi::SmallString<128> ch_name;
           for (char ch : *choice) {
-            ch_name.push_back(std::isprint(ch) ? ch : ' ');
+            ch_name.push_back(wpi::isPrint(ch) ? ch : ' ');
           }
-          os << "<input id=\"" << name << j << "\" type=\"radio\" name=\""
-             << name << "\" value=\"" << ch_name << "\" onclick=\"update('"
-             << name << "', " << j << ")\"";
+          fmt::print(os,
+                     "<input id=\"{0}{1}\" type=\"radio\" name=\"{0}\" "
+                     "value=\"{2}\" onclick=\"update('{0}', {1})\"",
+                     name, j, ch_name);
           if (j == valE) {
             os << " checked";
           }
-          os << " /><label for=\"" << name << j << "\">" << ch_name
-             << "</label>\n";
+          fmt::print(os, " /><label for=\"{}{}\">{}</label>\n", name, j,
+                     ch_name);
         }
         break;
       }
       case CS_PROP_STRING: {
         wpi::SmallString<128> strval_buf;
-        os << "<input type=\"text\" id=\"" << name << "box\" name=\"" << name
-           << "\" value=\""
-           << source.GetStringProperty(prop, strval_buf, &status) << "\" />\n";
-        os << "<input type=\"button\" value =\"Submit\" onclick=\"update('"
-           << name << "', " << name << "box.value)\" />\n";
+        fmt::print(os,
+                   "<input type=\"text\" id=\"{0}box\" name=\"{0}\" "
+                   "value=\"{1}\" />\n",
+                   name, source.GetStringProperty(prop, strval_buf, &status));
+        fmt::print(os,
+                   "<input type=\"button\" value =\"Submit\" "
+                   "onclick=\"update('{0}', {0}box.value)\" />\n",
+                   name);
         break;
       }
       default:
@@ -469,10 +464,8 @@ void MjpegServerImpl::ConnThread::SendHTML(wpi::raw_ostream& os,
         os << "unknown";
         break;
     }
-    os << "</td><td>" << mode.width;
-    os << "</td><td>" << mode.height;
-    os << "</td><td>" << mode.fps;
-    os << "</td></tr>";
+    fmt::print(os, "</td><td>{}</td><td>{}</td><td>{}</td></tr>", mode.width,
+               mode.height, mode.fps);
   }
   os << "</table>\n";
   os << endRootPage << "\r\n";
@@ -500,20 +493,21 @@ void MjpegServerImpl::ConnThread::SendJSON(wpi::raw_ostream& os,
     wpi::SmallString<128> name_buf;
     auto name = source.GetPropertyName(prop, name_buf, &status);
     auto kind = source.GetPropertyKind(prop);
-    os << "\n\"name\": \"" << name << '"';
-    os << ",\n\"id\": \"" << prop << '"';
-    os << ",\n\"type\": \"" << kind << '"';
-    os << ",\n\"min\": \"" << source.GetPropertyMin(prop, &status) << '"';
-    os << ",\n\"max\": \"" << source.GetPropertyMax(prop, &status) << '"';
-    os << ",\n\"step\": \"" << source.GetPropertyStep(prop, &status) << '"';
-    os << ",\n\"default\": \"" << source.GetPropertyDefault(prop, &status)
-       << '"';
+    fmt::print(os, "\n\"name\": \"{}\"", name);
+    fmt::print(os, ",\n\"id\": \"{}\"", prop);
+    fmt::print(os, ",\n\"type\": \"{}\"", kind);
+    fmt::print(os, ",\n\"min\": \"{}\"", source.GetPropertyMin(prop, &status));
+    fmt::print(os, ",\n\"max\": \"{}\"", source.GetPropertyMax(prop, &status));
+    fmt::print(os, ",\n\"step\": \"{}\"",
+               source.GetPropertyStep(prop, &status));
+    fmt::print(os, ",\n\"default\": \"{}\"",
+               source.GetPropertyDefault(prop, &status));
     os << ",\n\"value\": \"";
     switch (kind) {
       case CS_PROP_BOOLEAN:
       case CS_PROP_INTEGER:
       case CS_PROP_ENUM:
-        os << source.GetProperty(prop, &status);
+        fmt::print(os, "{}", source.GetProperty(prop, &status));
         break;
       case CS_PROP_STRING: {
         wpi::SmallString<128> strval_buf;
@@ -543,7 +537,7 @@ void MjpegServerImpl::ConnThread::SendJSON(wpi::raw_ostream& os,
         for (char ch : *choice) {
           ch_name.push_back(std::isprint(ch) ? ch : ' ');
         }
-        os << '"' << j << "\": \"" << ch_name << '"';
+        fmt::print(os, "\"{}\": \"{}\"", j, ch_name);
       }
       os << "}\n";
     }
@@ -579,29 +573,26 @@ void MjpegServerImpl::ConnThread::SendJSON(wpi::raw_ostream& os,
         os << "unknown";
         break;
     }
-    os << "\",\n\"width\": \"" << mode.width << '"';
-    os << ",\n\"height\": \"" << mode.height << '"';
-    os << ",\n\"fps\": \"" << mode.fps << '"';
+    fmt::print(os, "\",\n\"width\": \"{}\"", mode.width);
+    fmt::print(os, ",\n\"height\": \"{}\"", mode.height);
+    fmt::print(os, ",\n\"fps\": \"{}\"", mode.fps);
     os << '}';
   }
   os << "\n]\n}\n";
   os.flush();
 }
 
-MjpegServerImpl::MjpegServerImpl(const wpi::Twine& name, wpi::Logger& logger,
+MjpegServerImpl::MjpegServerImpl(std::string_view name, wpi::Logger& logger,
                                  Notifier& notifier, Telemetry& telemetry,
-                                 const wpi::Twine& listenAddress, int port,
+                                 std::string_view listenAddress, int port,
                                  std::unique_ptr<wpi::NetworkAcceptor> acceptor)
     : SinkImpl{name, logger, notifier, telemetry},
-      m_listenAddress(listenAddress.str()),
+      m_listenAddress(listenAddress),
       m_port(port),
       m_acceptor{std::move(acceptor)} {
   m_active = true;
 
-  wpi::SmallString<128> descBuf;
-  wpi::raw_svector_ostream desc{descBuf};
-  desc << "HTTP Server on port " << port;
-  SetDescription(desc.str());
+  SetDescription(fmt::format("HTTP Server on port {}", port));
 
   // Create properties
   m_widthProp = CreateProperty("width", [] {
@@ -659,7 +650,7 @@ void MjpegServerImpl::Stop() {
 // Send HTTP response and a stream of JPG-frames
 void MjpegServerImpl::ConnThread::SendStream(wpi::raw_socket_ostream& os) {
   if (m_noStreaming) {
-    SERROR("Too many simultaneous client streams");
+    SERROR("{}", "Too many simultaneous client streams");
     SendError(os, 503, "Too many simultaneous streams");
     return;
   }
@@ -672,7 +663,7 @@ void MjpegServerImpl::ConnThread::SendStream(wpi::raw_socket_ostream& os) {
   SendHeader(oss, 200, "OK", "multipart/x-mixed-replace;boundary=" BOUNDARY);
   os << oss.str();
 
-  SDEBUG("Headers send, sending stream now");
+  SDEBUG("{}", "Headers send, sending stream now");
 
   Frame::Time lastFrameTime = 0;
   Frame::Time timePerFrame = 0;
@@ -694,7 +685,7 @@ void MjpegServerImpl::ConnThread::SendStream(wpi::raw_socket_ostream& os) {
       std::this_thread::sleep_for(std::chrono::milliseconds(200));
       continue;
     }
-    SDEBUG4("waiting for frame");
+    SDEBUG4("{}", "waiting for frame");
     Frame frame = source->GetNextFrame(0.225);  // blocks
     if (!m_active) {
       break;
@@ -757,7 +748,7 @@ void MjpegServerImpl::ConnThread::SendStream(wpi::raw_socket_ostream& os) {
         continue;
     }
 
-    SDEBUG4("sending frame size=" << size << " addDHT=" << addDHT);
+    SDEBUG4("sending frame size={} addDHT={}", size, addDHT);
 
     // print the individual mimetype and the length
     // sending the content-length fixes random stream disruption observed
@@ -766,18 +757,18 @@ void MjpegServerImpl::ConnThread::SendStream(wpi::raw_socket_ostream& os) {
     double timestamp = lastFrameTime / 1000000.0;
     header.clear();
     oss << "\r\n--" BOUNDARY "\r\n"
-        << "Content-Type: image/jpeg\r\n"
-        << "Content-Length: " << size << "\r\n"
-        << "X-Timestamp: " << timestamp << "\r\n"
-        << "\r\n";
+        << "Content-Type: image/jpeg\r\n";
+    fmt::print(oss, "Content-Length: {}\r\n", size);
+    fmt::print(oss, "X-Timestamp: {}\r\n", timestamp);
+    oss << "\r\n";
     os << oss.str();
     if (addDHT) {
       // Insert DHT data immediately before SOF
-      os << wpi::StringRef(data, locSOF);
+      os << std::string_view(data, locSOF);
       os << JpegGetDHT();
-      os << wpi::StringRef(data + locSOF, image->size() - locSOF);
+      os << std::string_view(data + locSOF, image->size() - locSOF);
     } else {
-      os << wpi::StringRef(data, size);
+      os << std::string_view(data, size);
     }
     // os.flush();
   }
@@ -790,48 +781,50 @@ void MjpegServerImpl::ConnThread::ProcessRequest() {
 
   // Read the request string from the stream
   wpi::SmallString<128> reqBuf;
-  wpi::StringRef req = is.getline(reqBuf, 4096);
+  std::string_view req = is.getline(reqBuf, 4096);
   if (is.has_error()) {
-    SDEBUG("error getting request string");
+    SDEBUG("{}", "error getting request string");
     return;
   }
 
   enum { kCommand, kStream, kGetSettings, kGetSourceConfig, kRootPage } kind;
-  wpi::StringRef parameters;
+  std::string_view parameters;
   size_t pos;
 
-  SDEBUG("HTTP request: '" << req << "'\n");
+  SDEBUG("HTTP request: '{}'\n", req);
 
   // Determine request kind.  Most of these are for mjpgstreamer
   // compatibility, others are for Axis camera compatibility.
-  if ((pos = req.find("POST /stream")) != wpi::StringRef::npos) {
+  if ((pos = req.find("POST /stream")) != std::string_view::npos) {
     kind = kStream;
     parameters = req.substr(req.find('?', pos + 12)).substr(1);
-  } else if ((pos = req.find("GET /?action=stream")) != wpi::StringRef::npos) {
+  } else if ((pos = req.find("GET /?action=stream")) !=
+             std::string_view::npos) {
     kind = kStream;
     parameters = req.substr(req.find('&', pos + 19)).substr(1);
-  } else if ((pos = req.find("GET /stream.mjpg")) != wpi::StringRef::npos) {
+  } else if ((pos = req.find("GET /stream.mjpg")) != std::string_view::npos) {
     kind = kStream;
     parameters = req.substr(req.find('?', pos + 16)).substr(1);
-  } else if (req.find("GET /settings") != wpi::StringRef::npos &&
-             req.find(".json") != wpi::StringRef::npos) {
+  } else if (req.find("GET /settings") != std::string_view::npos &&
+             req.find(".json") != std::string_view::npos) {
     kind = kGetSettings;
-  } else if (req.find("GET /config") != wpi::StringRef::npos &&
-             req.find(".json") != wpi::StringRef::npos) {
+  } else if (req.find("GET /config") != std::string_view::npos &&
+             req.find(".json") != std::string_view::npos) {
     kind = kGetSourceConfig;
-  } else if (req.find("GET /input") != wpi::StringRef::npos &&
-             req.find(".json") != wpi::StringRef::npos) {
+  } else if (req.find("GET /input") != std::string_view::npos &&
+             req.find(".json") != std::string_view::npos) {
     kind = kGetSettings;
-  } else if (req.find("GET /output") != wpi::StringRef::npos &&
-             req.find(".json") != wpi::StringRef::npos) {
+  } else if (req.find("GET /output") != std::string_view::npos &&
+             req.find(".json") != std::string_view::npos) {
     kind = kGetSettings;
-  } else if ((pos = req.find("GET /?action=command")) != wpi::StringRef::npos) {
+  } else if ((pos = req.find("GET /?action=command")) !=
+             std::string_view::npos) {
     kind = kCommand;
     parameters = req.substr(req.find('&', pos + 20)).substr(1);
-  } else if (req.find("GET / ") != wpi::StringRef::npos || req == "GET /\n") {
+  } else if (req.find("GET / ") != std::string_view::npos || req == "GET /\n") {
     kind = kRootPage;
   } else {
-    SDEBUG("HTTP request resource not found");
+    SDEBUG("{}", "HTTP request resource not found");
     SendError(os, 404, "Resource not found");
     return;
   }
@@ -841,13 +834,13 @@ void MjpegServerImpl::ConnThread::ProcessRequest() {
       "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_"
       "-=&1234567890%./");
   parameters = parameters.substr(0, pos);
-  SDEBUG("command parameters: \"" << parameters << "\"");
+  SDEBUG("command parameters: \"{}\"", parameters);
 
   // Read the rest of the HTTP request.
   // The end of the request is marked by a single, empty line
   wpi::SmallString<128> lineBuf;
   for (;;) {
-    if (is.getline(lineBuf, 4096).startswith("\n")) {
+    if (wpi::starts_with(is.getline(lineBuf, 4096), "\n")) {
       break;
     }
     if (is.has_error()) {
@@ -859,7 +852,7 @@ void MjpegServerImpl::ConnThread::ProcessRequest() {
   switch (kind) {
     case kStream:
       if (auto source = GetSource()) {
-        SDEBUG("request for stream " << source->GetName());
+        SDEBUG("request for stream {}", source->GetName());
         if (!ProcessCommand(os, *source, parameters, false)) {
           return;
         }
@@ -873,11 +866,11 @@ void MjpegServerImpl::ConnThread::ProcessRequest() {
         SendHeader(os, 200, "OK", "text/plain");
         os << "Ignored due to no connected source."
            << "\r\n";
-        SDEBUG("Ignored due to no connected source.");
+        SDEBUG("{}", "Ignored due to no connected source.");
       }
       break;
     case kGetSettings:
-      SDEBUG("request for JSON file");
+      SDEBUG("{}", "request for JSON file");
       if (auto source = GetSource()) {
         SendJSON(os, *source, true);
       } else {
@@ -885,7 +878,7 @@ void MjpegServerImpl::ConnThread::ProcessRequest() {
       }
       break;
     case kGetSourceConfig:
-      SDEBUG("request for JSON file");
+      SDEBUG("{}", "request for JSON file");
       if (auto source = GetSource()) {
         SendHeader(os, 200, "OK", "application/json");
         CS_Status status = CS_OK;
@@ -896,7 +889,7 @@ void MjpegServerImpl::ConnThread::ProcessRequest() {
       }
       break;
     case kRootPage:
-      SDEBUG("request for root page");
+      SDEBUG("{}", "request for root page");
       SendHeader(os, 200, "OK", "text/html");
       if (auto source = GetSource()) {
         SendHTML(os, *source, false);
@@ -907,7 +900,7 @@ void MjpegServerImpl::ConnThread::ProcessRequest() {
       break;
   }
 
-  SDEBUG("leaving HTTP client thread");
+  SDEBUG("{}", "leaving HTTP client thread");
 }
 
 // worker thread for clients that connected to this server
@@ -934,7 +927,7 @@ void MjpegServerImpl::ServerThreadMain() {
     return;
   }
 
-  SDEBUG("waiting for clients to connect");
+  SDEBUG("{}", "waiting for clients to connect");
   while (m_active) {
     auto stream = m_acceptor->accept();
     if (!stream) {
@@ -945,7 +938,7 @@ void MjpegServerImpl::ServerThreadMain() {
       return;
     }
 
-    SDEBUG("client connection from " << stream->getPeerIP());
+    SDEBUG("client connection from {}", stream->getPeerIP());
 
     auto source = GetSource();
 
@@ -984,7 +977,7 @@ void MjpegServerImpl::ServerThreadMain() {
     thr->m_cond.notify_one();
   }
 
-  SDEBUG("leaving server thread");
+  SDEBUG("{}", "leaving server thread");
 }
 
 void MjpegServerImpl::SetSourceImpl(std::shared_ptr<SourceImpl> source) {
@@ -1007,19 +1000,15 @@ void MjpegServerImpl::SetSourceImpl(std::shared_ptr<SourceImpl> source) {
 
 namespace cs {
 
-CS_Sink CreateMjpegServer(const wpi::Twine& name,
-                          const wpi::Twine& listenAddress, int port,
-                          CS_Status* status) {
+CS_Sink CreateMjpegServer(std::string_view name, std::string_view listenAddress,
+                          int port, CS_Status* status) {
   auto& inst = Instance::GetInstance();
-  wpi::SmallString<128> listenAddressBuf;
   return inst.CreateSink(
       CS_SINK_MJPEG,
       std::make_shared<MjpegServerImpl>(
           name, inst.logger, inst.notifier, inst.telemetry, listenAddress, port,
-          std::unique_ptr<wpi::NetworkAcceptor>(new wpi::TCPAcceptor(
-              port,
-              listenAddress.toNullTerminatedStringRef(listenAddressBuf).data(),
-              inst.logger))));
+          std::unique_ptr<wpi::NetworkAcceptor>(
+              new wpi::TCPAcceptor(port, listenAddress, inst.logger))));
 }
 
 std::string GetMjpegServerListenAddress(CS_Sink sink, CS_Status* status) {

cscore/src/main/native/cpp/MjpegServerImpl.h

@@ -8,6 +8,7 @@
 #include <atomic>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <thread>
 #include <vector>
 
@@ -15,7 +16,6 @@
 #include <wpi/NetworkStream.h>
 #include <wpi/SafeThread.h>
 #include <wpi/SmallVector.h>
-#include <wpi/Twine.h>
 #include <wpi/raw_istream.h>
 #include <wpi/raw_ostream.h>
 #include <wpi/raw_socket_ostream.h>
@@ -28,9 +28,9 @@ class SourceImpl;
 
 class MjpegServerImpl : public SinkImpl {
  public:
-  MjpegServerImpl(const wpi::Twine& name, wpi::Logger& logger,
+  MjpegServerImpl(std::string_view name, wpi::Logger& logger,
                   Notifier& notifier, Telemetry& telemetry,
-                  const wpi::Twine& listenAddress, int port,
+                  std::string_view listenAddress, int port,
                   std::unique_ptr<wpi::NetworkAcceptor> acceptor);
   ~MjpegServerImpl() override;
 

cscore/src/main/native/cpp/Notifier.cpp

@@ -32,7 +32,7 @@ unsigned int Notifier::AddPolled(unsigned int pollerUid, int eventMask) {
   return DoAdd(pollerUid, eventMask);
 }
 
-void Notifier::NotifySource(const wpi::Twine& name, CS_Source source,
+void Notifier::NotifySource(std::string_view name, CS_Source source,
                             CS_EventKind kind) {
   Send(UINT_MAX, name, source, static_cast<RawEvent::Kind>(kind));
 }
@@ -49,9 +49,9 @@ void Notifier::NotifySourceVideoMode(const SourceImpl& source,
 }
 
 void Notifier::NotifySourceProperty(const SourceImpl& source, CS_EventKind kind,
-                                    const wpi::Twine& propertyName,
-                                    int property, CS_PropertyKind propertyKind,
-                                    int value, const wpi::Twine& valueStr) {
+                                    std::string_view propertyName, int property,
+                                    CS_PropertyKind propertyKind, int value,
+                                    std::string_view valueStr) {
   auto handleData = Instance::GetInstance().FindSource(source);
   Send(UINT_MAX, propertyName, handleData.first,
        static_cast<RawEvent::Kind>(kind),
@@ -59,7 +59,7 @@ void Notifier::NotifySourceProperty(const SourceImpl& source, CS_EventKind kind,
        value, valueStr);
 }
 
-void Notifier::NotifySink(const wpi::Twine& name, CS_Sink sink,
+void Notifier::NotifySink(std::string_view name, CS_Sink sink,
                           CS_EventKind kind) {
   Send(UINT_MAX, name, sink, static_cast<RawEvent::Kind>(kind));
 }
@@ -69,7 +69,7 @@ void Notifier::NotifySink(const SinkImpl& sink, CS_EventKind kind) {
   NotifySink(sink.GetName(), handleData.first, kind);
 }
 
-void Notifier::NotifySinkSourceChanged(const wpi::Twine& name, CS_Sink sink,
+void Notifier::NotifySinkSourceChanged(std::string_view name, CS_Sink sink,
                                        CS_Source source) {
   RawEvent event{name, sink, RawEvent::kSinkSourceChanged};
   event.sourceHandle = source;
@@ -77,9 +77,9 @@ void Notifier::NotifySinkSourceChanged(const wpi::Twine& name, CS_Sink sink,
 }
 
 void Notifier::NotifySinkProperty(const SinkImpl& sink, CS_EventKind kind,
-                                  const wpi::Twine& propertyName, int property,
+                                  std::string_view propertyName, int property,
                                   CS_PropertyKind propertyKind, int value,
-                                  const wpi::Twine& valueStr) {
+                                  std::string_view valueStr) {
   auto handleData = Instance::GetInstance().FindSink(sink);
   Send(UINT_MAX, propertyName, handleData.first,
        static_cast<RawEvent::Kind>(kind),

cscore/src/main/native/cpp/Notifier.h

@@ -65,22 +65,21 @@ class Notifier : public wpi::CallbackManager<Notifier, impl::NotifierThread> {
   unsigned int AddPolled(unsigned int pollerUid, int eventMask);
 
   // Notification events
-  void NotifySource(const wpi::Twine& name, CS_Source source,
-                    CS_EventKind kind);
+  void NotifySource(std::string_view name, CS_Source source, CS_EventKind kind);
   void NotifySource(const SourceImpl& source, CS_EventKind kind);
   void NotifySourceVideoMode(const SourceImpl& source, const VideoMode& mode);
   void NotifySourceProperty(const SourceImpl& source, CS_EventKind kind,
-                            const wpi::Twine& propertyName, int property,
+                            std::string_view propertyName, int property,
                             CS_PropertyKind propertyKind, int value,
-                            const wpi::Twine& valueStr);
-  void NotifySink(const wpi::Twine& name, CS_Sink sink, CS_EventKind kind);
+                            std::string_view valueStr);
+  void NotifySink(std::string_view name, CS_Sink sink, CS_EventKind kind);
   void NotifySink(const SinkImpl& sink, CS_EventKind kind);
-  void NotifySinkSourceChanged(const wpi::Twine& name, CS_Sink sink,
+  void NotifySinkSourceChanged(std::string_view name, CS_Sink sink,
                                CS_Source source);
   void NotifySinkProperty(const SinkImpl& sink, CS_EventKind kind,
-                          const wpi::Twine& propertyName, int property,
+                          std::string_view propertyName, int property,
                           CS_PropertyKind propertyKind, int value,
-                          const wpi::Twine& valueStr);
+                          std::string_view valueStr);
   void NotifyNetworkInterfacesChanged();
   void NotifyTelemetryUpdated();
   void NotifyUsbCamerasChanged();

cscore/src/main/native/cpp/PropertyContainer.cpp

@@ -11,15 +11,14 @@
 
 using namespace cs;
 
-int PropertyContainer::GetPropertyIndex(const wpi::Twine& name) const {
+int PropertyContainer::GetPropertyIndex(std::string_view name) const {
   // We can't fail, so instead we create a new index if caching fails.
   CS_Status status = 0;
   if (!m_properties_cached) {
     CacheProperties(&status);
   }
   std::scoped_lock lock(m_mutex);
-  wpi::SmallVector<char, 64> nameBuf;
-  int& ndx = m_properties[name.toStringRef(nameBuf)];
+  int& ndx = m_properties[name];
   if (ndx == 0) {
     // create a new index
     ndx = m_propertyData.size() + 1;
@@ -28,7 +27,7 @@ int PropertyContainer::GetPropertyIndex(const wpi::Twine& name) const {
   return ndx;
 }
 
-wpi::ArrayRef<int> PropertyContainer::EnumerateProperties(
+wpi::span<int> PropertyContainer::EnumerateProperties(
     wpi::SmallVectorImpl<int>& vec, CS_Status* status) const {
   if (!m_properties_cached && !CacheProperties(status)) {
     return {};
@@ -55,7 +54,7 @@ CS_PropertyKind PropertyContainer::GetPropertyKind(int property) const {
   return prop->propKind;
 }
 
-wpi::StringRef PropertyContainer::GetPropertyName(
+std::string_view PropertyContainer::GetPropertyName(
     int property, wpi::SmallVectorImpl<char>& buf, CS_Status* status) const {
   if (!m_properties_cached && !CacheProperties(status)) {
     return {};
@@ -108,7 +107,7 @@ void PropertyContainer::SetProperty(int property, int value,
     return;
   }
 
-  UpdatePropertyValue(property, false, value, wpi::Twine{});
+  UpdatePropertyValue(property, false, value, {});
 }
 
 int PropertyContainer::GetPropertyMin(int property, CS_Status* status) const {
@@ -164,7 +163,7 @@ int PropertyContainer::GetPropertyDefault(int property,
   return prop->defaultValue;
 }
 
-wpi::StringRef PropertyContainer::GetStringProperty(
+std::string_view PropertyContainer::GetStringProperty(
     int property, wpi::SmallVectorImpl<char>& buf, CS_Status* status) const {
   if (!m_properties_cached && !CacheProperties(status)) {
     return {};
@@ -181,10 +180,10 @@ wpi::StringRef PropertyContainer::GetStringProperty(
   }
   buf.clear();
   buf.append(prop->valueStr.begin(), prop->valueStr.end());
-  return wpi::StringRef(buf.data(), buf.size());
+  return {buf.data(), buf.size()};
 }
 
-void PropertyContainer::SetStringProperty(int property, const wpi::Twine& value,
+void PropertyContainer::SetStringProperty(int property, std::string_view value,
                                           CS_Status* status) {
   std::scoped_lock lock(m_mutex);
   auto prop = GetProperty(property);
@@ -225,7 +224,7 @@ std::vector<std::string> PropertyContainer::GetEnumPropertyChoices(
 }
 
 std::unique_ptr<PropertyImpl> PropertyContainer::CreateEmptyProperty(
-    const wpi::Twine& name) const {
+    std::string_view name) const {
   return std::make_unique<PropertyImpl>(name);
 }
 
@@ -237,16 +236,15 @@ bool PropertyContainer::CacheProperties(CS_Status* status) const {
 
 bool PropertyContainer::SetPropertiesJson(const wpi::json& config,
                                           wpi::Logger& logger,
-                                          wpi::StringRef logName,
+                                          std::string_view logName,
                                           CS_Status* status) {
   for (auto&& prop : config) {
     std::string name;
     try {
       name = prop.at("name").get<std::string>();
     } catch (const wpi::json::exception& e) {
-      WPI_WARNING(logger,
-                  logName << ": SetConfigJson: could not read property name: "
-                          << e.what());
+      WPI_WARNING(logger, "{}: SetConfigJson: could not read property name: {}",
+                  logName, e.what());
       continue;
     }
     int n = GetPropertyIndex(name);
@@ -254,24 +252,24 @@ bool PropertyContainer::SetPropertiesJson(const wpi::json& config,
       auto& v = prop.at("value");
       if (v.is_string()) {
         std::string val = v.get<std::string>();
-        WPI_INFO(logger, logName << ": SetConfigJson: setting property '"
-                                 << name << "' to '" << val << '\'');
+        WPI_INFO(logger, "{}: SetConfigJson: setting property '{}' to '{}'",
+                 logName, name, val);
         SetStringProperty(n, val, status);
       } else if (v.is_boolean()) {
         bool val = v.get<bool>();
-        WPI_INFO(logger, logName << ": SetConfigJson: setting property '"
-                                 << name << "' to " << val);
+        WPI_INFO(logger, "{}: SetConfigJson: setting property '{}' to {}",
+                 logName, name, val);
         SetProperty(n, val, status);
       } else {
         int val = v.get<int>();
-        WPI_INFO(logger, logName << ": SetConfigJson: setting property '"
-                                 << name << "' to " << val);
+        WPI_INFO(logger, "{}: SetConfigJson: setting property '{}' to {}",
+                 logName, name, val);
         SetProperty(n, val, status);
       }
     } catch (const wpi::json::exception& e) {
       WPI_WARNING(logger,
-                  logName << ": SetConfigJson: could not read property value: "
-                          << e.what());
+                  "{}: SetConfigJson: could not read property value: {}",
+                  logName, e.what());
       continue;
     }
   }

cscore/src/main/native/cpp/PropertyContainer.h

@@ -9,20 +9,20 @@
 #include <cstddef>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <vector>
 
-#include <wpi/ArrayRef.h>
-#include <wpi/SmallVector.h>
 #include <wpi/StringMap.h>
-#include <wpi/StringRef.h>
-#include <wpi/Twine.h>
 #include <wpi/mutex.h>
+#include <wpi/span.h>
 
 #include "PropertyImpl.h"
 #include "cscore_cpp.h"
 
 namespace wpi {
 class Logger;
+template <typename T>
+class SmallVectorImpl;
 class json;
 }  // namespace wpi
 
@@ -32,28 +32,29 @@ class PropertyContainer {
  public:
   virtual ~PropertyContainer() = default;
 
-  int GetPropertyIndex(const wpi::Twine& name) const;
-  wpi::ArrayRef<int> EnumerateProperties(wpi::SmallVectorImpl<int>& vec,
-                                         CS_Status* status) const;
+  int GetPropertyIndex(std::string_view name) const;
+  wpi::span<int> EnumerateProperties(wpi::SmallVectorImpl<int>& vec,
+                                     CS_Status* status) const;
   CS_PropertyKind GetPropertyKind(int property) const;
-  wpi::StringRef GetPropertyName(int property, wpi::SmallVectorImpl<char>& buf,
-                                 CS_Status* status) const;
+  std::string_view GetPropertyName(int property,
+                                   wpi::SmallVectorImpl<char>& buf,
+                                   CS_Status* status) const;
   int GetProperty(int property, CS_Status* status) const;
   virtual void SetProperty(int property, int value, CS_Status* status);
   int GetPropertyMin(int property, CS_Status* status) const;
   int GetPropertyMax(int property, CS_Status* status) const;
   int GetPropertyStep(int property, CS_Status* status) const;
   int GetPropertyDefault(int property, CS_Status* status) const;
-  wpi::StringRef GetStringProperty(int property,
-                                   wpi::SmallVectorImpl<char>& buf,
-                                   CS_Status* status) const;
-  virtual void SetStringProperty(int property, const wpi::Twine& value,
+  std::string_view GetStringProperty(int property,
+                                     wpi::SmallVectorImpl<char>& buf,
+                                     CS_Status* status) const;
+  virtual void SetStringProperty(int property, std::string_view value,
                                  CS_Status* status);
   std::vector<std::string> GetEnumPropertyChoices(int property,
                                                   CS_Status* status) const;
 
   bool SetPropertiesJson(const wpi::json& config, wpi::Logger& logger,
-                         wpi::StringRef logName, CS_Status* status);
+                         std::string_view logName, CS_Status* status);
   wpi::json GetPropertiesJsonObject(CS_Status* status);
 
  protected:
@@ -76,10 +77,9 @@ class PropertyContainer {
   // @tparam NewFunc functor that returns a std::unique_ptr<PropertyImpl>
   // @tparam UpdateFunc functor that takes a PropertyImpl&.
   template <typename NewFunc, typename UpdateFunc>
-  int CreateOrUpdateProperty(const wpi::Twine& name, NewFunc newFunc,
+  int CreateOrUpdateProperty(std::string_view name, NewFunc newFunc,
                              UpdateFunc updateFunc) {
-    wpi::SmallVector<char, 64> nameBuf;
-    int& ndx = m_properties[name.toStringRef(nameBuf)];
+    int& ndx = m_properties[name];
     if (ndx == 0) {
       // create a new index
       ndx = m_propertyData.size() + 1;
@@ -91,7 +91,7 @@ class PropertyContainer {
     return ndx;
   }
   template <typename NewFunc>
-  int CreateProperty(const wpi::Twine& name, NewFunc newFunc) {
+  int CreateProperty(std::string_view name, NewFunc newFunc) {
     return CreateOrUpdateProperty(name, newFunc, [](PropertyImpl&) {});
   }
 
@@ -100,7 +100,7 @@ class PropertyContainer {
   // Note: called with m_mutex held.
   // The default implementation simply creates a PropertyImpl object.
   virtual std::unique_ptr<PropertyImpl> CreateEmptyProperty(
-      const wpi::Twine& name) const;
+      std::string_view name) const;
 
   // Cache properties.  Implementations must return false and set status to
   // CS_SOURCE_IS_DISCONNECTED if not possible to cache.
@@ -111,7 +111,7 @@ class PropertyContainer {
 
   // Update property value; must be called with m_mutex held.
   virtual void UpdatePropertyValue(int property, bool setString, int value,
-                                   const wpi::Twine& valueStr) = 0;
+                                   std::string_view valueStr) = 0;
 
   // Whether CacheProperties() has been successful at least once (and thus
   // should not be called again)

cscore/src/main/native/cpp/PropertyImpl.cpp

@@ -6,18 +6,18 @@
 
 using namespace cs;
 
-PropertyImpl::PropertyImpl(const wpi::Twine& name_) : name{name_.str()} {}
-PropertyImpl::PropertyImpl(const wpi::Twine& name_, CS_PropertyKind kind_,
+PropertyImpl::PropertyImpl(std::string_view name_) : name{name_} {}
+PropertyImpl::PropertyImpl(std::string_view name_, CS_PropertyKind kind_,
                            int step_, int defaultValue_, int value_)
-    : name{name_.str()},
+    : name{name_},
       propKind{kind_},
       step{step_},
       defaultValue{defaultValue_},
       value{value_} {}
-PropertyImpl::PropertyImpl(const wpi::Twine& name_, CS_PropertyKind kind_,
+PropertyImpl::PropertyImpl(std::string_view name_, CS_PropertyKind kind_,
                            int minimum_, int maximum_, int step_,
                            int defaultValue_, int value_)
-    : name{name_.str()},
+    : name{name_},
       propKind{kind_},
       hasMinimum{true},
       hasMaximum{true},
@@ -43,11 +43,10 @@ void PropertyImpl::SetValue(int v) {
   }
 }
 
-void PropertyImpl::SetValue(const wpi::Twine& v) {
+void PropertyImpl::SetValue(std::string_view v) {
   bool valueChanged = false;
-  std::string vStr = v.str();
-  if (valueStr != vStr) {
-    valueStr = vStr;
+  if (valueStr != v) {
+    valueStr = v;
     valueChanged = true;
   }
   bool wasValueSet = valueSet;

cscore/src/main/native/cpp/PropertyImpl.h

@@ -6,11 +6,10 @@
 #define CSCORE_PROPERTYIMPL_H_
 
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <wpi/Signal.h>
-#include <wpi/StringRef.h>
-#include <wpi/Twine.h>
 
 #include "cscore_c.h"
 
@@ -20,17 +19,17 @@ namespace cs {
 class PropertyImpl {
  public:
   PropertyImpl() = default;
-  explicit PropertyImpl(const wpi::Twine& name_);
-  PropertyImpl(const wpi::Twine& name_, CS_PropertyKind kind_, int step_,
+  explicit PropertyImpl(std::string_view name_);
+  PropertyImpl(std::string_view name_, CS_PropertyKind kind_, int step_,
                int defaultValue_, int value_);
-  PropertyImpl(const wpi::Twine& name_, CS_PropertyKind kind_, int minimum_,
+  PropertyImpl(std::string_view name_, CS_PropertyKind kind_, int minimum_,
                int maximum_, int step_, int defaultValue_, int value_);
   virtual ~PropertyImpl() = default;
   PropertyImpl(const PropertyImpl& oth) = delete;
   PropertyImpl& operator=(const PropertyImpl& oth) = delete;
 
   void SetValue(int v);
-  void SetValue(const wpi::Twine& v);
+  void SetValue(std::string_view v);
   void SetDefaultValue(int v);
 
   std::string name;

cscore/src/main/native/cpp/RawSinkImpl.cpp

@@ -10,14 +10,14 @@
 
 using namespace cs;
 
-RawSinkImpl::RawSinkImpl(const wpi::Twine& name, wpi::Logger& logger,
+RawSinkImpl::RawSinkImpl(std::string_view name, wpi::Logger& logger,
                          Notifier& notifier, Telemetry& telemetry)
     : SinkImpl{name, logger, notifier, telemetry} {
   m_active = true;
   // m_thread = std::thread(&RawSinkImpl::ThreadMain, this);
 }
 
-RawSinkImpl::RawSinkImpl(const wpi::Twine& name, wpi::Logger& logger,
+RawSinkImpl::RawSinkImpl(std::string_view name, wpi::Logger& logger,
                          Notifier& notifier, Telemetry& telemetry,
                          std::function<void(uint64_t time)> processFrame)
     : SinkImpl{name, logger, notifier, telemetry} {}
@@ -127,7 +127,7 @@ void RawSinkImpl::ThreadMain() {
       std::this_thread::sleep_for(std::chrono::seconds(1));
       continue;
     }
-    SDEBUG4("waiting for frame");
+    SDEBUG4("{}", "waiting for frame");
     Frame frame = source->GetNextFrame();  // blocks
     if (!m_active) {
       break;
@@ -143,14 +143,14 @@ void RawSinkImpl::ThreadMain() {
 }
 
 namespace cs {
-CS_Sink CreateRawSink(const wpi::Twine& name, CS_Status* status) {
+CS_Sink CreateRawSink(std::string_view name, CS_Status* status) {
   auto& inst = Instance::GetInstance();
   return inst.CreateSink(CS_SINK_RAW,
                          std::make_shared<RawSinkImpl>(
                              name, inst.logger, inst.notifier, inst.telemetry));
 }
 
-CS_Sink CreateRawSinkCallback(const wpi::Twine& name,
+CS_Sink CreateRawSinkCallback(std::string_view name,
                               std::function<void(uint64_t time)> processFrame,
                               CS_Status* status) {
   auto& inst = Instance::GetInstance();

cscore/src/main/native/cpp/RawSinkImpl.h

@@ -9,9 +9,9 @@
 
 #include <atomic>
 #include <functional>
+#include <string_view>
 #include <thread>
 
-#include <wpi/Twine.h>
 #include <wpi/condition_variable.h>
 
 #include "Frame.h"
@@ -23,9 +23,9 @@ class SourceImpl;
 
 class RawSinkImpl : public SinkImpl {
  public:
-  RawSinkImpl(const wpi::Twine& name, wpi::Logger& logger, Notifier& notifier,
+  RawSinkImpl(std::string_view name, wpi::Logger& logger, Notifier& notifier,
               Telemetry& telemetry);
-  RawSinkImpl(const wpi::Twine& name, wpi::Logger& logger, Notifier& notifier,
+  RawSinkImpl(std::string_view name, wpi::Logger& logger, Notifier& notifier,
               Telemetry& telemetry,
               std::function<void(uint64_t time)> processFrame);
   ~RawSinkImpl() override;

cscore/src/main/native/cpp/RawSourceImpl.cpp

@@ -14,7 +14,7 @@
 
 using namespace cs;
 
-RawSourceImpl::RawSourceImpl(const wpi::Twine& name, wpi::Logger& logger,
+RawSourceImpl::RawSourceImpl(std::string_view name, wpi::Logger& logger,
                              Notifier& notifier, Telemetry& telemetry,
                              const VideoMode& mode)
     : ConfigurableSourceImpl{name, logger, notifier, telemetry, mode} {}
@@ -47,7 +47,7 @@ void RawSourceImpl::PutFrame(const CS_RawFrame& image) {
 }
 
 namespace cs {
-CS_Source CreateRawSource(const wpi::Twine& name, const VideoMode& mode,
+CS_Source CreateRawSource(std::string_view name, const VideoMode& mode,
                           CS_Status* status) {
   auto& inst = Instance::GetInstance();
   return inst.CreateSource(CS_SOURCE_RAW, std::make_shared<RawSourceImpl>(

cscore/src/main/native/cpp/RawSourceImpl.h

@@ -9,11 +9,9 @@
 #include <functional>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <vector>
 
-#include <wpi/ArrayRef.h>
-#include <wpi/Twine.h>
-
 #include "ConfigurableSourceImpl.h"
 #include "SourceImpl.h"
 #include "cscore_raw.h"
@@ -22,7 +20,7 @@ namespace cs {
 
 class RawSourceImpl : public ConfigurableSourceImpl {
  public:
-  RawSourceImpl(const wpi::Twine& name, wpi::Logger& logger, Notifier& notifier,
+  RawSourceImpl(std::string_view name, wpi::Logger& logger, Notifier& notifier,
                 Telemetry& telemetry, const VideoMode& mode);
   ~RawSourceImpl() override;
 

cscore/src/main/native/cpp/SinkImpl.cpp

@@ -12,12 +12,12 @@
 
 using namespace cs;
 
-SinkImpl::SinkImpl(const wpi::Twine& name, wpi::Logger& logger,
+SinkImpl::SinkImpl(std::string_view name, wpi::Logger& logger,
                    Notifier& notifier, Telemetry& telemetry)
     : m_logger(logger),
       m_notifier(notifier),
       m_telemetry(telemetry),
-      m_name{name.str()} {}
+      m_name{name} {}
 
 SinkImpl::~SinkImpl() {
   if (m_source) {
@@ -28,15 +28,16 @@ SinkImpl::~SinkImpl() {
   }
 }
 
-void SinkImpl::SetDescription(const wpi::Twine& description) {
+void SinkImpl::SetDescription(std::string_view description) {
   std::scoped_lock lock(m_mutex);
-  m_description = description.str();
+  m_description = description;
 }
 
-wpi::StringRef SinkImpl::GetDescription(wpi::SmallVectorImpl<char>& buf) const {
+std::string_view SinkImpl::GetDescription(
+    wpi::SmallVectorImpl<char>& buf) const {
   std::scoped_lock lock(m_mutex);
   buf.append(m_description.begin(), m_description.end());
-  return wpi::StringRef{buf.data(), buf.size()};
+  return {buf.data(), buf.size()};
 }
 
 void SinkImpl::Enable() {
@@ -106,28 +107,27 @@ std::string SinkImpl::GetError() const {
   if (!m_source) {
     return "no source connected";
   }
-  return m_source->GetCurFrame().GetError();
+  return std::string{m_source->GetCurFrame().GetError()};
 }
 
-wpi::StringRef SinkImpl::GetError(wpi::SmallVectorImpl<char>& buf) const {
+std::string_view SinkImpl::GetError(wpi::SmallVectorImpl<char>& buf) const {
   std::scoped_lock lock(m_mutex);
   if (!m_source) {
     return "no source connected";
   }
   // Make a copy as it's shared data
-  wpi::StringRef error = m_source->GetCurFrame().GetError();
+  std::string_view error = m_source->GetCurFrame().GetError();
   buf.clear();
   buf.append(error.data(), error.data() + error.size());
-  return wpi::StringRef{buf.data(), buf.size()};
+  return {buf.data(), buf.size()};
 }
 
-bool SinkImpl::SetConfigJson(wpi::StringRef config, CS_Status* status) {
+bool SinkImpl::SetConfigJson(std::string_view config, CS_Status* status) {
   wpi::json j;
   try {
     j = wpi::json::parse(config);
   } catch (const wpi::json::parse_error& e) {
-    SWARNING("SetConfigJson: parse error at byte " << e.byte << ": "
-                                                   << e.what());
+    SWARNING("SetConfigJson: parse error at byte {}: {}", e.byte, e.what());
     *status = CS_PROPERTY_WRITE_FAILED;
     return false;
   }
@@ -169,12 +169,12 @@ void SinkImpl::NotifyPropertyCreated(int propIndex, PropertyImpl& prop) {
   if (prop.propKind == CS_PROP_ENUM) {
     m_notifier.NotifySinkProperty(*this, CS_SINK_PROPERTY_CHOICES_UPDATED,
                                   prop.name, propIndex, prop.propKind,
-                                  prop.value, wpi::Twine{});
+                                  prop.value, {});
   }
 }
 
 void SinkImpl::UpdatePropertyValue(int property, bool setString, int value,
-                                   const wpi::Twine& valueStr) {
+                                   std::string_view valueStr) {
   auto prop = GetProperty(property);
   if (!prop) {
     return;

cscore/src/main/native/cpp/SinkImpl.h

@@ -7,10 +7,9 @@
 
 #include <memory>
 #include <string>
+#include <string_view>
 
 #include <wpi/Logger.h>
-#include <wpi/StringRef.h>
-#include <wpi/Twine.h>
 #include <wpi/mutex.h>
 
 #include "SourceImpl.h"
@@ -27,16 +26,16 @@ class Telemetry;
 
 class SinkImpl : public PropertyContainer {
  public:
-  explicit SinkImpl(const wpi::Twine& name, wpi::Logger& logger,
+  explicit SinkImpl(std::string_view name, wpi::Logger& logger,
                     Notifier& notifier, Telemetry& telemetry);
   ~SinkImpl() override;
   SinkImpl(const SinkImpl& queue) = delete;
   SinkImpl& operator=(const SinkImpl& queue) = delete;
 
-  wpi::StringRef GetName() const { return m_name; }
+  std::string_view GetName() const { return m_name; }
 
-  void SetDescription(const wpi::Twine& description);
-  wpi::StringRef GetDescription(wpi::SmallVectorImpl<char>& buf) const;
+  void SetDescription(std::string_view description);
+  std::string_view GetDescription(wpi::SmallVectorImpl<char>& buf) const;
 
   void Enable();
   void Disable();
@@ -50,9 +49,9 @@ class SinkImpl : public PropertyContainer {
   }
 
   std::string GetError() const;
-  wpi::StringRef GetError(wpi::SmallVectorImpl<char>& buf) const;
+  std::string_view GetError(wpi::SmallVectorImpl<char>& buf) const;
 
-  bool SetConfigJson(wpi::StringRef config, CS_Status* status);
+  bool SetConfigJson(std::string_view config, CS_Status* status);
   virtual bool SetConfigJson(const wpi::json& config, CS_Status* status);
   std::string GetConfigJson(CS_Status* status);
   virtual wpi::json GetConfigJsonObject(CS_Status* status);
@@ -61,7 +60,7 @@ class SinkImpl : public PropertyContainer {
   // PropertyContainer implementation
   void NotifyPropertyCreated(int propIndex, PropertyImpl& prop) override;
   void UpdatePropertyValue(int property, bool setString, int value,
-                           const wpi::Twine& valueStr) override;
+                           std::string_view valueStr) override;
 
   virtual void SetSourceImpl(std::shared_ptr<SourceImpl> source);
 

cscore/src/main/native/cpp/SourceImpl.cpp

@@ -8,6 +8,7 @@
 #include <cstring>
 #include <memory>
 
+#include <wpi/StringExtras.h>
 #include <wpi/json.h>
 #include <wpi/timestamp.h>
 
@@ -19,13 +20,13 @@ using namespace cs;
 
 static constexpr size_t kMaxImagesAvail = 32;
 
-SourceImpl::SourceImpl(const wpi::Twine& name, wpi::Logger& logger,
+SourceImpl::SourceImpl(std::string_view name, wpi::Logger& logger,
                        Notifier& notifier, Telemetry& telemetry)
     : m_logger(logger),
       m_notifier(notifier),
       m_telemetry(telemetry),
-      m_name{name.str()} {
-  m_frame = Frame{*this, wpi::StringRef{}, 0};
+      m_name{name} {
+  m_frame = Frame{*this, std::string_view{}, 0};
 }
 
 SourceImpl::~SourceImpl() {
@@ -41,16 +42,16 @@ SourceImpl::~SourceImpl() {
   // Everything else can clean up itself.
 }
 
-void SourceImpl::SetDescription(const wpi::Twine& description) {
+void SourceImpl::SetDescription(std::string_view description) {
   std::scoped_lock lock(m_mutex);
-  m_description = description.str();
+  m_description = description;
 }
 
-wpi::StringRef SourceImpl::GetDescription(
+std::string_view SourceImpl::GetDescription(
     wpi::SmallVectorImpl<char>& buf) const {
   std::scoped_lock lock(m_mutex);
   buf.append(m_description.begin(), m_description.end());
-  return wpi::StringRef{buf.data(), buf.size()};
+  return {buf.data(), buf.size()};
 }
 
 void SourceImpl::SetConnected(bool connected) {
@@ -93,7 +94,7 @@ Frame SourceImpl::GetNextFrame(double timeout) {
 void SourceImpl::Wakeup() {
   {
     std::scoped_lock lock{m_frameMutex};
-    m_frame = Frame{*this, wpi::StringRef{}, 0};
+    m_frame = Frame{*this, std::string_view{}, 0};
   }
   m_frameCv.notify_all();
 }
@@ -168,13 +169,12 @@ bool SourceImpl::SetFPS(int fps, CS_Status* status) {
   return SetVideoMode(mode, status);
 }
 
-bool SourceImpl::SetConfigJson(wpi::StringRef config, CS_Status* status) {
+bool SourceImpl::SetConfigJson(std::string_view config, CS_Status* status) {
   wpi::json j;
   try {
     j = wpi::json::parse(config);
   } catch (const wpi::json::parse_error& e) {
-    SWARNING("SetConfigJson: parse error at byte " << e.byte << ": "
-                                                   << e.what());
+    SWARNING("SetConfigJson: parse error at byte {}: {}", e.byte, e.what());
     *status = CS_PROPERTY_WRITE_FAILED;
     return false;
   }
@@ -188,23 +188,22 @@ bool SourceImpl::SetConfigJson(const wpi::json& config, CS_Status* status) {
   if (config.count("pixel format") != 0) {
     try {
       auto str = config.at("pixel format").get<std::string>();
-      wpi::StringRef s(str);
-      if (s.equals_lower("mjpeg")) {
+      if (wpi::equals_lower(str, "mjpeg")) {
         mode.pixelFormat = cs::VideoMode::kMJPEG;
-      } else if (s.equals_lower("yuyv")) {
+      } else if (wpi::equals_lower(str, "yuyv")) {
         mode.pixelFormat = cs::VideoMode::kYUYV;
-      } else if (s.equals_lower("rgb565")) {
+      } else if (wpi::equals_lower(str, "rgb565")) {
         mode.pixelFormat = cs::VideoMode::kRGB565;
-      } else if (s.equals_lower("bgr")) {
+      } else if (wpi::equals_lower(str, "bgr")) {
         mode.pixelFormat = cs::VideoMode::kBGR;
-      } else if (s.equals_lower("gray")) {
+      } else if (wpi::equals_lower(str, "gray")) {
         mode.pixelFormat = cs::VideoMode::kGray;
       } else {
-        SWARNING("SetConfigJson: could not understand pixel format value '"
-                 << str << '\'');
+        SWARNING("SetConfigJson: could not understand pixel format value '{}'",
+                 str);
       }
     } catch (const wpi::json::exception& e) {
-      SWARNING("SetConfigJson: could not read pixel format: " << e.what());
+      SWARNING("SetConfigJson: could not read pixel format: {}", e.what());
     }
   }
 
@@ -213,7 +212,7 @@ bool SourceImpl::SetConfigJson(const wpi::json& config, CS_Status* status) {
     try {
       mode.width = config.at("width").get<unsigned int>();
     } catch (const wpi::json::exception& e) {
-      SWARNING("SetConfigJson: could not read width: " << e.what());
+      SWARNING("SetConfigJson: could not read width: {}", e.what());
     }
   }
 
@@ -222,7 +221,7 @@ bool SourceImpl::SetConfigJson(const wpi::json& config, CS_Status* status) {
     try {
       mode.height = config.at("height").get<unsigned int>();
     } catch (const wpi::json::exception& e) {
-      SWARNING("SetConfigJson: could not read height: " << e.what());
+      SWARNING("SetConfigJson: could not read height: {}", e.what());
     }
   }
 
@@ -231,30 +230,31 @@ bool SourceImpl::SetConfigJson(const wpi::json& config, CS_Status* status) {
     try {
       mode.fps = config.at("fps").get<unsigned int>();
     } catch (const wpi::json::exception& e) {
-      SWARNING("SetConfigJson: could not read fps: " << e.what());
+      SWARNING("SetConfigJson: could not read fps: {}", e.what());
     }
   }
 
   // if all of video mode is set, use SetVideoMode, otherwise piecemeal it
   if (mode.pixelFormat != VideoMode::kUnknown && mode.width != 0 &&
       mode.height != 0 && mode.fps != 0) {
-    SINFO("SetConfigJson: setting video mode to pixelFormat "
-          << mode.pixelFormat << ", width " << mode.width << ", height "
-          << mode.height << ", fps " << mode.fps);
+    SINFO(
+        "SetConfigJson: setting video mode to pixelFormat {}, width {}, height "
+        "{}, fps {}",
+        mode.pixelFormat, mode.width, mode.height, mode.fps);
     SetVideoMode(mode, status);
   } else {
     if (mode.pixelFormat != cs::VideoMode::kUnknown) {
-      SINFO("SetConfigJson: setting pixelFormat " << mode.pixelFormat);
+      SINFO("SetConfigJson: setting pixelFormat {}", mode.pixelFormat);
       SetPixelFormat(static_cast<cs::VideoMode::PixelFormat>(mode.pixelFormat),
                      status);
     }
     if (mode.width != 0 && mode.height != 0) {
-      SINFO("SetConfigJson: setting width " << mode.width << ", height "
-                                            << mode.height);
+      SINFO("SetConfigJson: setting width {}, height {}", mode.width,
+            mode.height);
       SetResolution(mode.width, mode.height, status);
     }
     if (mode.fps != 0) {
-      SINFO("SetConfigJson: setting fps " << mode.fps);
+      SINFO("SetConfigJson: setting fps {}", mode.fps);
       SetFPS(mode.fps, status);
     }
   }
@@ -263,10 +263,10 @@ bool SourceImpl::SetConfigJson(const wpi::json& config, CS_Status* status) {
   if (config.count("brightness") != 0) {
     try {
       int val = config.at("brightness").get<int>();
-      SINFO("SetConfigJson: setting brightness to " << val);
+      SINFO("SetConfigJson: setting brightness to {}", val);
       SetBrightness(val, status);
     } catch (const wpi::json::exception& e) {
-      SWARNING("SetConfigJson: could not read brightness: " << e.what());
+      SWARNING("SetConfigJson: could not read brightness: {}", e.what());
     }
   }
 
@@ -276,24 +276,24 @@ bool SourceImpl::SetConfigJson(const wpi::json& config, CS_Status* status) {
       auto& setting = config.at("white balance");
       if (setting.is_string()) {
         auto str = setting.get<std::string>();
-        wpi::StringRef s(str);
-        if (s.equals_lower("auto")) {
-          SINFO("SetConfigJson: setting white balance to auto");
+        if (wpi::equals_lower(str, "auto")) {
+          SINFO("SetConfigJson: setting white balance to {}", "auto");
           SetWhiteBalanceAuto(status);
-        } else if (s.equals_lower("hold")) {
-          SINFO("SetConfigJson: setting white balance to hold current");
+        } else if (wpi::equals_lower(str, "hold")) {
+          SINFO("SetConfigJson: setting white balance to {}", "hold current");
           SetWhiteBalanceHoldCurrent(status);
         } else {
-          SWARNING("SetConfigJson: could not understand white balance value '"
-                   << str << '\'');
+          SWARNING(
+              "SetConfigJson: could not understand white balance value '{}'",
+              str);
         }
       } else {
         int val = setting.get<int>();
-        SINFO("SetConfigJson: setting white balance to " << val);
+        SINFO("SetConfigJson: setting white balance to {}", val);
         SetWhiteBalanceManual(val, status);
       }
     } catch (const wpi::json::exception& e) {
-      SWARNING("SetConfigJson: could not read white balance: " << e.what());
+      SWARNING("SetConfigJson: could not read white balance: {}", e.what());
     }
   }
 
@@ -303,24 +303,23 @@ bool SourceImpl::SetConfigJson(const wpi::json& config, CS_Status* status) {
       auto& setting = config.at("exposure");
       if (setting.is_string()) {
         auto str = setting.get<std::string>();
-        wpi::StringRef s(str);
-        if (s.equals_lower("auto")) {
-          SINFO("SetConfigJson: setting exposure to auto");
+        if (wpi::equals_lower(str, "auto")) {
+          SINFO("SetConfigJson: setting exposure to {}", "auto");
           SetExposureAuto(status);
-        } else if (s.equals_lower("hold")) {
-          SINFO("SetConfigJson: setting exposure to hold current");
+        } else if (wpi::equals_lower(str, "hold")) {
+          SINFO("SetConfigJson: setting exposure to {}", "hold current");
           SetExposureHoldCurrent(status);
         } else {
-          SWARNING("SetConfigJson: could not understand exposure value '"
-                   << str << '\'');
+          SWARNING("SetConfigJson: could not understand exposure value '{}'",
+                   str);
         }
       } else {
         int val = setting.get<int>();
-        SINFO("SetConfigJson: setting exposure to " << val);
+        SINFO("SetConfigJson: setting exposure to {}", val);
         SetExposureManual(val, status);
       }
     } catch (const wpi::json::exception& e) {
-      SWARNING("SetConfigJson: could not read exposure: " << e.what());
+      SWARNING("SetConfigJson: could not read exposure: {}", e.what());
     }
   }
 
@@ -344,7 +343,7 @@ wpi::json SourceImpl::GetConfigJsonObject(CS_Status* status) {
   wpi::json j;
 
   // pixel format
-  wpi::StringRef pixelFormat;
+  std::string_view pixelFormat;
   switch (m_mode.pixelFormat) {
     case VideoMode::kMJPEG:
       pixelFormat = "mjpeg";
@@ -440,14 +439,12 @@ std::unique_ptr<Image> SourceImpl::AllocImage(
 }
 
 void SourceImpl::PutFrame(VideoMode::PixelFormat pixelFormat, int width,
-                          int height, wpi::StringRef data, Frame::Time time) {
+                          int height, std::string_view data, Frame::Time time) {
   auto image = AllocImage(pixelFormat, width, height, data.size());
 
   // Copy in image data
-  SDEBUG4("Copying data to "
-          << reinterpret_cast<const void*>(image->data()) << " from "
-          << reinterpret_cast<const void*>(data.data()) << " (" << data.size()
-          << " bytes)");
+  SDEBUG4("Copying data to {} from {} ({} bytes)", fmt::ptr(image->data()),
+          fmt::ptr(data.data()), data.size());
   std::memcpy(image->data(), data.data(), data.size());
 
   PutFrame(std::move(image), time);
@@ -468,7 +465,7 @@ void SourceImpl::PutFrame(std::unique_ptr<Image> image, Frame::Time time) {
   m_frameCv.notify_all();
 }
 
-void SourceImpl::PutError(const wpi::Twine& msg, Frame::Time time) {
+void SourceImpl::PutError(std::string_view msg, Frame::Time time) {
   // Update frame
   {
     std::scoped_lock lock{m_frameMutex};
@@ -487,12 +484,12 @@ void SourceImpl::NotifyPropertyCreated(int propIndex, PropertyImpl& prop) {
   if (prop.propKind == CS_PROP_ENUM) {
     m_notifier.NotifySourceProperty(*this, CS_SOURCE_PROPERTY_CHOICES_UPDATED,
                                     prop.name, propIndex, prop.propKind,
-                                    prop.value, wpi::Twine{});
+                                    prop.value, {});
   }
 }
 
 void SourceImpl::UpdatePropertyValue(int property, bool setString, int value,
-                                     const wpi::Twine& valueStr) {
+                                     std::string_view valueStr) {
   auto prop = GetProperty(property);
   if (!prop) {
     return;

cscore/src/main/native/cpp/SourceImpl.h

@@ -9,12 +9,10 @@
 #include <cstddef>
 #include <memory>
 #include <string>
+#include <string_view>
 #include <vector>
 
-#include <wpi/ArrayRef.h>
 #include <wpi/Logger.h>
-#include <wpi/StringRef.h>
-#include <wpi/Twine.h>
 #include <wpi/condition_variable.h>
 #include <wpi/mutex.h>
 
@@ -37,7 +35,7 @@ class SourceImpl : public PropertyContainer {
   friend class Frame;
 
  public:
-  SourceImpl(const wpi::Twine& name, wpi::Logger& logger, Notifier& notifier,
+  SourceImpl(std::string_view name, wpi::Logger& logger, Notifier& notifier,
              Telemetry& telemetry);
   ~SourceImpl() override;
   SourceImpl(const SourceImpl& oth) = delete;
@@ -45,10 +43,10 @@ class SourceImpl : public PropertyContainer {
 
   virtual void Start() = 0;
 
-  wpi::StringRef GetName() const { return m_name; }
+  std::string_view GetName() const { return m_name; }
 
-  void SetDescription(const wpi::Twine& description);
-  wpi::StringRef GetDescription(wpi::SmallVectorImpl<char>& buf) const;
+  void SetDescription(std::string_view description);
+  std::string_view GetDescription(wpi::SmallVectorImpl<char>& buf) const;
 
   void SetConnectionStrategy(CS_ConnectionStrategy strategy) {
     m_strategy = static_cast<int>(strategy);
@@ -128,7 +126,7 @@ class SourceImpl : public PropertyContainer {
   virtual bool SetResolution(int width, int height, CS_Status* status);
   virtual bool SetFPS(int fps, CS_Status* status);
 
-  bool SetConfigJson(wpi::StringRef config, CS_Status* status);
+  bool SetConfigJson(std::string_view config, CS_Status* status);
   virtual bool SetConfigJson(const wpi::json& config, CS_Status* status);
   std::string GetConfigJson(CS_Status* status);
   virtual wpi::json GetConfigJsonObject(CS_Status* status);
@@ -141,12 +139,12 @@ class SourceImpl : public PropertyContainer {
  protected:
   void NotifyPropertyCreated(int propIndex, PropertyImpl& prop) override;
   void UpdatePropertyValue(int property, bool setString, int value,
-                           const wpi::Twine& valueStr) override;
+                           std::string_view valueStr) override;
 
   void PutFrame(VideoMode::PixelFormat pixelFormat, int width, int height,
-                wpi::StringRef data, Frame::Time time);
+                std::string_view data, Frame::Time time);
   void PutFrame(std::unique_ptr<Image> image, Frame::Time time);
-  void PutError(const wpi::Twine& msg, Frame::Time time);
+  void PutError(std::string_view msg, Frame::Time time);
 
   // Notification functions for corresponding atomics
   virtual void NumSinksChanged() = 0;