gecko-dev/accessible/base/EventQueue.h
James Teh 7d2201e688 Bug 1192108: Fire focus events after mutation events but before any other events. r=eeejay
It's critical that we fire mutation events first because our RemoteAccessible tree is created thus and we can't fire events on RemoteAccessibles we haven't created yet.
Beyond that, though, focus events are of primary importance.
See the comments in EventQueue::ProcessEventQueue for the reasons.

Differential Revision: https://phabricator.services.mozilla.com/D145319
2022-05-06 23:59:43 +00:00

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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_EventQueue_h_
#define mozilla_a11y_EventQueue_h_
#include "AccEvent.h"
namespace mozilla {
namespace a11y {
class DocAccessible;
/**
* Used to organize and coalesce pending events.
*/
class EventQueue {
protected:
explicit EventQueue(DocAccessible* aDocument) : mDocument(aDocument) {}
/**
* Put an accessible event into the queue to process it later.
*/
bool PushEvent(AccEvent* aEvent);
/**
* Puts name and/or description change events into the queue, if needed.
*/
bool PushNameOrDescriptionChange(LocalAccessible* aTarget);
/**
* Process events from the queue and fires events.
*/
void ProcessEventQueue();
private:
EventQueue(const EventQueue&) = delete;
EventQueue& operator=(const EventQueue&) = delete;
// Event queue processing
/**
* Coalesce redundant events from the queue.
*/
void CoalesceEvents();
/**
* Coalesce events from the same subtree.
*/
void CoalesceReorderEvents(AccEvent* aTailEvent);
/**
* Coalesce two selection change events within the same select control.
*/
void CoalesceSelChangeEvents(AccSelChangeEvent* aTailEvent,
AccSelChangeEvent* aThisEvent,
uint32_t aThisIndex);
protected:
/**
* The document accessible reference owning this queue.
*/
DocAccessible* mDocument;
/**
* Pending events array. Don't make this an AutoTArray; we use
* SwapElements() on it.
*/
nsTArray<RefPtr<AccEvent>> mEvents;
// Pending focus event.
RefPtr<AccEvent> mFocusEvent;
};
} // namespace a11y
} // namespace mozilla
#endif // mozilla_a11y_EventQueue_h_