lib: istream-seekable - Change stream to be blocking=TRUE after reaching EOF

After EOF is reached, the stream is now fully read into file or memory.
read()s can no longer return 0, so blocking=TRUE can be used.

Some callers were reusing the seekable stream in places that required
blocking=TRUE.

Fixes at least with imapsieve vnd.dovecot report extension:
Panic: file ostream.c: line 427 (o_stream_nsend_istream): assertion failed: (instream->blocking)

diff --git a/src/lib/istream-seekable.c b/src/lib/istream-seekable.c
index 875bba667f25884b50db81552630828633b2a7da..67ff65620b72576ae0971287b5e52c22589d5673 100644 (file)
--- a/src/lib/istream-seekable.c
+++ b/src/lib/istream-seekable.c
@@ -164,6 +164,10 @@ static ssize_t read_more(struct seekable_istream *sstream)
                        /* last one, EOF */
                        sstream->size = sstream->istream.istream.v_offset;
                        sstream->istream.istream.eof = TRUE;
+                       /* Now that EOF is reached, the stream can't return 0
+                          anymore. Callers can now use this stream in places
+                          that assert that blocking==TRUE. */
+                       sstream->istream.istream.blocking = TRUE;
                        unref_streams(sstream);
                        return -1;
                }