Add gdk_frame_timings_get/set_slept_before()

Add functions that tell us whether the main loop slept before we drew
a frame. Blocking with the frame clock frozen doesn't count as sleeping.
We'll use this to advertise to the compositor whether we
are drawing as fast as possible (and it should do the same) or timing
frames carefully (and it should do the same.)

https://bugzilla.gnome.org/show_bug.cgi?id=685460

gdk/gdkframeclockidle.c

@@ -39,6 +39,7 @@ struct _GdkFrameClockIdlePrivate
   guint64 timer_base;
   guint64 frame_time;
   guint64 min_next_frame_time;
+  gint64 sleep_serial;
 
   guint flush_idle_id;
   guint paint_idle_id;
@@ -60,6 +61,58 @@ G_DEFINE_TYPE_WITH_CODE (GdkFrameClockIdle, gdk_frame_clock_idle, G_TYPE_OBJECT,
 			 G_IMPLEMENT_INTERFACE (GDK_TYPE_FRAME_CLOCK,
 						gdk_frame_clock_idle_interface_init))
 
+static gint64 sleep_serial;
+static gint64 sleep_source_prepare_time;
+static GSource *sleep_source;
+
+gboolean
+sleep_source_prepare (GSource *source,
+                      gint    *timeout)
+{
+  sleep_source_prepare_time = g_source_get_time (source);
+  *timeout = -1;
+  return FALSE;
+}
+
+gboolean
+sleep_source_check (GSource *source)
+{
+  if (g_source_get_time (source) != sleep_source_prepare_time)
+    sleep_serial++;
+
+  return FALSE;
+}
+
+gboolean
+sleep_source_dispatch (GSource     *source,
+                       GSourceFunc  callback,
+                       gpointer     user_data)
+{
+  return TRUE;
+}
+
+static GSourceFuncs sleep_source_funcs = {
+  sleep_source_prepare,
+  sleep_source_check,
+  sleep_source_dispatch,
+  NULL /* finalize */
+};
+
+static gint64
+get_sleep_serial (void)
+{
+  if (sleep_source == NULL)
+    {
+      sleep_source = g_source_new (&sleep_source_funcs, sizeof (GSource));
+
+      g_source_set_priority (sleep_source, G_PRIORITY_HIGH);
+      g_source_attach (sleep_source, NULL);
+      g_source_unref (sleep_source);
+    }
+
+  return sleep_serial;
+}
+
 static void
 gdk_frame_clock_idle_class_init (GdkFrameClockIdleClass *klass)
 {
@@ -244,6 +297,9 @@ gdk_frame_clock_paint_idle (void *data)
               timings = gdk_frame_history_get_timings (priv->history, frame_counter);
               gdk_frame_timings_set_frame_time (timings, priv->frame_time);
 
+              gdk_frame_timings_set_slept_before (timings,
+                                                  priv->sleep_serial != get_sleep_serial ());
+
               priv->phase = GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT;
 
               /* We always emit ::before-paint and ::after-paint if
@@ -322,6 +378,9 @@ gdk_frame_clock_paint_idle (void *data)
       priv->min_next_frame_time = 0;
     }
 
+  if (priv->freeze_count == 0)
+    priv->sleep_serial = get_sleep_serial ();
+
   return FALSE;
 }
 
@@ -383,6 +442,8 @@ gdk_frame_clock_idle_thaw (GdkFrameClock *clock)
        * run and do it for us. */
       if (priv->paint_idle_id == 0)
         priv->phase = GDK_FRAME_CLOCK_PHASE_NONE;
+
+      priv->sleep_serial = get_sleep_serial ();
     }
 }
 

gdk/gdkframetimings.c

@@ -23,13 +23,15 @@ struct _GdkFrameTimings
 {
   guint ref_count;
 
-  gboolean complete;
   gint64 frame_counter;
   guint64 cookie;
   gint64 frame_time;
   gint64 drawn_time;
   gint64 presentation_time;
   gint64 refresh_interval;
+
+  guint complete : 1;
+  guint slept_before : 1;
 };
 
 G_DEFINE_BOXED_TYPE (GdkFrameTimings, gdk_frame_timings,
@@ -111,6 +113,23 @@ gdk_frame_timings_set_complete (GdkFrameTimings *timings,
   timings->complete = complete;
 }
 
+gboolean
+gdk_frame_timings_get_slept_before (GdkFrameTimings *timings)
+{
+  g_return_val_if_fail (timings != NULL, FALSE);
+
+  return timings->slept_before;
+}
+
+void
+gdk_frame_timings_set_slept_before (GdkFrameTimings *timings,
+                                    gboolean         slept_before)
+{
+  g_return_if_fail (timings != NULL);
+
+  timings->slept_before = slept_before;
+}
+
 gint64
 gdk_frame_timings_get_frame_time (GdkFrameTimings *timings)
 {

gdk/gdkframetimings.h

@@ -45,6 +45,10 @@ gboolean         gdk_frame_timings_get_complete          (GdkFrameTimings *timin
 void             gdk_frame_timings_set_complete          (GdkFrameTimings *timings,
                                                           gboolean         complete);
 
+gboolean         gdk_frame_timings_get_slept_before      (GdkFrameTimings *timings);
+void             gdk_frame_timings_set_slept_before      (GdkFrameTimings *timings,
+                                                          gboolean         slept_before);
+
 gint64           gdk_frame_timings_get_frame_time        (GdkFrameTimings *timings);
 void             gdk_frame_timings_set_frame_time        (GdkFrameTimings *timings,
                                                           gint64           frame_time);