From f0c220046645f3ff01891d2fedf1c79e74bc14b9 Mon Sep 17 00:00:00 2001
From: Ivan Molodetskikh <yalterz@gmail.com>
Date: Mon, 12 Oct 2020 14:10:43 +0300
Subject: [PATCH] wayland: Store map of ready presentation feedbacks

These are feedbacks for updates that were drawn or otherwise displayed
on screen, and need to be fired as soon as their presentation happens.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1484>
---
 .../meta-wayland-presentation-time-private.h  | 10 ++++
 src/wayland/meta-wayland-presentation-time.c  | 52 +++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/src/wayland/meta-wayland-presentation-time-private.h b/src/wayland/meta-wayland-presentation-time-private.h
index 234ac3495..0a1298bbf 100644
--- a/src/wayland/meta-wayland-presentation-time-private.h
+++ b/src/wayland/meta-wayland-presentation-time-private.h
@@ -39,6 +39,13 @@ typedef struct _MetaWaylandPresentationFeedback
 typedef struct _MetaWaylandPresentationTime
 {
   GList *feedback_surfaces;
+
+  /*
+   * A mapping from (ClutterStageView *) to a
+   * (MetaWaylandPresentationFeedback *) wl_list of presentation-time feedbacks
+   * that are scheduled to be presented.
+   */
+  GHashTable *feedbacks;
 } MetaWaylandPresentationTime;
 
 void meta_wayland_init_presentation_time (MetaWaylandCompositor *compositor);
@@ -49,4 +56,7 @@ void meta_wayland_presentation_feedback_present (MetaWaylandPresentationFeedback
                                                  ClutterFrameInfo                *frame_info,
                                                  MetaWaylandOutput               *output);
 
+struct wl_list * meta_wayland_presentation_time_ensure_feedbacks (MetaWaylandPresentationTime *presentation_time,
+                                                                  ClutterStageView            *stage_view);
+
 #endif /* META_WAYLAND_PRESENTATION_TIME_PRIVATE_H */
diff --git a/src/wayland/meta-wayland-presentation-time.c b/src/wayland/meta-wayland-presentation-time.c
index ef74d1150..54351690a 100644
--- a/src/wayland/meta-wayland-presentation-time.c
+++ b/src/wayland/meta-wayland-presentation-time.c
@@ -111,9 +111,43 @@ wp_presentation_bind (struct wl_client *client,
   wp_presentation_send_clock_id (resource, CLOCK_MONOTONIC);
 }
 
+static void
+destroy_feedback_list (gpointer data)
+{
+  struct wl_list *feedbacks = data;
+
+  while (!wl_list_empty (feedbacks))
+    {
+      MetaWaylandPresentationFeedback *feedback =
+        wl_container_of (feedbacks->next, feedback, link);
+
+      meta_wayland_presentation_feedback_discard (feedback);
+    }
+
+  g_free (feedbacks);
+}
+
+static void
+on_monitors_changed (MetaMonitorManager    *manager,
+                     MetaWaylandCompositor *compositor)
+{
+  /* All ClutterStageViews were re-created, so clear our map. */
+  g_hash_table_remove_all (compositor->presentation_time.feedbacks);
+}
+
 void
 meta_wayland_init_presentation_time (MetaWaylandCompositor *compositor)
 {
+  MetaBackend *backend = compositor->backend;
+  MetaMonitorManager *monitor_manager =
+    meta_backend_get_monitor_manager (backend);
+
+  compositor->presentation_time.feedbacks =
+    g_hash_table_new_full (NULL, NULL, NULL, destroy_feedback_list);
+
+  g_signal_connect (monitor_manager, "monitors-changed-internal",
+                    G_CALLBACK (on_monitors_changed), compositor);
+
   if (wl_global_create (compositor->wayland_display,
                         &wp_presentation_interface,
                         META_WP_PRESENTATION_VERSION,
@@ -252,3 +286,21 @@ meta_wayland_presentation_feedback_present (MetaWaylandPresentationFeedback *fee
 
   wl_resource_destroy (feedback->resource);
 }
+
+struct wl_list *
+meta_wayland_presentation_time_ensure_feedbacks (MetaWaylandPresentationTime *presentation_time,
+                                                 ClutterStageView            *stage_view)
+{
+  if (!g_hash_table_contains (presentation_time->feedbacks, stage_view))
+    {
+      struct wl_list *list;
+
+      list = g_new0 (struct wl_list, 1);
+      wl_list_init (list);
+      g_hash_table_insert (presentation_time->feedbacks, stage_view, list);
+
+      return list;
+    }
+
+  return g_hash_table_lookup (presentation_time->feedbacks, stage_view);
+}