avcodec/codec_internal: Add FFCodec, hide internal part of AVCodec

Up until now, codec.h contains both public and private parts
of AVCodec. This exposes the internals of AVCodec to users
and leads them into the temptation of actually using them
and forces us to forward-declare structures and types that
users can't use at all.

This commit changes this by adding a new structure FFCodec to
codec_internal.h that extends AVCodec, i.e. contains the public
AVCodec as first member; the private fields of AVCodec are moved
to this structure, leaving codec.h clean.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 18 insertions, 17 deletions

diff --git a/libavcodec/tests/avcodec.c b/libavcodec/tests/avcodec.c
index b77d7c4bdc..075ad632c4 100644
--- a/libavcodec/tests/avcodec.c
+++ b/libavcodec/tests/avcodec.c
@@ -37,14 +37,14 @@ do {                                                            \
 #define ERR(msg)           ERR_INTERNAL(msg, )
 #define ERR_EXT(msg, ...)  ERR_INTERNAL(msg, , __VA_ARGS__)
 
-static int priv_data_size_wrong(const AVCodec *codec)
+static int priv_data_size_wrong(const FFCodec *codec)
 {
     if (codec->priv_data_size < 0 ||
-        codec->priv_class && codec->priv_data_size < sizeof(AVClass*))
+        codec->p.priv_class && codec->priv_data_size < sizeof(AVClass*))
         return 1;
-    if (!codec->priv_class || !codec->priv_class->option)
+    if (!codec->p.priv_class || !codec->p.priv_class->option)
         return 0;
-    for (const AVOption *opt = codec->priv_class->option; opt->name; opt++) {
+    for (const AVOption *opt = codec->p.priv_class->option; opt->name; opt++) {
         if (opt->offset >= codec->priv_data_size ||
             opt->type == AV_OPT_TYPE_CONST && opt->offset != 0 ||
             opt->type != AV_OPT_TYPE_CONST && (opt->offset < sizeof(AVClass*) || opt->offset < 0)) {
@@ -62,6 +62,7 @@ int main(void){
     int ret = 0;
 
     while (codec = av_codec_iterate(&iter)) {
+        const FFCodec *const codec2 = ffcodec(codec);
         const AVCodecDescriptor *desc;
         int is_decoder, is_encoder;
 
@@ -88,14 +89,14 @@ int main(void){
         if (codec->type != AVMEDIA_TYPE_VIDEO) {
             if (codec->pix_fmts || codec->supported_framerates)
                 ERR("Non-video codec %s has video-only fields set\n");
-            if (codec->caps_internal & FF_CODEC_CAP_EXPORTS_CROPPING)
+            if (codec2->caps_internal & FF_CODEC_CAP_EXPORTS_CROPPING)
                 ERR("Non-video codec %s exports cropping\n");
         }
-        if (codec->caps_internal  & FF_CODEC_CAP_SLICE_THREAD_HAS_MF &&
+        if (codec2->caps_internal  & FF_CODEC_CAP_SLICE_THREAD_HAS_MF &&
             !(codec->capabilities & AV_CODEC_CAP_SLICE_THREADS))
             ERR("Codec %s wants mainfunction despite not being "
                 "slice-threading capable");
-        if (codec->caps_internal  & FF_CODEC_CAP_AUTO_THREADS &&
+        if (codec2->caps_internal  & FF_CODEC_CAP_AUTO_THREADS &&
             !(codec->capabilities & (AV_CODEC_CAP_FRAME_THREADS |
                                      AV_CODEC_CAP_SLICE_THREADS |
                                      AV_CODEC_CAP_OTHER_THREADS)))
@@ -108,11 +109,11 @@ int main(void){
             continue;
         }
         if (is_encoder) {
-            if (codec->type == AVMEDIA_TYPE_SUBTITLE ^ !!codec->encode_sub)
+            if (codec->type == AVMEDIA_TYPE_SUBTITLE ^ !!codec2->encode_sub)
                 ERR("Encoder %s is both subtitle encoder and not subtitle encoder.");
-            if (!!codec->encode_sub + !!codec->encode2 + !!codec->receive_packet != 1)
+            if (!!codec2->encode_sub + !!codec2->encode2 + !!codec2->receive_packet != 1)
                 ERR("Encoder %s does not implement exactly one encode API.\n");
-            if (codec->update_thread_context || codec->update_thread_context_for_user || codec->bsfs)
+            if (codec2->update_thread_context || codec2->update_thread_context_for_user || codec2->bsfs)
                 ERR("Encoder %s has decoder-only thread functions or bsf.\n");
             if (codec->type == AVMEDIA_TYPE_AUDIO) {
                 if (!codec->sample_fmts) {
@@ -120,7 +121,7 @@ int main(void){
                     ret = 1;
                 }
             }
-            if (codec->caps_internal & (FF_CODEC_CAP_ALLOCATE_PROGRESS |
+            if (codec2->caps_internal & (FF_CODEC_CAP_ALLOCATE_PROGRESS |
                                         FF_CODEC_CAP_SETS_PKT_DTS |
                                         FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM |
                                         FF_CODEC_CAP_EXPORTS_CROPPING |
@@ -134,26 +135,26 @@ int main(void){
                 codec->capabilities & AV_CODEC_CAP_ENCODER_FLUSH)
                 ERR("Frame-threaded encoder %s claims to support flushing\n");
         } else {
-            if (codec->type == AVMEDIA_TYPE_SUBTITLE && !codec->decode)
+            if (codec->type == AVMEDIA_TYPE_SUBTITLE && !codec2->decode)
                 ERR("Subtitle decoder %s does not implement decode callback\n");
-            if (codec->type == AVMEDIA_TYPE_SUBTITLE && codec->bsfs)
+            if (codec->type == AVMEDIA_TYPE_SUBTITLE && codec2->bsfs)
                 ERR("Automatic bitstream filtering unsupported for subtitles; "
                     "yet decoder %s has it set\n");
-            if (!!codec->decode + !!codec->receive_frame != 1)
+            if (!!codec2->decode + !!codec2->receive_frame != 1)
                 ERR("Decoder %s does not implement exactly one decode API.\n");
             if (codec->capabilities & (AV_CODEC_CAP_SMALL_LAST_FRAME    |
                                        AV_CODEC_CAP_VARIABLE_FRAME_SIZE |
                                        AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE |
                                        AV_CODEC_CAP_ENCODER_FLUSH))
                 ERR("Decoder %s has encoder-only capabilities\n");
-            if (codec->caps_internal & FF_CODEC_CAP_ALLOCATE_PROGRESS &&
+            if (codec2->caps_internal & FF_CODEC_CAP_ALLOCATE_PROGRESS &&
                 !(codec->capabilities & AV_CODEC_CAP_FRAME_THREADS))
                 ERR("Decoder %s wants allocated progress without supporting"
                     "frame threads\n");
         }
-        if (priv_data_size_wrong(codec))
+        if (priv_data_size_wrong(codec2))
             ERR_EXT("Private context of codec %s is impossibly-sized (size %d).",
-                    codec->priv_data_size);
+                    codec2->priv_data_size);
         if (!(desc = avcodec_descriptor_get(codec->id))) {
             ERR("Codec %s lacks a corresponding descriptor\n");
         } else if (desc->type != codec->type)