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// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <map>
#include <vector>
#include <boost/range/algorithm_ext/erase.hpp>
#include "common/common.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/mutex.h"
#include "core/hle/kernel/thread.h"
namespace Kernel {
/**
* Resumes a thread waiting for the specified mutex
* @param mutex The mutex that some thread is waiting on
*/
static void ResumeWaitingThread(Mutex* mutex) {
// Reset mutex lock thread handle, nothing is waiting
mutex->lock_count = 0;
mutex->holding_thread = nullptr;
// Find the next waiting thread for the mutex...
auto next_thread = mutex->WakeupNextThread();
if (next_thread != nullptr) {
mutex->Acquire(next_thread);
}
}
void ReleaseThreadMutexes(Thread* thread) {
for (auto& mtx : thread->held_mutexes) {
ResumeWaitingThread(mtx.get());
}
thread->held_mutexes.clear();
}
Mutex::Mutex() {}
Mutex::~Mutex() {}
SharedPtr<Mutex> Mutex::Create(bool initial_locked, std::string name) {
SharedPtr<Mutex> mutex(new Mutex);
mutex->lock_count = 0;
mutex->name = std::move(name);
mutex->holding_thread = nullptr;
// Acquire mutex with current thread if initialized as locked...
if (initial_locked)
mutex->Acquire();
return mutex;
}
bool Mutex::ShouldWait() {
return lock_count > 0 && holding_thread != GetCurrentThread();;
}
void Mutex::Acquire() {
Acquire(GetCurrentThread());
}
void Mutex::Acquire(SharedPtr<Thread> thread) {
_assert_msg_(Kernel, !ShouldWait(), "object unavailable!");
// Actually "acquire" the mutex only if we don't already have it...
if (lock_count == 0) {
thread->held_mutexes.insert(this);
holding_thread = std::move(thread);
}
lock_count++;
}
void Mutex::Release() {
// Only release if the mutex is held...
if (lock_count > 0) {
lock_count--;
// Yield to the next thread only if we've fully released the mutex...
if (lock_count == 0) {
holding_thread->held_mutexes.erase(this);
ResumeWaitingThread(this);
}
}
}
} // namespace
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