Don't redraw status line unless it has actually changed. Stops extraneous

updates between clock/#() changes and doesn't require manual status-interval 0
when no updates are occuring.

CHANGES

@@ -1,3 +1,8 @@
+10 February 2009
+
+* No longer redraw the status line every status-interval unless it has actually
+  changed.
+
 08 February 2009
 
 * Don't treat empty arguments ("") differently when parsing configuration
@@ -1085,7 +1090,7 @@
   (including mutt, emacs). No status bar yet and no key remapping or other
   customisation.
 
-$Id: CHANGES,v 1.249 2009-02-08 16:38:19 nicm Exp $
+$Id: CHANGES,v 1.250 2009-02-10 00:18:06 nicm Exp $
 
  LocalWords:  showw utf UTF fulvio ciriaco joshe OSC APC gettime abc DEF OA clr
  LocalWords:  rivo nurges lscm Erdely eol smysession mysession ek dstname RB ms

grid.c

@@ -1,4 +1,4 @@
-/* $Id: grid.c,v 1.7 2009-01-17 18:47:36 nicm Exp $ */
+/* $Id: grid.c,v 1.8 2009-02-10 00:18:06 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -119,6 +119,30 @@ grid_destroy(struct grid_data *gd)
 	xfree(gd);
 }
 
+/* Compare grids. */
+int
+grid_compare(struct grid_data *ga, struct grid_data *gb)
+{
+	struct grid_cell	*gca, *gcb;
+	u_int			 xx, yy;
+
+	if (ga->sx != gb->sx || ga->sy != ga->sy)
+		return (1);
+
+	for (yy = 0; yy < ga->sy; yy++) {
+		if (ga->size[yy] != gb->size[yy])
+			return (1);
+		for (xx = 0; xx < ga->sx; xx++) {
+			gca = &ga->data[yy][xx];
+			gcb = &gb->data[yy][xx];
+			if (memcmp(gca, gcb, sizeof (struct grid_cell)) != 0)
+				return (1);
+		}
+	}
+
+	return (0);
+}
+
 /* Scroll a line into the history. */
 void
 grid_scroll_line(struct grid_data *gd)

server.c

@@ -1,4 +1,4 @@
-/* $Id: server.c,v 1.118 2009-02-08 16:26:43 nicm Exp $ */
+/* $Id: server.c,v 1.119 2009-02-10 00:18:06 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -464,7 +464,7 @@ server_check_redraw(struct client *c)
 {
 	struct session	*s;
 	char		 title[512];
-	int		 flags;
+	int		 flags, redraw;
 
 	if (c == NULL || c->session == NULL)
 		return;
@@ -487,11 +487,13 @@ server_check_redraw(struct client *c)
 
 	if (c->flags & (CLIENT_REDRAW|CLIENT_STATUS)) {
 		if (c->message_string != NULL)
-			status_message_redraw(c);
+			redraw = status_message_redraw(c);
 		else if (c->prompt_string != NULL)
-			status_prompt_redraw(c);
+			redraw = status_prompt_redraw(c);
 		else
-			status_redraw(c);
+			redraw = status_redraw(c);
+		if (!redraw)
+			c->flags &= ~CLIENT_STATUS;
 	}
 
 	if (c->flags & CLIENT_REDRAW) {

status.c

@@ -1,4 +1,4 @@
-/* $Id: status.c,v 1.71 2009-02-01 18:14:49 tcunha Exp $ */
+/* $Id: status.c,v 1.72 2009-02-10 00:18:06 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -38,14 +38,14 @@ void	status_prompt_add_history(struct client *);
 char   *status_prompt_complete(const char *);
 
 /* Draw status for client on the last lines of given context. */
-void
+int
 status_redraw(struct client *c)
 {
 	struct screen_write_ctx		ctx;
 	struct session		       *s = c->session;
 	struct winlink		       *wl;
 	struct window_pane	       *wp;
-	struct screen		       *sc = NULL;
+	struct screen		       *sc = NULL, old_status;
 	char		 	       *left, *right, *text, *ptr;
 	size_t				llen, rlen, offset, xx, yy, sy;
 	size_t				size, start, width;
@@ -54,11 +54,9 @@ status_redraw(struct client *c)
 
 	left = right = NULL;
 
-	/* Resize the target screen. */
-	if (screen_size_x(&c->status) != c->sx) {
-		screen_free(&c->status);
-		screen_init(&c->status, c->sx, 1, 0);
-	}
+	/* Create the target screen. */
+	memcpy(&old_status, &c->status, sizeof old_status);
+	screen_init(&c->status, c->sx, 1, 0);
 
 	/* No status line? */
 	if (c->sy == 0 || !options_get_number(&s->options, "status"))
@@ -285,6 +283,13 @@ out:
 		xfree(left);
 	if (right != NULL)
 		xfree(right);
+
+	if (grid_compare(c->status.grid, old_status.grid) == 0) {
+		screen_free(&old_status);
+		return (0);
+	}
+	screen_free(&old_status);
+	return (1);
 }
 
 char *
@@ -484,20 +489,19 @@ status_print(struct session *s, struct winlink *wl, struct grid_cell *gc)
 }
 
 /* Draw client message on status line of present else on last line. */
-void
+int
 status_message_redraw(struct client *c)
 {
 	struct screen_write_ctx		ctx;
 	struct session		       *s = c->session;
+	struct screen		        old_status;
 	size_t			        len;
 	struct grid_cell		gc;
 
 	if (c->sx == 0 || c->sy == 0)
-		return;
-	if (screen_size_x(&c->status) != c->sx) {
-		screen_free(&c->status);
-		screen_init(&c->status, c->sx, 1, 0);
-	}
+		return (0);
+	memcpy(&old_status, &c->status, sizeof old_status);
+	screen_init(&c->status, c->sx, 1, 0);
 
 	len = strlen(c->message_string);
 	if (len > c->sx)
@@ -516,24 +520,30 @@ status_message_redraw(struct client *c)
 		screen_write_putc(&ctx, &gc, ' ');
 
 	screen_write_stop(&ctx);
+
+	if (grid_compare(c->status.grid, old_status.grid) == 0) {
+		screen_free(&old_status);
+		return (0);
+	}
+	screen_free(&old_status);
+	return (1);
 }
 
 /* Draw client prompt on status line of present else on last line. */
-void
+int
 status_prompt_redraw(struct client *c)
 {
 	struct screen_write_ctx	ctx;
 	struct session		       *s = c->session;
+	struct screen		        old_status;
 	size_t			        i, size, left, len, offset, n;
 	char				ch;
 	struct grid_cell		gc;
 
 	if (c->sx == 0 || c->sy == 0)
-		return;
-	if (screen_size_x(&c->status) != c->sx) {
-		screen_free(&c->status);
-		screen_init(&c->status, c->sx, 1, 0);
-	}
+		return (0);
+	memcpy(&old_status, &c->status, sizeof old_status);
+	screen_init(&c->status, c->sx, 1, 0);
 	offset = 0;
 
 	len = strlen(c->prompt_string);
@@ -587,6 +597,13 @@ status_prompt_redraw(struct client *c)
 	screen_write_putc(&ctx, &gc, ch);
 
 	screen_write_stop(&ctx);
+
+	if (grid_compare(c->status.grid, old_status.grid) == 0) {
+		screen_free(&old_status);
+		return (0);
+	}
+	screen_free(&old_status);
+	return (1);
 }
 
 /* Handle keys in prompt. */

tmux.h

@@ -1,4 +1,4 @@
-/* $Id: tmux.h,v 1.262 2009-02-09 18:08:01 nicm Exp $ */
+/* $Id: tmux.h,v 1.263 2009-02-10 00:18:06 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -1296,9 +1296,9 @@ void	 server_lock(void);
 int	 server_unlock(const char *);
 
 /* status.c */
-void	 status_redraw(struct client *);
-void	 status_message_redraw(struct client *);
-void	 status_prompt_redraw(struct client *);
+int	 status_redraw(struct client *);
+int	 status_message_redraw(struct client *);
+int	 status_prompt_redraw(struct client *);
 void	 status_prompt_key(struct client *, int);
 
 /* resize.c */
@@ -1326,6 +1326,7 @@ int	 attributes_fromstring(const char *);
 extern const struct grid_cell grid_default_cell;
 struct grid_data *grid_create(u_int, u_int, u_int);
 void	 grid_destroy(struct grid_data *);
+int	 grid_compare(struct grid_data *, struct grid_data *);
 void	 grid_reduce_line(struct grid_data *, u_int, u_int);
 void	 grid_expand_line(struct grid_data *, u_int, u_int);
 void	 grid_scroll_line(struct grid_data *);