lavf: allow custom IO for all files

Some (de)muxers open additional files beyond the main IO context.
Currently, they call avio_open() directly, which prevents the caller
from using custom IO for such streams.

This commit adds callbacks to AVFormatContext that default to
avio_open2()/avio_close(), but can be overridden by the caller. All
muxers and demuxers using AVIO are switched to using those callbacks
instead of calling avio_open()/avio_close() directly.

(de)muxers that use the URLProtocol layer directly instead of AVIO
remain unconverted for now. This should be fixed in later commits.

1 files changed, 14 insertions, 0 deletions

diff --git a/libavformat/options.c b/libavformat/options.c
index a6fbbd2623..c7fa51f41f 100644
--- a/libavformat/options.c
+++ b/libavformat/options.c
@@ -90,12 +90,26 @@ static const AVClass av_format_context_class = {
     .child_class_next = format_child_class_next,
 };
 
+static int io_open_default(AVFormatContext *s, AVIOContext **pb,
+                           const char *url, int flags, AVDictionary **options)
+{
+    return avio_open2(pb, url, flags, &s->interrupt_callback, options);
+}
+
+static void io_close_default(AVFormatContext *s, AVIOContext *pb)
+{
+    avio_close(pb);
+}
+
 static void avformat_get_context_defaults(AVFormatContext *s)
 {
     memset(s, 0, sizeof(AVFormatContext));
 
     s->av_class = &av_format_context_class;
 
+    s->io_open  = io_open_default;
+    s->io_close = io_close_default;
+
     av_opt_set_defaults(s);
 }