defensive programming; check meta_screen_get_compositor_data() throughout

2008-06-05  Thomas Thurman  <tthurman@gnome.org>

        * src/compositor/compositor-xrender.c (paint_root, destroy_win,
        create_root_buffer, paint_windows, repair_screen, window_has_shadow,
        xrender_set_active_window, paint_dock_shadows, unmap_win, restack_win,
        make_shadow, resize_win, process_property_notify, free_win,
        process_configure_notify, process_circulate_notify, add_damage):
        defensive programming; check meta_screen_get_compositor_data()
        throughout in case it returns NULL.  In particular, when this
        happened in a certain situation in xrender_set_active_window
        this caused a segfault; refs #530702 (and LP#178953 has more data)
        but this doesn't close them.


svn path=/trunk/; revision=3751

1 files changed, 81 insertions, 23 deletions

diff --git a/src/compositor/compositor-xrender.c b/src/compositor/compositor-xrender.c
index f50f4adc..c2b60ac5 100644
--- a/src/compositor/compositor-xrender.c
+++ b/src/compositor/compositor-xrender.c
@@ -478,18 +478,28 @@ make_shadow (MetaDisplay   *display,
   Display *xdisplay = meta_display_get_xdisplay (display);
   XImage *ximage;
   guchar *data;
-  shadow *shad = info->shadows[shadow_type];
-  int msize = shad->gaussian_map->size;
+  shadow *shad;
+  int msize;
   int ylimit, xlimit;
-  int swidth = width + msize;
-  int sheight = height + msize;
-  int centre = msize / 2;
+  int swidth, sheight;
+  int centre;
   int x, y;
   guchar d;
   int x_diff;
   int opacity_int = (int)(opacity * 25);
   int screen_number = meta_screen_get_screen_number (screen);
 
+  if (info==NULL)
+    {
+      return NULL;
+    }
+
+  shad = info->shadows[shadow_type];
+  msize = shad->gaussian_map->size;
+  swidth = width + msize;
+  sheight = height + msize;
+  centre = msize / 2;
+
   data = g_malloc (swidth * sheight * sizeof (guchar));
 
   ximage = XCreateImage (xdisplay, DefaultVisual (xdisplay, screen_number),
@@ -824,6 +834,11 @@ create_root_buffer (MetaScreen *screen)
   Visual *visual;
   int depth, screen_width, screen_height, screen_number;
 
+  if (info == NULL)
+    {
+      return None;
+    }
+
   meta_screen_get_size (screen, &screen_width, &screen_height);
   screen_number = meta_screen_get_screen_number (screen);
   visual = DefaultVisual (xdisplay, screen_number);
@@ -851,6 +866,11 @@ paint_root (MetaScreen *screen,
   MetaCompScreen *info = meta_screen_get_compositor_data (screen);
   int width, height;
 
+  if (info == NULL)
+    {
+      return;
+    }
+
   g_return_if_fail (root_buffer != None);
 
   if (info->root_tile == None) 
@@ -869,7 +889,7 @@ window_has_shadow (MetaCompWindow *cw)
 {
   MetaCompScreen *info = meta_screen_get_compositor_data (cw->screen);
 
-  if (info->have_shadows == FALSE)
+  if (info == NULL || info->have_shadows == FALSE)
     return FALSE;
 
   /* Always put a shadow around windows with a frame - This should override
@@ -1070,6 +1090,11 @@ paint_dock_shadows (MetaScreen   *screen,
   MetaCompScreen *info = meta_screen_get_compositor_data (screen);
   GSList *d;
 
+  if (info == NULL)
+    {
+      return;
+    }
+
   for (d = info->dock_windows; d; d = d->next) 
     {
       MetaCompWindow *cw = d->data;
@@ -1109,6 +1134,11 @@ paint_windows (MetaScreen   *screen,
   MetaCompWindow *cw;
   XserverRegion paint_region, desktop_region;
 
+  if (info == NULL)
+    {
+      return;
+    }
+
   meta_screen_get_size (screen, &screen_width, &screen_height);
   screen_number = meta_screen_get_screen_number (screen);
   xroot = meta_screen_get_xroot (screen);
@@ -1364,7 +1394,7 @@ repair_screen (MetaScreen *screen)
   MetaDisplay *display = meta_screen_get_display (screen);
   Display *xdisplay = meta_display_get_xdisplay (display);
 
-  if (info->all_damage != None) 
+  if (info!=NULL && info->all_damage != None) 
     {
       meta_error_trap_push (display);
       paint_all (screen, info->all_damage);
@@ -1436,7 +1466,7 @@ add_damage (MetaScreen     *screen,
 
   /*  dump_xserver_region ("add_damage", display, damage); */
 
-  if (info->all_damage) 
+  if (info != NULL && info->all_damage)
     {
       XFixesUnionRegion (xdisplay, info->all_damage, info->all_damage, damage);
       XFixesDestroyRegion (xdisplay, damage);
@@ -1579,7 +1609,7 @@ free_win (MetaCompWindow *cw,
 
       /* The window may not have been added to the list in this case,
          but we can check anyway */
-      if (cw->type == META_COMP_WINDOW_DOCK)
+      if (info!=NULL && cw->type == META_COMP_WINDOW_DOCK)
         info->dock_windows = g_slist_remove (info->dock_windows, cw);
 
       g_free (cw);
@@ -1626,7 +1656,7 @@ unmap_win (MetaDisplay *display,
   MetaCompWindow *cw = find_window_for_screen (screen, id);
   MetaCompScreen *info = meta_screen_get_compositor_data (screen);
 
-  if (cw == NULL) 
+  if (cw == NULL || info == NULL)
     {
       return;
     }
@@ -1878,8 +1908,11 @@ destroy_win (MetaDisplay *display,
     }
   
   info = meta_screen_get_compositor_data (screen);
-  info->windows = g_list_remove (info->windows, (gconstpointer) cw);
-  g_hash_table_remove (info->windows_by_xid, (gpointer) xwindow);
+  if (info != NULL)
+    {
+      info->windows = g_list_remove (info->windows, (gconstpointer) cw);
+      g_hash_table_remove (info->windows_by_xid, (gpointer) xwindow);
+    }
   
   free_win (cw, TRUE);
 }
@@ -1896,6 +1929,11 @@ restack_win (MetaCompWindow *cw,
   screen = cw->screen;
   info = meta_screen_get_compositor_data (screen);
 
+  if (info == NULL)
+    {
+      return;
+    }
+
   sibling = g_list_find (info->windows, (gconstpointer) cw);
   next = g_list_next (sibling);
   previous_above = None;
@@ -2045,7 +2083,10 @@ resize_win (MetaCompWindow *cw,
   dump_xserver_region ("resize_win", display, damage);
   add_damage (screen, damage);
 
-  info->clip_changed = TRUE;
+  if (info != NULL)
+    {
+      info->clip_changed = TRUE;
+    }
 }
 
 /* event processors must all be called with an error trap in place */
@@ -2075,7 +2116,10 @@ process_circulate_notify (MetaCompositorXRender  *compositor,
     above = None;
   restack_win (cw, above);
 
-  info->clip_changed = TRUE;
+  if (info != NULL)
+    {
+      info->clip_changed = TRUE;
+    }
 
 #ifdef USE_IDLE_REPAINT
   add_repair (compositor->display);
@@ -2133,7 +2177,7 @@ process_configure_notify (MetaCompositorXRender  *compositor,
         return;
 
       info = meta_screen_get_compositor_data (screen);
-      if (info->root_buffer)
+      if (info != NULL && info->root_buffer)
         {
           XRenderFreePicture (xdisplay, info->root_buffer);
           info->root_buffer = None;
@@ -2167,7 +2211,7 @@ process_property_notify (MetaCompositorXRender *compositor,
               MetaCompScreen *info = meta_screen_get_compositor_data (screen);
               Window xroot = meta_screen_get_xroot (screen);
 
-              if (info->root_tile)
+              if (info != NULL && info->root_tile)
                 {
                   XClearArea (xdisplay, xroot, 0, 0, 0, 0, TRUE);
                   XRenderFreePicture (xdisplay, info->root_tile);
@@ -2809,8 +2853,8 @@ xrender_set_active_window (MetaCompositor *compositor,
   MetaDisplay *display;
   Display *xdisplay;
   MetaCompWindow *old_focus = NULL, *new_focus = NULL;
-  MetaCompScreen *info;
-  MetaWindow *old_focus_win;
+  MetaCompScreen *info = NULL;
+  MetaWindow *old_focus_win = NULL;
 
   if (compositor == NULL)
     return;
@@ -2818,7 +2862,11 @@ xrender_set_active_window (MetaCompositor *compositor,
   display = xrc->display;
   xdisplay = meta_display_get_xdisplay (display);
   info = meta_screen_get_compositor_data (screen);
-  old_focus_win = info->focus_window;
+
+  if (info != NULL)
+    {
+      old_focus_win = info->focus_window;
+    }
 
   if (old_focus_win) 
     {
@@ -2837,7 +2885,11 @@ xrender_set_active_window (MetaCompositor *compositor,
                                           meta_window_get_xwindow (window));
     }
 
-  info->focus_window = window;
+  if (info != NULL)
+    {
+      info->focus_window = window;
+    }
+
   if (old_focus)
     {
       XserverRegion damage;
@@ -2877,8 +2929,11 @@ xrender_set_active_window (MetaCompositor *compositor,
           
           dump_xserver_region ("resize_win", display, damage);
           add_damage (screen, damage);
-          
-          info->clip_changed = TRUE;
+
+          if (info != NULL)
+            {
+              info->clip_changed = TRUE;
+            }
         }
     }
 
@@ -2919,7 +2974,10 @@ xrender_set_active_window (MetaCompositor *compositor,
       dump_xserver_region ("resize_win", display, damage);
       add_damage (screen, damage);
 
-      info->clip_changed = TRUE;
+      if (info != NULL)
+        {
+          info->clip_changed = TRUE;
+        }
     }
 #ifdef USE_IDLE_REPAINT
   add_repair (display);