lavu: add thread message API.

1 files changed, 184 insertions, 0 deletions

diff --git a/libavutil/threadmessage.c b/libavutil/threadmessage.c
new file mode 100644
index 0000000000..b7fcbe28c0
--- /dev/null
+++ b/libavutil/threadmessage.c
@@ -0,0 +1,184 @@
+/*
+ * 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 */
+}