libavformat: fix incorrect handling of incomplete AVBPrint.

Change some internal APIs a bit to make it harder to make
such mistakes.
In particular, have the read chunk functions return an error
when the result is incomplete.
This might be less flexible, but since there has been no
use-case for that so far, avoiding coding mistakes seems better.
Add a function to queue a AVBPrint directly (ff_subtitles_queue_insert_bprint).
Also fixes a leak in lrcdec when ff_subtitles_queue_insert fails.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

1 files changed, 15 insertions, 4 deletions

diff --git a/libavformat/subtitles.c b/libavformat/subtitles.c
index 3ba5e2b217..6c221e4b29 100644
--- a/libavformat/subtitles.c
+++ b/libavformat/subtitles.c
@@ -145,6 +145,14 @@ AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
     return sub;
 }
 
+AVPacket *ff_subtitles_queue_insert_bprint(FFDemuxSubtitlesQueue *q,
+                                           const AVBPrint *event, int merge)
+{
+    if (!av_bprint_is_complete(event))
+        return NULL;
+    return ff_subtitles_queue_insert(q, event->str, event->len, merge);
+}
+
 static int cmp_pkt_sub_ts_pos(const void *a, const void *b)
 {
     const AVPacket *s1 = *(const AVPacket **)a;
@@ -347,13 +355,15 @@ int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c)
     do {
         av_bprint_chars(buf, *c, 1);
         *c = ff_text_r8(tr);
+        if (i == INT_MAX)
+            return AVERROR_INVALIDDATA;
         i++;
     } while (*c != end_chr && *c);
     if (end_chr == '>') {
         av_bprint_chars(buf, '>', 1);
         *c = 0;
     }
-    return i;
+    return av_bprint_is_complete(buf) ? i : AVERROR(ENOMEM);
 }
 
 const char *ff_smil_get_attr_ptr(const char *s, const char *attr)
@@ -381,7 +391,7 @@ static inline int is_eol(char c)
     return c == '\r' || c == '\n';
 }
 
-void ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf)
+int ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf)
 {
     char eol_buf[5], last_was_cr = 0;
     int n = 0, i = 0, nb_eol = 0;
@@ -421,15 +431,16 @@ void ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf)
         av_bprint_chars(buf, c, 1);
         n++;
     }
+    return av_bprint_is_complete(buf) ? 0 : AVERROR(ENOMEM);
 }
 
-void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
+int ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
 {
     FFTextReader tr;
     tr.buf_pos = tr.buf_len = 0;
     tr.type = 0;
     tr.pb = pb;
-    ff_subtitles_read_text_chunk(&tr, buf);
+    return ff_subtitles_read_text_chunk(&tr, buf);
 }
 
 ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)