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nsDocAccessible.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2003
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Original Author: Aaron Leventhal (aaronl@netscape.com)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
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 * the provisions above, a recipient may use your version of this file under
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 * ***** END LICENSE BLOCK ***** */

#ifndef _nsDocAccessible_H_
#define _nsDocAccessible_H_

#include "nsHyperTextAccessibleWrap.h"
#include "nsIAccessibleDocument.h"
#include "nsIDocument.h"
#include "nsIDocumentObserver.h"
#include "nsIEditor.h"
#include "nsIObserver.h"
#include "nsIScrollPositionListener.h"
#include "nsITimer.h"
#include "nsIWeakReference.h"
#include "nsCOMArray.h"
#include "nsIDocShellTreeNode.h"

class nsIScrollableView;

const PRUint32 kDefaultCacheSize = 256;

#define NS_DOCACCESSIBLE_IMPL_CID                       \
{  /* 9735bc5f-a4b6-4668-ab73-6f8434c8e750 */           \
  0x9735bc5f,                                           \
  0xa4b6,                                               \
  0x4668,                                               \
  { 0xab, 0x73, 0x6f, 0x84, 0x34, 0xc8, 0xe7, 0x50 }    \
}

class nsDocAccessible : public nsHyperTextAccessibleWrap,
                        public nsIAccessibleDocument,
                        public nsIDocumentObserver,
                        public nsIObserver,
                        public nsIScrollPositionListener,
                        public nsSupportsWeakReference
{  
  NS_DECL_ISUPPORTS_INHERITED
  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsDocAccessible, nsAccessible)

  NS_DECL_NSIACCESSIBLEDOCUMENT
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_DOCACCESSIBLE_IMPL_CID)

  NS_DECL_NSIOBSERVER

public:
  nsDocAccessible(nsIDOMNode *aNode, nsIWeakReference* aShell);
  virtual ~nsDocAccessible();

  // nsIAccessible
  NS_IMETHOD GetName(nsAString& aName);
  NS_IMETHOD GetDescription(nsAString& aDescription);
  NS_IMETHOD GetAttributes(nsIPersistentProperties **aAttributes);
  NS_IMETHOD GetFocusedChild(nsIAccessible **aFocusedChild);
  NS_IMETHOD GetParent(nsIAccessible **aParent);
  NS_IMETHOD TakeFocus(void);

  // nsIScrollPositionListener
  NS_IMETHOD ScrollPositionWillChange(nsIScrollableView *aView,
                                      nscoord aX, nscoord aY);
  virtual void ViewPositionDidChange(nsIScrollableView* aScrollable,
                                     nsTArray<nsIWidget::Configuration>* aConfigurations) {}
  NS_IMETHOD ScrollPositionDidChange(nsIScrollableView *aView,
                                     nscoord aX, nscoord aY);

  // nsIDocumentObserver
  NS_DECL_NSIDOCUMENTOBSERVER

  // nsAccessNode
  virtual nsresult Init();
  virtual nsresult Shutdown();
  virtual nsIFrame* GetFrame();
  virtual PRBool IsDefunct();

  // nsAccessible
  virtual nsresult GetRoleInternal(PRUint32 *aRole);
  virtual nsresult GetStateInternal(PRUint32 *aState, PRUint32 *aExtraState);
  virtual nsresult GetARIAState(PRUint32 *aState, PRUint32 *aExtraState);
  virtual void SetRoleMapEntry(nsRoleMapEntry* aRoleMapEntry);

  // nsIAccessibleText
  NS_IMETHOD GetAssociatedEditor(nsIEditor **aEditor);

  // nsDocAccessible

  /**
   * Non-virtual method to fire a delayed event after a 0 length timeout.
   *
   * @param aEvent       [in] the nsIAccessibleEvent event type
   * @param aDOMNode     [in] DOM node the accesible event should be fired for
   * @param aAllowDupes  [in] rule to process an event (see EEventRule constants)
   * @param aIsAsynch    [in] set to PR_TRUE if this is not being called from
   *                      code synchronous with a DOM event
   */
  nsresult FireDelayedToolkitEvent(PRUint32 aEvent, nsIDOMNode *aDOMNode,
                                   nsAccEvent::EEventRule aAllowDupes = nsAccEvent::eRemoveDupes,
                                   PRBool aIsAsynch = PR_FALSE);

  /**
   * Fire accessible event after timeout.
   *
   * @param aEvent  [in] the event to fire
   */
  nsresult FireDelayedAccessibleEvent(nsIAccessibleEvent *aEvent);

  /**
   * Find the accessible object in the accessibility cache that corresponds to
   * the given node or the first ancestor of it that has an accessible object
   * associated with it. Clear that accessible object's parent's cache of
   * accessible children and remove the accessible object and any descendants
   * from the accessible cache. Fires proper events. New accessible objects will
   * be created and cached again on demand.
   *
   * @param aContent  [in] the child that is changing
   * @param aEvent    [in] the event from nsIAccessibleEvent that caused
   *                   the change.
   */
  void InvalidateCacheSubtree(nsIContent *aContent, PRUint32 aEvent);

  /**
   * Cache access node.
   *
   * @param  aUniquID     [in] the unique identifier of accessible
   * @param  aAccessNode  [in] accessible to cache
   */
  void CacheAccessNode(void *aUniqueID, nsIAccessNode *aAccessNode);

  /**
   * Remove the given access node from document cache.
   */
  void RemoveAccessNodeFromCache(nsIAccessNode *aAccessNode);

  /**
   * Fires pending events.
   */
  void FlushPendingEvents();

  /**
   * Fire document load events.
   *
   * @param  aEventType  [in] nsIAccessibleEvent constant
   */
  virtual void FireDocLoadEvents(PRUint32 aEventType);

  /**
   * Process the case when anchor was clicked.
   */
  virtual void FireAnchorJumpEvent();

  /**
   * Used to flush pending events, called after timeout. See FlushPendingEvents.
   */
  static void FlushEventsCallback(nsITimer *aTimer, void *aClosure);

protected:
  /**
   * Iterates through sub documents and shut them down.
   */
  void ShutdownChildDocuments(nsIDocShellTreeItem *aStart);

    virtual void GetBoundsRect(nsRect& aRect, nsIFrame** aRelativeFrame);
    virtual nsresult AddEventListeners();
    virtual nsresult RemoveEventListeners();
    void AddScrollListener();
    void RemoveScrollListener();

    /**
     * For any accessibles in this subtree, invalidate their knowledge of
     * their children. Only weak refrences are destroyed, not accessibles.
     * @param aStartNode  The root of the subrtee to invalidate accessible child refs in
     */
    void InvalidateChildrenInSubtree(nsIDOMNode *aStartNode);
    void RefreshNodes(nsIDOMNode *aStartNode);
    static void ScrollTimerCallback(nsITimer *aTimer, void *aClosure);

    /**
     * Fires accessible events when attribute is changed.
     *
     * @param aContent - node that attribute is changed for
     * @param aNameSpaceID - namespace of changed attribute
     * @param aAttribute - changed attribute
     */
    void AttributeChangedImpl(nsIContent* aContent, PRInt32 aNameSpaceID, nsIAtom* aAttribute);

    /**
     * Fires accessible events when ARIA attribute is changed.
     *
     * @param aContent - node that attribute is changed for
     * @param aAttribute - changed attribute
     */
    void ARIAAttributeChanged(nsIContent* aContent, nsIAtom* aAttribute);

    /**
     * Fire text changed event for character data changed. The method is used
     * from nsIMutationObserver methods.
     *
     * @param aContent     the text node holding changed data
     * @param aInfo        info structure describing how the data was changed
     * @param aIsInserted  the flag pointed whether removed or inserted
     *                     characters should be cause of event
     */
    void FireTextChangeEventForText(nsIContent *aContent,
                                    CharacterDataChangeInfo* aInfo,
                                    PRBool aIsInserted);

    /**
     * Create a text change event for a changed node
     * @param aContainerAccessible, the first accessible in the container
     * @param aChangeNode, the node that is being inserted or removed, or shown/hidden
     * @param aAccessibleForChangeNode, the accessible for that node, or nsnull if none exists
     * @param aIsInserting, is aChangeNode being created or shown (vs. removed or hidden)
     */
    already_AddRefed<nsIAccessibleTextChangeEvent>
    CreateTextChangeEventForNode(nsIAccessible *aContainerAccessible,
                                 nsIDOMNode *aChangeNode,
                                 nsIAccessible *aAccessibleForNode,
                                 PRBool aIsInserting,
                                 PRBool aIsAsynch);

    /**
     * Fire show/hide events for either the current node if it has an accessible,
     * or the first-line accessible descendants of the given node.
     *
     * @param aDOMNode               the given node
     * @param aEventType             event type to fire an event
     * @param aAvoidOnThisNode       Call with PR_TRUE the first time to prevent event firing on root node for change
     * @param aDelay                 whether to fire the event on a delay
     * @param aForceIsFromUserInput  the event is known to be from user input
     */
    nsresult FireShowHideEvents(nsIDOMNode *aDOMNode, PRBool aAvoidOnThisNode, PRUint32 aEventType,
                                PRBool aDelay, PRBool aForceIsFromUserInput);

    /**
     * If the given accessible object is a ROLE_ENTRY, fire a value change event for it
     */
    void FireValueChangeForTextFields(nsIAccessible *aPossibleTextFieldAccessible);

    nsAccessNodeHashtable mAccessNodeCache;
    void *mWnd;
    nsCOMPtr<nsIDocument> mDocument;
    nsCOMPtr<nsITimer> mScrollWatchTimer;
    nsCOMPtr<nsITimer> mFireEventTimer;
    PRUint16 mScrollPositionChangedTicks; // Used for tracking scroll events
    PRPackedBool mIsContentLoaded;
    PRPackedBool mIsLoadCompleteFired;
    nsCOMArray<nsIAccessibleEvent> mEventsToFire;

protected:
    PRBool mIsAnchor;
    PRBool mIsAnchorJumped;
    PRBool mInFlushPendingEvents;
    static PRUint32 gLastFocusedAccessiblesState;
    static nsIAtom *gLastFocusedFrameType;
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsDocAccessible,
                              NS_DOCACCESSIBLE_IMPL_CID)

#endif  

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