[FFmpeg-devel] [PATCH 48/49] fftools: add a multistream thread-safe queue
Anton Khirnov
anton at khirnov.net
Mon Apr 4 14:30:36 EEST 2022
It is similar to AVThreadMessageQueue, but supports multiple streams,
each with its own EOF state.
---
fftools/Makefile | 1 +
fftools/thread_queue.c | 232 +++++++++++++++++++++++++++++++++++++++++
fftools/thread_queue.h | 37 +++++++
3 files changed, 270 insertions(+)
create mode 100644 fftools/thread_queue.c
create mode 100644 fftools/thread_queue.h
diff --git a/fftools/Makefile b/fftools/Makefile
index f015df6846..b0de4f4c61 100644
--- a/fftools/Makefile
+++ b/fftools/Makefile
@@ -15,6 +15,7 @@ OBJS-ffmpeg += \
fftools/ffmpeg_mux.o \
fftools/ffmpeg_opt.o \
fftools/sync_queue.o \
+ fftools/thread_queue.o \
define DOFFTOOL
OBJS-$(1) += fftools/cmdutils.o fftools/opt_common.o fftools/$(1).o $(OBJS-$(1)-yes)
diff --git a/fftools/thread_queue.c b/fftools/thread_queue.c
new file mode 100644
index 0000000000..9ec02ca772
--- /dev/null
+++ b/fftools/thread_queue.c
@@ -0,0 +1,232 @@
+/*
+ * 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 <string.h>
+
+#include "libavutil/avassert.h"
+#include "libavutil/error.h"
+#include "libavutil/fifo.h"
+#include "libavutil/mem.h"
+#include "libavutil/thread.h"
+
+#include "thread_queue.h"
+
+enum {
+ FINISHED_SEND = (1 << 0),
+ FINISHED_RECV = (1 << 1),
+};
+
+typedef struct ThreadQueueStream {
+ AVFifo *fifo;
+ int finished;
+} ThreadQueueStream;
+
+struct ThreadQueue {
+ ThreadQueueStream *streams;
+ unsigned int nb_streams;
+
+ void (*elem_free)(void *);
+
+ pthread_mutex_t lock;
+ pthread_cond_t cond;
+};
+
+void tq_free(ThreadQueue **ptq)
+{
+ ThreadQueue *tq = *ptq;
+
+ if (!tq)
+ return;
+
+ for (unsigned int i = 0; i < tq->nb_streams; i++) {
+ ThreadQueueStream *st = &tq->streams[i];
+
+ if (st->fifo && tq->elem_free) {
+ void *elem;
+ while (av_fifo_read(st->fifo, &elem, 1) >= 0)
+ tq->elem_free(elem);
+ }
+ av_fifo_freep2(&tq->streams[i].fifo);
+ }
+ av_freep(&tq->streams);
+
+ pthread_cond_destroy(&tq->cond);
+ pthread_mutex_destroy(&tq->lock);
+
+ av_freep(ptq);
+}
+
+ThreadQueue *tq_alloc(unsigned int nb_streams,
+ size_t nb_elems, size_t elem_size,
+ void (*elem_free)(void *))
+{
+ ThreadQueue *tq;
+ int ret;
+
+ tq = av_mallocz(sizeof(*tq));
+ if (!tq)
+ return NULL;
+
+ tq->elem_free = elem_free;
+
+ ret = pthread_cond_init(&tq->cond, NULL);
+ if (ret) {
+ av_freep(&tq);
+ return NULL;
+ }
+
+ ret = pthread_mutex_init(&tq->lock, NULL);
+ if (ret) {
+ pthread_cond_destroy(&tq->cond);
+ av_freep(&tq);
+ return NULL;
+ }
+
+ tq->streams = av_calloc(nb_streams, sizeof(*tq->streams));
+ if (!tq->streams)
+ goto fail;
+ tq->nb_streams = nb_streams;
+
+ for (unsigned int i = 0; i < nb_streams; i++) {
+ ThreadQueueStream *st = &tq->streams[i];
+
+ st->fifo = av_fifo_alloc2(nb_elems, elem_size, 0);
+ if (!st->fifo)
+ goto fail;
+ }
+
+ return tq;
+fail:
+ tq_free(&tq);
+ return NULL;
+}
+
+int tq_send(ThreadQueue *tq, unsigned int stream_idx, void *data)
+{
+ ThreadQueueStream *st;
+ int ret;
+
+ av_assert0(stream_idx < tq->nb_streams);
+ st = &tq->streams[stream_idx];
+
+ pthread_mutex_lock(&tq->lock);
+
+ if (st->finished & FINISHED_SEND) {
+ ret = AVERROR(EINVAL);
+ goto finish;
+ }
+
+ while (!(st->finished & FINISHED_RECV) && !av_fifo_can_write(st->fifo))
+ pthread_cond_wait(&tq->cond, &tq->lock);
+
+ if (st->finished & FINISHED_RECV)
+ ret = AVERROR_EOF;
+ else {
+ ret = av_fifo_write(st->fifo, data, 1);
+ if (ret >= 0)
+ pthread_cond_broadcast(&tq->cond);
+ }
+
+finish:
+ pthread_mutex_unlock(&tq->lock);
+
+ return ret;
+}
+
+static int receive_locked(ThreadQueue *tq, int *stream_idx,
+ void *data)
+{
+ unsigned int nb_finished = 0;
+
+ for (unsigned int i = 0; i < tq->nb_streams; i++) {
+ ThreadQueueStream *st = &tq->streams[i];
+
+ if (av_fifo_read(st->fifo, data, 1) >= 0) {
+ *stream_idx = i;
+ return 0;
+ }
+
+ if (st->finished & FINISHED_SEND) {
+ /* return EOF to the consumer at most once for each stream */
+ if (!(st->finished & FINISHED_RECV)) {
+ st->finished |= FINISHED_RECV;
+ *stream_idx = i;
+ return AVERROR_EOF;
+ }
+
+ nb_finished++;
+ }
+ }
+
+ return nb_finished == tq->nb_streams ? AVERROR_EOF : AVERROR(EAGAIN);
+}
+
+int tq_receive(ThreadQueue *tq, int *stream_idx, void *data)
+{
+ int ret;
+
+ *stream_idx = -1;
+
+ pthread_mutex_lock(&tq->lock);
+
+ while (1) {
+ ret = receive_locked(tq, stream_idx, data);
+ if (ret == AVERROR(EAGAIN)) {
+ pthread_cond_wait(&tq->cond, &tq->lock);
+ continue;
+ }
+
+ break;
+ }
+
+ if (ret == 0)
+ pthread_cond_broadcast(&tq->cond);
+
+ pthread_mutex_unlock(&tq->lock);
+
+ return ret;
+}
+
+void tq_send_finish(ThreadQueue *tq, unsigned int stream_idx)
+{
+ av_assert0(stream_idx < tq->nb_streams);
+
+ pthread_mutex_lock(&tq->lock);
+
+ /* mark the stream as send-finished;
+ * the next time the consumer thread tries to read this stream it will get
+ * and EOF and recv-finished flag will be set */
+ tq->streams[stream_idx].finished |= FINISHED_SEND;
+ pthread_cond_broadcast(&tq->cond);
+
+ pthread_mutex_unlock(&tq->lock);
+}
+
+void tq_receive_finish(ThreadQueue *tq, unsigned int stream_idx)
+{
+ av_assert0(stream_idx < tq->nb_streams);
+
+ pthread_mutex_lock(&tq->lock);
+
+ /* mark the stream as send/recv-finished;
+ * both send AND recvs for this stream will now return EOF */
+ tq->streams[stream_idx].finished |= FINISHED_SEND | FINISHED_RECV;
+ pthread_cond_broadcast(&tq->cond);
+
+ pthread_mutex_unlock(&tq->lock);
+}
diff --git a/fftools/thread_queue.h b/fftools/thread_queue.h
new file mode 100644
index 0000000000..aaf491fe3c
--- /dev/null
+++ b/fftools/thread_queue.h
@@ -0,0 +1,37 @@
+/*
+ * 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
+ */
+
+#ifndef FFTOOLS_THREAD_QUEUE_H
+#define FFTOOLS_THREAD_QUEUE_H
+
+#include <string.h>
+
+typedef struct ThreadQueue ThreadQueue;
+
+ThreadQueue *tq_alloc(unsigned int nb_streams,
+ size_t nb_elems, size_t elem_size,
+ void (*elem_free)(void *));
+void tq_free(ThreadQueue **tq);
+
+int tq_send(ThreadQueue *tq, unsigned int stream_idx, void *data);
+void tq_send_finish(ThreadQueue *tq, unsigned int stream_idx);
+
+int tq_receive(ThreadQueue *tq, int *stream_idx, void *data);
+void tq_receive_finish(ThreadQueue *tq, unsigned int stream_idx);
+
+#endif // FFTOOLS_THREAD_QUEUE_H
--
2.34.1
More information about the ffmpeg-devel
mailing list