Use std::string_view and fmtlib across all libraries (#3402)

- Twine, StringRef, Format, and NativeFormatting have been removed
- Logging now uses fmtlib style formatting
- Nearly all uses of wpi::outs/errs have been replaced with fmt::print() or
std::puts()/std::fputs() (for unformatted strings).
- A wpi/fmt/raw_ostream.h header has been added to enable
fmt::print() with wpi::raw_ostream

wpimath/src/main/native/cpp/trajectory/TrajectoryGenerator.cpp

@@ -6,7 +6,7 @@
 
 #include <utility>
 
-#include <wpi/raw_ostream.h>
+#include <fmt/format.h>
 
 #include "frc/spline/SplineHelper.h"
 #include "frc/spline/SplineParameterizer.h"
@@ -22,7 +22,7 @@ void TrajectoryGenerator::ReportError(const char* error) {
   if (s_errorFunc) {
     s_errorFunc(error);
   } else {
-    wpi::errs() << "TrajectoryGenerator error: " << error << "\n";
+    fmt::print(stderr, "TrajectoryGenerator error: {}\n", error);
   }
 }
 

wpimath/src/main/native/cpp/trajectory/TrajectoryUtil.cpp

@@ -6,6 +6,7 @@
 
 #include <system_error>
 
+#include <fmt/format.h>
 #include <wpi/SmallString.h>
 #include <wpi/json.h>
 #include <wpi/raw_istream.h>
@@ -14,13 +15,12 @@
 using namespace frc;
 
 void TrajectoryUtil::ToPathweaverJson(const Trajectory& trajectory,
-                                      const wpi::Twine& path) {
+                                      std::string_view path) {
   std::error_code error_code;
 
-  wpi::SmallString<128> buf;
-  wpi::raw_fd_ostream output{path.toStringRef(buf), error_code};
+  wpi::raw_fd_ostream output{path, error_code};
   if (error_code) {
-    throw std::runtime_error(("Cannot open file: " + path).str());
+    throw std::runtime_error(fmt::format("Cannot open file: {}", path));
   }
 
   wpi::json json = trajectory.States();
@@ -28,13 +28,12 @@ void TrajectoryUtil::ToPathweaverJson(const Trajectory& trajectory,
   output.flush();
 }
 
-Trajectory TrajectoryUtil::FromPathweaverJson(const wpi::Twine& path) {
+Trajectory TrajectoryUtil::FromPathweaverJson(std::string_view path) {
   std::error_code error_code;
 
-  wpi::SmallString<128> buf;
-  wpi::raw_fd_istream input{path.toStringRef(buf), error_code};
+  wpi::raw_fd_istream input{path, error_code};
   if (error_code) {
-    throw std::runtime_error(("Cannot open file: " + path).str());
+    throw std::runtime_error(fmt::format("Cannot open file: {}", path));
   }
 
   wpi::json json;
@@ -48,8 +47,7 @@ std::string TrajectoryUtil::SerializeTrajectory(const Trajectory& trajectory) {
   return json.dump();
 }
 
-Trajectory TrajectoryUtil::DeserializeTrajectory(
-    const wpi::StringRef json_str) {
+Trajectory TrajectoryUtil::DeserializeTrajectory(std::string_view json_str) {
   wpi::json json = wpi::json::parse(json_str);
   return Trajectory{json.get<std::vector<Trajectory::State>>()};
 }

wpimath/src/main/native/include/frc/spline/SplineParameterizer.h

@@ -33,8 +33,6 @@
 #include <utility>
 #include <vector>
 
-#include <wpi/Twine.h>
-
 #include "frc/spline/Spline.h"
 #include "units/angle.h"
 #include "units/curvature.h"

wpimath/src/main/native/include/frc/trajectory/TrajectoryUtil.h

@@ -5,9 +5,7 @@
 #pragma once
 
 #include <string>
-
-#include <wpi/StringRef.h>
-#include <wpi/Twine.h>
+#include <string_view>
 
 #include "frc/trajectory/Trajectory.h"
 
@@ -25,7 +23,7 @@ class TrajectoryUtil {
    * @return The interpolated state.
    */
   static void ToPathweaverJson(const Trajectory& trajectory,
-                               const wpi::Twine& path);
+                               std::string_view path);
   /**
    * Imports a Trajectory from a PathWeaver-style JSON file.
    *
@@ -33,7 +31,7 @@ class TrajectoryUtil {
    *
    * @return The trajectory represented by the file.
    */
-  static Trajectory FromPathweaverJson(const wpi::Twine& path);
+  static Trajectory FromPathweaverJson(std::string_view path);
 
   /**
    * Deserializes a Trajectory from PathWeaver-style JSON.
@@ -51,6 +49,6 @@ class TrajectoryUtil {
    *
    * @return the string containing the serialized JSON
    */
-  static Trajectory DeserializeTrajectory(wpi::StringRef json_str);
+  static Trajectory DeserializeTrajectory(std::string_view json_str);
 };
 }  // namespace frc