mutex.h

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/**
 * @file mutex.h
 * @brief Mutex synchronization primitive.
 * @author plutoo
 * @copyright libnx Authors
 */
#pragma once
#include <sys/lock.h>
#include "../types.h"
 
/// Mutex datatype, defined in newlib.
typedef _LOCK_T Mutex;
/// Recursive mutex datatype, defined in newlib.
typedef _LOCK_RECURSIVE_T RMutex;
 
/**
 * @brief Initializes a mutex.
 * @param m Mutex object.
 * @note A mutex can also be statically initialized by assigning 0 to it.
 */
static inline void mutexInit(Mutex* m)
{
    *m = INVALID_HANDLE;
}
 
/**
 * @brief Locks a mutex.
 * @param m Mutex object.
 */
void mutexLock(Mutex* m);
 
/**
 * @brief Attempts to lock a mutex without waiting.
 * @param m Mutex object.
 * @return 1 if the mutex has been acquired successfully, and 0 on contention.
 */
bool mutexTryLock(Mutex* m);
 
/**
 * @brief Unlocks a mutex.
 * @param m Mutex object.
 */
void mutexUnlock(Mutex* m);
 
/**
 * @brief Gets whether the current thread owns the mutex.
 * @param m Mutex object.
 * @return 1 if the mutex is locked by the current thread, and 0 otherwise.
 */
bool mutexIsLockedByCurrentThread(const Mutex* m);
 
/**
 * @brief Initializes a recursive mutex.
 * @param m Recursive mutex object.
 * @note A recursive mutex can also be statically initialized by assigning {0,0,0} to it.
 */
static inline void rmutexInit(RMutex* m)
{
    m->lock = 0;
    m->thread_tag = 0;
    m->counter = 0;
}
 
/**
 * @brief Locks a recursive mutex.
 * @param m Recursive mutex object.
 */
void rmutexLock(RMutex* m);
 
/**
 * @brief Attempts to lock a recursive mutex without waiting.
 * @param m Recursive mutex object.
 * @return 1 if the mutex has been acquired successfully, and 0 on contention.
 */
bool rmutexTryLock(RMutex* m);
 
/**
 * @brief Unlocks a recursive mutex.
 * @param m Recursive mutex object.
 */
void rmutexUnlock(RMutex* m);