From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Thu, 22 Oct 2020 09:22:40 +0000 (+0300)
Subject: lib: i_stream_read() - Don't create empty snapshots
X-Git-Tag: 2.3.14.rc1~283
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8299232acbd010177d8048071b9ecff0a8620704;p=thirdparty%2Fdovecot%2Fcore.git

lib: i_stream_read() - Don't create empty snapshots

This allows the read() implementation to read data into the existing
memarea. Otherwise a new memarea might have to be created because the old
one is referenced by the snapshot.
---

diff --git a/src/lib/istream.c b/src/lib/istream.c
index 4b5e810df0..06fd93e8ca 100644
--- a/src/lib/istream.c
+++ b/src/lib/istream.c
@@ -266,8 +266,10 @@ ssize_t i_stream_read(struct istream *stream)
 	}
 #endif
 
-	_stream->prev_snapshot =
-		_stream->snapshot(_stream, _stream->prev_snapshot);
+	if (_stream->skip != _stream->pos || _stream->prev_snapshot != NULL) {
+		_stream->prev_snapshot =
+			_stream->snapshot(_stream, _stream->prev_snapshot);
+	}
 	ret = i_stream_read_memarea(stream);
 	if (ret > 0)
 		i_stream_snapshot_free(&_stream->prev_snapshot);