From: Timo Sirainen <tss@iki.fi>
Date: Wed, 24 Jun 2009 01:15:21 +0000 (-0400)
Subject: istreams: Added a default seek() implementation for non-seekable streams.
X-Git-Tag: 2.0.alpha1~530
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=12a3540693ab69ec622e04d1b3b66962b8b2a3d9;p=thirdparty%2Fdovecot%2Fcore.git

istreams: Added a default seek() implementation for non-seekable streams.

--HG--
branch : HEAD
---

diff --git a/src/lib-mail/istream-dot.c b/src/lib-mail/istream-dot.c
index 0e26f166a3..a080b2c2ef 100644
--- a/src/lib-mail/istream-dot.c
+++ b/src/lib-mail/istream-dot.c
@@ -199,13 +199,6 @@ end:
 	return ret;
 }
 
-static void
-i_stream_dot_seek(struct istream_private *stream ATTR_UNUSED,
-		   uoff_t v_offset ATTR_UNUSED, bool mark ATTR_UNUSED)
-{
-	i_panic("dot-istream: seeking unsupported currently");
-}
-
 static const struct stat *
 i_stream_dot_stat(struct istream_private *stream, bool exact)
 {
@@ -220,7 +213,6 @@ struct istream *i_stream_create_dot(struct istream *input, bool send_last_lf)
 	dstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
 
 	dstream->istream.read = i_stream_dot_read;
-	dstream->istream.seek = i_stream_dot_seek;
 	dstream->istream.stat = i_stream_dot_stat;
 
 	dstream->istream.istream.blocking = input->blocking;
diff --git a/src/lib/istream-crlf.c b/src/lib/istream-crlf.c
index 97baac0818..28d98d342f 100644
--- a/src/lib/istream-crlf.c
+++ b/src/lib/istream-crlf.c
@@ -133,32 +133,6 @@ static ssize_t i_stream_crlf_read_lf(struct istream_private *stream)
 	return ret;
 }
 
-static void
-i_stream_crlf_seek(struct istream_private *stream,
-		   uoff_t v_offset, bool mark ATTR_UNUSED)
-{
-	size_t available;
-
-	if (stream->istream.v_offset > v_offset)
-		i_panic("crlf-istream: seeking unsupported currently");
-
-	while (stream->istream.v_offset < v_offset) {
-		(void)i_stream_crlf_read_crlf(stream);
-
-		available = stream->pos - stream->skip;
-		if (available == 0) {
-			stream->istream.stream_errno = ESPIPE;
-			return;
-		}
-		if (available <= v_offset - stream->istream.v_offset)
-			i_stream_skip(&stream->istream, available);
-		else {
-			i_stream_skip(&stream->istream,
-				      v_offset - stream->istream.v_offset);
-		}
-	}
-}
-
 static const struct stat *
 i_stream_crlf_stat(struct istream_private *stream, bool exact)
 {
@@ -175,7 +149,6 @@ i_stream_create_crlf_full(struct istream *input, bool crlf)
 
 	cstream->istream.read = crlf ? i_stream_crlf_read_crlf :
 		i_stream_crlf_read_lf;
-	cstream->istream.seek = i_stream_crlf_seek;
 	cstream->istream.stat = i_stream_crlf_stat;
 
 	cstream->istream.istream.blocking = input->blocking;
diff --git a/src/lib/istream-tee.c b/src/lib/istream-tee.c
index 40871cb1e1..41dc68b63e 100644
--- a/src/lib/istream-tee.c
+++ b/src/lib/istream-tee.c
@@ -155,13 +155,6 @@ static ssize_t i_stream_tee_read(struct istream_private *stream)
 	return ret;
 }
 
-static void ATTR_NORETURN
-i_stream_tee_seek(struct istream_private *stream ATTR_UNUSED,
-		  uoff_t v_offset ATTR_UNUSED, bool mark ATTR_UNUSED)
-{
-	i_panic("tee-istream: seeking unsupported currently");
-}
-
 static const struct stat *
 i_stream_tee_stat(struct istream_private *stream, bool exact)
 {
@@ -210,7 +203,6 @@ struct istream *tee_i_stream_create_child(struct tee_istream *tee)
 		i_stream_tee_set_max_buffer_size;
 
 	tstream->istream.read = i_stream_tee_read;
-	tstream->istream.seek = i_stream_tee_seek;
 	tstream->istream.stat = i_stream_tee_stat;
 	tstream->istream.sync = i_stream_tee_sync;
 
diff --git a/src/lib/istream.c b/src/lib/istream.c
index def9acbe8e..c6e7979b82 100644
--- a/src/lib/istream.c
+++ b/src/lib/istream.c
@@ -496,6 +496,31 @@ static void i_stream_default_destroy(struct iostream_private *stream)
 	}
 }
 
+static void
+i_stream_default_seek(struct istream_private *stream,
+		      uoff_t v_offset, bool mark ATTR_UNUSED)
+{
+	size_t available;
+
+	if (stream->istream.v_offset > v_offset)
+		i_panic("stream doesn't support seeking backwards");
+
+	while (stream->istream.v_offset < v_offset) {
+		(void)i_stream_read(&stream->istream);
+
+		available = stream->pos - stream->skip;
+		if (available == 0) {
+			stream->istream.stream_errno = ESPIPE;
+			return;
+		}
+		if (available <= v_offset - stream->istream.v_offset)
+			i_stream_skip(&stream->istream, available);
+		else {
+			i_stream_skip(&stream->istream,
+				      v_offset - stream->istream.v_offset);
+		}
+	}
+}
 static const struct stat *
 i_stream_default_stat(struct istream_private *stream, bool exact ATTR_UNUSED)
 {
@@ -533,6 +558,10 @@ i_stream_create(struct istream_private *_stream, struct istream *parent, int fd)
 
 	if (_stream->iostream.destroy == NULL)
 		_stream->iostream.destroy = i_stream_default_destroy;
+	if (_stream->seek == NULL) {
+		i_assert(!_stream->istream.seekable);
+		_stream->seek = i_stream_default_seek;
+	}
 	if (_stream->stat == NULL)
 		_stream->stat = i_stream_default_stat;
 	if (_stream->get_size == NULL)