mirror of
https://github.com/dolphin-emu/dolphin.git
synced 2024-09-20 19:31:53 +02:00
e149ad4f0a
SPDX standardizes how source code conveys its copyright and licensing information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX tags are adopted in many large projects, including things like the Linux kernel.
84 lines
2.1 KiB
C++
84 lines
2.1 KiB
C++
// Copyright 2014 Dolphin Emulator Project
|
|
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
|
|
// 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())
|
|
{
|
|
// Lock and immediately unlock m_mutex.
|
|
{
|
|
// Holding the lock at any time between the change of our flag and notify call
|
|
// is sufficient to prevent a race where both of these actions
|
|
// happen between the other thread's predicate test and wait call
|
|
// which would cause wait to block until the next spurious wakeup or timeout.
|
|
|
|
// Unlocking before notification is a micro-optimization to prevent
|
|
// the notified thread from immediately blocking on the mutex.
|
|
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
|