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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 "common/common.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/mutex.h"
#include "core/hle/kernel/thread.h"
namespace Kernel {
class Mutex : public WaitObject {
public:
std::string GetTypeName() const override { return "Mutex"; }
std::string GetName() const override { return name; }
static const HandleType HANDLE_TYPE = HandleType::Mutex;
HandleType GetHandleType() const override { return HANDLE_TYPE; }
bool initial_locked; ///< Initial lock state when mutex was created
bool locked; ///< Current locked state
Handle lock_thread; ///< Handle to thread that currently has mutex
std::string name; ///< Name of mutex (optional)
SharedPtr<Thread> current_thread; ///< Thread that has acquired the mutex
bool ShouldWait() override;
void Acquire() override;
};
////////////////////////////////////////////////////////////////////////////////////////////////////
typedef std::multimap<Handle, Handle> MutexMap;
static MutexMap g_mutex_held_locks;
/**
* Acquires the specified mutex for the specified thread
* @param mutex Mutex that is to be acquired
* @param thread Thread that will acquired
*/
void MutexAcquireLock(Mutex* mutex, Handle thread = GetCurrentThread()->GetHandle()) {
g_mutex_held_locks.insert(std::make_pair(thread, mutex->GetHandle()));
mutex->lock_thread = thread;
mutex->current_thread = Kernel::g_handle_table.Get<Thread>(thread);
}
/**
* Resumes a thread waiting for the specified mutex
* @param mutex The mutex that some thread is waiting on
*/
void ResumeWaitingThread(Mutex* mutex) {
// Find the next waiting thread for the mutex...
auto next_thread = mutex->ReleaseNextThread();
if (next_thread != nullptr) {
MutexAcquireLock(mutex, next_thread->GetHandle());
} else {
// Reset mutex lock thread handle, nothing is waiting
mutex->locked = false;
mutex->lock_thread = -1;
}
}
void MutexEraseLock(Mutex* mutex) {
Handle handle = mutex->GetHandle();
auto locked = g_mutex_held_locks.equal_range(mutex->lock_thread);
for (MutexMap::iterator iter = locked.first; iter != locked.second; ++iter) {
if (iter->second == handle) {
g_mutex_held_locks.erase(iter);
break;
}
}
mutex->lock_thread = -1;
}
void ReleaseThreadMutexes(Handle thread) {
auto locked = g_mutex_held_locks.equal_range(thread);
// Release every mutex that the thread holds, and resume execution on the waiting threads
for (MutexMap::iterator iter = locked.first; iter != locked.second; ++iter) {
Mutex* mutex = g_handle_table.Get<Mutex>(iter->second).get();
ResumeWaitingThread(mutex);
}
// Erase all the locks that this thread holds
g_mutex_held_locks.erase(thread);
}
bool LockMutex(Mutex* mutex) {
// Mutex alread locked?
if (mutex->locked) {
return false;
}
MutexAcquireLock(mutex);
return true;
}
bool ReleaseMutex(Mutex* mutex) {
MutexEraseLock(mutex);
ResumeWaitingThread(mutex);
return true;
}
/**
* Releases a mutex
* @param handle Handle to mutex to release
*/
ResultCode ReleaseMutex(Handle handle) {
Mutex* mutex = Kernel::g_handle_table.Get<Mutex>(handle).get();
if (mutex == nullptr) return InvalidHandle(ErrorModule::Kernel);
if (!ReleaseMutex(mutex)) {
// TODO(yuriks): Verify error code, this one was pulled out of thin air. I'm not even sure
// what error condition this is supposed to be signaling.
return ResultCode(ErrorDescription::AlreadyDone, ErrorModule::Kernel,
ErrorSummary::NothingHappened, ErrorLevel::Temporary);
}
return RESULT_SUCCESS;
}
/**
* Creates a mutex
* @param handle Reference to handle for the newly created mutex
* @param initial_locked Specifies if the mutex should be locked initially
* @param name Optional name of mutex
* @return Pointer to new Mutex object
*/
Mutex* CreateMutex(Handle& handle, bool initial_locked, const std::string& name) {
Mutex* mutex = new Mutex;
// TODO(yuriks): Fix error reporting
handle = Kernel::g_handle_table.Create(mutex).ValueOr(INVALID_HANDLE);
mutex->locked = mutex->initial_locked = initial_locked;
mutex->name = name;
mutex->current_thread = nullptr;
// Acquire mutex with current thread if initialized as locked...
if (mutex->locked) {
MutexAcquireLock(mutex);
// Otherwise, reset lock thread handle
} else {
mutex->lock_thread = -1;
}
return mutex;
}
/**
* Creates a mutex
* @param initial_locked Specifies if the mutex should be locked initially
* @param name Optional name of mutex
* @return Handle to newly created object
*/
Handle CreateMutex(bool initial_locked, const std::string& name) {
Handle handle;
Mutex* mutex = CreateMutex(handle, initial_locked, name);
return handle;
}
bool Mutex::ShouldWait() {
return locked && current_thread != GetCurrentThread();
}
void Mutex::Acquire() {
_assert_msg_(Kernel, !ShouldWait(), "object unavailable!");
locked = true;
MutexAcquireLock(this);
}
} // namespace
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