[mutter/gnome-3-30] workspace: Focus only ancestors that are focusable

[Florian Müllner <fmuellner src gnome org>]

commit b95700dabc1e582e3757353850bb57f5d5b94aff
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Tue Nov 13 08:31:52 2018 +0100

    workspace: Focus only ancestors that are focusable
    
    When destroying a window that has a parent, we initially try to focus one of
    its ancestors. However if no ancestor can be focused, then we should instead
    focus the default focus window instead of trying to request focus for a window
    that can't get focus anyways.
    
    Fixes https://gitlab.gnome.org/GNOME/mutter/issues/308
    (cherry picked from commit eccc791f3b3451216f957e67fec47a73b65ed2b2)

 src/core/workspace.c | 37 +++++++++++++++++++++++++++----------
 1 file changed, 27 insertions(+), 10 deletions(-)
---
diff --git a/src/core/workspace.c b/src/core/workspace.c
index e9b693e0b..ba146d646 100644
--- a/src/core/workspace.c
+++ b/src/core/workspace.c
@@ -86,6 +86,12 @@ typedef struct _MetaWorkspaceLogicalMonitorData
   MetaRectangle logical_monitor_work_area;
 } MetaWorkspaceLogicalMonitorData;
 
+typedef struct _MetaWorkspaceFocusableAncestorData
+{
+  MetaWorkspace *workspace;
+  MetaWindow *out_window;
+} MetaWorkspaceFocusableAncestorData;
+
 static MetaWorkspaceLogicalMonitorData *
 meta_workspace_get_logical_monitor_data (MetaWorkspace      *workspace,
                                          MetaLogicalMonitor *logical_monitor)
@@ -1327,13 +1333,20 @@ meta_workspace_focus_default_window (MetaWorkspace *workspace,
 }
 
 static gboolean
-record_ancestor (MetaWindow *window,
-                 void       *data)
+find_focusable_ancestor (MetaWindow *window,
+                         gpointer    user_data)
 {
-  MetaWindow **result = data;
+  MetaWorkspaceFocusableAncestorData *data = user_data;
+
+  if (!window->unmanaging && (window->input || window->take_focus) &&
+      meta_window_located_on_workspace (window, data->workspace) &&
+      meta_window_showing_on_its_workspace (window))
+    {
+      data->out_window = window;
+      return FALSE;
+    }
 
-  *result = window;
-  return FALSE; /* quit with the first ancestor we find */
+  return TRUE;
 }
 
 /* Focus ancestor of not_this_one if there is one */
@@ -1355,11 +1368,15 @@ focus_ancestor_or_top_window (MetaWorkspace *workspace,
   if (not_this_one)
     {
       MetaWindow *ancestor;
-      ancestor = NULL;
-      meta_window_foreach_ancestor (not_this_one, record_ancestor, &ancestor);
-      if (ancestor != NULL &&
-          meta_window_located_on_workspace (ancestor, workspace) &&
-          meta_window_showing_on_its_workspace (ancestor))
+      MetaWorkspaceFocusableAncestorData data;
+
+      data = (MetaWorkspaceFocusableAncestorData) {
+        .workspace = workspace,
+      };
+      meta_window_foreach_ancestor (not_this_one, find_focusable_ancestor, &data);
+      ancestor = data.out_window;
+
+      if (ancestor)
         {
           meta_topic (META_DEBUG_FOCUS,
                       "Focusing %s, ancestor of %s\n",