lavu/opt: add a more general child class iteration API

Use opaque iteration state instead of the previous child class. This
mirrors similar changes done in lavf/lavc.

Deprecate the av_opt_child_class_next() API.

1 files changed, 18 insertions, 0 deletions

diff --git a/libavutil/log.h b/libavutil/log.h
index 9c14188a9c..8edd6bbf2b 100644
--- a/libavutil/log.h
+++ b/libavutil/log.h
@@ -112,6 +112,7 @@ typedef struct AVClass {
      */
     void* (*child_next)(void *obj, void *prev);
 
+#if FF_API_CHILD_CLASS_NEXT
     /**
      * Return an AVClass corresponding to the next potential
      * AVOptions-enabled child.
@@ -120,7 +121,9 @@ typedef struct AVClass {
      * child_next iterates over _already existing_ objects, while
      * child_class_next iterates over _all possible_ children.
      */
+    attribute_deprecated
     const struct AVClass* (*child_class_next)(const struct AVClass *prev);
+#endif
 
     /**
      * Category used for visualization (like color)
@@ -140,6 +143,21 @@ typedef struct AVClass {
      * available since version (52.12)
      */
     int (*query_ranges)(struct AVOptionRanges **, void *obj, const char *key, int flags);
+
+    /**
+     * Iterate over the AVClasses corresponding to potential AVOptions-enabled
+     * children.
+     *
+     * @param iter pointer to opaque iteration state. The caller must initialize
+     *             *iter to NULL before the first call.
+     * @return AVClass for the next AVOptions-enabled child or NULL if there are
+     *         no more such children.
+     *
+     * @note The difference between child_next and this is that child_next
+     *       iterates over _already existing_ objects, while child_class_iterate
+     *       iterates over _all possible_ children.
+     */
+    const struct AVClass* (*child_class_iterate)(void **iter);
 } AVClass;
 
 /**