dolphin/Source/Core/Common/Event.h

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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
#include "Common/StdConditionVariable.h"
#include "Common/StdMutex.h"
namespace Common {
class Event
{
public:
Event()
: is_set(false)
{}
void Set()
{
std::lock_guard<std::mutex> lk(m_mutex);
if (!is_set)
{
is_set = true;
m_condvar.notify_one();
}
}
void Wait()
{
std::unique_lock<std::mutex> lk(m_mutex);
m_condvar.wait(lk, [&]{ return is_set; });
is_set = false;
}
void Reset()
{
std::unique_lock<std::mutex> lk(m_mutex);
// no other action required, since wait loops on
// the predicate and any lingering signal will get
// cleared on the first iteration
is_set = false;
}
private:
volatile bool is_set;
std::condition_variable m_condvar;
std::mutex m_mutex;
};
} // namespace Common