xref: /external/webkit/Source/WebCore/accessibility/AccessibilityObject.h

/*
 * Copyright (C) 2008, 2009, 2011 Apple Inc. All rights reserved.
 * Copyright (C) 2008 Nuanti Ltd.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef AccessibilityObject_h
#define AccessibilityObject_h

#include "IntRect.h"
#include "VisiblePosition.h"
#include "VisibleSelection.h"
#include <wtf/Forward.h>
#include <wtf/RefPtr.h>
#include <wtf/Vector.h>

#if PLATFORM(MAC)
#include <wtf/RetainPtr.h>
#elif PLATFORM(WIN) && !OS(WINCE)
#include "AccessibilityObjectWrapperWin.h"
#include "COMPtr.h"
#elif PLATFORM(CHROMIUM)
#include "AccessibilityObjectWrapper.h"
#endif

typedef struct _NSRange NSRange;

#ifdef __OBJC__
@class AccessibilityObjectWrapper;
@class NSArray;
@class NSAttributedString;
@class NSData;
@class NSMutableAttributedString;
@class NSString;
@class NSValue;
@class NSView;
#else
class NSArray;
class NSAttributedString;
class NSData;
class NSMutableAttributedString;
class NSString;
class NSValue;
class NSView;
#if PLATFORM(GTK)
typedef struct _AtkObject AtkObject;
typedef struct _AtkObject AccessibilityObjectWrapper;
#else
class AccessibilityObjectWrapper;
#endif
#endif

namespace WebCore {

class AXObjectCache;
class Element;
class Frame;
class FrameView;
class HTMLAnchorElement;
class HTMLAreaElement;
class IntPoint;
class IntSize;
class Node;
class RenderObject;
class RenderListItem;
class VisibleSelection;
class Widget;

typedef unsigned AXID;

enum AccessibilityRole {
    UnknownRole = 1,
    ButtonRole,
    RadioButtonRole,
    CheckBoxRole,
    SliderRole,
    TabGroupRole,
    TextFieldRole,
    StaticTextRole,
    TextAreaRole,
    ScrollAreaRole,
    PopUpButtonRole,
    MenuButtonRole,
    TableRole,
    ApplicationRole,
    GroupRole,
    RadioGroupRole,
    ListRole,
    ScrollBarRole,
    ValueIndicatorRole,
    ImageRole,
    MenuBarRole,
    MenuRole,
    MenuItemRole,
    ColumnRole,
    RowRole,
    ToolbarRole,
    BusyIndicatorRole,
    ProgressIndicatorRole,
    WindowRole,
    DrawerRole,
    SystemWideRole,
    OutlineRole,
    IncrementorRole,
    BrowserRole,
    ComboBoxRole,
    SplitGroupRole,
    SplitterRole,
    ColorWellRole,
    GrowAreaRole,
    SheetRole,
    HelpTagRole,
    MatteRole,
    RulerRole,
    RulerMarkerRole,
    LinkRole,
    DisclosureTriangleRole,
    GridRole,
    CellRole,
    ColumnHeaderRole,
    RowHeaderRole,
    // AppKit includes SortButtonRole but it is misnamed and really a subrole of ButtonRole so we do not include it here.

    // WebCore-specific roles
    WebCoreLinkRole,
    ImageMapLinkRole,
    ImageMapRole,
    ListMarkerRole,
    WebAreaRole,
    HeadingRole,
    ListBoxRole,
    ListBoxOptionRole,
    TableHeaderContainerRole,
    DefinitionListTermRole,
    DefinitionListDefinitionRole,
    AnnotationRole,
    SliderThumbRole,
    IgnoredRole,
    PresentationalRole,
    TabRole,
    TabListRole,
    TabPanelRole,
    TreeRole,
    TreeGridRole,
    TreeItemRole,
    DirectoryRole,
    EditableTextRole,
    ListItemRole,
    MenuListPopupRole,
    MenuListOptionRole,
    ParagraphRole,
    LabelRole,
    DivRole,
    FormRole,

    // ARIA Grouping roles
    LandmarkApplicationRole,
    LandmarkBannerRole,
    LandmarkComplementaryRole,
    LandmarkContentInfoRole,
    LandmarkMainRole,
    LandmarkNavigationRole,
    LandmarkSearchRole,

    ApplicationAlertRole,
    ApplicationAlertDialogRole,
    ApplicationDialogRole,
    ApplicationLogRole,
    ApplicationMarqueeRole,
    ApplicationStatusRole,
    ApplicationTimerRole,

    DocumentRole,
    DocumentArticleRole,
    DocumentMathRole,
    DocumentNoteRole,
    DocumentRegionRole,

    UserInterfaceTooltipRole
};

enum AccessibilityOrientation {
    AccessibilityOrientationVertical,
    AccessibilityOrientationHorizontal,
};

enum AccessibilityObjectInclusion {
    IncludeObject,
    IgnoreObject,
    DefaultBehavior,
};

enum AccessibilityButtonState {
    ButtonStateOff = 0,
    ButtonStateOn,
    ButtonStateMixed,
};

enum AccessibilitySortDirection {
    SortDirectionNone,
    SortDirectionAscending,
    SortDirectionDescending,
};

struct VisiblePositionRange {

    VisiblePosition start;
    VisiblePosition end;

    VisiblePositionRange() {}

    VisiblePositionRange(const VisiblePosition& s, const VisiblePosition& e)
        : start(s)
        , end(e)
    { }

    bool isNull() const { return start.isNull() || end.isNull(); }
};

struct PlainTextRange {

    unsigned start;
    unsigned length;

    PlainTextRange()
        : start(0)
        , length(0)
    { }

    PlainTextRange(unsigned s, unsigned l)
        : start(s)
        , length(l)
    { }

    bool isNull() const { return !start && !length; }
};

class AccessibilityObject : public RefCounted<AccessibilityObject> {
protected:
    AccessibilityObject();
public:
    virtual ~AccessibilityObject();
    virtual void detach();

    typedef Vector<RefPtr<AccessibilityObject> > AccessibilityChildrenVector;

    virtual bool isAccessibilityRenderObject() const { return false; }
    virtual bool isAccessibilityScrollbar() const { return false; }
    virtual bool isAccessibilityScrollView() const { return false; }

    virtual bool isAnchor() const { return false; }
    virtual bool isAttachment() const { return false; }
    virtual bool isHeading() const { return false; }
    virtual bool isLink() const { return false; }
    virtual bool isImage() const { return false; }
    virtual bool isNativeImage() const { return false; }
    virtual bool isImageButton() const { return false; }
    virtual bool isPasswordField() const { return false; }
    virtual bool isNativeTextControl() const { return false; }
    virtual bool isWebArea() const { return false; }
    virtual bool isCheckbox() const { return roleValue() == CheckBoxRole; }
    virtual bool isRadioButton() const { return roleValue() == RadioButtonRole; }
    virtual bool isListBox() const { return roleValue() == ListBoxRole; }
    virtual bool isMediaTimeline() const { return false; }
    virtual bool isMenuRelated() const { return false; }
    virtual bool isMenu() const { return false; }
    virtual bool isMenuBar() const { return false; }
    virtual bool isMenuButton() const { return false; }
    virtual bool isMenuItem() const { return false; }
    virtual bool isFileUploadButton() const { return false; }
    virtual bool isInputImage() const { return false; }
    virtual bool isProgressIndicator() const { return false; }
    virtual bool isSlider() const { return false; }
    virtual bool isInputSlider() const { return false; }
    virtual bool isControl() const { return false; }
    virtual bool isList() const { return false; }
    virtual bool isAccessibilityTable() const { return false; }
    virtual bool isDataTable() const { return false; }
    virtual bool isTableRow() const { return false; }
    virtual bool isTableColumn() const { return false; }
    virtual bool isTableCell() const { return false; }
    virtual bool isFieldset() const { return false; }
    virtual bool isGroup() const { return false; }
    virtual bool isARIATreeGridRow() const { return false; }
    virtual bool isImageMapLink() const { return false; }
    virtual bool isMenuList() const { return false; }
    virtual bool isMenuListPopup() const { return false; }
    virtual bool isMenuListOption() const { return false; }
    bool isTextControl() const { return roleValue() == TextAreaRole || roleValue() == TextFieldRole; }
    bool isTabList() const { return roleValue() == TabListRole; }
    bool isTabItem() const { return roleValue() == TabRole; }
    bool isRadioGroup() const { return roleValue() == RadioGroupRole; }
    bool isComboBox() const { return roleValue() == ComboBoxRole; }
    bool isTree() const { return roleValue() == TreeRole; }
    bool isTreeItem() const { return roleValue() == TreeItemRole; }
    bool isScrollbar() const { return roleValue() == ScrollBarRole; }
    bool isButton() const { return roleValue() == ButtonRole; }
    bool isListItem() const { return roleValue() == ListItemRole; }
    bool isCheckboxOrRadio() const { return isCheckbox() || isRadioButton(); }
    bool isScrollView() const { return roleValue() == ScrollAreaRole; }

    virtual bool isChecked() const { return false; }
    virtual bool isEnabled() const { return false; }
    virtual bool isSelected() const { return false; }
    virtual bool isFocused() const { return false; }
    virtual bool isHovered() const { return false; }
    virtual bool isIndeterminate() const { return false; }
    virtual bool isLoaded() const { return false; }
    virtual bool isMultiSelectable() const { return false; }
    virtual bool isOffScreen() const { return false; }
    virtual bool isPressed() const { return false; }
    virtual bool isReadOnly() const { return false; }
    virtual bool isVisited() const { return false; }
    virtual bool isRequired() const { return false; }
    virtual bool isLinked() const { return false; }
    virtual bool isExpanded() const;
    virtual bool isVisible() const { return true; }
    virtual bool isCollapsed() const { return false; }
    virtual void setIsExpanded(bool) { }

    virtual bool canSetFocusAttribute() const { return false; }
    virtual bool canSetTextRangeAttributes() const { return false; }
    virtual bool canSetValueAttribute() const { return false; }
    virtual bool canSetNumericValue() const { return false; }
    virtual bool canSetSelectedAttribute() const { return false; }
    virtual bool canSetSelectedChildrenAttribute() const { return false; }
    virtual bool canSetExpandedAttribute() const { return false; }

    // A programmatic way to set a name on an AccessibleObject.
    virtual void setAccessibleName(String&) { }

    virtual Node* node() const { return 0; }
    virtual RenderObject* renderer() const { return 0; }
    virtual bool accessibilityIsIgnored() const  { return true; }

    virtual int headingLevel() const { return 0; }
    virtual AccessibilityButtonState checkboxOrRadioValue() const;
    virtual String valueDescription() const { return String(); }
    virtual float valueForRange() const { return 0.0f; }
    virtual float maxValueForRange() const { return 0.0f; }
    virtual float minValueForRange() const { return 0.0f; }
    virtual AccessibilityObject* selectedRadioButton() { return 0; }
    virtual AccessibilityObject* selectedTabItem() { return 0; }
    virtual int layoutCount() const { return 0; }
    virtual double estimatedLoadingProgress() const { return 0; }
    static bool isARIAControl(AccessibilityRole);
    static bool isARIAInput(AccessibilityRole);
    virtual bool supportsARIAOwns() const { return false; }
    virtual void ariaOwnsElements(AccessibilityChildrenVector&) const { }
    virtual bool supportsARIAFlowTo() const { return false; }
    virtual void ariaFlowToElements(AccessibilityChildrenVector&) const { }
    virtual bool ariaHasPopup() const { return false; }
    bool ariaIsMultiline() const;
    virtual const AtomicString& invalidStatus() const;
    bool supportsARIAExpanded() const;
    AccessibilitySortDirection sortDirection() const;

    // ARIA drag and drop
    virtual bool supportsARIADropping() const { return false; }
    virtual bool supportsARIADragging() const { return false; }
    virtual bool isARIAGrabbed() { return false; }
    virtual void setARIAGrabbed(bool) { }
    virtual void determineARIADropEffects(Vector<String>&) { }

    // Called on the root AX object to return the deepest available element.
    virtual AccessibilityObject* accessibilityHitTest(const IntPoint&) const { return 0; }
    // Called on the AX object after the render tree determines which is the right AccessibilityRenderObject.
    virtual AccessibilityObject* elementAccessibilityHitTest(const IntPoint&) const;

    virtual AccessibilityObject* focusedUIElement() const;

    virtual AccessibilityObject* firstChild() const { return 0; }
    virtual AccessibilityObject* lastChild() const { return 0; }
    virtual AccessibilityObject* previousSibling() const { return 0; }
    virtual AccessibilityObject* nextSibling() const { return 0; }
    virtual AccessibilityObject* parentObject() const = 0;
    virtual AccessibilityObject* parentObjectUnignored() const;
    virtual AccessibilityObject* parentObjectIfExists() const { return 0; }
    static AccessibilityObject* firstAccessibleObjectFromNode(const Node*);

    virtual AccessibilityObject* observableObject() const { return 0; }
    virtual void linkedUIElements(AccessibilityChildrenVector&) const { }
    virtual AccessibilityObject* titleUIElement() const { return 0; }
    virtual bool exposesTitleUIElement() const { return true; }
    virtual AccessibilityObject* correspondingLabelForControlElement() const { return 0; }
    virtual AccessibilityObject* correspondingControlForLabelElement() const { return 0; }
    virtual AccessibilityObject* scrollBar(AccessibilityOrientation) const { return 0; }

    virtual AccessibilityRole ariaRoleAttribute() const { return UnknownRole; }
    virtual bool isPresentationalChildOfAriaRole() const { return false; }
    virtual bool ariaRoleHasPresentationalChildren() const { return false; }

    void setRoleValue(AccessibilityRole role) { m_role = role; }
    virtual AccessibilityRole roleValue() const { return m_role; }
    virtual String ariaLabeledByAttribute() const { return String(); }
    virtual String ariaDescribedByAttribute() const { return String(); }
    virtual String accessibilityDescription() const { return String(); }

    virtual AXObjectCache* axObjectCache() const;
    AXID axObjectID() const { return m_id; }
    void setAXObjectID(AXID axObjectID) { m_id = axObjectID; }

    static AccessibilityObject* anchorElementForNode(Node*);
    virtual Element* anchorElement() const { return 0; }
    virtual Element* actionElement() const { return 0; }
    virtual IntRect boundingBoxRect() const { return IntRect(); }
    virtual IntRect elementRect() const = 0;
    virtual IntSize size() const { return elementRect().size(); }
    virtual IntPoint clickPoint() const;

    virtual PlainTextRange selectedTextRange() const { return PlainTextRange(); }
    unsigned selectionStart() const { return selectedTextRange().start; }
    unsigned selectionEnd() const { return selectedTextRange().length; }

    virtual KURL url() const { return KURL(); }
    virtual VisibleSelection selection() const { return VisibleSelection(); }
    virtual String stringValue() const { return String(); }
    virtual String title() const { return String(); }
    virtual String helpText() const { return String(); }
    virtual String textUnderElement() const { return String(); }
    virtual String text() const { return String(); }
    virtual int textLength() const { return 0; }
    virtual String selectedText() const { return String(); }
    virtual const AtomicString& accessKey() const { return nullAtom; }
    const String& actionVerb() const;
    virtual Widget* widget() const { return 0; }
    virtual Widget* widgetForAttachmentView() const { return 0; }
    virtual Document* document() const;
    virtual FrameView* topDocumentFrameView() const { return 0; }
    virtual FrameView* documentFrameView() const;
    String language() const;
    virtual unsigned hierarchicalLevel() const { return 0; }
    const AtomicString& placeholderValue() const;

    virtual void setFocused(bool) { }
    virtual void setSelectedText(const String&) { }
    virtual void setSelectedTextRange(const PlainTextRange&) { }
    virtual void setValue(const String&) { }
    virtual void setValue(float) { }
    virtual void setSelected(bool) { }
    virtual void setSelectedRows(AccessibilityChildrenVector&) { }

    virtual void makeRangeVisible(const PlainTextRange&) { }
    virtual bool press() const;
    bool performDefaultAction() const { return press(); }

    virtual AccessibilityOrientation orientation() const;
    virtual void increment() { }
    virtual void decrement() { }

    virtual void childrenChanged() { }
    virtual void contentChanged() { }
    virtual const AccessibilityChildrenVector& children() { return m_children; }
    virtual void addChildren() { }
    virtual bool canHaveChildren() const { return true; }
    virtual bool hasChildren() const { return m_haveChildren; }
    virtual void updateChildrenIfNecessary();
    virtual void selectedChildren(AccessibilityChildrenVector&) { }
    virtual void visibleChildren(AccessibilityChildrenVector&) { }
    virtual void tabChildren(AccessibilityChildrenVector&) { }
    virtual bool shouldFocusActiveDescendant() const { return false; }
    virtual AccessibilityObject* activeDescendant() const { return 0; }
    virtual void handleActiveDescendantChanged() { }
    virtual void handleAriaExpandedChanged() { }

    static AccessibilityRole ariaRoleToWebCoreRole(const String&);
    const AtomicString& getAttribute(const QualifiedName&) const;

    virtual VisiblePositionRange visiblePositionRange() const { return VisiblePositionRange(); }
    virtual VisiblePositionRange visiblePositionRangeForLine(unsigned) const { return VisiblePositionRange(); }

    VisiblePositionRange visiblePositionRangeForUnorderedPositions(const VisiblePosition&, const VisiblePosition&) const;
    VisiblePositionRange positionOfLeftWord(const VisiblePosition&) const;
    VisiblePositionRange positionOfRightWord(const VisiblePosition&) const;
    VisiblePositionRange leftLineVisiblePositionRange(const VisiblePosition&) const;
    VisiblePositionRange rightLineVisiblePositionRange(const VisiblePosition&) const;
    VisiblePositionRange sentenceForPosition(const VisiblePosition&) const;
    VisiblePositionRange paragraphForPosition(const VisiblePosition&) const;
    VisiblePositionRange styleRangeForPosition(const VisiblePosition&) const;
    VisiblePositionRange visiblePositionRangeForRange(const PlainTextRange&) const;

    String stringForVisiblePositionRange(const VisiblePositionRange&) const;
    virtual IntRect boundsForVisiblePositionRange(const VisiblePositionRange&) const { return IntRect(); }
    int lengthForVisiblePositionRange(const VisiblePositionRange&) const;
    virtual void setSelectedVisiblePositionRange(const VisiblePositionRange&) const { }

    virtual VisiblePosition visiblePositionForPoint(const IntPoint&) const { return VisiblePosition(); }
    VisiblePosition nextVisiblePosition(const VisiblePosition& visiblePos) const { return visiblePos.next(); }
    VisiblePosition previousVisiblePosition(const VisiblePosition& visiblePos) const { return visiblePos.previous(); }
    VisiblePosition nextWordEnd(const VisiblePosition&) const;
    VisiblePosition previousWordStart(const VisiblePosition&) const;
    VisiblePosition nextLineEndPosition(const VisiblePosition&) const;
    VisiblePosition previousLineStartPosition(const VisiblePosition&) const;
    VisiblePosition nextSentenceEndPosition(const VisiblePosition&) const;
    VisiblePosition previousSentenceStartPosition(const VisiblePosition&) const;
    VisiblePosition nextParagraphEndPosition(const VisiblePosition&) const;
    VisiblePosition previousParagraphStartPosition(const VisiblePosition&) const;
    virtual VisiblePosition visiblePositionForIndex(unsigned, bool /*lastIndexOK */) const { return VisiblePosition(); }

    virtual VisiblePosition visiblePositionForIndex(int) const { return VisiblePosition(); }
    virtual int indexForVisiblePosition(const VisiblePosition&) const { return 0; }

    AccessibilityObject* accessibilityObjectForPosition(const VisiblePosition&) const;
    int lineForPosition(const VisiblePosition&) const;
    PlainTextRange plainTextRangeForVisiblePositionRange(const VisiblePositionRange&) const;
    virtual int index(const VisiblePosition&) const { return -1; }

    virtual PlainTextRange doAXRangeForLine(unsigned) const { return PlainTextRange(); }
    PlainTextRange doAXRangeForPosition(const IntPoint&) const;
    virtual PlainTextRange doAXRangeForIndex(unsigned) const { return PlainTextRange(); }
    PlainTextRange doAXStyleRangeForIndex(unsigned) const;

    virtual String doAXStringForRange(const PlainTextRange&) const { return String(); }
    virtual IntRect doAXBoundsForRange(const PlainTextRange&) const { return IntRect(); }
    String listMarkerTextForNodeAndPosition(Node*, const VisiblePosition&) const;

    unsigned doAXLineForIndex(unsigned);

    virtual String stringValueForMSAA() const { return String(); }
    virtual String stringRoleForMSAA() const { return String(); }
    virtual String nameForMSAA() const { return String(); }
    virtual String descriptionForMSAA() const { return String(); }
    virtual AccessibilityRole roleValueForMSAA() const { return roleValue(); }

    // Used by an ARIA tree to get all its rows.
    void ariaTreeRows(AccessibilityChildrenVector&);
    // Used by an ARIA tree item to get all of its direct rows that it can disclose.
    void ariaTreeItemDisclosedRows(AccessibilityChildrenVector&);
    // Used by an ARIA tree item to get only its content, and not its child tree items and groups.
    void ariaTreeItemContent(AccessibilityChildrenVector&);

    // ARIA live-region features.
    bool supportsARIALiveRegion() const;
    bool isInsideARIALiveRegion() const;
    virtual const AtomicString& ariaLiveRegionStatus() const { return nullAtom; }
    virtual const AtomicString& ariaLiveRegionRelevant() const { return nullAtom; }
    virtual bool ariaLiveRegionAtomic() const { return false; }
    virtual bool ariaLiveRegionBusy() const { return false; }

    bool supportsARIAAttributes() const;

    // CSS3 Speech properties.
    virtual ESpeak speakProperty() const { return SpeakNormal; }

#if HAVE(ACCESSIBILITY)
#if PLATFORM(GTK)
    AccessibilityObjectWrapper* wrapper() const;
    void setWrapper(AccessibilityObjectWrapper*);
#else
    AccessibilityObjectWrapper* wrapper() const { return m_wrapper.get(); }
    void setWrapper(AccessibilityObjectWrapper* wrapper)
    {
        m_wrapper = wrapper;
    }
#endif
#endif

#if HAVE(ACCESSIBILITY)
    // a platform-specific method for determining if an attachment is ignored
    bool accessibilityIgnoreAttachment() const;
    // gives platforms the opportunity to indicate if and how an object should be included
    AccessibilityObjectInclusion accessibilityPlatformIncludesObject() const;
#else
    bool accessibilityIgnoreAttachment() const { return true; }
    AccessibilityObjectInclusion accessibilityPlatformIncludesObject() const { return DefaultBehavior; }
#endif

    // allows for an AccessibilityObject to update its render tree or perform
    // other operations update type operations
    virtual void updateBackingStore() { }

protected:
    AXID m_id;
    AccessibilityChildrenVector m_children;
    mutable bool m_haveChildren;
    AccessibilityRole m_role;

    virtual void clearChildren();
    virtual bool isDetached() const { return true; }

#if PLATFORM(GTK)
    bool allowsTextRanges() const;
    unsigned getLengthForTextRange() const;
#else
    bool allowsTextRanges() const { return isTextControl(); }
    unsigned getLengthForTextRange() const { return text().length(); }
#endif

#if PLATFORM(MAC)
    RetainPtr<AccessibilityObjectWrapper> m_wrapper;
#elif PLATFORM(WIN) && !OS(WINCE)
    COMPtr<AccessibilityObjectWrapper> m_wrapper;
#elif PLATFORM(GTK)
    AtkObject* m_wrapper;
#elif PLATFORM(CHROMIUM)
    RefPtr<AccessibilityObjectWrapper> m_wrapper;
#endif
};

} // namespace WebCore

#endif // AccessibilityObject_h