dovecot-2.0-sslstream: istream-concat: Fixed a lot of bugs.

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.0-sslstream/rev/891d8650f3f8
changeset: 10185:891d8650f3f8
user:      Timo Sirainen <tss at iki.fi>
date:      Mon Oct 26 17:07:06 2009 -0400
description:
istream-concat: Fixed a lot of bugs.

diffstat:

1 file changed, 47 insertions(+), 41 deletions(-)
src/lib/istream-concat.c |   88 ++++++++++++++++++++++++----------------------

diffs (172 lines):

diff -r 65c6568515ce -r 891d8650f3f8 src/lib/istream-concat.c
--- a/src/lib/istream-concat.c	Mon Oct 26 17:06:21 2009 -0400
+++ b/src/lib/istream-concat.c	Mon Oct 26 17:07:06 2009 -0400
@@ -12,7 +12,7 @@ struct concat_istream {
 	uoff_t *input_size;
 
 	unsigned int cur_idx, unknown_size_idx;
-	size_t prev_size;
+	size_t prev_stream_left, prev_skip;
 };
 
 static void i_stream_concat_close(struct iostream_private *stream)
@@ -52,31 +52,28 @@ static void i_stream_concat_read_next(st
 
 	i_assert(cstream->cur_input->eof);
 
+	data = i_stream_get_data(cstream->cur_input, &data_size);
 	cstream->cur_idx++;
 	cstream->cur_input = cstream->input[cstream->cur_idx];
 	i_stream_seek(cstream->cur_input, 0);
 
-	if (cstream->istream.pos == cstream->istream.skip) {
-		i_assert(cstream->prev_size == 0);
-		cstream->istream.skip = 0;
-		cstream->istream.pos = 0;
+	if (cstream->prev_stream_left > 0 || cstream->istream.pos == 0) {
+		cstream->prev_stream_left += data_size;
+		i_assert(cstream->prev_stream_left ==
+			 cstream->istream.pos - cstream->istream.skip);
 		return;
 	}
-
-	/* we need to keep the current data */
-	data = cstream->istream.buffer + cstream->istream.skip;
-	data_size = cstream->istream.pos - cstream->istream.skip;
-
-	cstream->istream.skip = cstream->istream.pos = 0;
 
 	/* we already verified that the data size is less than the
 	   maximum buffer size */
+	cstream->istream.pos = 0;
 	if (!i_stream_get_buffer_space(&cstream->istream, data_size, &size))
 		i_unreached();
 	i_assert(size >= data_size);
 
-	cstream->prev_size = data_size;
+	cstream->prev_stream_left = data_size;
 	memcpy(cstream->istream.w_buffer, data, data_size);
+	cstream->istream.skip = 0;
 	cstream->istream.pos = data_size;
 }
 
@@ -84,7 +81,7 @@ static ssize_t i_stream_concat_read(stru
 {
 	struct concat_istream *cstream = (struct concat_istream *)stream;
 	const unsigned char *data;
-	size_t size, pos, skip;
+	size_t size, pos, cur_pos, bytes_skipped;
 	ssize_t ret;
 	bool last_stream;
 
@@ -93,29 +90,32 @@ static ssize_t i_stream_concat_read(stru
 		return -1;
 	}
 
-	skip = stream->skip;
-	if (cstream->prev_size > 0) {
-		if (stream->skip < cstream->prev_size) {
-			cstream->prev_size -= stream->skip;
-			skip = 0;
-		} else {
-			/* we don't need the buffer anymore */
-			skip -= cstream->prev_size;
-			stream->skip -= cstream->prev_size;
-			cstream->prev_size = 0;
-
-			i_free_and_null(stream->w_buffer);
-			stream->buffer = NULL;
-			stream->buffer_size = 0;
-		}
-	} 
-	i_stream_skip(cstream->cur_input, skip);
-
+	i_assert(stream->skip >= cstream->prev_skip);
+	bytes_skipped = stream->skip - cstream->prev_skip;
+
+	if (cstream->prev_stream_left == 0) {
+		/* no need to worry about buffers, skip everything */
+		i_assert(cstream->prev_skip == 0);
+	} else if (bytes_skipped < cstream->prev_stream_left) {
+		/* we're still skipping inside buffer */
+		cstream->prev_stream_left -= bytes_skipped;
+		bytes_skipped = 0;
+	} else {
+		/* done with the buffer */
+		bytes_skipped -= cstream->prev_stream_left;
+		cstream->prev_stream_left = 0;
+	}
+	i_stream_skip(cstream->cur_input, bytes_skipped);
+	stream->pos -= bytes_skipped;
+	stream->skip -= bytes_skipped;
+
+	cur_pos = stream->pos - stream->skip - cstream->prev_stream_left;
 	data = i_stream_get_data(cstream->cur_input, &pos);
-	if (pos > stream->pos)
+	if (pos > cur_pos)
 		ret = 0;
 	else {
 		/* need to read more */
+		i_assert(cur_pos == pos);
 		ret = i_stream_read(cstream->cur_input);
 		if (ret == -2 || ret == 0)
 			return ret;
@@ -129,11 +129,11 @@ static ssize_t i_stream_concat_read(stru
 		/* we either read something or we're at EOF */
 		last_stream = cstream->input[cstream->cur_idx+1] == NULL;
 		if (ret == -1 && !last_stream) {
-			if (stream->pos - stream->skip >=
-			    stream->max_buffer_size)
+			if (stream->pos >= stream->max_buffer_size)
 				return -2;
 
 			i_stream_concat_read_next(cstream);
+			cstream->prev_skip = stream->skip;
 			return i_stream_concat_read(stream);
 		}
 
@@ -142,23 +142,28 @@ static ssize_t i_stream_concat_read(stru
 		data = i_stream_get_data(cstream->cur_input, &pos);
 	}
 
-	if (stream->w_buffer == NULL) {
+	if (cstream->prev_stream_left == 0) {
 		stream->buffer = data;
 		stream->pos -= stream->skip;
 		stream->skip = 0;
+	} else if (pos == cur_pos) {
+		stream->buffer = stream->w_buffer;
 	} else {
-		if (!i_stream_get_buffer_space(stream, pos, &size))
+		stream->buffer = stream->w_buffer;
+		if (!i_stream_get_buffer_space(stream, pos - cur_pos, &size))
 			return -2;
 
 		if (pos > size)
 			pos = size;
-		memcpy(stream->w_buffer + stream->pos, data, pos);
-	}
-
-	pos += cstream->prev_size;
+		memcpy(stream->w_buffer + stream->pos,
+		       data + cur_pos, pos - cur_pos);
+	}
+	pos += stream->skip + cstream->prev_stream_left;
+
 	ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) :
 		(ret == 0 ? 0 : -1);
 	stream->pos = pos;
+	cstream->prev_skip = stream->skip;
 	return ret;
 }
 
@@ -201,7 +206,8 @@ static void i_stream_concat_seek(struct 
 
 	stream->istream.v_offset = v_offset;
 	stream->skip = stream->pos = 0;
-	cstream->prev_size = 0;
+	cstream->prev_stream_left = 0;
+	cstream->prev_skip = 0;
 
 	cstream->cur_idx = find_v_offset(cstream, &v_offset);
 	if (cstream->cur_idx == (unsigned int)-1) {