/*

   Simple DirectMedia Layer

   Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>

   This software is provided 'as-is', without any express or implied

   warranty.  In no event will the authors be held liable for any damages

   arising from the use of this software.

   Permission is granted to anyone to use this software for any purpose,

   including commercial applications, and to alter it and redistribute it

   freely, subject to the following restrictions:

   1. The origin of this software must not be misrepresented; you must not

      claim that you wrote the original software. If you use this software

      in a product, an acknowledgment in the product documentation would be

      appreciated but is not required.

   2. Altered source versions must be plainly marked as such, and must not be

      misrepresented as being the original software.

   3. This notice may not be removed or altered from any source distribution.

 */

 #include "SDL_config.h"

 #define _GNU_SOURCE

 #include <pthread.h>

 #include <errno.h>

 #include "SDL_thread.h"

 #if !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX && \

     !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP

 #define FAKE_RECURSIVE_MUTEX 1

 #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_LockMutex(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_TryLockMutex(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 if (errno == EBUSY) {

             retval = SDL_MUTEX_TIMEDOUT;

         } else {

             SDL_SetError("pthread_mutex_trylock() failed");

             retval = -1;

         }

     }

 #else

     if (pthread_mutex_trylock(&mutex->id) != 0) {

         if (errno == EBUSY) {

             retval = SDL_MUTEX_TIMEDOUT;

         } else {

             SDL_SetError("pthread_mutex_trylock() failed");

             retval = -1;

         }

     }

 #endif

     return retval;

 }

 int

 SDL_UnlockMutex(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;

 }

 /* vi: set ts=4 sw=4 expandtab: */