master e465ea816d: Don't unnecessarily call monitor change functions

[Po Lu]

branch: master
commit e465ea816d6a64a21822549982928c48961fec99
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Don't unnecessarily call monitor change functions
    
    * src/xterm.c (handle_one_xevent): If monitor attributes didn't
    change, don't send monitor change event.
    (x_term_init, mark_xterm): Mark and init new field.
    * src/xterm.h (struct x_display_info): New field
    `last_monitor_attributes_list'.
---
 src/xterm.c | 47 +++++++++++++++++++++++++++++++++++++----------
 src/xterm.h |  4 ++++
 2 files changed, 41 insertions(+), 10 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index add0c848db..05ede2e580 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -20119,6 +20119,7 @@ handle_one_xevent (struct x_display_info *dpyinfo,
        {
          union buffered_input_event *ev;
          Time timestamp;
+         Lisp_Object current_monitors;
 
          if (event->type == (dpyinfo->xrandr_event_base
                              + RRScreenChangeNotify))
@@ -20144,6 +20145,18 @@ handle_one_xevent (struct x_display_info *dpyinfo,
          inev.ie.kind = MONITORS_CHANGED_EVENT;
          inev.ie.timestamp = timestamp;
          XSETTERMINAL (inev.ie.arg, dpyinfo->terminal);
+
+         /* Also don't do anything if the monitor configuration
+            didn't really change.  */
+
+         current_monitors
+           = Fx_display_monitor_attributes_list (inev.ie.arg);
+
+         if (Fequal (current_monitors,
+                     dpyinfo->last_monitor_attributes_list))
+           inev.ie.kind = NO_EVENT;
+
+         dpyinfo->last_monitor_attributes_list = current_monitors;
        }
 #endif
     OTHER:
@@ -24447,9 +24460,15 @@ x_term_init (Lisp_Object display_name, char 
*xrm_option, char *resource_name)
 #endif
 
 #ifdef HAVE_XRANDR
+  Lisp_Object term;
+
+  dpyinfo->last_monitor_attributes_list = Qnil;
   dpyinfo->xrandr_supported_p
     = XRRQueryExtension (dpy, &dpyinfo->xrandr_event_base,
                         &dpyinfo->xrandr_error_base);
+
+  XSETTERMINAL (term, terminal);
+
   if (dpyinfo->xrandr_supported_p)
     {
       XRRQueryVersion (dpy, &dpyinfo->xrandr_major_version,
@@ -24457,15 +24476,20 @@ x_term_init (Lisp_Object display_name, char 
*xrm_option, char *resource_name)
 
       if (dpyinfo->xrandr_major_version == 1
          && dpyinfo->xrandr_minor_version >= 2)
-       XRRSelectInput (dpyinfo->display,
-                       dpyinfo->root_window,
-                       (RRScreenChangeNotifyMask
-                        | RRCrtcChangeNotifyMask
-                        | RROutputChangeNotifyMask
-                        /* Emacs doesn't actually need this, but GTK
-                           selects for it when the display is
-                           initialized.  */
-                        | RROutputPropertyNotifyMask));
+       {
+         dpyinfo->last_monitor_attributes_list
+           = Fx_display_monitor_attributes_list (term);
+
+         XRRSelectInput (dpyinfo->display,
+                         dpyinfo->root_window,
+                         (RRScreenChangeNotifyMask
+                          | RRCrtcChangeNotifyMask
+                          | RROutputChangeNotifyMask
+                          /* Emacs doesn't actually need this, but GTK
+                             selects for it when the display is
+                             initialized.  */
+                          | RROutputPropertyNotifyMask));
+       }
     }
 #endif
 
@@ -25274,7 +25298,7 @@ mark_xterm (void)
       mark_object (val);
     }
 
-#if defined HAVE_XINPUT2 || defined USE_TOOLKIT_SCROLL_BARS
+#if defined HAVE_XINPUT2 || defined USE_TOOLKIT_SCROLL_BARS || defined 
HAVE_XRANDR
   for (dpyinfo = x_display_list; dpyinfo; dpyinfo = dpyinfo->next)
     {
 #ifdef HAVE_XINPUT2
@@ -25284,6 +25308,9 @@ mark_xterm (void)
 #ifdef USE_TOOLKIT_SCROLL_BARS
       for (i = 0; i < dpyinfo->n_protected_windows; ++i)
        mark_object (dpyinfo->protected_windows[i]);
+#endif
+#ifdef HAVE_XRANDR
+      mark_object (dpyinfo->last_monitor_attributes_list);
 #endif
     }
 #endif
diff --git a/src/xterm.h b/src/xterm.h
index 8571bd9d39..c59992fdaa 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -607,6 +607,10 @@ struct x_display_info
   int xrandr_error_base;
   int xrandr_major_version;
   int xrandr_minor_version;
+
+  /* This is used to determine if the monitor configuration really
+     changed upon receiving a monitor change event.  */
+  Lisp_Object last_monitor_attributes_list;
 #endif
 
 #if defined USE_CAIRO || defined HAVE_XRENDER