master 5ed566cae0: Improve x_wait_for_cell_change

[Po Lu]

branch: master
commit 5ed566cae08d4f39920bea81fd6bf2160f38348f
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Improve x_wait_for_cell_change
    
    * src/xterm.c (x_wait_for_cell_change): Keep processing events
    while still XPending.
---
 src/xterm.c | 51 +++++++++++++++++++++++++++++++++++----------------
 1 file changed, 35 insertions(+), 16 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index 7235a1e959..186014b0b4 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -14849,13 +14849,19 @@ x_wait_for_cell_change (Lisp_Object cell, struct 
timespec timeout)
   fd_set fds;
   int fd, maxfd;
 #ifndef USE_GTK
-  int finish;
+  int finish, rc;
   XEvent event;
+  fd_set rfds;
 #endif
   struct input_event hold_quit;
   struct timespec current, at;
 
   at = timespec_add (current_timespec (), timeout);
+  FD_ZERO (&rfds);
+
+#ifndef USE_GTK
+  rc = 0;
+#endif
 
   while (true)
     {
@@ -14865,26 +14871,35 @@ x_wait_for_cell_change (Lisp_Object cell, struct 
timespec timeout)
       for (dpyinfo = x_display_list; dpyinfo;
           dpyinfo = dpyinfo->next)
        {
+         fd = ConnectionNumber (dpyinfo->display);
+
 #ifndef USE_GTK
-         if (XPending (dpyinfo->display))
+         if ((rc < 0 || FD_ISSET (fd, &rfds))
+             /* If pselect failed, the erroring display's IO error
+                handler will eventually be called.  */
+             && XPending (dpyinfo->display))
            {
-             EVENT_INIT (hold_quit);
+             while (XPending (dpyinfo->display))
+               {
+                 EVENT_INIT (hold_quit);
 
-             XNextEvent (dpyinfo->display, &event);
-             handle_one_xevent (dpyinfo, &event,
-                                &finish, &hold_quit);
+                 XNextEvent (dpyinfo->display, &event);
+                 handle_one_xevent (dpyinfo, &event,
+                                    &finish, &hold_quit);
 
-             /* Make us quit now.  */
-             if (hold_quit.kind != NO_EVENT)
-               kbd_buffer_store_event (&hold_quit);
+                 if (!NILP (XCAR (cell)))
+                   return;
 
-             if (!NILP (XCAR (cell)))
-               return;
+                 if (finish == X_EVENT_GOTO_OUT)
+                   break;
+
+                 /* Make us quit now.  */
+                 if (hold_quit.kind != NO_EVENT)
+                   kbd_buffer_store_event (&hold_quit);
+               }
            }
 #endif
 
-         fd = XConnectionNumber (dpyinfo->display);
-
          if (fd > maxfd)
            maxfd = fd;
 
@@ -14929,10 +14944,14 @@ x_wait_for_cell_change (Lisp_Object cell, struct 
timespec timeout)
 
       timeout = timespec_sub (at, current);
 
-      /* We don't have to check the return of pselect, because if an
-        error occurs XPending will call the IO error handler, which
-        then brings us out of this loop.  */
+#ifndef USE_GTK
+      rc = pselect (maxfd, &fds, NULL, NULL, &timeout, NULL);
+
+      if (rc > 0)
+       rfds = fds;
+#else
       pselect (maxfd, &fds, NULL, NULL, &timeout, NULL);
+#endif
     }
 }