Use wpi::mutex instead of std::mutex. (#730)

This uses a priority-aware mutex on Linux platforms.

Fixes #729.

hal/src/main/native/include/HAL/cpp/SerialHelper.h

@@ -9,12 +9,12 @@
 
 #include <stdint.h>
 
-#include <mutex>
 #include <string>
 #include <vector>
 
 #include <llvm/SmallString.h>
 #include <llvm/SmallVector.h>
+#include <support/mutex.h>
 
 #include "HAL/SerialPort.h"
 
@@ -46,7 +46,7 @@ class SerialHelper {
 
   int32_t m_resourceHandle;
 
-  static std::mutex m_nameMutex;
+  static wpi::mutex m_nameMutex;
   static std::string m_usbNames[2];
 };
 }  // namespace hal

hal/src/main/native/include/HAL/cpp/priority_mutex.h

@@ -1,92 +0,0 @@
-/*----------------------------------------------------------------------------*/
-/* Copyright (c) 2016-2017 FIRST. All Rights Reserved.                        */
-/* Open Source Software - may be modified and shared by FRC teams. The code   */
-/* must be accompanied by the FIRST BSD license file in the root directory of */
-/* the project.                                                               */
-/*----------------------------------------------------------------------------*/
-
-#pragma once
-
-// Allows usage with std::lock_guard without including <mutex> separately
-#include <mutex>
-
-#if !defined(__linux__)
-namespace hal {
-// We do not want to use pthreads if in the simulator; however, in the
-// simulator, we do not care about priority inversion.
-typedef std::mutex priority_mutex;
-typedef std::recursive_mutex priority_recursive_mutex;
-}  // namespace hal
-#else  // Covers rest of file.
-
-#include <pthread.h>
-
-namespace hal {
-
-class priority_recursive_mutex {
- public:
-  typedef pthread_mutex_t* native_handle_type;
-
-  constexpr priority_recursive_mutex() noexcept = default;
-  priority_recursive_mutex(const priority_recursive_mutex&) = delete;
-  priority_recursive_mutex& operator=(const priority_recursive_mutex&) = delete;
-
-  // Lock the mutex, blocking until it's available.
-  void lock();
-
-  // Unlock the mutex.
-  void unlock();
-
-  // Tries to lock the mutex.
-  bool try_lock() noexcept;
-
-  pthread_mutex_t* native_handle();
-
- private:
-// Do the equivalent of setting PTHREAD_PRIO_INHERIT and
-// PTHREAD_MUTEX_RECURSIVE_NP.
-#if __WORDSIZE == 64
-  pthread_mutex_t m_mutex = {
-      {0, 0, 0, 0, 0x20 | PTHREAD_MUTEX_RECURSIVE_NP, 0, 0, {0, 0}}};
-#else
-  pthread_mutex_t m_mutex = {
-      {0, 0, 0, 0x20 | PTHREAD_MUTEX_RECURSIVE_NP, 0, {0}}};
-#endif
-};
-
-class priority_mutex {
- public:
-  typedef pthread_mutex_t* native_handle_type;
-
-  constexpr priority_mutex() noexcept = default;
-  priority_mutex(const priority_mutex&) = delete;
-  priority_mutex& operator=(const priority_mutex&) = delete;
-
-  // Lock the mutex, blocking until it's available.
-  void lock();
-
-  // Unlock the mutex.
-  void unlock();
-
-  // Tries to lock the mutex.
-  bool try_lock() noexcept;
-
-  pthread_mutex_t* native_handle();
-
- private:
-// Do the equivalent of setting PTHREAD_PRIO_INHERIT.
-#if __WORDSIZE == 64
-  pthread_mutex_t m_mutex = {{0, 0, 0, 0, 0x20, 0, 0, {0, 0}}};
-#else
-  pthread_mutex_t m_mutex = {{0, 0, 0, 0x20, 0, {0}}};
-#endif
-};
-}  // namespace hal
-
-#endif  // FRC_SIMULATOR
-
-// For backwards compatibility
-#ifndef NAMESPACED_PRIORITY
-using hal::priority_mutex;            // NOLINT
-using hal::priority_recursive_mutex;  // NOLINT
-#endif