1 files changed, 128 insertions, 0 deletions
diff --git a/accessible/base/EventTree.h b/accessible/base/EventTree.h
new file mode 100644
index 0000000000..a6efd81b79
--- /dev/null
+++ b/accessible/base/EventTree.h
@@ -0,0 +1,128 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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_a11y_EventTree_h_
+#define mozilla_a11y_EventTree_h_
+
+#include "AccEvent.h"
+#include "Accessible.h"
+
+#include "mozilla/a11y/DocAccessible.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+
+namespace mozilla {
+namespace a11y {
+
+class NotificationController;
+
+/**
+ * This class makes sure required tasks are done before and after tree
+ * mutations. Currently this only includes group info invalidation. You must
+ * have an object of this class on the stack when calling methods that mutate
+ * the accessible tree.
+ */
+class TreeMutation final {
+ public:
+  static const bool kNoEvents = true;
+  static const bool kNoShutdown = true;
+
+  explicit TreeMutation(Accessible* aParent, bool aNoEvents = false);
+  ~TreeMutation();
+
+  void AfterInsertion(Accessible* aChild);
+  void BeforeRemoval(Accessible* aChild, bool aNoShutdown = false);
+  void Done();
+
+ private:
+  NotificationController* Controller() const {
+    return mParent->Document()->Controller();
+  }
+
+  static EventTree* const kNoEventTree;
+
+#ifdef A11Y_LOG
+  static const char* PrefixLog(void* aData, Accessible*);
+#endif
+
+  Accessible* mParent;
+  uint32_t mStartIdx;
+  uint32_t mStateFlagsCopy;
+
+  /*
+   * True if mutation events should be queued.
+   */
+  bool mQueueEvents;
+
+#ifdef DEBUG
+  bool mIsDone;
+#endif
+};
+
+/**
+ * A mutation events coalescence structure.
+ */
+class EventTree final {
+ public:
+  EventTree()
+      : mFirst(nullptr),
+        mNext(nullptr),
+        mContainer(nullptr),
+        mFireReorder(false) {}
+  explicit EventTree(Accessible* aContainer, bool aFireReorder)
+      : mFirst(nullptr),
+        mNext(nullptr),
+        mContainer(aContainer),
+        mFireReorder(aFireReorder) {}
+  ~EventTree() { Clear(); }
+
+  void Shown(Accessible* aTarget);
+  void Hidden(Accessible*, bool);
+
+  /**
+   * Return an event tree node for the given accessible.
+   */
+  const EventTree* Find(const Accessible* aContainer) const;
+
+  /**
+   * Add a mutation event to this event tree.
+   */
+  void Mutated(AccMutationEvent* aEv);
+
+#ifdef A11Y_LOG
+  void Log(uint32_t aLevel = UINT32_MAX) const;
+#endif
+
+ private:
+  /**
+   * Processes the event queue and fires events.
+   */
+  void Process(const RefPtr<DocAccessible>& aDeathGrip);
+
+  /**
+   * Return an event subtree for the given accessible.
+   */
+  EventTree* FindOrInsert(Accessible* aContainer);
+
+  void Clear();
+
+  UniquePtr<EventTree> mFirst;
+  UniquePtr<EventTree> mNext;
+
+  Accessible* mContainer;
+  nsTArray<RefPtr<AccMutationEvent>> mDependentEvents;
+  bool mFireReorder;
+
+  static NotificationController* Controller(Accessible* aAcc) {
+    return aAcc->Document()->Controller();
+  }
+
+  friend class NotificationController;
+};
+
+}  // namespace a11y
+}  // namespace mozilla
+
+#endif  // mozilla_a11y_EventQueue_h_