/*
  * 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 */
 }