flacdec: fix memleaks

While here refactor code.
Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavformat/flacdec.c

@@ -28,6 +28,8 @@
 #include "vorbiscomment.h"
 #include "libavcodec/bytestream.h"
 
+#define RETURN_ERROR(code) do { ret = (code); goto fail; } while (0)
+
 static int parse_picture(AVFormatContext *s, uint8_t *buf, int buf_size)
 {
     const CodecMime *mime = ff_id3v2_mime_tags;
@@ -47,8 +49,7 @@ static int parse_picture(AVFormatContext *s, uint8_t *buf, int buf_size)
     if (type >= FF_ARRAY_ELEMS(ff_id3v2_picture_types) || type < 0) {
         av_log(s, AV_LOG_ERROR, "Invalid picture type: %d.\n", type);
         if (s->error_recognition & AV_EF_EXPLODE) {
-            ret = AVERROR_INVALIDDATA;
-            goto fail;
+            RETURN_ERROR(AVERROR_INVALIDDATA);
         }
         type = 0;
     }
@@ -84,8 +85,7 @@ static int parse_picture(AVFormatContext *s, uint8_t *buf, int buf_size)
     len = avio_rb32(pb);
     if (len > 0) {
         if (!(desc = av_malloc(len + 1))) {
-            ret = AVERROR(ENOMEM);
-            goto fail;
+            RETURN_ERROR(AVERROR(ENOMEM));
         }
 
         if (avio_read(pb, desc, len) != len) {
@@ -111,8 +111,7 @@ static int parse_picture(AVFormatContext *s, uint8_t *buf, int buf_size)
         goto fail;
     }
     if (!(data = av_malloc(len))) {
-        ret = AVERROR(ENOMEM);
-        goto fail;
+        RETURN_ERROR(AVERROR(ENOMEM));
     }
     if (avio_read(pb, data, len) != len) {
         av_log(s, AV_LOG_ERROR, "Error reading attached picture data.\n");
@@ -123,8 +122,7 @@ static int parse_picture(AVFormatContext *s, uint8_t *buf, int buf_size)
 
     st = avformat_new_stream(s, NULL);
     if (!st) {
-        ret = AVERROR(ENOMEM);
-        goto fail;
+        RETURN_ERROR(AVERROR(ENOMEM));
     }
 
     av_init_packet(&st->attached_pic);
@@ -190,8 +188,7 @@ static int flac_read_header(AVFormatContext *s)
                 return AVERROR(ENOMEM);
             }
             if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {
-                av_freep(&buffer);
-                return AVERROR(EIO);
+                RETURN_ERROR(AVERROR(EIO));
             }
             break;
         /* skip metadata block for unsupported types */
@@ -205,12 +202,10 @@ static int flac_read_header(AVFormatContext *s)
             FLACStreaminfo si;
             /* STREAMINFO can only occur once */
             if (found_streaminfo) {
-                av_freep(&buffer);
-                return AVERROR_INVALIDDATA;
+                RETURN_ERROR(AVERROR_INVALIDDATA);
             }
             if (metadata_size != FLAC_STREAMINFO_SIZE) {
-                av_freep(&buffer);
-                return AVERROR_INVALIDDATA;
+                RETURN_ERROR(AVERROR_INVALIDDATA);
             }
             found_streaminfo = 1;
             st->codec->extradata      = buffer;
@@ -232,24 +227,25 @@ static int flac_read_header(AVFormatContext *s)
             const uint8_t *offset;
             int i, chapters, track, ti;
             if (metadata_size < 431)
-                return AVERROR_INVALIDDATA;
+                RETURN_ERROR(AVERROR_INVALIDDATA);
             offset = buffer + 395;
             chapters = bytestream_get_byte(&offset) - 1;
             if (chapters <= 0)
-                return AVERROR_INVALIDDATA;
+                RETURN_ERROR(AVERROR_INVALIDDATA);
             for (i = 0; i < chapters; i++) {
                 if (offset + 36 - buffer > metadata_size)
-                    return AVERROR_INVALIDDATA;
+                    RETURN_ERROR(AVERROR_INVALIDDATA);
                 start = bytestream_get_be64(&offset);
                 track = bytestream_get_byte(&offset);
                 bytestream_get_buffer(&offset, isrc, 12);
                 isrc[12] = 0;
                 offset += 14;
                 ti = bytestream_get_byte(&offset);
-                if (ti <= 0) return AVERROR_INVALIDDATA;
+                if (ti <= 0) RETURN_ERROR(AVERROR_INVALIDDATA);
                 offset += ti * 12;
                 avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);
             }
+            av_freep(&buffer);
         } else if (metadata_type == FLAC_METADATA_TYPE_PICTURE) {
             ret = parse_picture(s, buffer, metadata_size);
             av_freep(&buffer);
@@ -260,8 +256,7 @@ static int flac_read_header(AVFormatContext *s)
         } else {
             /* STREAMINFO must be the first block */
             if (!found_streaminfo) {
-                av_freep(&buffer);
-                return AVERROR_INVALIDDATA;
+                RETURN_ERROR(AVERROR_INVALIDDATA);
             }
             /* process supported blocks other than STREAMINFO */
             if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
@@ -274,6 +269,10 @@ static int flac_read_header(AVFormatContext *s)
     }
 
     return 0;
+
+fail:
+    av_free(buffer);
+    return ret;
 }
 
 static int flac_probe(AVProbeData *p)