Remove timeout in the main loop

From: Roberto E. Vargas Caballero <k0ga_AT_shike2.com>
Date: Sat, 15 Sep 2012 20:55:27 +0200

The main loop waits until there is some data to read in file descriptors of
the X server or the pseudo tty. But it uses a timeout in select(), which
causes that st awake each 20 ms, even it doesn't have something to do. This
pull request removes this problem removing the timeout, which is not needed.

---
 TODO |    1 -
 st.c |   27 +++------------------------
 2 files changed, 3 insertions(+), 25 deletions(-)
diff --dropbox a/TODO b/TODO
index 1996137..c77c105 100644
--- a/TODO
+++ b/TODO
_AT_@ -15,7 +15,6 @@ code & interface
 
 * clean selection code
 * clean and complete terminfo entry
-* remove the timeouts in the main loop
 
 bugs
 ----
diff --dropbox a/st.c b/st.c
index f4ad23d..d7ca875 100644
--- a/st.c
+++ b/st.c
_AT_@ -53,8 +53,6 @@
 #define XK_NO_MOD     UINT_MAX
 #define XK_ANY_MOD    0
 
-#define SELECT_TIMEOUT (20*1000) /* 20 ms */
-#define DRAW_TIMEOUT  (20*1000) /* 20 ms */
 #define REDRAW_TIMEOUT (80*1000) /* 80 ms */
 
 #define SERRNO strerror(errno)
_AT_@ -205,7 +203,6 @@ typedef struct {
 	int ch; /* char height */
 	int cw; /* char width  */
 	char state; /* focus, redraw, visible */
-	struct timeval lastdraw;
 } XWindow;
 
 typedef struct {
_AT_@ -250,7 +247,6 @@ static void drawregion(int, int, int, int);
 static void execsh(void);
 static void sigchld(int);
 static void run(void);
-static bool last_draw_too_old(void);
 
 static void csidump(void);
 static void csihandle(void);
_AT_@ -2158,7 +2154,6 @@ void
 draw() {
 	drawregion(0, 0, term.col, term.row);
 	xcopy();
-	gettimeofday(&xw.lastdraw, NULL);
 }
 
 void
_AT_@ -2345,41 +2340,25 @@ resize(XEvent *e) {
 	ttyresize(col, row);
 }
 
-bool
-last_draw_too_old(void) {
-	struct timeval now;
-	gettimeofday(&now, NULL);
-	return TIMEDIFF(now, xw.lastdraw) >= DRAW_TIMEOUT/1000;
-}
-
 void
 run(void) {
 	XEvent ev;
 	fd_set rfd;
 	int xfd = XConnectionNumber(xw.dpy);
-	struct timeval timeout = {0};
-	bool stuff_to_print = 0;
 
 	for(;;) {
 		FD_ZERO(&rfd);
 		FD_SET(cmdfd, &rfd);
 		FD_SET(xfd, &rfd);
-		timeout.tv_sec  = 0;
-		timeout.tv_usec = SELECT_TIMEOUT;
-		if(select(MAX(xfd, cmdfd)+1, &rfd, NULL, NULL, &timeout) < 0) {
+		if(select(MAX(xfd, cmdfd)+1, &rfd, NULL, NULL, NULL) < 0) {
 			if(errno == EINTR)
 				continue;
 			die("select failed: %s\n", SERRNO);
 		}
-		if(FD_ISSET(cmdfd, &rfd)) {
+		if(FD_ISSET(cmdfd, &rfd))
 			ttyread();
-			stuff_to_print = 1;
-		}
 
-		if(stuff_to_print && last_draw_too_old()) {
-			stuff_to_print = 0;
-			draw();
-		}
+		draw();
 
 		while(XPending(xw.dpy)) {
 			XNextEvent(xw.dpy, &ev);
-- 
1.7.10.4
--X1bOJ3K7DJ5YkBrT
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment; filename="0004-Render-only-once-in-each-main-loop-iteration.pull request"

Received on Mon Sep 17 2001 - 00:00:00 CEST