window: make determination of attached dialog windows more consistent

Different bits of code were using slightly different checks to test
whether a window was an attached dialog. Add a new
meta_window_is_attached_dialog(), and use that everywhere.

Also, freeze the is-attached status when the window is first shown,
rather than recomputing it each time the caller asks, since this could
cause problems if a window changes its type after it has already been
attached, etc. However, if an attached window's parent is destroyed,
or an attached window changes its transient-for, then fix things up by
destroying the old MetaWindow and creating a new one (causing
compositor unmap and map events to be fired off, allowing the display
of the window to be fixed up).

Remove some code in display.c that tried to fix existing windows if
the gconf setting changed, but which didn't actually do anything (at
least under gnome-shell). However, if 654643 was fixed then the new
behavior with this patch would be that changing the gconf setting
would affect new dialogs, but not existing ones.

https://bugzilla.gnome.org/show_bug.cgi?id=646761

src/core/window.c

@@ -669,6 +669,22 @@ maybe_filter_window (MetaDisplay       *display,
   return filtered;
 }
 
+gboolean
+meta_window_should_attach_to_parent (MetaWindow *window)
+{
+  MetaWindow *parent;
+
+  if (!meta_prefs_get_attach_modal_dialogs () ||
+      window->type != META_WINDOW_MODAL_DIALOG)
+    return FALSE;
+
+  parent = meta_window_get_transient_for (window);
+  if (!parent)
+    return FALSE;
+
+  return TRUE;
+}
+
 MetaWindow*
 meta_window_new_with_attrs (MetaDisplay       *display,
                             Window             xwindow,
@@ -1134,6 +1150,10 @@ meta_window_new_with_attrs (MetaDisplay       *display,
         meta_display_get_current_time_roundtrip (window->display);
   }
 
+  window->attached = meta_window_should_attach_to_parent (window);
+  if (window->attached)
+    recalc_window_features (window);
+
   if (window->decorated)
     meta_window_ensure_frame (window);
 
@@ -1490,6 +1510,24 @@ meta_window_apply_session_info (MetaWindow *window,
     }
 }
 
+static gboolean
+detach_foreach_func (MetaWindow *window,
+                     void       *data)
+{
+  GList **children = data;
+  MetaWindow *parent;
+
+  if (window->attached)
+    {
+      /* Only return the immediate children of the window being unmanaged */
+      parent = meta_window_get_transient_for (window);
+      if (parent->unmanaging)
+        *children = g_list_prepend (*children, window);
+    }
+
+  return TRUE;
+}
+
 void
 meta_window_unmanage (MetaWindow  *window,
                       guint32      timestamp)
@@ -1520,6 +1558,21 @@ meta_window_unmanage (MetaWindow  *window,
 
   window->unmanaging = TRUE;
 
+  if (meta_prefs_get_attach_modal_dialogs ())
+    {
+      GList *attached_children = NULL, *iter;
+
+      /* Detach any attached dialogs by unmapping and letting them
+       * be remapped after @window is destroyed.
+       */
+      meta_window_foreach_transient (window,
+                                     detach_foreach_func,
+                                     &attached_children);
+      for (iter = attached_children; iter; iter = iter->next)
+        meta_window_unmanage (iter->data, timestamp);
+      g_list_free (attached_children);
+    }
+
   if (window->fullscreen)
     {
       MetaGroup *group;
@@ -1678,8 +1731,12 @@ meta_window_unmanage (MetaWindow  *window,
           meta_error_trap_pop (window->display);
         }
 
-      /* And we need to be sure the window is mapped so other WMs
-       * know that it isn't Withdrawn
+      /* If we're unmanaging a window that is not withdrawn, then
+       * either (a) mutter is exiting, in which case we need to map
+       * the window so the next WM will know that it's not Withdrawn,
+       * or (b) we want to create a new MetaWindow to replace the
+       * current one, which will happen automatically if we re-map
+       * the X Window.
        */
       meta_error_trap_push (window->display);
       XMapWindow (window->display->xdisplay,
@@ -4238,12 +4295,10 @@ send_sync_request (MetaWindow *window)
 #endif
 
 static gboolean
-move_attached_dialog (MetaWindow *window,
-                      void       *data)
+maybe_move_attached_dialog (MetaWindow *window,
+                            void       *data)
 {
-  MetaWindow *parent = meta_window_get_transient_for (window);
-
-  if (window->type == META_WINDOW_MODAL_DIALOG && parent)
+  if (meta_window_is_attached_dialog (window))
     /* It ignores x,y for such a dialog  */
     meta_window_move (window, FALSE, 0, 0);
 
@@ -4765,8 +4820,7 @@ meta_window_move_resize_internal (MetaWindow          *window,
       window->frame_bounds = NULL;
     }
 
-  if (meta_prefs_get_attach_modal_dialogs ())
-    meta_window_foreach_transient (window, move_attached_dialog, NULL);
+  meta_window_foreach_transient (window, maybe_move_attached_dialog, NULL);
 }
 
 /**
@@ -6491,14 +6545,11 @@ meta_window_propagate_focus_appearance (MetaWindow *window,
 {
   MetaWindow *child, *parent, *focus_window;
 
-  if (!meta_prefs_get_attach_modal_dialogs ())
-    return;
-
   focus_window = window->display->focus_window;
 
   child = window;
   parent = meta_window_get_transient_for (child);
-  while (parent && (!focused || child->type == META_WINDOW_MODAL_DIALOG))
+  while (parent && (!focused || meta_window_is_attached_dialog (child)))
     {
       gboolean child_focus_state_changed;
 
@@ -7636,12 +7687,8 @@ recalc_window_features (MetaWindow *window)
   if (window->type == META_WINDOW_TOOLBAR)
     window->decorated = FALSE;
 
-  if (window->type == META_WINDOW_MODAL_DIALOG && meta_prefs_get_attach_modal_dialogs ())
-    {
-      MetaWindow *parent = meta_window_get_transient_for (window);
-      if (parent)
-        window->border_only = TRUE;
-    }
+  if (meta_window_is_attached_dialog (window))
+    window->border_only = TRUE;
 
   if (window->type == META_WINDOW_DESKTOP ||
       window->type == META_WINDOW_DOCK ||
@@ -8626,9 +8673,7 @@ update_resize (MetaWindow *window,
    * size changes apply to both sides, so that the dialog
    * remains centered to the parent.
    */
-  if (window->type == META_WINDOW_MODAL_DIALOG &&
-      meta_prefs_get_attach_modal_dialogs () &&
-      meta_window_get_transient_for (window) != NULL)
+  if (meta_window_is_attached_dialog (window))
     dx *= 2;
 
   new_w = window->display->grab_anchor_window_pos.width;
@@ -10240,8 +10285,7 @@ meta_window_get_frame_type (MetaWindow *window)
       break;
 
     case META_WINDOW_MODAL_DIALOG:
-      if (meta_prefs_get_attach_modal_dialogs () &&
-          meta_window_get_transient_for (window) != NULL)
+      if (meta_window_is_attached_dialog (window))
         base_type = META_FRAME_TYPE_ATTACHED;
       else
         base_type = META_FRAME_TYPE_MODAL_DIALOG;
@@ -10307,3 +10351,19 @@ meta_window_get_frame_bounds (MetaWindow *window)
 
   return window->frame_bounds;
 }
+
+/**
+ * meta_window_is_attached_dialog:
+ * @window: a #MetaWindow
+ *
+ * Tests if @window is should be attached to its parent window.
+ * (If the "attach_modal_dialogs" option is not enabled, this will
+ * always return %FALSE.)
+ *
+ * Return value: whether @window should be attached to its parent
+ */
+gboolean
+meta_window_is_attached_dialog (MetaWindow *window)
+{
+  return window->attached;
+}