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, 19 insertions, 17 deletions

diff --git a/libavcodec/avcodec.c b/libavcodec/avcodec.c
index 3374142394..fbe4a5e413 100644
--- a/libavcodec/avcodec.c
+++ b/libavcodec/avcodec.c
@@ -94,13 +94,13 @@ int avcodec_default_execute2(AVCodecContext *c, int (*func)(AVCodecContext *c2,
 
 static AVMutex codec_mutex = AV_MUTEX_INITIALIZER;
 
-static void lock_avcodec(const AVCodec *codec)
+static void lock_avcodec(const FFCodec *codec)
 {
     if (!(codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE) && codec->init)
         ff_mutex_lock(&codec_mutex);
 }
 
-static void unlock_avcodec(const AVCodec *codec)
+static void unlock_avcodec(const FFCodec *codec)
 {
     if (!(codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE) && codec->init)
         ff_mutex_unlock(&codec_mutex);
@@ -140,6 +140,7 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
 {
     int ret = 0;
     AVCodecInternal *avci;
+    const FFCodec *codec2;
 
     if (avcodec_is_open(avctx))
         return 0;
@@ -155,6 +156,7 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
     }
     if (!codec)
         codec = avctx->codec;
+    codec2 = ffcodec(codec);
 
     if ((avctx->codec_type == AVMEDIA_TYPE_UNKNOWN || avctx->codec_type == codec->type) &&
         avctx->codec_id == AV_CODEC_ID_NONE) {
@@ -194,9 +196,9 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
 
     avci->skip_samples_multiplier = 1;
 
-    if (codec->priv_data_size > 0) {
+    if (codec2->priv_data_size > 0) {
         if (!avctx->priv_data) {
-            avctx->priv_data = av_mallocz(codec->priv_data_size);
+            avctx->priv_data = av_mallocz(codec2->priv_data_size);
             if (!avctx->priv_data) {
                 ret = AVERROR(ENOMEM);
                 goto free_and_end;
@@ -327,25 +329,25 @@ FF_ENABLE_DEPRECATION_WARNINGS
 
     if (HAVE_THREADS
         && !(avci->frame_thread_encoder && (avctx->active_thread_type&FF_THREAD_FRAME))) {
-        /* Frame-threaded decoders call AVCodec.init for their child contexts. */
-        lock_avcodec(codec);
+        /* Frame-threaded decoders call FFCodec.init for their child contexts. */
+        lock_avcodec(codec2);
         ret = ff_thread_init(avctx);
-        unlock_avcodec(codec);
+        unlock_avcodec(codec2);
         if (ret < 0) {
             goto free_and_end;
         }
     }
-    if (!HAVE_THREADS && !(codec->caps_internal & FF_CODEC_CAP_AUTO_THREADS))
+    if (!HAVE_THREADS && !(codec2->caps_internal & FF_CODEC_CAP_AUTO_THREADS))
         avctx->thread_count = 1;
 
     if (!(avctx->active_thread_type & FF_THREAD_FRAME) ||
         avci->frame_thread_encoder) {
-        if (avctx->codec->init) {
-            lock_avcodec(codec);
-            ret = avctx->codec->init(avctx);
-            unlock_avcodec(codec);
+        if (codec2->init) {
+            lock_avcodec(codec2);
+            ret = codec2->init(avctx);
+            unlock_avcodec(codec2);
             if (ret < 0) {
-                avci->needs_close = avctx->codec->caps_internal & FF_CODEC_CAP_INIT_CLEANUP;
+                avci->needs_close = codec2->caps_internal & FF_CODEC_CAP_INIT_CLEANUP;
                 goto free_and_end;
             }
         }
@@ -439,8 +441,8 @@ void avcodec_flush_buffers(AVCodecContext *avctx)
 
     if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME)
         ff_thread_flush(avctx);
-    else if (avctx->codec->flush)
-        avctx->codec->flush(avctx);
+    else if (ffcodec(avctx->codec)->flush)
+        ffcodec(avctx->codec)->flush(avctx);
 
     avctx->pts_correction_last_pts =
     avctx->pts_correction_last_dts = INT64_MIN;
@@ -484,8 +486,8 @@ av_cold int avcodec_close(AVCodecContext *avctx)
         }
         if (HAVE_THREADS && avci->thread_ctx)
             ff_thread_free(avctx);
-        if (avci->needs_close && avctx->codec->close)
-            avctx->codec->close(avctx);
+        if (avci->needs_close && ffcodec(avctx->codec)->close)
+            ffcodec(avctx->codec)->close(avctx);
         avci->byte_buffer_size = 0;
         av_freep(&avci->byte_buffer);
         av_frame_free(&avci->buffer_frame);