lavfi: add new iteration API

Signed-off-by: Josh de Kock <josh@itanimul.li>

configure

@@ -3622,15 +3622,6 @@ for v in "$@"; do
     FFMPEG_CONFIGURATION="${FFMPEG_CONFIGURATION# } ${l}${r}"
 done
 
-find_things(){
-    thing=$1
-    pattern=$2
-    file=$source_path/$3
-    sed -n "s/^[^#]*$pattern.*([^,]*, *\([^,]*\)\(,.*\)*).*/\1_$thing/p" "$file"
-}
-
-FILTER_LIST=$(find_things   filter   FILTER   libavfilter/allfilters.c)
-
 find_things_extern(){
     thing=$1
     pattern=$2
@@ -3639,6 +3630,13 @@ find_things_extern(){
     sed -n "s/^[^#]*extern.*$pattern *ff_\([^ ]*\)_$thing;/\1_$out/p" "$file"
 }
 
+find_filters_extern(){
+    file=$source_path/$1
+    #sed -n "s/^extern AVFilter ff_\([avfsinkrc]\{2,5\}\)_\(\w\+\);/\2_filter/p" $file
+    sed -E -n "s/^extern AVFilter ff_([avfsinkrc]{2,5})_([a-zA-Z0-9_]+);/\2_filter/p" $file
+}
+
+FILTER_LIST=$(find_filters_extern libavfilter/allfilters.c)
 OUTDEV_LIST=$(find_things_extern muxer AVOutputFormat libavdevice/alldevices.c outdev)
 INDEV_LIST=$(find_things_extern demuxer AVInputFormat libavdevice/alldevices.c indev)
 MUXER_LIST=$(find_things_extern muxer AVOutputFormat libavformat/allformats.c)
@@ -7157,6 +7155,10 @@ echo "#endif /* AVUTIL_AVCONFIG_H */" >> $TMPH
 
 cp_if_changed $TMPH libavutil/avconfig.h
 
+full_filter_name(){
+    sed -n "s/^extern AVFilter ff_\([avfsinkrc]\{2,5\}\)_$1;/\1_$1/p" $source_path/libavfilter/allfilters.c
+}
+
 # generate the lists of enabled components
 print_enabled_components(){
     file=$1
@@ -7167,6 +7169,9 @@ print_enabled_components(){
     for c in $*; do
         if enabled $c; then
             case $name in
+                filter_list)
+                    c=$(full_filter_name $(remove_suffix _filter $c))
+                ;;
                 indev_list)
                     c=$(add_suffix _demuxer $(remove_suffix _indev $c))
                 ;;
@@ -7177,10 +7182,16 @@ print_enabled_components(){
             printf "    &ff_%s,\n" $c >> $TMPH
         fi
     done
+    if [ "$name" == "filter_list" ]; then
+        for c in asrc_abuffer vsrc_buffer asink_abuffer vsink_buffer; do
+            printf "    &ff_%s,\n" $c >> $TMPH
+        done
+    fi
     echo "    NULL };" >> $TMPH
     cp_if_changed $TMPH $file
 }
 
+print_enabled_components libavfilter/filter_list.c AVFilter filter_list $FILTER_LIST
 print_enabled_components libavcodec/codec_list.c AVCodec codec_list $CODEC_LIST
 print_enabled_components libavcodec/parser_list.c AVCodecParser parser_list $PARSER_LIST
 print_enabled_components libavcodec/bsf_list.c AVBitStreamFilter bitstream_filters $BSF_LIST

doc/APIchanges

@@ -15,6 +15,10 @@ libavutil:     2017-10-21
 
 API changes, most recent first:
 
+2018-xx-xx - xxxxxxx - lavc 7.13.100 - avcodec.h
+  Deprecate use of avfilter_register(), avfilter_register_all(),
+  avfilter_next(). Add av_filter_iterate().
+
 2018-03-xx - xxxxxxx - lavc 58.16.100 - avcodec.h
   Add FF_SUB_CHARENC_MODE_IGNORE.
 

doc/writing_filters.txt

@@ -31,10 +31,8 @@ If everything went right, you should get a foobar.png with Lena edge-detected.
 That's it, your new playground is ready.
 
 Some little details about what's going on:
-libavfilter/allfilters.c:avfilter_register_all() is called at runtime to create
-a list of the available filters, but it's important to know that this file is
-also parsed by the configure script, which in turn will define variables for
-the build system and the C:
+libavfilter/allfilters.c:this file is parsed by the configure script, which in turn
+will define variables for the build system and the C:
 
     --- after running configure ---
 

libavfilter/avfilter.c

@@ -575,51 +575,6 @@ int avfilter_process_command(AVFilterContext *filter, const char *cmd, const cha
     return AVERROR(ENOSYS);
 }
 
-static AVFilter *first_filter;
-static AVFilter **last_filter = &first_filter;
-
-const AVFilter *avfilter_get_by_name(const char *name)
-{
-    const AVFilter *f = NULL;
-
-    if (!name)
-        return NULL;
-
-    while ((f = avfilter_next(f)))
-        if (!strcmp(f->name, name))
-            return (AVFilter *)f;
-
-    return NULL;
-}
-
-static AVMutex filter_register_mutex = AV_MUTEX_INITIALIZER;
-
-int avfilter_register(AVFilter *filter)
-{
-    AVFilter **f;
-
-    /* the filter must select generic or internal exclusively */
-    av_assert0((filter->flags & AVFILTER_FLAG_SUPPORT_TIMELINE) != AVFILTER_FLAG_SUPPORT_TIMELINE);
-
-    ff_mutex_lock(&filter_register_mutex);
-    f = last_filter;
-
-    while (*f)
-        f = &(*f)->next;
-    *f = filter;
-    filter->next = NULL;
-    last_filter = &filter->next;
-
-    ff_mutex_unlock(&filter_register_mutex);
-
-    return 0;
-}
-
-const AVFilter *avfilter_next(const AVFilter *prev)
-{
-    return prev ? prev->next : first_filter;
-}
-
 int avfilter_pad_count(const AVFilterPad *pads)
 {
     int count;
@@ -648,10 +603,11 @@ static void *filter_child_next(void *obj, void *prev)
 
 static const AVClass *filter_child_class_next(const AVClass *prev)
 {
+    void *opaque = NULL;
     const AVFilter *f = NULL;
 
     /* find the filter that corresponds to prev */
-    while (prev && (f = avfilter_next(f)))
+    while (prev && (f = av_filter_iterate(&opaque)))
         if (f->priv_class == prev)
             break;
 
@@ -660,7 +616,7 @@ static const AVClass *filter_child_class_next(const AVClass *prev)
         return NULL;
 
     /* find next filter with specific options */
-    while ((f = avfilter_next(f)))
+    while ((f = av_filter_iterate(&opaque)))
         if (f->priv_class)
             return f->priv_class;
 

libavfilter/avfilter.h

@@ -697,7 +697,20 @@ int avfilter_config_links(AVFilterContext *filter);
  */
 int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
 
+/**
+ * Iterate over all registered filters.
+ *
+ * @param opaque a pointer where libavfilter will store the iteration state. Must
+ *               point to NULL to start the iteration.
+ *
+ * @return the next registered filter or NULL when the iteration is
+ *         finished
+ */
+const AVFilter *av_filter_iterate(void **opaque);
+
+#if FF_API_NEXT
 /** Initialize the filter system. Register all builtin filters. */
+attribute_deprecated
 void avfilter_register_all(void);
 
 /**
@@ -710,8 +723,18 @@ void avfilter_register_all(void);
  * @return 0 if the registration was successful, a negative value
  * otherwise
  */
+attribute_deprecated
 int avfilter_register(AVFilter *filter);
 
+/**
+ * Iterate over all registered filters.
+ * @return If prev is non-NULL, next registered filter after prev or NULL if
+ * prev is the last filter. If prev is NULL, return the first registered filter.
+ */
+attribute_deprecated
+const AVFilter *avfilter_next(const AVFilter *prev);
+#endif
+
 /**
  * Get a filter definition matching the given name.
  *
@@ -721,12 +744,6 @@ int avfilter_register(AVFilter *filter);
  */
 const AVFilter *avfilter_get_by_name(const char *name);
 
-/**
- * Iterate over all registered filters.
- * @return If prev is non-NULL, next registered filter after prev or NULL if
- * prev is the last filter. If prev is NULL, return the first registered filter.
- */
-const AVFilter *avfilter_next(const AVFilter *prev);
 
 /**
  * Initialize a filter with the supplied parameters.

libavfilter/version.h

@@ -58,5 +58,8 @@
 #ifndef FF_API_FILTER_GET_SET
 #define FF_API_FILTER_GET_SET               (LIBAVFILTER_VERSION_MAJOR < 8)
 #endif
+#ifndef FF_API_NEXT
+#define FF_API_NEXT                         (LIBAVFILTER_VERSION_MAJOR < 8)
+#endif
 
 #endif /* AVFILTER_VERSION_H */