MINOR: buffer: replace buffer_empty() with b_empty() or c_empty()

For the same consistency reasons, let's use b_empty() at the few places
where an empty buffer is expected, or c_empty() if it's done on a channel.
Some of these places were there to realign the buffer so
{b,c}_realign_if_empty() was used instead.

include/common/buffer.h

@@ -61,12 +61,6 @@ void buffer_dump(FILE *o, struct buffer *b, int from, int to);
 
 /***** FIXME: OLD API BELOW *****/
 
-/* Return non-zero only if the buffer is empty */
-static inline int buffer_empty(const struct buffer *buf)
-{
-	return !b_data(buf);
-}
-
 /* Returns non-zero if the buffer's INPUT is considered full, which means that
  * it holds at least as much INPUT data as (size - reserve). This also means
  * that data that are scheduled for output are considered as potential free

include/proto/channel.h

@@ -685,7 +685,7 @@ static inline int channel_alloc_buffer(struct channel *chn, struct buffer_wait *
  * to wake up as many streams/applets as possible. */
 static inline void channel_release_buffer(struct channel *chn, struct buffer_wait *wait)
 {
-	if (chn->buf->size && buffer_empty(chn->buf)) {
+	if (c_size(chn) && c_empty(chn)) {
 		b_free(&chn->buf);
 		offer_buffers(wait->target, tasks_run_queue);
 	}
@@ -728,8 +728,7 @@ static inline void channel_slow_realign(struct channel *chn, char *swap)
 static inline void co_skip(struct channel *chn, int len)
 {
 	b_del(chn->buf, len);
-	if (buffer_empty(chn->buf))
-		chn->buf->p = chn->buf->data;
+	c_realign_if_empty(chn);
 
 	/* notify that some data was written to the SI from the buffer */
 	chn->flags |= CF_WRITE_PARTIAL | CF_WRITE_EVENT;

src/buffer.c

@@ -102,9 +102,7 @@ int buffer_replace2(struct buffer *b, char *pos, char *end, const char *str, int
 		memcpy(pos, str, len);
 
 	b->i += delta;
-
-	if (buffer_empty(b))
-		b->p = b->data;
+	b_realign_if_empty(b);
 
 	return delta;
 }

src/channel.c

@@ -205,7 +205,7 @@ struct buffer *ci_swpbuf(struct channel *chn, struct buffer *buf)
 	if (unlikely(channel_input_closed(chn)))
 		return NULL;
 
-	if (!chn->buf->size || !buffer_empty(chn->buf))
+	if (!c_size(chn) || !c_empty(chn))
 		return buf;
 
 	old = chn->buf;

src/raw_sock.c

@@ -276,9 +276,7 @@ static size_t raw_sock_to_buf(struct connection *conn, struct buffer *buf, size_
 		}
 	}
 
-	/* let's realign the buffer to optimize I/O */
-	if (buffer_empty(buf))
-		buf->p = buf->data;
+	b_realign_if_empty(buf);
 
 	/* read the largest possible block. For this, we perform only one call
 	 * to recv() unless the buffer wraps and we exactly fill the first hunk,

src/ssl_sock.c

@@ -5351,10 +5351,7 @@ static size_t ssl_sock_to_buf(struct connection *conn, struct buffer *buf, size_
 		/* a handshake was requested */
 		return 0;
 
-	/* let's realign the buffer to optimize I/O */
-	if (buffer_empty(buf)) {
-		buf->p = buf->data;
-	}
+	b_realign_if_empty(buf);
 
 	/* read the largest possible block. For this, we perform only one call
 	 * to recv() unless the buffer wraps and we exactly fill the first hunk,

src/stream.c

@@ -456,11 +456,11 @@ void stream_release_buffers(struct stream *s)
 {
 	int offer = 0;
 
-	if (s->req.buf->size && buffer_empty(s->req.buf)) {
+	if (c_size(&s->req) && c_empty(&s->req)) {
 		offer = 1;
 		b_free(&s->req.buf);
 	}
-	if (s->res.buf->size && buffer_empty(s->res.buf)) {
+	if (c_size(&s->res) && c_empty(&s->res)) {
 		offer = 1;
 		b_free(&s->res.buf);
 	}