backends: Move clutter frame clock freeze/thaw API to ClutterSTage

It had nothing to do with EGL or the eglnative backend, and will be used
by non-native backends, so move it to a common place.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/170

clutter/clutter/clutter-mutter.h

@@ -46,6 +46,12 @@ void clutter_stage_capture_into (ClutterStage          *stage,
                                  cairo_rectangle_int_t *rect,
                                  uint8_t               *data);
 
+CLUTTER_EXPORT
+void clutter_stage_freeze_updates (ClutterStage *stage);
+
+CLUTTER_EXPORT
+void clutter_stage_thaw_updates (ClutterStage *stage);
+
 #undef __CLUTTER_H_INSIDE__
 
 #endif /* __CLUTTER_MUTTER_H__ */

clutter/clutter/clutter-stage.c

@@ -146,6 +146,8 @@ struct _ClutterStagePrivate
   gpointer paint_data;
   GDestroyNotify paint_notify;
 
+  int update_freeze_count;
+
   guint relayout_pending       : 1;
   guint redraw_pending         : 1;
   guint is_fullscreen          : 1;
@@ -4900,3 +4902,58 @@ clutter_stage_capture_into (ClutterStage          *stage,
   view = get_view_at_rect (stage, rect);
   capture_view_into (stage, paint, view, rect, data, rect->width * bpp);
 }
+
+/**
+ * clutter_stage_freeze_updates:
+ *
+ * Freezing updates makes Clutter stop processing events,
+ * redrawing, and advancing timelines, by pausing the master clock. This is
+ * necessary when implementing a display server, to ensure that Clutter doesn't
+ * keep trying to page flip when DRM master has been dropped, e.g. when VT
+ * switched away.
+ *
+ * The master clock starts out running, so if you are VT switched away on
+ * startup, you need to call this immediately.
+ *
+ * To thaw updates, use clutter_stage_thaw_updates().
+ */
+void
+clutter_stage_freeze_updates (ClutterStage *stage)
+{
+  ClutterStagePrivate *priv = stage->priv;
+
+  priv->update_freeze_count++;
+  if (priv->update_freeze_count == 1)
+    {
+      ClutterMasterClock *master_clock;
+
+      master_clock = _clutter_master_clock_get_default ();
+      _clutter_master_clock_set_paused (master_clock, TRUE);
+    }
+}
+
+/**
+ * clutter_stage_thaw_updates:
+ *
+ * Resumes a master clock that has previously been frozen with
+ * clutter_stage_freeze_updates(), and start pumping the master clock
+ * again at the next iteration. Note that if you're switching back to your
+ * own VT, you should probably also queue a stage redraw with
+ * clutter_stage_ensure_redraw().
+ */
+void
+clutter_stage_thaw_updates (ClutterStage *stage)
+{
+  ClutterStagePrivate *priv = stage->priv;
+
+  g_assert (priv->update_freeze_count > 0);
+
+  priv->update_freeze_count--;
+  if (priv->update_freeze_count == 0)
+    {
+      ClutterMasterClock *master_clock;
+
+      master_clock = _clutter_master_clock_get_default ();
+      _clutter_master_clock_set_paused (master_clock, FALSE);
+    }
+}

clutter/clutter/egl/clutter-backend-eglnative.c

@@ -333,57 +333,3 @@ clutter_egl_get_egl_display (void)
   return 0;
 #endif
 }
-
-/**
- * clutter_egl_freeze_master_clock:
- *
- * Freezing the master clock makes Clutter stop processing events,
- * redrawing, and advancing timelines. This is necessary when implementing
- * a display server, to ensure that Clutter doesn't keep trying to page
- * flip when DRM master has been dropped, e.g. when VT switched away.
- *
- * The master clock starts out running, so if you are VT switched away on
- * startup, you need to call this immediately.
- *
- * If you're also using the evdev backend, make sure to also use
- * clutter_evdev_release_devices() to make sure that Clutter doesn't also
- * access revoked evdev devices when VT switched away.
- *
- * To unthaw a frozen master clock, use clutter_egl_thaw_master_clock().
- *
- * Since: 1.20
- */
-void
-clutter_egl_freeze_master_clock (void)
-{
-  ClutterMasterClock *master_clock;
-
-  g_return_if_fail (CLUTTER_IS_BACKEND_EGL_NATIVE (clutter_get_default_backend ()));
-
-  master_clock = _clutter_master_clock_get_default ();
-  _clutter_master_clock_set_paused (master_clock, TRUE);
-}
-
-/**
- * clutter_egl_thaw_master_clock:
- *
- * Thaws a master clock that has previously been frozen with
- * clutter_egl_freeze_master_clock(), and start pumping the master clock
- * again at the next iteration. Note that if you're switching back to your
- * own VT, you should probably also queue a stage redraw with
- * clutter_stage_ensure_redraw().
- *
- * Since: 1.20
- */
-void
-clutter_egl_thaw_master_clock (void)
-{
-  ClutterMasterClock *master_clock;
-
-  g_return_if_fail (CLUTTER_IS_BACKEND_EGL_NATIVE (clutter_get_default_backend ()));
-
-  master_clock = _clutter_master_clock_get_default ();
-  _clutter_master_clock_set_paused (master_clock, FALSE);
-
-  _clutter_master_clock_start_running (master_clock);
-}

clutter/clutter/egl/clutter-egl.h

@@ -87,11 +87,6 @@ EGLDisplay      clutter_egl_display             (void);
 CLUTTER_EXPORT
 EGLDisplay      clutter_egl_get_egl_display     (void);
 
-CLUTTER_EXPORT
-void            clutter_egl_freeze_master_clock (void);
-CLUTTER_EXPORT
-void            clutter_egl_thaw_master_clock   (void);
-
 G_END_DECLS
 
 #endif /* __CLUTTER_EGL_H__ */

src/backends/native/meta-backend-native.c

@@ -44,8 +44,6 @@
 #include "backends/native/meta-renderer-native.h"
 #include "backends/native/meta-stage-native.h"
 #include "clutter/evdev/clutter-evdev.h"
-#include "clutter/egl/clutter-egl.h"
-#include "clutter/evdev/clutter-evdev.h"
 #include "core/meta-border.h"
 #include "meta/main.h"
 
@@ -625,13 +623,14 @@ void
 meta_backend_native_pause (MetaBackendNative *native)
 {
   MetaBackend *backend = META_BACKEND (native);
+  ClutterStage *stage = CLUTTER_STAGE (meta_backend_get_stage (backend));
   MetaMonitorManager *monitor_manager =
     meta_backend_get_monitor_manager (backend);
   MetaMonitorManagerKms *monitor_manager_kms =
     META_MONITOR_MANAGER_KMS (monitor_manager);
 
   clutter_evdev_release_devices ();
-  clutter_egl_freeze_master_clock ();
+  clutter_stage_freeze_updates (stage);
 
   meta_monitor_manager_kms_pause (monitor_manager_kms);
 }
@@ -639,20 +638,19 @@ meta_backend_native_pause (MetaBackendNative *native)
 void meta_backend_native_resume (MetaBackendNative *native)
 {
   MetaBackend *backend = META_BACKEND (native);
+  ClutterStage *stage = CLUTTER_STAGE (meta_backend_get_stage (backend));
   MetaMonitorManager *monitor_manager =
     meta_backend_get_monitor_manager (backend);
   MetaMonitorManagerKms *monitor_manager_kms =
     META_MONITOR_MANAGER_KMS (monitor_manager);
-  ClutterActor *stage;
   MetaIdleMonitor *idle_monitor;
 
   meta_monitor_manager_kms_resume (monitor_manager_kms);
 
   clutter_evdev_reclaim_devices ();
-  clutter_egl_thaw_master_clock ();
+  clutter_stage_thaw_updates (stage);
 
-  stage = meta_backend_get_stage (backend);
-  clutter_actor_queue_redraw (stage);
+  clutter_actor_queue_redraw (CLUTTER_ACTOR (stage));
 
   idle_monitor = meta_backend_get_idle_monitor (backend, 0);
   meta_idle_monitor_reset_idletime (idle_monitor);