[mutter/gnome-3-28] workspace: Focus only ancestors that are focusable

[Florian Müllner <fmuellner src gnome org>]

commit 68691cb1b93112f215fb94ad693eba431e99c426
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 a964e6603..d19494309 100644
--- a/src/core/workspace.c
+++ b/src/core/workspace.c
@@ -85,6 +85,12 @@ 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)
@@ -1319,13 +1325,20 @@ 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 */
@@ -1347,11 +1360,15 @@ 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",