1 files changed, 78 insertions, 0 deletions
diff --git a/dom/base/AnimationFrameProvider.h b/dom/base/AnimationFrameProvider.h
new file mode 100644
index 0000000000..bbc01910ee
--- /dev/null
+++ b/dom/base/AnimationFrameProvider.h
@@ -0,0 +1,78 @@
+/* -*- 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_dom_AnimationFrameProvider_h
+#define mozilla_dom_AnimationFrameProvider_h
+
+#include "mozilla/dom/AnimationFrameProviderBinding.h"
+#include "mozilla/HashTable.h"
+#include "mozilla/RefPtr.h"
+#include "nsTArray.h"
+
+namespace mozilla::dom {
+
+struct FrameRequest {
+  FrameRequest(FrameRequestCallback& aCallback, int32_t aHandle);
+  ~FrameRequest();
+
+  // Comparator operators to allow RemoveElementSorted with an
+  // integer argument on arrays of FrameRequest
+  bool operator==(int32_t aHandle) const { return mHandle == aHandle; }
+  bool operator<(int32_t aHandle) const { return mHandle < aHandle; }
+
+  RefPtr<FrameRequestCallback> mCallback;
+  int32_t mHandle;
+};
+
+class FrameRequestManager {
+ public:
+  FrameRequestManager() = default;
+  ~FrameRequestManager() = default;
+
+  nsresult Schedule(FrameRequestCallback& aCallback, int32_t* aHandle);
+  bool Cancel(int32_t aHandle);
+
+  bool IsEmpty() const { return mCallbacks.IsEmpty(); }
+
+  bool IsCanceled(int32_t aHandle) const {
+    return !mCanceledCallbacks.empty() && mCanceledCallbacks.has(aHandle);
+  }
+
+  void Take(nsTArray<FrameRequest>& aCallbacks) {
+    aCallbacks = std::move(mCallbacks);
+    mCanceledCallbacks.clear();
+  }
+
+  void Unlink();
+
+  void Traverse(nsCycleCollectionTraversalCallback& aCB);
+
+ private:
+  nsTArray<FrameRequest> mCallbacks;
+
+  // The set of frame request callbacks that were canceled but which we failed
+  // to find in mFrameRequestCallbacks.
+  HashSet<int32_t> mCanceledCallbacks;
+
+  /**
+   * The current frame request callback handle
+   */
+  int32_t mCallbackCounter = 0;
+};
+
+inline void ImplCycleCollectionUnlink(FrameRequestManager& aField) {
+  aField.Unlink();
+}
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback, FrameRequestManager& aField,
+    const char* aName, uint32_t aFlags) {
+  aField.Traverse(aCallback);
+}
+
+}  // namespace mozilla::dom
+
+#endif