[hal] Change usage reporting to string-based (#7763)

hal/src/main/native/systemcore/HAL.cpp

@@ -70,6 +70,7 @@ void InitializeHAL() {
   InitializeSerialPort();
   InitializeSmartIo();
   InitializeThreads();
+  InitializeUsageReporting();
 }
 }  // namespace init
 
@@ -343,16 +344,4 @@ void HAL_SimPeriodicBefore(void) {}
 
 void HAL_SimPeriodicAfter(void) {}
 
-int64_t HAL_Report(int32_t resource, int32_t instanceNumber, int32_t context,
-                   const char* feature) {
-  if (feature == nullptr) {
-    feature = "";
-  }
-
-  return 0;
-
-  // return FRC_NetworkCommunication_nUsageReporting_report(
-  //     resource, instanceNumber, context, feature);
-}
-
 }  // extern "C"

hal/src/main/native/systemcore/HALInitializer.h

@@ -43,4 +43,5 @@ extern void InitializePWM();
 extern void InitializeSerialPort();
 extern void InitializeSmartIo();
 extern void InitializeThreads();
+extern void InitializeUsageReporting();
 }  // namespace hal::init

hal/src/main/native/systemcore/UsageReporting.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 <stdint.h>
+
+#include <fmt/format.h>
+#include <networktables/NetworkTableInstance.h>
+#include <networktables/StringTopic.h>
+#include <wpi/StringMap.h>
+#include <wpi/string.h>
+
+#include "SystemServerInternal.h"
+
+namespace {
+struct SystemServerUsageReporting {
+  nt::NetworkTableInstance ntInst;
+  wpi::StringMap<nt::StringPublisher> publishers;
+
+  explicit SystemServerUsageReporting(nt::NetworkTableInstance inst)
+      : ntInst{inst} {}
+};
+
+}  // namespace
+
+static ::SystemServerUsageReporting* systemServerUsage;
+
+extern "C" {
+
+int32_t HAL_ReportUsage(const struct WPI_String* resource,
+                        const struct WPI_String* data) {
+  auto resourceStr = wpi::to_string_view(resource);
+  auto& publisher = systemServerUsage->publishers[resourceStr];
+  if (!publisher) {
+    publisher =
+        systemServerUsage->ntInst
+            .GetStringTopic(fmt::format("/UsageReporting/{}", resourceStr))
+            .Publish();
+  }
+  publisher.Set(wpi::to_string_view(data));
+
+  return 0;
+}
+
+}  // extern "C"
+
+namespace hal::init {
+void InitializeUsageReporting() {
+  systemServerUsage = new ::SystemServerUsageReporting{hal::GetSystemServer()};
+}
+}  // namespace hal::init