ffmpeg/libavutil/threadmessage.c

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2014-02-20 13:14:34 +00:00
/*
* Copyright (c) 2014 Nicolas George
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "fifo.h"
#include "threadmessage.h"
#if HAVE_THREADS
#if HAVE_PTHREADS
#include <pthread.h>
#elif HAVE_W32THREADS
#include "compat/w32pthreads.h"
#elif HAVE_OS2THREADS
#include "compat/os2threads.h"
#else
#error "Unknown threads implementation"
#endif
#endif
struct AVThreadMessageQueue {
#if HAVE_THREADS
AVFifoBuffer *fifo;
pthread_mutex_t lock;
pthread_cond_t cond;
int err_send;
int err_recv;
unsigned elsize;
#else
int dummy;
#endif
};
int av_thread_message_queue_alloc(AVThreadMessageQueue **mq,
unsigned nelem,
unsigned elsize)
{
#if HAVE_THREADS
AVThreadMessageQueue *rmq;
int ret = 0;
if (nelem > INT_MAX / elsize)
return AVERROR(EINVAL);
if (!(rmq = av_mallocz(sizeof(*rmq))))
return AVERROR(ENOMEM);
if ((ret = pthread_mutex_init(&rmq->lock, NULL))) {
av_free(rmq);
return AVERROR(ret);
}
if ((ret = pthread_cond_init(&rmq->cond, NULL))) {
pthread_mutex_destroy(&rmq->lock);
av_free(rmq);
return AVERROR(ret);
}
if (!(rmq->fifo = av_fifo_alloc(elsize * nelem))) {
pthread_cond_destroy(&rmq->cond);
pthread_mutex_destroy(&rmq->lock);
av_free(rmq);
return AVERROR(ret);
}
rmq->elsize = elsize;
*mq = rmq;
return 0;
#else
*mq = NULL;
return AVERROR(ENOSYS);
#endif /* HAVE_THREADS */
}
void av_thread_message_queue_free(AVThreadMessageQueue **mq)
{
#if HAVE_THREADS
if (*mq) {
av_fifo_freep(&(*mq)->fifo);
pthread_cond_destroy(&(*mq)->cond);
pthread_mutex_destroy(&(*mq)->lock);
av_freep(mq);
}
#endif
}
#if HAVE_THREADS
static int av_thread_message_queue_send_locked(AVThreadMessageQueue *mq,
void *msg,
unsigned flags)
{
while (!mq->err_send && av_fifo_space(mq->fifo) < mq->elsize) {
if ((flags & AV_THREAD_MESSAGE_NONBLOCK))
return AVERROR(EAGAIN);
pthread_cond_wait(&mq->cond, &mq->lock);
}
if (mq->err_send)
return mq->err_send;
av_fifo_generic_write(mq->fifo, msg, mq->elsize, NULL);
pthread_cond_signal(&mq->cond);
return 0;
}
static int av_thread_message_queue_recv_locked(AVThreadMessageQueue *mq,
void *msg,
unsigned flags)
{
while (!mq->err_recv && av_fifo_size(mq->fifo) < mq->elsize) {
if ((flags & AV_THREAD_MESSAGE_NONBLOCK))
return AVERROR(EAGAIN);
pthread_cond_wait(&mq->cond, &mq->lock);
}
if (av_fifo_size(mq->fifo) < mq->elsize)
return mq->err_recv;
av_fifo_generic_read(mq->fifo, msg, mq->elsize, NULL);
pthread_cond_signal(&mq->cond);
return 0;
}
#endif /* HAVE_THREADS */
int av_thread_message_queue_send(AVThreadMessageQueue *mq,
void *msg,
unsigned flags)
{
#if HAVE_THREADS
int ret;
pthread_mutex_lock(&mq->lock);
ret = av_thread_message_queue_send_locked(mq, msg, flags);
pthread_mutex_unlock(&mq->lock);
return ret;
#else
return AVERROR(ENOSYS);
#endif /* HAVE_THREADS */
}
int av_thread_message_queue_recv(AVThreadMessageQueue *mq,
void *msg,
unsigned flags)
{
#if HAVE_THREADS
int ret;
pthread_mutex_lock(&mq->lock);
ret = av_thread_message_queue_recv_locked(mq, msg, flags);
pthread_mutex_unlock(&mq->lock);
return ret;
#else
return AVERROR(ENOSYS);
#endif /* HAVE_THREADS */
}
void av_thread_message_queue_set_err_send(AVThreadMessageQueue *mq,
int err)
{
#if HAVE_THREADS
pthread_mutex_lock(&mq->lock);
mq->err_send = err;
pthread_cond_broadcast(&mq->cond);
pthread_mutex_unlock(&mq->lock);
#endif /* HAVE_THREADS */
}
void av_thread_message_queue_set_err_recv(AVThreadMessageQueue *mq,
int err)
{
#if HAVE_THREADS
pthread_mutex_lock(&mq->lock);
mq->err_recv = err;
pthread_cond_broadcast(&mq->cond);
pthread_mutex_unlock(&mq->lock);
#endif /* HAVE_THREADS */
}