avfiltergraph: make the AVFilterInOut alloc/free API public

This is required for letting applications to create and destroy
AVFilterInOut structs in a convenient way.

3 files changed, 31 insertions, 12 deletions

diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index fbd1dc457f..84fa32e64e 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -26,7 +26,7 @@
 #include "libavutil/samplefmt.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  2
-#define LIBAVFILTER_VERSION_MINOR 16
+#define LIBAVFILTER_VERSION_MINOR 17
 #define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
diff --git a/libavfilter/avfiltergraph.h b/libavfilter/avfiltergraph.h
index 538fd2cb95..a975926fd1 100644
--- a/libavfilter/avfiltergraph.h
+++ b/libavfilter/avfiltergraph.h
@@ -108,14 +108,28 @@ typedef struct AVFilterInOut {
 } AVFilterInOut;
 
 /**
+ * Create an AVFilterInOut.
+ * Must be free with avfilter_inout_free().
+ */
+AVFilterInOut *avfilter_inout_alloc(void);
+
+/**
+ * Free the AVFilterInOut in *inout, and set its pointer to NULL.
+ * If *inout is NULL, do nothing.
+ */
+void avfilter_inout_free(AVFilterInOut **inout);
+
+/**
  * Add a graph described by a string to a graph.
  *
  * @param graph   the filter graph where to link the parsed graph context
  * @param filters string to be parsed
  * @param inputs  linked list to the inputs of the graph, may be NULL.
- *                It is updated to contain the list of open inputs after the parsing.
+ *                It is updated to contain the list of open inputs after the parsing,
+ *                should be freed with avfilter_inout_free().
  * @param outputs linked list to the outputs of the graph, may be NULL.
- *                It is updated to contain the list of open outputs after the parsing.
+ *                It is updated to contain the list of open outputs after the parsing,
+ *                should be freed with avfilter_inout_free().
  * @return zero on success, a negative AVERROR code on error
  */
 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
diff --git a/libavfilter/graphparser.c b/libavfilter/graphparser.c
index ea0c5dda7f..d62ba8d205 100644
--- a/libavfilter/graphparser.c
+++ b/libavfilter/graphparser.c
@@ -168,13 +168,18 @@ static int parse_filter(AVFilterContext **filt_ctx, const char **buf, AVFilterGr
     return ret;
 }
 
-static void free_inout(AVFilterInOut *head)
+AVFilterInOut *avfilter_inout_alloc(void)
 {
-    while (head) {
-        AVFilterInOut *next = head->next;
-        av_free(head->name);
-        av_free(head);
-        head = next;
+    return av_mallocz(sizeof(AVFilterInOut));
+}
+
+void avfilter_inout_free(AVFilterInOut **inout)
+{
+    while (*inout) {
+        AVFilterInOut *next = (*inout)->next;
+        av_freep(&(*inout)->name);
+        av_freep(inout);
+        *inout = next;
     }
 }
 
@@ -396,8 +401,8 @@ int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
     for (; graph->filter_count > 0; graph->filter_count--)
         avfilter_free(graph->filters[graph->filter_count - 1]);
     av_freep(&graph->filters);
-    free_inout(*open_inputs);
-    free_inout(*open_outputs);
-    free_inout(curr_inputs);
+    avfilter_inout_free(open_inputs);
+    avfilter_inout_free(open_outputs);
+    avfilter_inout_free(&curr_inputs);
     return ret;
 }