[sdl_omap.git] / src / thread / pthread / SDL_sysmutex.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#include <pthread.h>

#include "SDL_thread.h"

#if !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX && \
    !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
#define FAKE_RECURSIVE_MUTEX
#endif

struct SDL_mutex {
	pthread_mutex_t id;
#if FAKE_RECURSIVE_MUTEX
	int recursive;
	pthread_t owner;
#endif
};

SDL_mutex *SDL_CreateMutex (void)
{
	SDL_mutex *mutex;
	pthread_mutexattr_t attr;

	/* Allocate the structure */
	mutex = (SDL_mutex *)SDL_calloc(1, sizeof(*mutex));
	if ( mutex ) {
		pthread_mutexattr_init(&attr);
#if SDL_THREAD_PTHREAD_RECURSIVE_MUTEX
		pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
#elif SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
		pthread_mutexattr_setkind_np(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
#else
		/* No extra attributes necessary */
#endif
		if ( pthread_mutex_init(&mutex->id, &attr) != 0 ) {
			SDL_SetError("pthread_mutex_init() failed");
			SDL_free(mutex);
			mutex = NULL;
		}
	} else {
		SDL_OutOfMemory();
	}
	return(mutex);
}

void SDL_DestroyMutex(SDL_mutex *mutex)
{
	if ( mutex ) {
		pthread_mutex_destroy(&mutex->id);
		SDL_free(mutex);
	}
}

/* Lock the mutex */
int SDL_mutexP(SDL_mutex *mutex)
{
	int retval;
#if FAKE_RECURSIVE_MUTEX
	pthread_t this_thread;
#endif

	if ( mutex == NULL ) {
		SDL_SetError("Passed a NULL mutex");
		return -1;
	}

	retval = 0;
#if FAKE_RECURSIVE_MUTEX
	this_thread = pthread_self();
	if ( mutex->owner == this_thread ) {
		++mutex->recursive;
	} else {
		/* The order of operations is important.
		   We set the locking thread id after we obtain the lock
		   so unlocks from other threads will fail.
		*/
		if ( pthread_mutex_lock(&mutex->id) == 0 ) {
			mutex->owner = this_thread;
			mutex->recursive = 0;
		} else {
			SDL_SetError("pthread_mutex_lock() failed");
			retval = -1;
		}
	}
#else
	if ( pthread_mutex_lock(&mutex->id) < 0 ) {
		SDL_SetError("pthread_mutex_lock() failed");
		retval = -1;
	}
#endif
	return retval;
}

int SDL_mutexV(SDL_mutex *mutex)
{
	int retval;

	if ( mutex == NULL ) {
		SDL_SetError("Passed a NULL mutex");
		return -1;
	}

	retval = 0;
#if FAKE_RECURSIVE_MUTEX
	/* We can only unlock the mutex if we own it */
	if ( pthread_self() == mutex->owner ) {
		if ( mutex->recursive ) {
			--mutex->recursive;
		} else {
			/* The order of operations is important.
			   First reset the owner so another thread doesn't lock
			   the mutex and set the ownership before we reset it,
			   then release the lock semaphore.
			 */
			mutex->owner = 0;
			pthread_mutex_unlock(&mutex->id);
		}
	} else {
		SDL_SetError("mutex not owned by this thread");
		retval = -1;
	}

#else
	if ( pthread_mutex_unlock(&mutex->id) < 0 ) {
		SDL_SetError("pthread_mutex_unlock() failed");
		retval = -1;
	}
#endif /* FAKE_RECURSIVE_MUTEX */

	return retval;
}
Commit	Line	Data
e14743d1	1	/*
	2	SDL - Simple DirectMedia Layer
	3	Copyright (C) 1997-2009 Sam Lantinga
	4
	5	This library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	This library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
	16	License along with this library; if not, write to the Free Software
	17	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	18
	19	Sam Lantinga
	20	slouken@libsdl.org
	21	*/
	22	#include "SDL_config.h"
	23
	24	#include <pthread.h>
	25
	26	#include "SDL_thread.h"
	27
	28	#if !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX && \
	29	!SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
	30	#define FAKE_RECURSIVE_MUTEX
	31	#endif
	32
	33	struct SDL_mutex {
	34	pthread_mutex_t id;
	35	#if FAKE_RECURSIVE_MUTEX
	36	int recursive;
	37	pthread_t owner;
	38	#endif
	39	};
	40
	41	SDL_mutex *SDL_CreateMutex (void)
	42	{
	43	SDL_mutex *mutex;
	44	pthread_mutexattr_t attr;
	45
	46	/* Allocate the structure */
	47	mutex = (SDL_mutex )SDL_calloc(1, sizeof(mutex));
	48	if ( mutex ) {
	49	pthread_mutexattr_init(&attr);
	50	#if SDL_THREAD_PTHREAD_RECURSIVE_MUTEX
	51	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
	52	#elif SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
	53	pthread_mutexattr_setkind_np(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
	54	#else
	55	/* No extra attributes necessary */
	56	#endif
	57	if ( pthread_mutex_init(&mutex->id, &attr) != 0 ) {
	58	SDL_SetError("pthread_mutex_init() failed");
	59	SDL_free(mutex);
	60	mutex = NULL;
	61	}
	62	} else {
	63	SDL_OutOfMemory();
	64	}
65	return(mutex);
66	}
67
68	void SDL_DestroyMutex(SDL_mutex *mutex)
69	{
70	if ( mutex ) {
71	pthread_mutex_destroy(&mutex->id);
72	SDL_free(mutex);
73	}
74	}
75
76	/* Lock the mutex */
77	int SDL_mutexP(SDL_mutex *mutex)
78	{
79	int retval;
80	#if FAKE_RECURSIVE_MUTEX
81	pthread_t this_thread;
82	#endif
83
84	if ( mutex == NULL ) {
85	SDL_SetError("Passed a NULL mutex");
86	return -1;
87	}
88
89	retval = 0;
90	#if FAKE_RECURSIVE_MUTEX
91	this_thread = pthread_self();
92	if ( mutex->owner == this_thread ) {
93	++mutex->recursive;
94	} else {
95	/* The order of operations is important.
96	We set the locking thread id after we obtain the lock
97	so unlocks from other threads will fail.
98	*/
99	if ( pthread_mutex_lock(&mutex->id) == 0 ) {
100	mutex->owner = this_thread;
101	mutex->recursive = 0;
102	} else {
103	SDL_SetError("pthread_mutex_lock() failed");
104	retval = -1;
105	}
106	}
107	#else
108	if ( pthread_mutex_lock(&mutex->id) < 0 ) {
109	SDL_SetError("pthread_mutex_lock() failed");
110	retval = -1;
111	}
112	#endif
113	return retval;
114	}
115
116	int SDL_mutexV(SDL_mutex *mutex)
117	{
118	int retval;
119
120	if ( mutex == NULL ) {
121	SDL_SetError("Passed a NULL mutex");
122	return -1;
123	}
124
125	retval = 0;
126	#if FAKE_RECURSIVE_MUTEX
127	/* We can only unlock the mutex if we own it */
128	if ( pthread_self() == mutex->owner ) {
129	if ( mutex->recursive ) {
130	--mutex->recursive;
131	} else {
132	/* The order of operations is important.
133	First reset the owner so another thread doesn't lock
134	the mutex and set the ownership before we reset it,
135	then release the lock semaphore.
136	*/
137	mutex->owner = 0;
138	pthread_mutex_unlock(&mutex->id);
139	}
140	} else {
141	SDL_SetError("mutex not owned by this thread");
142	retval = -1;
143	}
144
145	#else
146	if ( pthread_mutex_unlock(&mutex->id) < 0 ) {
147	SDL_SetError("pthread_mutex_unlock() failed");
148	retval = -1;
149	}
150	#endif /* FAKE_RECURSIVE_MUTEX */
151
152	return retval;
153	}