1 files changed, 89 insertions, 0 deletions
diff --git a/gfx/layers/apz/util/APZTaskRunnable.h b/gfx/layers/apz/util/APZTaskRunnable.h
new file mode 100644
index 0000000000..f5de21abd4
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+++ b/gfx/layers/apz/util/APZTaskRunnable.h
@@ -0,0 +1,89 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_layers_RepaintRequestRunnable_h
+#define mozilla_layers_RepaintRequestRunnable_h
+
+#include <deque>
+#include <unordered_set>
+
+#include "mozilla/layers/GeckoContentController.h"
+#include "mozilla/layers/RepaintRequest.h"
+#include "mozilla/layers/ScrollableLayerGuid.h"
+#include "nsThreadUtils.h"
+
+namespace mozilla {
+namespace layers {
+
+class GeckoContentController;
+
+// A runnable invoked in nsRefreshDriver::Tick as an early runnable.
+class APZTaskRunnable final : public Runnable {
+ public:
+  explicit APZTaskRunnable(GeckoContentController* aController)
+      : Runnable("RepaintRequestRunnable"),
+        mController(aController),
+        mRegisteredPresShellId(0),
+        mNeedsFlushCompleteNotification(false) {}
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_DECL_NSIRUNNABLE
+
+      // Queue a RepaintRequest.
+      // If there's already a RepaintRequest having the same scroll id, the old
+      // one will be discarded.
+      void
+      QueueRequest(const RepaintRequest& aRequest);
+  void QueueFlushCompleteNotification();
+  void Revoke() {
+    mController = nullptr;
+    mRegisteredPresShellId = 0;
+  }
+
+ private:
+  void EnsureRegisterAsEarlyRunner();
+  bool IsRegisteredWithCurrentPresShell() const;
+  bool IsTestControllingRefreshesEnabled() const;
+
+  // Use a GeckoContentController raw pointer here since the owner of the
+  // GeckoContentController instance (an APZChild instance) holds a strong
+  // reference of this APZTaskRunnable instance and will call Revoke() before
+  // the GeckoContentController gets destroyed in the dtor of the APZChild
+  // instance.
+  GeckoContentController* mController;
+
+  struct RepaintRequestKey {
+    ScrollableLayerGuid::ViewID mScrollId;
+    RepaintRequest::ScrollOffsetUpdateType mScrollUpdateType;
+    bool operator==(const RepaintRequestKey& aOther) const {
+      return mScrollId == aOther.mScrollId &&
+             mScrollUpdateType == aOther.mScrollUpdateType;
+    }
+    struct HashFn {
+      std::size_t operator()(const RepaintRequestKey& aKey) const {
+        return HashGeneric(aKey.mScrollId, aKey.mScrollUpdateType);
+      }
+    };
+  };
+  using RepaintRequests =
+      std::unordered_set<RepaintRequestKey, RepaintRequestKey::HashFn>;
+  // We have an unordered_map and a deque for pending RepaintRequests. The
+  // unordered_map is for quick lookup and the deque is for processing the
+  // pending RepaintRequests in the order we queued.
+  RepaintRequests mPendingRepaintRequestMap;
+  std::deque<RepaintRequest> mPendingRepaintRequestQueue;
+  // This APZTaskRunnable instance is per APZChild instance, which means its
+  // lifetime is tied to the APZChild instance, thus this APZTaskRunnable
+  // instance will be (re-)used for different pres shells so we'd need to
+  // have to remember the pres shell which is currently tied to the APZChild
+  // to deliver queued requests and notifications to the proper pres shell.
+  uint32_t mRegisteredPresShellId;
+  bool mNeedsFlushCompleteNotification;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // mozilla_layers_RepaintRequestRunnable_h