1 files changed, 101 insertions, 0 deletions
diff --git a/dom/l10n/L10nMutations.h b/dom/l10n/L10nMutations.h
new file mode 100644
index 0000000000..afc08445e0
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+++ b/dom/l10n/L10nMutations.h
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+/* -*- 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_l10n_L10nMutations_h
+#define mozilla_dom_l10n_L10nMutations_h
+
+#include "nsCycleCollectionParticipant.h"
+#include "nsHashKeys.h"
+#include "nsRefreshObservers.h"
+#include "nsStubMutationObserver.h"
+#include "nsTHashSet.h"
+
+class nsRefreshDriver;
+
+namespace mozilla::dom {
+class Document;
+class DOMLocalization;
+/**
+ * L10nMutations manage observing roots for localization
+ * changes and coalescing pending translations into
+ * batches - one per animation frame.
+ */
+class L10nMutations final : public nsStubMultiMutationObserver,
+                            public nsARefreshObserver {
+ public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(L10nMutations, nsIMutationObserver)
+  NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
+  NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
+  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
+  NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
+
+  explicit L10nMutations(DOMLocalization* aDOMLocalization);
+
+  /**
+   * Pause root observation.
+   * This is useful for injecting already-translated
+   * content into an observed root, without causing
+   * superflues translation.
+   */
+  void PauseObserving();
+
+  /**
+   * Resume root observation.
+   */
+  void ResumeObserving();
+
+  /**
+   * Disconnect roots, stop refresh observer
+   * and break the cycle collection deadlock
+   * by removing the reference to mDOMLocalization.
+   */
+  void Disconnect();
+
+  /**
+   * Called when PresShell gets created for the document.
+   * If there are already pending mutations, this
+   * will schedule the refresh driver to translate them.
+   */
+  void OnCreatePresShell();
+
+  bool HasPendingMutations() const {
+    return !mPendingElements.IsEmpty() || mPendingPromises;
+  }
+
+  MOZ_CAN_RUN_SCRIPT void PendingPromiseSettled();
+
+ private:
+  bool mObserving = false;
+  bool mBlockingLoad = false;
+  bool mPendingBlockingLoadFlush = false;
+  uint32_t mPendingPromises = 0;
+  RefPtr<nsRefreshDriver> mRefreshDriver;
+  DOMLocalization* mDOMLocalization;
+
+  // The hash is used to speed up lookups into mPendingElements, which we need
+  // to guarantee some consistent ordering of operations.
+  nsTHashSet<RefPtr<Element>> mPendingElementsHash;
+  nsTArray<RefPtr<Element>> mPendingElements;
+
+  Document* GetDocument() const;
+
+  MOZ_CAN_RUN_SCRIPT void WillRefresh(mozilla::TimeStamp aTime) override;
+
+  void StartRefreshObserver();
+  void StopRefreshObserver();
+  void L10nElementChanged(Element* aElement);
+  MOZ_CAN_RUN_SCRIPT void FlushPendingTranslations();
+  MOZ_CAN_RUN_SCRIPT void FlushPendingTranslationsBeforeLoad();
+  MOZ_CAN_RUN_SCRIPT void MaybeFirePendingTranslationsFinished();
+
+  ~L10nMutations();
+  bool IsInRoots(nsINode* aNode);
+};
+
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_l10n_L10nMutations_h__