From a7fe8e527c5f170a17e4d4ae95189ee812e43bab Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Tue, 8 May 2012 20:40:09 +0200
Subject: [PATCH] MINOR: http: replace http_message_realign() with 
 buffer_slow_realign()

There is no more reason for the realign function being HTTP specific,
it only operates on a buffer now. Let's move it to buffers.c instead.

It's likely that buffer_bounce_realign is broken (not used), this will
have to be inspected. The function is worth rewriting as it can be
cheaper than buffer_slow_realign() to realign large wrapping buffers.
---
 include/proto/buffers.h |  1 +
 src/buffers.c           | 28 ++++++++++++++++++++++++++++
 src/proto_http.c        | 38 ++------------------------------------
 3 files changed, 31 insertions(+), 36 deletions(-)

diff --git a/include/proto/buffers.h b/include/proto/buffers.h
index 3b98f178a..6f8e2c15d 100644
--- a/include/proto/buffers.h
+++ b/include/proto/buffers.h
@@ -48,6 +48,7 @@ int bo_getblk(struct buffer *buf, char *blk, int len, int offset);
 int buffer_replace2(struct buffer *b, char *pos, char *end, const char *str, int len);
 int buffer_insert_line2(struct buffer *b, char *pos, const char *str, int len);
 void buffer_dump(FILE *o, struct buffer *b, int from, int to);
+void buffer_slow_realign(struct buffer *buf);
 void buffer_bounce_realign(struct buffer *buf);
 unsigned long long buffer_forward(struct buffer *buf, unsigned long long bytes);
 
diff --git a/src/buffers.c b/src/buffers.c
index e71f8522c..7becb4863 100644
--- a/src/buffers.c
+++ b/src/buffers.c
@@ -388,6 +388,34 @@ int buffer_insert_line2(struct buffer *b, char *pos, const char *str, int len)
 }
 
 
+/* This function realigns input data in a possibly wrapping buffer so that it
+ * becomes contiguous and starts at the beginning of the buffer area. The
+ * function may only be used when the buffer's output is empty.
+ */
+void buffer_slow_realign(struct buffer *buf)
+{
+	/* two possible cases :
+	 *   - the buffer is in one contiguous block, we move it in-place
+	 *   - the buffer is in two blocks, we move it via the swap_buffer
+	 */
+	if (buf->i) {
+		int block1 = buf->i;
+		int block2 = 0;
+		if (buf->p + buf->i > buf->data + buf->size) {
+			/* non-contiguous block */
+			block1 = buf->data + buf->size - buf->p;
+			block2 = buf->p + buf->i - (buf->data + buf->size);
+		}
+		if (block2)
+			memcpy(swap_buffer, buf->data, block2);
+		memmove(buf->data, buf->p, block1);
+		if (block2)
+			memcpy(buf->data + block1, swap_buffer, block2);
+	}
+
+	buf->p = buf->data;
+}
+
 /* Realigns a possibly non-contiguous buffer by bouncing bytes from source to
  * destination. It does not use any intermediate buffer and does the move in
  * place, though it will be slower than a simple memmove() on contiguous data,
diff --git a/src/proto_http.c b/src/proto_http.c
index 637c856ba..3db7de1fa 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -1961,40 +1961,6 @@ int http_skip_chunk_crlf(struct http_msg *msg)
 	return 1;
 }
 
-/* This function realigns a possibly wrapping http message at the beginning
- * of its buffer. The function may only be used when the buffer's tail is
- * empty.
- */
-void http_message_realign(struct http_msg *msg)
-{
-	struct buffer *buf = msg->buf;
-
-	/* two possible cases :
-	 *   - the buffer is in one contiguous block, we move it in-place
-	 *   - the buffer is in two blocks, we move it via the swap_buffer
-	 */
-	if (buf->i) {
-		int block1 = buf->i;
-		int block2 = 0;
-		if (buf->p + buf->i > buf->data + buf->size) {
-			/* non-contiguous block */
-			block1 = buf->data + buf->size - buf->p;
-			block2 = buf->p + buf->i - (buf->data + buf->size);
-		}
-		if (block2)
-			memcpy(swap_buffer, buf->data, block2);
-		memmove(buf->data, buf->p, block1);
-		if (block2)
-			memcpy(buf->data + block1, swap_buffer, block2);
-	}
-
-	/* adjust all known pointers */
-	buf->p = buf->data;
-	buf->flags &= ~BF_FULL;
-	if (bi_full(buf))
-		buf->flags |= BF_FULL;
-}
-
 /* This stream analyser waits for a complete HTTP request. It returns 1 if the
  * processing can continue on next analysers, or zero if it either needs more
  * data or wants to immediately abort the request (eg: timeout, error, ...). It
@@ -2063,7 +2029,7 @@ int http_wait_for_request(struct session *s, struct buffer *req, int an_bit)
 			}
 			if (bi_end(req) < b_ptr(req, msg->next) ||
 			    bi_end(req) > req->data + req->size - global.tune.maxrewrite)
-				http_message_realign(msg);
+				buffer_slow_realign(msg->buf);
 		}
 
 		/* Note that we have the same problem with the response ; we
@@ -4473,7 +4439,7 @@ int http_wait_for_response(struct session *s, struct buffer *rep, int an_bit)
 				return 0;
 			}
 			if (rep->i <= rep->size - global.tune.maxrewrite)
-				http_message_realign(msg);
+				buffer_slow_realign(msg->buf);
 		}
 
 		if (likely(msg->next < rep->i))