lavfi: create Libav-API compatibility layer for avfilter_graph_parse() at the next bump

Add function avfilter_graph_parse_ptr() and favor it in place of
avfilter_graph_parse(), which will be restored with the old/Libav
signature at the next bump.

If HAVE_INCOMPATIBLE_LIBAV_API is enabled it will use the
Libav-compatible signature for avfilter_graph_parse().

At the next major bump the current implementation of
avfilter_graph_parse() should be dropped in favor of the Libav/old
implementation.

Should address trac ticket #2672.

3 files changed, 72 insertions, 30 deletions

diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index 1f7da428af..0001cd7fc6 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -1311,6 +1311,29 @@ AVFilterInOut *avfilter_inout_alloc(void);
  */
 void avfilter_inout_free(AVFilterInOut **inout);
 
+#if HAVE_INCOMPATIBLE_LIBAV_ABI || !FF_API_OLD_GRAPH_PARSE
+/**
+ * Add a graph described by a string to a graph.
+ *
+ * @note The caller must provide the lists of inputs and outputs,
+ * which therefore must be known before calling the function.
+ *
+ * @note The inputs parameter describes inputs of the already existing
+ * part of the graph; i.e. from the point of view of the newly created
+ * part, they are outputs. Similarly the outputs parameter describes
+ * outputs of the already existing filters, which are provided as
+ * inputs to the parsed filters.
+ *
+ * @param graph   the filter graph where to link the parsed grap context
+ * @param filters string to be parsed
+ * @param inputs  linked list to the inputs of the graph
+ * @param outputs linked list to the outputs of the graph
+ * @return zero on success, a negative AVERROR code on error
+ */
+int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
+                         AVFilterInOut *inputs, AVFilterInOut *outputs,
+                         void *log_ctx);
+#else
 /**
  * Add a graph described by a string to a graph.
  *
@@ -1323,10 +1346,30 @@ void avfilter_inout_free(AVFilterInOut **inout);
  *                If non-NULL, *outputs is updated to contain the list of open outputs
  *                after the parsing, should be freed with avfilter_inout_free().
  * @return non negative on success, a negative AVERROR code on error
+ * @deprecated Use avfilter_graph_parse_ptr() instead.
  */
+attribute_deprecated
 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
                          AVFilterInOut **inputs, AVFilterInOut **outputs,
                          void *log_ctx);
+#endif
+
+/**
+ * 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  pointer to a linked list to the inputs of the graph, may be NULL.
+ *                If non-NULL, *inputs is updated to contain the list of open inputs
+ *                after the parsing, should be freed with avfilter_inout_free().
+ * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
+ *                If non-NULL, *outputs is updated to contain the list of open outputs
+ *                after the parsing, should be freed with avfilter_inout_free().
+ * @return non negative on success, a negative AVERROR code on error
+ */
+int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,
+                             AVFilterInOut **inputs, AVFilterInOut **outputs,
+                             void *log_ctx);
 
 /**
  * Add a graph described by a string to a graph.
@@ -1341,21 +1384,13 @@ int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
  *                     caller using avfilter_inout_free().
  * @return zero on success, a negative AVERROR code on error
  *
- * @note the difference between avfilter_graph_parse2() and
- * avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
- * the lists of inputs and outputs, which therefore must be known before calling
- * the function. On the other hand, avfilter_graph_parse2() \em returns the
- * inputs and outputs that are left unlinked after parsing the graph and the
- * caller then deals with them. Another difference is that in
- * avfilter_graph_parse(), the inputs parameter describes inputs of the
- * <em>already existing</em> part of the graph; i.e. from the point of view of
- * the newly created part, they are outputs. Similarly the outputs parameter
- * describes outputs of the already existing filters, which are provided as
- * inputs to the parsed filters.
- * avfilter_graph_parse2() takes the opposite approach -- it makes no reference
- * whatsoever to already existing parts of the graph and the inputs parameter
- * will on return contain inputs of the newly parsed part of the graph.
- * Analogously the outputs parameter will contain outputs of the newly created
+ * @note This function returns the inputs and outputs that are left
+ * unlinked after parsing the graph and the caller then deals with
+ * them.
+ * @note This function makes no reference whatsoever to already
+ * existing parts of the graph and the inputs parameter will on return
+ * contain inputs of the newly parsed part of the graph.  Analogously
+ * the outputs parameter will contain outputs of the newly created
  * filters.
  */
 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
diff --git a/libavfilter/graphparser.c b/libavfilter/graphparser.c
index 9241cf3bf2..6cf19e9860 100644
--- a/libavfilter/graphparser.c
+++ b/libavfilter/graphparser.c
@@ -447,14 +447,12 @@ int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
     return ret;
 }
 
+#if HAVE_INCOMPATIBLE_LIBAV_ABI || !FF_API_OLD_GRAPH_PARSE
 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
-                         AVFilterInOut **open_inputs_ptr, AVFilterInOut **open_outputs_ptr,
-                         void *log_ctx)
+                         AVFilterInOut *open_inputs,
+                         AVFilterInOut *open_outputs, void *log_ctx)
 {
-#if 0
     int ret;
-    AVFilterInOut *open_inputs  = open_inputs_ptr  ? *open_inputs_ptr  : NULL;
-    AVFilterInOut *open_outputs = open_outputs_ptr ? *open_outputs_ptr : NULL;
     AVFilterInOut *cur, *match, *inputs = NULL, *outputs = NULL;
 
     if ((ret = avfilter_graph_parse2(graph, filters, &inputs, &outputs)) < 0)
@@ -508,14 +506,22 @@ int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
     }
     avfilter_inout_free(&inputs);
     avfilter_inout_free(&outputs);
-    /* clear open_in/outputs only if not passed as parameters */
-    if (open_inputs_ptr) *open_inputs_ptr = open_inputs;
-    else avfilter_inout_free(&open_inputs);
-    if (open_outputs_ptr) *open_outputs_ptr = open_outputs;
-    else avfilter_inout_free(&open_outputs);
+    avfilter_inout_free(&open_inputs);
+    avfilter_inout_free(&open_outputs);
     return ret;
-}
 #else
+int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
+                         AVFilterInOut **inputs, AVFilterInOut **outputs,
+                         void *log_ctx)
+{
+    return avfilter_graph_parse_ptr(graph, filters, inputs, outputs, log_ctx);
+}
+#endif
+
+int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,
+                         AVFilterInOut **open_inputs_ptr, AVFilterInOut **open_outputs_ptr,
+                         void *log_ctx)
+{
     int index = 0, ret = 0;
     char chr = 0;
 
@@ -595,5 +601,3 @@ end:
     }
     return ret;
 }
-
-#endif
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 1bc6b7e001..ee94f5856f 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,8 +30,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  77
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR  78
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \
@@ -79,5 +79,8 @@
 #ifndef FF_API_OLD_FILTER_REGISTER
 #define FF_API_OLD_FILTER_REGISTER          (LIBAVFILTER_VERSION_MAJOR < 4)
 #endif
+#ifndef FF_API_OLD_GRAPH_PARSE
+#define FF_API_OLD_GRAPH_PARSE              (LIBAVFILTER_VERSION_MAJOR < 4)
+#endif
 
 #endif /* AVFILTER_VERSION_H */