[gtk/wip/on-the-fence-about-damage: 1/5] gdkframeclockidle: handle frame clock getting frozen during paint

[Ray Strode <halfline src gnome org>]

commit 504f8905a328b9dedfad8dc2b1f1254eaedf835c
Author: Ray Strode <rstrode redhat com>
Date:   Wed May 27 14:50:17 2020 -0400

    gdkframeclockidle: handle frame clock getting frozen during paint
    
    At the moment if the frame clock is frozen while in the paint phase,
    when it's later thawed, it redoes the paint phase instead of
    correctly proceeding to after_paint.
    
    This commit fixes that.

 gdk/gdkframeclockidle.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)
---
diff --git a/gdk/gdkframeclockidle.c b/gdk/gdkframeclockidle.c
index 2312e30b25..d95785bdc8 100644
--- a/gdk/gdkframeclockidle.c
+++ b/gdk/gdkframeclockidle.c
@@ -207,6 +207,7 @@ gdk_frame_clock_idle_get_frame_time (GdkFrameClock *clock)
 #define RUN_PAINT_IDLE(priv)                                            \
   ((priv)->freeze_count == 0 &&                                         \
    (((priv)->requested & ~GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS) != 0 ||   \
+    (priv)->phase > GDK_FRAME_CLOCK_PHASE_PAINT ||                      \
     (priv)->updating_count > 0))
 
 static void
@@ -235,6 +236,12 @@ maybe_start_idle (GdkFrameClockIdle *clock_idle)
           g_source_set_name_by_id (priv->flush_idle_id, "[gtk] gdk_frame_clock_flush_idle");
         }
 
+      /* If we've already painted the frame, then we should finish up this tick as quickly
+       * as possible
+       */
+      if (priv->phase > GDK_FRAME_CLOCK_PHASE_PAINT)
+        min_interval = 0;
+
       if (!priv->in_paint_idle &&
          priv->paint_idle_id == 0 && RUN_PAINT_IDLE (priv))
         {
@@ -452,6 +459,7 @@ gdk_frame_clock_paint_idle (void *data)
                   priv->requested &= ~GDK_FRAME_CLOCK_PHASE_PAINT;
                   _gdk_frame_clock_emit_paint (clock);
                 }
+              priv->phase = GDK_FRAME_CLOCK_PHASE_AFTER_PAINT;
             }
           G_GNUC_FALLTHROUGH;
 
@@ -463,11 +471,11 @@ gdk_frame_clock_paint_idle (void *data)
               /* the ::after-paint phase doesn't get repeated on freeze/thaw,
                */
               priv->phase = GDK_FRAME_CLOCK_PHASE_NONE;
-            }
 #ifdef G_ENABLE_DEBUG
-            if (GDK_DEBUG_CHECK (FRAMES))
-              timings->frame_end_time = g_get_monotonic_time ();
+              if (GDK_DEBUG_CHECK (FRAMES))
+                timings->frame_end_time = g_get_monotonic_time ();
 #endif /* G_ENABLE_DEBUG */
+            }
           G_GNUC_FALLTHROUGH;
 
         case GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS: