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/*
* Copyright (C) 2014 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef WaitableEvent_h
#define WaitableEvent_h
#include "platform/PlatformExport.h"
#include "wtf/Vector.h"
#include <memory>
namespace base {
class WaitableEvent;
}; // namespace base
namespace blink {
// Provides a thread synchronization that can be used to allow one thread to
// wait until another thread to finish some work.
class PLATFORM_EXPORT WaitableEvent {
public:
// If ResetPolicy::Manual is specified on creation, to set the event state
// to non-signaled, a consumer must call reset(). Otherwise, the system
// automatically resets the event state to non-signaled after a single
// waiting thread has been released.
enum class ResetPolicy { Auto, Manual };
// Specify the initial state on creation.
enum class InitialState { NonSignaled, Signaled };
explicit WaitableEvent(ResetPolicy = ResetPolicy::Auto,
InitialState = InitialState::NonSignaled);
~WaitableEvent();
// Puts the event in the un-signaled state.
void reset();
// Waits indefinitely for the event to be signaled.
void wait();
// Puts the event in the signaled state. Causing any thread blocked on Wait
// to be woken up. The event state is reset to non-signaled after
// a waiting thread has been released.
void signal();
// Waits on multiple events and returns the index of the object that
// has been signaled. Any event objects given to this method must
// not deleted while this wait is happening.
static size_t waitMultiple(const WTF::Vector<WaitableEvent*>& events);
private:
WaitableEvent(const WaitableEvent&) = delete;
void operator=(const WaitableEvent&) = delete;
std::unique_ptr<base::WaitableEvent> m_impl;
};
} // namespace blink
#endif // WaitableEvent_h
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