1 files changed, 108 insertions, 0 deletions
diff --git a/dom/animation/AnimationTarget.h b/dom/animation/AnimationTarget.h
new file mode 100644
index 0000000000..3a0dacb9aa
--- /dev/null
+++ b/dom/animation/AnimationTarget.h
@@ -0,0 +1,108 @@
+/* -*- 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_AnimationTarget_h
+#define mozilla_AnimationTarget_h
+
+#include "mozilla/Attributes.h"     // For MOZ_NON_OWNING_REF
+#include "mozilla/HashFunctions.h"  // For HashNumber, AddToHash
+#include "mozilla/HashTable.h"      // For DefaultHasher, PointerHasher
+#include "mozilla/Maybe.h"
+#include "mozilla/RefPtr.h"
+#include "nsCSSPseudoElements.h"
+
+namespace mozilla {
+
+namespace dom {
+class Element;
+}  // namespace dom
+
+struct OwningAnimationTarget {
+  OwningAnimationTarget() = default;
+
+  OwningAnimationTarget(dom::Element* aElement, PseudoStyleType aType)
+      : mElement(aElement), mPseudoType(aType) {}
+
+  explicit OwningAnimationTarget(dom::Element* aElement) : mElement(aElement) {}
+
+  bool operator==(const OwningAnimationTarget& aOther) const {
+    return mElement == aOther.mElement && mPseudoType == aOther.mPseudoType;
+  }
+
+  explicit operator bool() const { return !!mElement; }
+
+  // mElement represents the parent element of a pseudo-element, not the
+  // generated content element.
+  RefPtr<dom::Element> mElement;
+  PseudoStyleType mPseudoType = PseudoStyleType::NotPseudo;
+};
+
+struct NonOwningAnimationTarget {
+  NonOwningAnimationTarget() = default;
+
+  NonOwningAnimationTarget(dom::Element* aElement, PseudoStyleType aType)
+      : mElement(aElement), mPseudoType(aType) {}
+
+  explicit NonOwningAnimationTarget(const OwningAnimationTarget& aOther)
+      : mElement(aOther.mElement), mPseudoType(aOther.mPseudoType) {}
+
+  bool operator==(const NonOwningAnimationTarget& aOther) const {
+    return mElement == aOther.mElement && mPseudoType == aOther.mPseudoType;
+  }
+
+  NonOwningAnimationTarget& operator=(const OwningAnimationTarget& aOther) {
+    mElement = aOther.mElement;
+    mPseudoType = aOther.mPseudoType;
+    return *this;
+  }
+
+  explicit operator bool() const { return !!mElement; }
+
+  // mElement represents the parent element of a pseudo-element, not the
+  // generated content element.
+  dom::Element* MOZ_NON_OWNING_REF mElement = nullptr;
+  PseudoStyleType mPseudoType = PseudoStyleType::NotPseudo;
+};
+
+// Helper functions for cycle-collecting Maybe<OwningAnimationTarget>
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback,
+    Maybe<OwningAnimationTarget>& aTarget, const char* aName,
+    uint32_t aFlags = 0) {
+  if (aTarget) {
+    ImplCycleCollectionTraverse(aCallback, aTarget->mElement, aName, aFlags);
+  }
+}
+
+inline void ImplCycleCollectionUnlink(Maybe<OwningAnimationTarget>& aTarget) {
+  if (aTarget) {
+    ImplCycleCollectionUnlink(aTarget->mElement);
+  }
+}
+
+// A DefaultHasher specialization for OwningAnimationTarget.
+template <>
+struct DefaultHasher<OwningAnimationTarget> {
+  using Key = OwningAnimationTarget;
+  using Lookup = OwningAnimationTarget;
+  using PtrHasher = PointerHasher<dom::Element*>;
+
+  static HashNumber hash(const Lookup& aLookup) {
+    return AddToHash(PtrHasher::hash(aLookup.mElement.get()),
+                     static_cast<uint8_t>(aLookup.mPseudoType));
+  }
+
+  static bool match(const Key& aKey, const Lookup& aLookup) {
+    return PtrHasher::match(aKey.mElement.get(), aLookup.mElement.get()) &&
+           aKey.mPseudoType == aLookup.mPseudoType;
+  }
+
+  static void rekey(Key& aKey, Key&& aNewKey) { aKey = std::move(aNewKey); }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_AnimationTarget_h