michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef mozilla_a11y_EventQueue_h_
michael@0: #define mozilla_a11y_EventQueue_h_
michael@0: 
michael@0: #include "AccEvent.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace a11y {
michael@0: 
michael@0: class DocAccessible;
michael@0: 
michael@0: /**
michael@0:  * Used to organize and coalesce pending events.
michael@0:  */
michael@0: class EventQueue
michael@0: {
michael@0: protected:
michael@0:   EventQueue(DocAccessible* aDocument) : mDocument(aDocument) { }
michael@0: 
michael@0:   /**
michael@0:    * Put an accessible event into the queue to process it later.
michael@0:    */
michael@0:   bool PushEvent(AccEvent* aEvent);
michael@0: 
michael@0:   /**
michael@0:    * Process events from the queue and fires events.
michael@0:    */
michael@0:   void ProcessEventQueue();
michael@0: 
michael@0: private:
michael@0:   EventQueue(const EventQueue&) MOZ_DELETE;
michael@0:   EventQueue& operator = (const EventQueue&) MOZ_DELETE;
michael@0: 
michael@0:   // Event queue processing
michael@0:   /**
michael@0:    * Coalesce redundant events from the queue.
michael@0:    */
michael@0:   void CoalesceEvents();
michael@0: 
michael@0:   /**
michael@0:    * Coalesce events from the same subtree.
michael@0:    */
michael@0:   void CoalesceReorderEvents(AccEvent* aTailEvent);
michael@0: 
michael@0:   /**
michael@0:    * Coalesce two selection change events within the same select control.
michael@0:    */
michael@0:   void CoalesceSelChangeEvents(AccSelChangeEvent* aTailEvent,
michael@0:                                AccSelChangeEvent* aThisEvent,
michael@0:                                uint32_t aThisIndex);
michael@0: 
michael@0:   /**
michael@0:    * Coalesce text change events caused by sibling hide events.
michael@0:    */
michael@0:   void CoalesceTextChangeEventsFor(AccHideEvent* aTailEvent,
michael@0:                                    AccHideEvent* aThisEvent);
michael@0:   void CoalesceTextChangeEventsFor(AccShowEvent* aTailEvent,
michael@0:                                    AccShowEvent* aThisEvent);
michael@0: 
michael@0:   /**
michael@0:     * Create text change event caused by hide or show event. When a node is
michael@0:     * hidden/removed or shown/appended, the text in an ancestor hyper text will
michael@0:     * lose or get new characters.
michael@0:     */
michael@0:    void CreateTextChangeEventFor(AccMutationEvent* aEvent);
michael@0: 
michael@0: protected:
michael@0: 
michael@0:   /**
michael@0:    * The document accessible reference owning this queue.
michael@0:    */
michael@0:   DocAccessible* mDocument;
michael@0: 
michael@0:   /**
michael@0:    * Pending events array. Don't make this an nsAutoTArray; we use
michael@0:    * SwapElements() on it.
michael@0:    */
michael@0:   nsTArray<nsRefPtr<AccEvent> > mEvents;
michael@0: };
michael@0: 
michael@0: } // namespace a11y
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // mozilla_a11y_EventQueue_h_