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/* -*- 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 */
#ifndef mozilla_a11y_EventTree_h_
#define mozilla_a11y_EventTree_h_
#include "AccEvent.h"
#include "LocalAccessible.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 {
static const bool kNoEvents = true;
static const bool kNoShutdown = true;
explicit TreeMutation(LocalAccessible* aParent, bool aNoEvents = false);
void AfterInsertion(LocalAccessible* aChild);
void BeforeRemoval(LocalAccessible* aChild, bool aNoShutdown = false);
void Done();
NotificationController* Controller() const {
return mParent->Document()->Controller();
static EventTree* const kNoEventTree;
#ifdef A11Y_LOG
static const char* PrefixLog(void* aData, LocalAccessible*);
LocalAccessible* mParent;
uint32_t mStartIdx;
uint32_t mStateFlagsCopy;
* True if mutation events should be queued.
bool mQueueEvents;
#ifdef DEBUG
bool mIsDone;
* A mutation events coalescence structure.
class EventTree final {
: mFirst(nullptr),
mFireReorder(false) {}
explicit EventTree(LocalAccessible* aContainer, bool aFireReorder)
: mFirst(nullptr),
mFireReorder(aFireReorder) {}
~EventTree() { Clear(); }
void Shown(LocalAccessible* aTarget);
void Hidden(LocalAccessible*, bool);
* Return an event tree node for the given accessible.
const EventTree* Find(const LocalAccessible* 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;
* Processes the event queue and fires events.
void Process(const RefPtr<DocAccessible>& aDeathGrip);
* Return an event subtree for the given accessible.
EventTree* FindOrInsert(LocalAccessible* aContainer);
void Clear();
UniquePtr<EventTree> mFirst;
UniquePtr<EventTree> mNext;
LocalAccessible* mContainer;
nsTArray<RefPtr<AccMutationEvent>> mDependentEvents;
bool mFireReorder;
static NotificationController* Controller(LocalAccessible* aAcc) {
return aAcc->Document()->Controller();
friend class NotificationController;
} // namespace a11y
} // namespace mozilla
#endif // mozilla_a11y_EventQueue_h_