cmdutils/avtools: simplify show_help() by using av_opt_child_class_next()

avconv.c

@@ -3676,11 +3676,7 @@ static void show_usage(void)
 
 static void show_help(void)
 {
-    AVCodec *c;
-    AVOutputFormat *oformat = NULL;
-    AVInputFormat  *iformat = NULL;
-    const AVClass *class;
-
+    int flags = AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_ENCODING_PARAM;
     av_log_set_callback(log_callback_help);
     show_usage();
     show_help_options(options, "Main options:\n",
@@ -3707,41 +3703,9 @@ static void show_help(void)
                       OPT_GRAB,
                       OPT_GRAB);
     printf("\n");
-    class = avcodec_get_class();
-    av_opt_show2(&class, NULL, AV_OPT_FLAG_ENCODING_PARAM|AV_OPT_FLAG_DECODING_PARAM, 0);
-    printf("\n");
-
-    /* individual codec options */
-    c = NULL;
-    while ((c = av_codec_next(c))) {
-        if (c->priv_class) {
-            av_opt_show2(&c->priv_class, NULL, AV_OPT_FLAG_ENCODING_PARAM|AV_OPT_FLAG_DECODING_PARAM, 0);
-            printf("\n");
-        }
-    }
-
-    class = avformat_get_class();
-    av_opt_show2(&class, NULL, AV_OPT_FLAG_ENCODING_PARAM|AV_OPT_FLAG_DECODING_PARAM, 0);
-    printf("\n");
-
-    /* individual muxer options */
-    while ((oformat = av_oformat_next(oformat))) {
-        if (oformat->priv_class) {
-            av_opt_show2(&oformat->priv_class, NULL, AV_OPT_FLAG_ENCODING_PARAM, 0);
-            printf("\n");
-        }
-    }
-
-    /* individual demuxer options */
-    while ((iformat = av_iformat_next(iformat))) {
-        if (iformat->priv_class) {
-            av_opt_show2(&iformat->priv_class, NULL, AV_OPT_FLAG_DECODING_PARAM, 0);
-            printf("\n");
-        }
-    }
-
-    class = sws_get_class();
-    av_opt_show2(&class, NULL, AV_OPT_FLAG_ENCODING_PARAM|AV_OPT_FLAG_DECODING_PARAM, 0);
+    show_help_children(avcodec_get_class(), flags);
+    show_help_children(avformat_get_class(), flags);
+    show_help_children(sws_get_class(), flags);
 }
 
 static int opt_target(OptionsContext *o, const char *opt, const char *arg)

avplay.c

@@ -2996,7 +2996,6 @@ static void show_usage(void)
 
 static void show_help(void)
 {
-    const AVClass *class;
     av_log_set_callback(log_callback_help);
     show_usage();
     show_help_options(options, "Main options:\n",
@@ -3004,18 +3003,10 @@ static void show_help(void)
     show_help_options(options, "\nAdvanced options:\n",
                       OPT_EXPERT, OPT_EXPERT);
     printf("\n");
-    class = avcodec_get_class();
-    av_opt_show2(&class, NULL,
-                 AV_OPT_FLAG_DECODING_PARAM, 0);
-    printf("\n");
-    class = avformat_get_class();
-    av_opt_show2(&class, NULL,
-                 AV_OPT_FLAG_DECODING_PARAM, 0);
+    show_help_children(avcodec_get_class(), AV_OPT_FLAG_DECODING_PARAM);
+    show_help_children(avformat_get_class(), AV_OPT_FLAG_DECODING_PARAM);
 #if !CONFIG_AVFILTER
-    printf("\n");
-    class = sws_get_class();
-    av_opt_show2(&class, NULL,
-                 AV_OPT_FLAG_ENCODING_PARAM, 0);
+    show_help_children(sws_get_class(), AV_OPT_FLAG_ENCODING_PARAM);
 #endif
     printf("\nWhile playing:\n"
            "q, ESC              quit\n"

avprobe.c

@@ -360,13 +360,11 @@ static void opt_input_file(void *optctx, const char *arg)
 
 static void show_help(void)
 {
-    const AVClass *class = avformat_get_class();
     av_log_set_callback(log_callback_help);
     show_usage();
     show_help_options(options, "Main options:\n", 0, 0);
     printf("\n");
-    av_opt_show2(&class, NULL,
-                 AV_OPT_FLAG_DECODING_PARAM, 0);
+    show_help_children(avformat_get_class(), AV_OPT_FLAG_DECODING_PARAM);
 }
 
 static void opt_pretty(void)

cmdutils.c

@@ -130,6 +130,16 @@ void show_help_options(const OptionDef *options, const char *msg, int mask, int
     }
 }
 
+void show_help_children(const AVClass *class, int flags)
+{
+    const AVClass *child = NULL;
+    av_opt_show2(&class, NULL, flags, 0);
+    printf("\n");
+
+    while (child = av_opt_child_class_next(class, child))
+        show_help_children(child, flags);
+}
+
 static const OptionDef* find_option(const OptionDef *po, const char *name){
     const char *p = strchr(name, ':');
     int len = p ? p - name : strlen(name);

cmdutils.h

@@ -154,6 +154,12 @@ typedef struct {
 
 void show_help_options(const OptionDef *options, const char *msg, int mask, int value);
 
+/**
+ * Show help for all options with given flags in class and all its
+ * children.
+ */
+void show_help_children(const AVClass *class, int flags);
+
 /**
  * Parse the command line arguments.
  *