[hal] Initial SystemCore empty HAL (#7454)

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

@@ -0,0 +1,90 @@
+// 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/Threads.h"
+
+#include <pthread.h>
+#include <sched.h>
+
+#include "hal/Errors.h"
+
+namespace hal::init {
+void InitializeThreads() {}
+}  // namespace hal::init
+
+extern "C" {
+
+int32_t HAL_GetThreadPriority(NativeThreadHandle handle, HAL_Bool* isRealTime,
+                              int32_t* status) {
+  sched_param sch;
+  int policy;
+  int success = pthread_getschedparam(
+      *reinterpret_cast<const pthread_t*>(handle), &policy, &sch);
+  if (success == 0) {
+    *status = 0;
+  } else {
+    *status = HAL_THREAD_PRIORITY_ERROR;
+    return -1;
+  }
+  if (policy == SCHED_FIFO || policy == SCHED_RR) {
+    *isRealTime = true;
+    return sch.sched_priority;
+  } else {
+    *isRealTime = false;
+    // 0 is the only supported priority for non-real-time
+    return 0;
+  }
+}
+
+int32_t HAL_GetCurrentThreadPriority(HAL_Bool* isRealTime, int32_t* status) {
+  auto thread = pthread_self();
+  return HAL_GetThreadPriority(&thread, isRealTime, status);
+}
+
+HAL_Bool HAL_SetThreadPriority(NativeThreadHandle handle, HAL_Bool realTime,
+                               int32_t priority, int32_t* status) {
+  if (handle == nullptr) {
+    *status = NULL_PARAMETER;
+    return false;
+  }
+
+  int scheduler = realTime ? SCHED_FIFO : SCHED_OTHER;
+  if (realTime) {
+    // We don't support setting priorities for non RT threads
+    // so we don't need to check for proper range
+    if (priority < sched_get_priority_min(scheduler) ||
+        priority > sched_get_priority_max(scheduler)) {
+      *status = HAL_THREAD_PRIORITY_RANGE_ERROR;
+      return false;
+    }
+  }
+
+  sched_param sch;
+  int policy;
+  pthread_getschedparam(*reinterpret_cast<const pthread_t*>(handle), &policy,
+                        &sch);
+  if (scheduler == SCHED_FIFO || scheduler == SCHED_RR) {
+    sch.sched_priority = priority;
+  } else {
+    // Only need to set 0 priority for non RT thread
+    sch.sched_priority = 0;
+  }
+
+  if (pthread_setschedparam(*reinterpret_cast<const pthread_t*>(handle),
+                            scheduler, &sch)) {
+    *status = HAL_THREAD_PRIORITY_ERROR;
+    return false;
+  } else {
+    *status = 0;
+    return true;
+  }
+}
+
+HAL_Bool HAL_SetCurrentThreadPriority(HAL_Bool realTime, int32_t priority,
+                                      int32_t* status) {
+  auto thread = pthread_self();
+  return HAL_SetThreadPriority(&thread, realTime, priority, status);
+}
+
+}  // extern "C"