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/*
* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef WEBRTC_RTC_BASE_PLATFORM_THREAD_H_
#define WEBRTC_RTC_BASE_PLATFORM_THREAD_H_
#include <string>
#include "webrtc/rtc_base/constructormagic.h"
#include "webrtc/rtc_base/event.h"
#include "webrtc/rtc_base/platform_thread_types.h"
#include "webrtc/rtc_base/thread_checker.h"
namespace rtc {
PlatformThreadId CurrentThreadId();
PlatformThreadRef CurrentThreadRef();
// Compares two thread identifiers for equality.
bool IsThreadRefEqual(const PlatformThreadRef& a, const PlatformThreadRef& b);
// Sets the current thread name.
void SetCurrentThreadName(const char* name);
// Callback function that the spawned thread will enter once spawned.
// A return value of false is interpreted as that the function has no
// more work to do and that the thread can be released.
typedef bool (*ThreadRunFunctionDeprecated)(void*);
typedef void (*ThreadRunFunction)(void*);
enum ThreadPriority {
#ifdef WEBRTC_WIN
kLowPriority = THREAD_PRIORITY_BELOW_NORMAL,
kNormalPriority = THREAD_PRIORITY_NORMAL,
kHighPriority = THREAD_PRIORITY_ABOVE_NORMAL,
kHighestPriority = THREAD_PRIORITY_HIGHEST,
kRealtimePriority = THREAD_PRIORITY_TIME_CRITICAL
#else
kLowPriority = 1,
kNormalPriority = 2,
kHighPriority = 3,
kHighestPriority = 4,
kRealtimePriority = 5
#endif
};
// Represents a simple worker thread. The implementation must be assumed
// to be single threaded, meaning that all methods of the class, must be
// called from the same thread, including instantiation.
class PlatformThread {
public:
PlatformThread(ThreadRunFunctionDeprecated func,
void* obj,
const char* thread_name);
PlatformThread(ThreadRunFunction func,
void* obj,
const char* thread_name,
ThreadPriority priority = kNormalPriority);
virtual ~PlatformThread();
const std::string& name() const { return name_; }
// Spawns a thread and tries to set thread priority according to the priority
// from when CreateThread was called.
void Start();
bool IsRunning() const;
// Returns an identifier for the worker thread that can be used to do
// thread checks.
PlatformThreadRef GetThreadRef() const;
// Stops (joins) the spawned thread.
void Stop();
// Set the priority of the thread. Must be called when thread is running.
// TODO(tommi): Make private and only allow public support via ctor.
bool SetPriority(ThreadPriority priority);
protected:
#if defined(WEBRTC_WIN)
// Exposed to derived classes to allow for special cases specific to Windows.
bool QueueAPC(PAPCFUNC apc_function, ULONG_PTR data);
#endif
private:
void Run();
ThreadRunFunctionDeprecated const run_function_deprecated_ = nullptr;
ThreadRunFunction const run_function_ = nullptr;
const ThreadPriority priority_ = kNormalPriority;
void* const obj_;
// TODO(pbos): Make sure call sites use string literals and update to a const
// char* instead of a std::string.
const std::string name_;
rtc::ThreadChecker thread_checker_;
rtc::ThreadChecker spawned_thread_checker_;
#if defined(WEBRTC_WIN)
static DWORD WINAPI StartThread(void* param);
bool stop_ = false;
HANDLE thread_ = nullptr;
DWORD thread_id_ = 0;
#else
static void* StartThread(void* param);
// An atomic flag that we use to stop the thread. Only modified on the
// controlling thread and checked on the worker thread.
volatile int stop_flag_ = 0;
pthread_t thread_ = 0;
#endif // defined(WEBRTC_WIN)
RTC_DISALLOW_COPY_AND_ASSIGN(PlatformThread);
};
} // namespace rtc
#endif // WEBRTC_RTC_BASE_PLATFORM_THREAD_H_