core: Untangle input focus management

In all places (including src/wayland) we tap into meta_x11_display* focus
API, which then calls meta_display* API. This relation is backwards, so
rework input focus management so it's the other way around.

We now have high-level meta_display_(un)set_input_focus functions, which
perform the backend-independent maintenance, and calls into the X11
functions where relevant. These functions are what callers should use.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/420

src/core/display.c

@@ -779,10 +779,12 @@ meta_display_open (void)
       if (old_active_window)
         meta_window_focus (old_active_window, timestamp);
       else
-        meta_x11_display_focus_the_no_focus_window (display->x11_display, timestamp);
+        meta_display_unset_input_focus (display, timestamp);
+    }
+  else
+    {
+      meta_display_unset_input_focus (display, timestamp);
     }
-  else if (display->x11_display)
-    meta_x11_display_focus_the_no_focus_window (display->x11_display, timestamp);
 
   meta_idle_monitor_init_dbus ();
 
@@ -1307,6 +1309,51 @@ meta_display_timestamp_too_old (MetaDisplay *display,
   return FALSE;
 }
 
+void
+meta_display_set_input_focus (MetaDisplay *display,
+                              MetaWindow  *window,
+                              gboolean     focus_frame,
+                              guint32      timestamp)
+{
+  if (meta_display_timestamp_too_old (display, &timestamp))
+    return;
+
+  if (display->x11_display)
+    {
+      MetaX11Display *x11_display = display->x11_display;
+      Window xwindow;
+      gulong serial;
+
+      meta_x11_error_trap_push (x11_display);
+
+      if (window)
+        xwindow = focus_frame ? window->frame->xwindow : window->xwindow;
+      else
+        xwindow = x11_display->no_focus_window;
+
+      meta_x11_display_set_input_focus (x11_display, xwindow, timestamp);
+      serial = XNextRequest (x11_display->xdisplay);
+
+      meta_x11_display_update_focus_window (x11_display, xwindow, serial, TRUE);
+
+      meta_x11_error_trap_pop (display->x11_display);
+    }
+
+  meta_display_update_focus_window (display, window);
+
+  display->last_focus_time = timestamp;
+
+  if (window == NULL || window != display->autoraise_window)
+    meta_display_remove_autoraise_callback (display);
+}
+
+void
+meta_display_unset_input_focus (MetaDisplay *display,
+                                guint32      timestamp)
+{
+  meta_display_set_input_focus (display, NULL, FALSE, timestamp);
+}
+
 void
 meta_display_register_wayland_window (MetaDisplay *display,
                                       MetaWindow  *window)

src/core/window.c

@@ -8088,8 +8088,7 @@ mouse_mode_focus (MetaWindow  *window,
                       "Unsetting focus from %s due to mouse entering "
                       "the DESKTOP window\n",
                       display->focus_window->desc);
-          meta_x11_display_focus_the_no_focus_window (display->x11_display,
-                                                      timestamp);
+          meta_display_unset_input_focus (display, timestamp);
         }
     }
 }

src/core/workspace.c

@@ -1308,8 +1308,7 @@ meta_workspace_focus_default_window (MetaWorkspace *workspace,
           meta_topic (META_DEBUG_FOCUS,
                       "Setting focus to no_focus_window, since no valid "
                       "window to focus found.\n");
-          meta_x11_display_focus_the_no_focus_window (workspace->display->x11_display,
-                                                      timestamp);
+          meta_display_unset_input_focus (workspace->display, timestamp);
         }
     }
 }
@@ -1381,8 +1380,7 @@ focus_ancestor_or_top_window (MetaWorkspace *workspace,
   else
     {
       meta_topic (META_DEBUG_FOCUS, "No MRU window to focus found; focusing no_focus_window.\n");
-      meta_x11_display_focus_the_no_focus_window (workspace->display->x11_display,
-                                                  timestamp);
+      meta_display_unset_input_focus (workspace->display, timestamp);
     }
 }
 

src/meta/display.h

@@ -297,4 +297,13 @@ MetaSoundPlayer * meta_display_get_sound_player (MetaDisplay *display);
 META_EXPORT
 MetaSelection * meta_display_get_selection (MetaDisplay *display);
 
+META_EXPORT
+void meta_display_set_input_focus   (MetaDisplay *display,
+                                     MetaWindow  *window,
+                                     gboolean     focus_frame,
+                                     guint32      timestamp);
+META_EXPORT
+void meta_display_unset_input_focus (MetaDisplay *display,
+                                     guint32      timestamp);
+
 #endif

src/meta/meta-x11-display.h

@@ -63,27 +63,4 @@ META_EXPORT
 gboolean meta_x11_display_xwindow_is_a_no_focus_window (MetaX11Display *x11_display,
                                                         Window xwindow);
 
-/* meta_x11_display_set_input_focus_window is like XSetInputFocus, except
- * that (a) it can't detect timestamps later than the current time,
- * since Mutter isn't part of the XServer, and thus gives erroneous
- * behavior in this circumstance (so don't do it), (b) it uses
- * display->last_focus_time since we don't have access to the true
- * Xserver one, (c) it makes use of display->user_time since checking
- * whether a window should be allowed to be focused should depend
- * on user_time events (see bug 167358, comment 15 in particular)
- */
-META_EXPORT
-void meta_x11_display_set_input_focus_window (MetaX11Display *x11_display,
-                                              MetaWindow     *window,
-                                              gboolean        focus_frame,
-                                              guint32         timestamp);
-
-/* meta_x11_display_focus_the_no_focus_window is called when the
- * designated no_focus_window should be focused, but is otherwise the
- * same as meta_display_set_input_focus_window
- */
-META_EXPORT
-void meta_x11_display_focus_the_no_focus_window (MetaX11Display *x11_display,
-                                                 guint32         timestamp);
-
 #endif /* META_X11_DISPLAY_H */

src/wayland/meta-window-wayland.c

@@ -142,11 +142,13 @@ meta_window_wayland_focus (MetaWindow *window,
                            guint32     timestamp)
 {
   if (meta_window_is_focusable (window))
-    meta_x11_display_set_input_focus_window (window->display->x11_display,
+    {
+      meta_display_set_input_focus (window->display,
                                     window,
                                     FALSE,
                                     timestamp);
     }
+}
 
 static void
 surface_state_changed (MetaWindow *window)

src/x11/meta-x11-display-private.h

@@ -245,5 +245,8 @@ void meta_x11_display_update_focus_window (MetaX11Display *x11_display,
                                            Window          xwindow,
                                            gulong          serial,
                                            gboolean        focused_by_us);
+void meta_x11_display_set_input_focus (MetaX11Display *x11_display,
+                                       Window          xwindow,
+                                       guint32         timestamp);
 
 #endif /* META_X11_DISPLAY_PRIVATE_H */

src/x11/meta-x11-display.c

@@ -1838,17 +1838,11 @@ meta_x11_display_update_focus_window (MetaX11Display *x11_display,
   meta_x11_display_update_active_window_hint (x11_display);
 }
 
-static void
-request_xserver_input_focus_change (MetaX11Display *x11_display,
-                                    MetaWindow     *meta_window,
+void
+meta_x11_display_set_input_focus (MetaX11Display *x11_display,
                                   Window          xwindow,
                                   guint32         timestamp)
 {
-  gulong serial;
-
-  if (meta_display_timestamp_too_old (x11_display->display, &timestamp))
-    return;
-
   meta_x11_error_trap_push (x11_display);
 
   /* In order for mutter to know that the focus request succeeded, we track
@@ -1861,8 +1855,6 @@ request_xserver_input_focus_change (MetaX11Display *x11_display,
    */
   XGrabServer (x11_display->xdisplay);
 
-  serial = XNextRequest (x11_display->xdisplay);
-
   XSetInputFocus (x11_display->xdisplay,
                   xwindow,
                   RevertToPointerRoot,
@@ -1876,27 +1868,7 @@ request_xserver_input_focus_change (MetaX11Display *x11_display,
   XUngrabServer (x11_display->xdisplay);
   XFlush (x11_display->xdisplay);
 
-  meta_display_update_focus_window (x11_display->display, meta_window);
-  meta_x11_display_update_focus_window (x11_display, xwindow, serial, TRUE);
-
   meta_x11_error_trap_pop (x11_display);
-
-  x11_display->display->last_focus_time = timestamp;
-
-  if (meta_window == NULL || meta_window != x11_display->display->autoraise_window)
-    meta_display_remove_autoraise_callback (x11_display->display);
-}
-
-void
-meta_x11_display_set_input_focus_window (MetaX11Display *x11_display,
-                                         MetaWindow     *window,
-                                         gboolean        focus_frame,
-                                         guint32         timestamp)
-{
-  request_xserver_input_focus_change (x11_display,
-                                      window,
-                                      focus_frame ? window->frame->xwindow : window->xwindow,
-                                      timestamp);
 }
 
 void
@@ -1904,20 +1876,12 @@ meta_x11_display_set_input_focus_xwindow (MetaX11Display *x11_display,
                                           Window          window,
                                           guint32         timestamp)
 {
-  request_xserver_input_focus_change (x11_display,
-                                      NULL,
-                                      window,
-                                      timestamp);
-}
+  gulong serial;
 
-void
-meta_x11_display_focus_the_no_focus_window (MetaX11Display *x11_display,
-                                            guint32         timestamp)
-{
-  request_xserver_input_focus_change (x11_display,
-                                      NULL,
-                                      x11_display->no_focus_window,
-                                      timestamp);
+  meta_display_unset_input_focus (x11_display->display, timestamp);
+  serial = XNextRequest (x11_display->xdisplay);
+  meta_x11_display_set_input_focus (x11_display, window, timestamp);
+  meta_x11_display_update_focus_window (x11_display, window, serial, TRUE);
 }
 
 static MetaX11DisplayLogicalMonitorData *

src/x11/window-x11.c

@@ -794,7 +794,7 @@ meta_window_x11_focus (MetaWindow *window,
     {
       meta_topic (META_DEBUG_FOCUS,
                   "Focusing frame of %s\n", window->desc);
-      meta_x11_display_set_input_focus_window (window->display->x11_display,
+      meta_display_set_input_focus (window->display,
                                     window,
                                     TRUE,
                                     timestamp);
@@ -806,7 +806,7 @@ meta_window_x11_focus (MetaWindow *window,
           meta_topic (META_DEBUG_FOCUS,
                       "Setting input focus on %s since input = true\n",
                       window->desc);
-          meta_x11_display_set_input_focus_window (window->display->x11_display,
+          meta_display_set_input_focus (window->display,
                                         window,
                                         FALSE,
                                         timestamp);
@@ -832,8 +832,7 @@ meta_window_x11_focus (MetaWindow *window,
                */
               if (window->display->focus_window != NULL &&
                   window->display->focus_window->unmanaging)
-                meta_x11_display_focus_the_no_focus_window (window->display->x11_display,
-                                                            timestamp);
+                meta_display_unset_input_focus (window->display, timestamp);
             }
 
           request_take_focus (window, timestamp);