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, 7 insertions, 4 deletions

diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index b18af6d0a8..1666f5dabb 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -71,13 +71,15 @@ void av_fast_padded_mallocz(void *ptr, unsigned int *size, size_t min_size)
         memset(*p, 0, min_size + AV_INPUT_BUFFER_PADDING_SIZE);
 }
 
-int av_codec_is_encoder(const AVCodec *codec)
+int av_codec_is_encoder(const AVCodec *avcodec)
 {
+    const FFCodec *const codec = ffcodec(avcodec);
     return codec && (codec->encode_sub || codec->encode2 || codec->receive_packet);
 }
 
-int av_codec_is_decoder(const AVCodec *codec)
+int av_codec_is_decoder(const AVCodec *avcodec)
 {
+    const FFCodec *const codec = ffcodec(avcodec);
     return codec && (codec->decode || codec->receive_frame);
 }
 
@@ -435,7 +437,7 @@ void ff_color_frame(AVFrame *frame, const int c[4])
 }
 
 int avpriv_codec_get_cap_skip_frame_fill_param(const AVCodec *codec){
-    return !!(codec->caps_internal & FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM);
+    return !!(ffcodec(codec)->caps_internal & FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM);
 }
 
 const char *avcodec_get_name(enum AVCodecID id)
@@ -868,8 +870,9 @@ int ff_match_2uint16(const uint16_t(*tab)[2], int size, int a, int b)
     return i;
 }
 
-const AVCodecHWConfig *avcodec_get_hw_config(const AVCodec *codec, int index)
+const AVCodecHWConfig *avcodec_get_hw_config(const AVCodec *avcodec, int index)
 {
+    const FFCodec *const codec = ffcodec(avcodec);
     int i;
     if (!codec->hw_configs || index < 0)
         return NULL;