[mutter] mutter-window: request DamageReportBoundingBox report level

[Robert Bragg <rbragg src gnome org>]

commit 91d82bf8c78ac7d2ae8a39f5ed619a413e2d6320
Author: Robert Bragg <robert linux intel com>
Date:   Thu May 13 21:43:30 2010 +0100

    mutter-window: request DamageReportBoundingBox report level
    
    In commit d34ae764769 I switched mutter-window to ask for Raw rectangles
    from the X server. This avoided 2 non synchronous and 2 synchronous X
    requests per window with damage, per frame; 2 (non-sync) to
    create/destroy a temporary region to copy the damage region into, 1 to
    request the server to copy the damage region into a our given region and
    another to fetch that region back into the client. The problem with raw
    events though is that it's possible to DOS the compositor with them.
    
    Instead of receiving an event for every bit of damage this patch instead
    asks the server to only report BoundingBox changes to the damage region.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=611838

 src/compositor/mutter-window.c |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)
---
diff --git a/src/compositor/mutter-window.c b/src/compositor/mutter-window.c
index 5116b31..f253494 100644
--- a/src/compositor/mutter-window.c
+++ b/src/compositor/mutter-window.c
@@ -68,6 +68,7 @@ struct _MutterWindowPrivate
   guint             redecorating           : 1;
 
   guint		    needs_damage_all       : 1;
+  guint		    received_damage        : 1;
 
   guint		    needs_pixmap           : 1;
   guint		    needs_reshape          : 1;
@@ -337,7 +338,7 @@ mutter_window_constructed (GObject *object)
     priv->damage = None;
   else
     priv->damage = XDamageCreate (xdisplay, xwindow,
-                                  XDamageReportRawRectangles);
+                                  XDamageReportBoundingBox);
 
   format = XRenderFindVisualFormat (xdisplay, priv->attrs.visual);
 
@@ -1652,6 +1653,8 @@ mutter_window_process_damage (MutterWindow       *self,
   MutterWindowPrivate *priv = self->priv;
   ClutterX11TexturePixmap *texture_x11 = CLUTTER_X11_TEXTURE_PIXMAP (priv->actor);
 
+  priv->received_damage = TRUE;
+
   if (is_frozen (self))
     {
       /* The window is frozen due to an effect in progress: we ignore damage
@@ -1748,6 +1751,11 @@ mutter_window_update_shape (MutterWindow   *self,
 void
 mutter_window_pre_paint (MutterWindow *self)
 {
+  MutterWindowPrivate *priv = self->priv;
+  MetaScreen          *screen   = priv->screen;
+  MetaDisplay         *display  = meta_screen_get_display (screen);
+  Display             *xdisplay = meta_display_get_xdisplay (display);
+
   if (is_frozen (self))
     {
       /* The window is frozen due to a pending animation: we'll wait until
@@ -1755,6 +1763,12 @@ mutter_window_pre_paint (MutterWindow *self)
       return;
     }
 
+  if (priv->received_damage)
+    {
+      XDamageSubtract (xdisplay, priv->damage, None, None);
+      priv->received_damage = FALSE;
+    }
+
   check_needs_reshape (self);
   check_needs_pixmap (self);
 }