gstreamer/subprojects/gst-libav/ext/libav/gstavprotocol.c
Sebastian Dröge 7daa040d24 avdemux: Never return 0 from read function
Instead return AVERROR_EOF. The read function must never ever return 0 according
to the documentation, and in practice this leads to infinite loops.

Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/3369

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7390>
2024-08-21 11:05:11 +03:00

373 lines
8.7 KiB
C

/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
* <2006> Edward Hervey <bilboed@bilboed.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <errno.h>
#include <libavformat/avformat.h>
#include <gst/gst.h>
#include "gstav.h"
#include "gstavprotocol.h"
typedef struct _GstProtocolInfo GstProtocolInfo;
struct _GstProtocolInfo
{
GstPad *pad;
guint64 offset;
gboolean eos;
gint set_streamheader;
};
static int
gst_ffmpegdata_peek (void *priv_data, unsigned char *buf, int size)
{
GstProtocolInfo *info;
GstBuffer *inbuf = NULL;
GstFlowReturn ret;
int total = 0;
info = (GstProtocolInfo *) priv_data;
GST_DEBUG ("Pulling %d bytes at position %" G_GUINT64_FORMAT, size,
info->offset);
ret = gst_pad_pull_range (info->pad, info->offset, (guint) size, &inbuf);
switch (ret) {
case GST_FLOW_OK:
total = (gint) gst_buffer_get_size (inbuf);
gst_buffer_extract (inbuf, 0, buf, total);
gst_buffer_unref (inbuf);
break;
case GST_FLOW_EOS:
total = 0;
break;
case GST_FLOW_FLUSHING:
total = -1;
break;
default:
case GST_FLOW_ERROR:
total = -2;
break;
}
GST_DEBUG ("Got %d (%s) return result %d", ret, gst_flow_get_name (ret),
total);
return total;
}
static int
gst_ffmpegdata_read (void *priv_data, unsigned char *buf, int size)
{
gint res;
GstProtocolInfo *info;
info = (GstProtocolInfo *) priv_data;
GST_DEBUG ("Reading %d bytes of data at position %" G_GUINT64_FORMAT, size,
info->offset);
res = gst_ffmpegdata_peek (priv_data, buf, size);
if (res >= 0)
info->offset += res;
GST_DEBUG ("Returning %d bytes", res);
return res == 0 ? AVERROR_EOF : res;
}
static int
#if LIBAVUTIL_VERSION_MAJOR >= 59
gst_ffmpegdata_write (void *priv_data, const uint8_t * buf, int size)
#else
gst_ffmpegdata_write (void *priv_data, uint8_t * buf, int size)
#endif
{
GstProtocolInfo *info;
GstBuffer *outbuf;
GST_DEBUG ("Writing %d bytes", size);
info = (GstProtocolInfo *) priv_data;
/* create buffer and push data further */
outbuf = gst_buffer_new_and_alloc (size);
gst_buffer_fill (outbuf, 0, buf, size);
if (gst_pad_push (info->pad, outbuf) != GST_FLOW_OK)
return 0;
info->offset += size;
return size;
}
static int64_t
gst_ffmpegdata_seek (void *priv_data, int64_t pos, int whence)
{
GstProtocolInfo *info;
guint64 newpos = 0, oldpos;
GST_DEBUG ("Seeking to %" G_GINT64_FORMAT ", whence=%d",
(gint64) pos, whence);
info = (GstProtocolInfo *) priv_data;
/* TODO : if we are push-based, we need to return sensible info */
if (GST_PAD_IS_SINK (info->pad)) {
/* sinkpad */
switch (whence) {
case SEEK_SET:
newpos = (guint64) pos;
break;
case SEEK_CUR:
newpos = info->offset + pos;
break;
case SEEK_END:
case AVSEEK_SIZE:
/* ffmpeg wants to know the current end position in bytes ! */
{
gint64 duration;
GST_DEBUG ("Seek end");
if (gst_pad_is_linked (info->pad))
if (gst_pad_query_duration (GST_PAD_PEER (info->pad),
GST_FORMAT_BYTES, &duration))
newpos = ((guint64) duration) + pos;
}
break;
default:
g_assert (0);
break;
}
/* FIXME : implement case for push-based behaviour */
if (whence != AVSEEK_SIZE)
info->offset = newpos;
} else if (GST_PAD_IS_SRC (info->pad)) {
GstSegment segment;
oldpos = info->offset;
/* srcpad */
switch (whence) {
case SEEK_SET:
{
info->offset = (guint64) pos;
break;
}
case SEEK_CUR:
info->offset += pos;
break;
default:
break;
}
newpos = info->offset;
if (newpos != oldpos) {
gst_segment_init (&segment, GST_FORMAT_BYTES);
segment.start = newpos;
segment.time = newpos;
gst_pad_push_event (info->pad, gst_event_new_segment (&segment));
}
} else {
g_assert_not_reached ();
}
GST_DEBUG ("Now at offset %" G_GUINT64_FORMAT " (returning %" G_GUINT64_FORMAT
")", info->offset, newpos);
return newpos;
}
int
gst_ffmpegdata_close (AVIOContext * h)
{
GstProtocolInfo *info;
if (h == NULL)
return 0;
info = (GstProtocolInfo *) h->opaque;
if (info == NULL)
return 0;
GST_LOG ("Closing file");
if (GST_PAD_IS_SRC (info->pad)) {
/* send EOS - that closes down the stream */
gst_pad_push_event (info->pad, gst_event_new_eos ());
}
/* clean up data */
g_free (info);
h->opaque = NULL;
av_freep (&h->buffer);
av_free (h);
return 0;
}
int
gst_ffmpegdata_open (GstPad * pad, int flags, AVIOContext ** context)
{
GstProtocolInfo *info;
static const int buffer_size = 4096;
unsigned char *buffer = NULL;
info = g_new0 (GstProtocolInfo, 1);
info->set_streamheader = flags & GST_FFMPEG_URL_STREAMHEADER;
flags &= ~GST_FFMPEG_URL_STREAMHEADER;
/* we don't support R/W together */
if ((flags & AVIO_FLAG_WRITE) && (flags & AVIO_FLAG_READ)) {
GST_WARNING ("Only read-only or write-only are supported");
g_free (info);
return -EINVAL;
}
/* make sure we're a pad and that we're of the right type */
g_return_val_if_fail (GST_IS_PAD (pad), -EINVAL);
if ((flags & AVIO_FLAG_READ))
g_return_val_if_fail (GST_PAD_IS_SINK (pad), -EINVAL);
if ((flags & AVIO_FLAG_WRITE))
g_return_val_if_fail (GST_PAD_IS_SRC (pad), -EINVAL);
info->eos = FALSE;
info->pad = pad;
info->offset = 0;
buffer = av_malloc (buffer_size);
if (buffer == NULL) {
GST_WARNING ("Failed to allocate buffer");
g_free (info);
return -ENOMEM;
}
*context =
avio_alloc_context (buffer, buffer_size, flags, (void *) info,
gst_ffmpegdata_read, gst_ffmpegdata_write, gst_ffmpegdata_seek);
if (*context == NULL) {
GST_WARNING ("Failed to allocate memory");
g_free (info);
av_free (buffer);
return -ENOMEM;
}
(*context)->seekable = AVIO_SEEKABLE_NORMAL;
if (!(flags & AVIO_FLAG_WRITE)) {
(*context)->buf_ptr = (*context)->buf_end;
(*context)->write_flag = 0;
}
return 0;
}
/* specialized protocol for cross-thread pushing,
* based on ffmpeg's pipe protocol */
static int
gst_ffmpeg_pipe_read (void *priv_data, uint8_t * buf, int size)
{
GstFFMpegPipe *ffpipe;
guint available;
ffpipe = (GstFFMpegPipe *) priv_data;
GST_LOG ("requested size %d", size);
GST_FFMPEG_PIPE_MUTEX_LOCK (ffpipe);
GST_LOG ("requested size %d", size);
while ((available = gst_adapter_available (ffpipe->adapter)) < size
&& !ffpipe->eos) {
GST_DEBUG ("Available:%d, requested:%d", available, size);
ffpipe->needed = size;
GST_FFMPEG_PIPE_SIGNAL (ffpipe);
GST_FFMPEG_PIPE_WAIT (ffpipe);
}
size = MIN (available, size);
if (size) {
GST_LOG ("Getting %d bytes", size);
gst_adapter_copy (ffpipe->adapter, buf, 0, size);
gst_adapter_flush (ffpipe->adapter, size);
GST_LOG ("%" G_GSIZE_FORMAT " bytes left in adapter",
gst_adapter_available (ffpipe->adapter));
ffpipe->needed = 0;
}
GST_FFMPEG_PIPE_MUTEX_UNLOCK (ffpipe);
return size > 0 ? size : AVERROR_EOF;
}
int
gst_ffmpeg_pipe_close (AVIOContext * h)
{
GST_LOG ("Closing pipe");
if (h == NULL)
return 0;
h->opaque = NULL;
av_freep (&h->buffer);
av_free (h);
return 0;
}
int
gst_ffmpeg_pipe_open (GstFFMpegPipe * ffpipe, int flags, AVIOContext ** context)
{
static const int buffer_size = 4096;
unsigned char *buffer = NULL;
/* sanity check */
g_return_val_if_fail (GST_IS_ADAPTER (ffpipe->adapter), -EINVAL);
buffer = av_malloc (buffer_size);
if (buffer == NULL) {
GST_WARNING ("Failed to allocate buffer");
return -ENOMEM;
}
*context =
avio_alloc_context (buffer, buffer_size, 0, (void *) ffpipe,
gst_ffmpeg_pipe_read, NULL, NULL);
if (*context == NULL) {
GST_WARNING ("Failed to allocate memory");
av_free (buffer);
return -ENOMEM;
}
(*context)->seekable = 0;
(*context)->buf_ptr = (*context)->buf_end;
return 0;
}