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// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
// Multithreaded event class. This allows waiting in a thread for an event to
// be triggered in another thread. While waiting, the CPU will be available for
// other tasks.
// * Set(): triggers the event and wakes up the waiting thread.
// * Wait(): waits for the event to be triggered.
// * Reset(): tries to reset the event before the waiting thread sees it was
// triggered. Usually a bad idea.
#pragma once
#ifdef _WIN32
#include <concrt.h>
#endif
#include <chrono>
#include <condition_variable>
#include <mutex>
#include "Common/Flag.h"
namespace Common {
class Event final
{
public:
void Set()
{
if (m_flag.TestAndSet())
{
std::lock_guard<std::mutex> lk(m_mutex);
m_condvar.notify_one();
}
}
void Wait()
{
if (m_flag.TestAndClear())
return;
std::unique_lock<std::mutex> lk(m_mutex);
m_condvar.wait(lk, [&]{ return m_flag.TestAndClear(); });
}
template<class Rep, class Period>
bool WaitFor(const std::chrono::duration<Rep, Period>& rel_time)
{
if (m_flag.TestAndClear())
return true;
std::unique_lock<std::mutex> lk(m_mutex);
bool signaled = m_condvar.wait_for(lk, rel_time,
[&]{ return m_flag.TestAndClear(); });
return signaled;
}
void Reset()
{
// no other action required, since wait loops on
// the predicate and any lingering signal will get
// cleared on the first iteration
m_flag.Clear();
}
private:
Flag m_flag;
std::condition_variable m_condvar;
std::mutex m_mutex;
};
} // namespace Common
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