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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 RTC_BASE_PLATFORM_UITHREAD_H_
#define RTC_BASE_PLATFORM_UITHREAD_H_
#if defined(WEBRTC_WIN)
# include "Assertions.h"
# include "rtc_base/deprecated/recursive_critical_section.h"
# include "rtc_base/platform_thread.h"
# include "api/sequence_checker.h"
# include "ThreadSafety.h"
namespace rtc {
/*
* Windows UI thread for screen capture
* Launches a thread which enters a message wait loop after calling the
* provided ThreadRunFunction once. A repeating timer event might be registered
* with a callback through the Win32 API. If so, that timer will cause WM_TIMER
* messages to appear in the threads message queue. This will wake the thread
* which will then first look to see if it received the WM_QUIT message, then
* it will pass any non WM_QUIT messages on to the registered message handlers
* (synchronously on the current thread). In the case oF WM_TIMER the
* registered handler calls the NativeEventCallback which is simply the
* ThreadRunFunction which was passed to the constructor.
*
* Shutdown of the message wait loop is triggered by sending a WM_CLOSE which
* will start tearing down the "window" which hosts the UI thread. This will
* cause a WM_DESTROY message to be received. Upon reception a WM_QUIT message
* is enqueued. When the message wait loop receives a WM_QUIT message it stops,
* thus allowing the thread to be joined.
*
* Note: that the only source of a WM_CLOSE should be PlatformUIThread::Stop.
* Note: because PlatformUIThread::Stop is called from a different thread than
* PlatformUIThread::Run, it is possible that Stop can race Run.
*
* After being stopped PlatformUIThread can not be started again.
*
*/
class PlatformUIThread {
public:
PlatformUIThread(std::function<void()> func, const char* name,
ThreadAttributes attributes)
: name_(name),
native_event_callback_(std::move(func)),
monitor_thread_(PlatformThread::SpawnJoinable([this]() { Run(); }, name,
attributes)) {}
virtual ~PlatformUIThread();
void Stop();
/**
* Request a recurring callback.
*/
bool RequestCallbackTimer(unsigned int milliseconds);
protected:
void Run();
private:
static LRESULT CALLBACK EventWindowProc(HWND, UINT, WPARAM, LPARAM);
void NativeEventCallback();
// Initialize the UI thread that is servicing the timer events
bool InternalInit();
// Needs to be initialized before monitor_thread_ as it takes a string view to
// name_
std::string name_;
RecursiveCriticalSection cs_;
std::function<void()> native_event_callback_;
webrtc::SequenceChecker thread_checker_;
PlatformThread monitor_thread_;
HWND hwnd_ MOZ_GUARDED_BY(cs_) = nullptr;
UINT_PTR timerid_ MOZ_GUARDED_BY(cs_) = 0;
unsigned int timeout_ MOZ_GUARDED_BY(cs_) = 0;
enum class State {
UNSTARTED,
STARTED,
STOPPED,
};
State state_ MOZ_GUARDED_BY(cs_) = State::UNSTARTED;
};
} // namespace rtc
#endif
#endif // RTC_BASE_PLATFORM_UITHREAD_H_
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