gecko-dev/accessible/base/EventTree.h

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2.9 KiB
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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 http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_a11y_EventTree_h_
#define mozilla_a11y_EventTree_h_
#include "AccEvent.h"
#include "Accessible.h"
#include "mozilla/RefPtr.h"
#include "mozilla/UniquePtr.h"
namespace mozilla {
namespace a11y {
/**
* 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_