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, 20 insertions, 17 deletions

diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index c13de8081b..f9fdb935f6 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -188,14 +188,15 @@ static int extract_packet_props(AVCodecInternal *avci, const AVPacket *pkt)
 static int decode_bsfs_init(AVCodecContext *avctx)
 {
     AVCodecInternal *avci = avctx->internal;
+    const FFCodec *const codec = ffcodec(avctx->codec);
     int ret;
 
     if (avci->bsf)
         return 0;
 
-    ret = av_bsf_list_parse_str(avctx->codec->bsfs, &avci->bsf);
+    ret = av_bsf_list_parse_str(codec->bsfs, &avci->bsf);
     if (ret < 0) {
-        av_log(avctx, AV_LOG_ERROR, "Error parsing decoder bitstream filters '%s': %s\n", avctx->codec->bsfs, av_err2str(ret));
+        av_log(avctx, AV_LOG_ERROR, "Error parsing decoder bitstream filters '%s': %s\n", codec->bsfs, av_err2str(ret));
         if (ret != AVERROR(ENOMEM))
             ret = AVERROR_BUG;
         goto fail;
@@ -233,7 +234,7 @@ int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt)
     if (ret < 0)
         return ret;
 
-    if (!(avctx->codec->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
+    if (!(ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
         ret = extract_packet_props(avctx->internal, pkt);
         if (ret < 0)
             goto finish;
@@ -295,6 +296,7 @@ static inline int decode_simple_internal(AVCodecContext *avctx, AVFrame *frame,
 {
     AVCodecInternal   *avci = avctx->internal;
     AVPacket     *const pkt = avci->in_pkt;
+    const FFCodec *const codec = ffcodec(avctx->codec);
     int got_frame, actual_got_frame;
     int ret;
 
@@ -320,9 +322,9 @@ static inline int decode_simple_internal(AVCodecContext *avctx, AVFrame *frame,
     if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME) {
         ret = ff_thread_decode_frame(avctx, frame, &got_frame, pkt);
     } else {
-        ret = avctx->codec->decode(avctx, frame, &got_frame, pkt);
+        ret = codec->decode(avctx, frame, &got_frame, pkt);
 
-        if (!(avctx->codec->caps_internal & FF_CODEC_CAP_SETS_PKT_DTS))
+        if (!(codec->caps_internal & FF_CODEC_CAP_SETS_PKT_DTS))
             frame->pkt_dts = pkt->dts;
         if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
             if(!avctx->has_b_frames)
@@ -507,7 +509,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
         pkt->size                -= consumed;
         pkt->pts                  = AV_NOPTS_VALUE;
         pkt->dts                  = AV_NOPTS_VALUE;
-        if (!(avctx->codec->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
+        if (!(codec->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
             avci->last_pkt_props->size -= consumed; // See extract_packet_props() comment.
             avci->last_pkt_props->pts = AV_NOPTS_VALUE;
             avci->last_pkt_props->dts = AV_NOPTS_VALUE;
@@ -539,12 +541,13 @@ static int decode_simple_receive_frame(AVCodecContext *avctx, AVFrame *frame)
 static int decode_receive_frame_internal(AVCodecContext *avctx, AVFrame *frame)
 {
     AVCodecInternal *avci = avctx->internal;
+    const FFCodec *const codec = ffcodec(avctx->codec);
     int ret;
 
     av_assert0(!frame->buf[0]);
 
-    if (avctx->codec->receive_frame) {
-        ret = avctx->codec->receive_frame(avctx, frame);
+    if (codec->receive_frame) {
+        ret = codec->receive_frame(avctx, frame);
         if (ret != AVERROR(EAGAIN))
             av_packet_unref(avci->last_pkt_props);
     } else
@@ -553,7 +556,7 @@ static int decode_receive_frame_internal(AVCodecContext *avctx, AVFrame *frame)
     if (ret == AVERROR_EOF)
         avci->draining_done = 1;
 
-    if (!(avctx->codec->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS) &&
+    if (!(codec->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS) &&
         IS_EMPTY(avci->last_pkt_props)) {
         // May fail if the FIFO is empty.
         av_fifo_read(avci->pkt_props, avci->last_pkt_props, 1);
@@ -859,7 +862,7 @@ int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
         if (avctx->pkt_timebase.num && avpkt->pts != AV_NOPTS_VALUE)
             sub->pts = av_rescale_q(avpkt->pts,
                                     avctx->pkt_timebase, AV_TIME_BASE_Q);
-        ret = avctx->codec->decode(avctx, sub, got_sub_ptr, pkt);
+        ret = ffcodec(avctx->codec)->decode(avctx, sub, got_sub_ptr, pkt);
         if (pkt == avci->buffer_pkt) // did we recode?
             av_packet_unref(avci->buffer_pkt);
         if (ret < 0) {
@@ -909,11 +912,11 @@ enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *avctx,
 
     // If a device was supplied when the codec was opened, assume that the
     // user wants to use it.
-    if (avctx->hw_device_ctx && avctx->codec->hw_configs) {
+    if (avctx->hw_device_ctx && ffcodec(avctx->codec)->hw_configs) {
         AVHWDeviceContext *device_ctx =
             (AVHWDeviceContext*)avctx->hw_device_ctx->data;
         for (i = 0;; i++) {
-            config = &avctx->codec->hw_configs[i]->public;
+            config = &ffcodec(avctx->codec)->hw_configs[i]->public;
             if (!config)
                 break;
             if (!(config->methods &
@@ -1025,7 +1028,7 @@ int avcodec_get_hw_frames_parameters(AVCodecContext *avctx,
     int i, ret;
 
     for (i = 0;; i++) {
-        hw_config = avctx->codec->hw_configs[i];
+        hw_config = ffcodec(avctx->codec)->hw_configs[i];
         if (!hw_config)
             return AVERROR(ENOENT);
         if (hw_config->public.pix_fmt == hw_pix_fmt)
@@ -1169,9 +1172,9 @@ int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt)
             break;
         }
 
-        if (avctx->codec->hw_configs) {
+        if (ffcodec(avctx->codec)->hw_configs) {
             for (i = 0;; i++) {
-                hw_config = avctx->codec->hw_configs[i];
+                hw_config = ffcodec(avctx->codec)->hw_configs[i];
                 if (!hw_config)
                     break;
                 if (hw_config->public.pix_fmt == user_choice)
@@ -1538,7 +1541,7 @@ int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
         { AV_PKT_DATA_DYNAMIC_HDR10_PLUS,         AV_FRAME_DATA_DYNAMIC_HDR_PLUS },
     };
 
-    if (!(avctx->codec->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
+    if (!(ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
         frame->pts = pkt->pts;
         frame->pkt_pos      = pkt->pos;
         frame->pkt_duration = pkt->duration;
@@ -1739,7 +1742,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
 
 end:
     if (avctx->codec_type == AVMEDIA_TYPE_VIDEO && !override_dimensions &&
-        !(avctx->codec->caps_internal & FF_CODEC_CAP_EXPORTS_CROPPING)) {
+        !(ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_EXPORTS_CROPPING)) {
         frame->width  = avctx->width;
         frame->height = avctx->height;
     }