Fix memleak caused by the fact that url_open_buf() allocates a context

when calling, but url_close_buf() doesn't free it. The better solution
is to not allocate it at all, init it with init_put_byte() and then
not have to close it at all. In the case where we do need to hold it
around for longer than within the function context, we allocate it with
av_alloc_put_byte() and free it with av_free() instead. Discussed in ML
thread "[PATCH] fix small memleak in rdt.c".

Originally committed as revision 15850 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rdt.c

@@ -115,7 +115,7 @@ ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
 static int
 rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
 {
-    ByteIOContext *pb;
+    ByteIOContext pb;
     int size;
     uint32_t tag;
 
@@ -135,34 +135,34 @@ rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
      */
     if (!rdt->mlti_data)
         return -1;
-    url_open_buf(&pb, rdt->mlti_data, rdt->mlti_data_size, URL_RDONLY);
-    tag = get_le32(pb);
+    init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
+                  NULL, NULL, NULL, NULL);
+    tag = get_le32(&pb);
     if (tag == MKTAG('M', 'L', 'T', 'I')) {
         int num, chunk_nr;
 
         /* read index of MDPR chunk numbers */
-        num = get_be16(pb);
+        num = get_be16(&pb);
         if (rule_nr < 0 || rule_nr >= num)
             return -1;
-        url_fskip(pb, rule_nr * 2);
-        chunk_nr = get_be16(pb);
-        url_fskip(pb, (num - 1 - rule_nr) * 2);
+        url_fskip(&pb, rule_nr * 2);
+        chunk_nr = get_be16(&pb);
+        url_fskip(&pb, (num - 1 - rule_nr) * 2);
 
         /* read MDPR chunks */
-        num = get_be16(pb);
+        num = get_be16(&pb);
         if (chunk_nr >= num)
             return -1;
         while (chunk_nr--)
-            url_fskip(pb, get_be32(pb));
-        size = get_be32(pb);
+            url_fskip(&pb, get_be32(&pb));
+        size = get_be32(&pb);
     } else {
         size = rdt->mlti_data_size;
-        url_fseek(pb, 0, SEEK_SET);
+        url_fseek(&pb, 0, SEEK_SET);
     }
-    if (ff_rm_read_mdpr_codecdata(rdt->rmctx, pb, st, size) < 0)
+    if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, size) < 0)
         return -1;
 
-    url_close_buf(pb);
     return 0;
 }
 
@@ -258,30 +258,30 @@ rdt_parse_packet (PayloadContext *rdt, AVStream *st,
                   const uint8_t *buf, int len, int flags)
 {
     int seq = 1, res;
-    ByteIOContext *pb;
+    ByteIOContext pb;
     RMContext *rm = rdt->rmctx->priv_data;
 
     if (rm->audio_pkt_cnt == 0) {
         int pos;
 
-        url_open_buf (&pb, buf, len, URL_RDONLY);
+        init_put_byte(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
         flags = (flags & PKT_FLAG_KEY) ? 2 : 0;
-        res = ff_rm_parse_packet (rdt->rmctx, pb, st, len, pkt,
+        res = ff_rm_parse_packet (rdt->rmctx, &pb, st, len, pkt,
                                   &seq, &flags, timestamp);
-        pos = url_ftell(pb);
-        url_close_buf (pb);
+        pos = url_ftell(&pb);
         if (res < 0)
             return res;
         if (rm->audio_pkt_cnt > 0 &&
             st->codec->codec_id == CODEC_ID_AAC) {
             memcpy (rdt->buffer, buf + pos, len - pos);
-            url_open_buf (&rdt->rmctx->pb, rdt->buffer, len - pos, URL_RDONLY);
+            rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0,
+                                                NULL, NULL, NULL, NULL);
         }
     } else {
         ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb, st, pkt);
         if (rm->audio_pkt_cnt == 0 &&
             st->codec->codec_id == CODEC_ID_AAC)
-            url_close_buf (rdt->rmctx->pb);
+            av_freep(&rdt->rmctx->pb);
     }
     pkt->stream_index = st->index;
     pkt->pts = *timestamp;