[FFmpeg-devel] [PATCH 1/7] lavfi: add a closed field to AVFilerLink.

[Nicolas George]

It will help forward errors and maintain consistency.

Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
---
 libavfilter/audio.c    |    5 +++++
 libavfilter/avfilter.c |    9 +++++++++
 libavfilter/avfilter.h |   17 +++++++++++++++++
 libavfilter/version.h  |    2 +-
 libavfilter/video.c    |    5 +++++
 5 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/libavfilter/audio.c b/libavfilter/audio.c
index 525b471..e7306b1 100644
--- a/libavfilter/audio.c
+++ b/libavfilter/audio.c
@@ -172,6 +172,11 @@ int ff_filter_samples_framed(AVFilterLink *link, AVFilterBufferRef *samplesref)
 
     FF_TPRINTF_START(NULL, filter_samples); ff_tlog_link(NULL, link, 1);
 
+    if (link->closed) {
+        avfilter_unref_buffer(samplesref);
+        return AVERROR_EOF;
+    }
+
     if (!(filter_samples = dst->filter_samples))
         filter_samples = default_filter_samples;
 
diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
index b1df537..861a57d 100644
--- a/libavfilter/avfilter.c
+++ b/libavfilter/avfilter.c
@@ -159,6 +159,11 @@ void avfilter_link_free(AVFilterLink **link)
     av_freep(link);
 }
 
+void avfilter_link_set_closed(AVFilterLink *link, int closed)
+{
+    link->closed = closed;
+}
+
 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
                            unsigned filt_srcpad_idx, unsigned filt_dstpad_idx)
 {
@@ -325,6 +330,8 @@ int ff_request_frame(AVFilterLink *link)
     int ret = -1;
     FF_TPRINTF_START(NULL, request_frame); ff_tlog_link(NULL, link, 1);
 
+    if (link->closed)
+        return AVERROR_EOF;
     if (link->srcpad->request_frame)
         ret = link->srcpad->request_frame(link);
     else if (link->src->inputs[0])
@@ -335,6 +342,8 @@ int ff_request_frame(AVFilterLink *link)
         ff_filter_samples_framed(link, pbuf);
         return 0;
     }
+    if (ret == AVERROR_EOF)
+        link->closed = 1;
     return ret;
 }
 
diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index 9891a72..c0575ce 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -697,6 +697,18 @@ struct AVFilterLink {
      * by the filters.
      */
     AVFilterBufferRef *cur_buf_copy;
+
+    /**
+     * True if the link is closed.
+     * If set, all attemps of start_frame, filter_samples or request_frame
+     * will fail with AVERROR_EOF, and if necessary the reference will be
+     * destroyed.
+     * If request_frame returns AVERROR_EOF, this flag is set on the
+     * corresponding link.
+     * It can be set also be set by either the source or the destination
+     * filter.
+     */
+    int closed;
 };
 
 /**
@@ -717,6 +729,11 @@ int avfilter_link(AVFilterContext *src, unsigned srcpad,
 void avfilter_link_free(AVFilterLink **link);
 
 /**
+ * Set the closed field of a link.
+ */
+void avfilter_link_set_closed(AVFilterLink *link, int closed);
+
+/**
  * Negotiate the media format, dimensions, etc of all inputs to a filter.
  *
  * @param filter the filter to negotiate the properties for its inputs
diff --git a/libavfilter/version.h b/libavfilter/version.h
index db415d9..a008d94 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -29,7 +29,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  12
+#define LIBAVFILTER_VERSION_MINOR  13
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
diff --git a/libavfilter/video.c b/libavfilter/video.c
index 86332bc..9ab8edb 100644
--- a/libavfilter/video.c
+++ b/libavfilter/video.c
@@ -248,6 +248,11 @@ int ff_start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
 
     FF_TPRINTF_START(NULL, start_frame); ff_tlog_link(NULL, link, 0); ff_tlog(NULL, " "); ff_tlog_ref(NULL, picref, 1);
 
+    if (link->closed) {
+        avfilter_unref_buffer(picref);
+        return AVERROR_EOF;
+    }
+
     if (!(start_frame = dst->start_frame))
         start_frame = default_start_frame;
 
-- 
1.7.10.4