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      1 /*
      2  * Copyright (C) 2012, Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #ifndef AXNodeObject_h
     30 #define AXNodeObject_h
     31 
     32 #include "core/accessibility/AXObject.h"
     33 #include "platform/geometry/LayoutRect.h"
     34 #include "wtf/Forward.h"
     35 
     36 namespace WebCore {
     37 
     38 class AXObjectCache;
     39 class Element;
     40 class Frame;
     41 class FrameView;
     42 class HitTestResult;
     43 class HTMLAnchorElement;
     44 class HTMLAreaElement;
     45 class HTMLElement;
     46 class HTMLLabelElement;
     47 class HTMLMapElement;
     48 class HTMLSelectElement;
     49 class IntPoint;
     50 class IntSize;
     51 class Node;
     52 class RenderListBox;
     53 class RenderTextControl;
     54 class RenderView;
     55 class VisibleSelection;
     56 class Widget;
     57 
     58 class AXNodeObject : public AXObject {
     59 protected:
     60     explicit AXNodeObject(Node*);
     61 
     62 public:
     63     static PassRefPtr<AXNodeObject> create(Node*);
     64     virtual ~AXNodeObject();
     65 
     66 protected:
     67     // Protected data.
     68     AccessibilityRole m_ariaRole;
     69     bool m_childrenDirty;
     70 #ifndef NDEBUG
     71     bool m_initialized;
     72 #endif
     73 
     74     virtual bool computeAccessibilityIsIgnored() const OVERRIDE;
     75     virtual AccessibilityRole determineAccessibilityRole();
     76 
     77     String accessibilityDescriptionForElements(Vector<Element*> &elements) const;
     78     void alterSliderValue(bool increase);
     79     String ariaAccessibilityDescription() const;
     80     void ariaLabeledByElements(Vector<Element*>& elements) const;
     81     void changeValueByStep(bool increase);
     82     AccessibilityRole determineAriaRoleAttribute() const;
     83     void elementsFromAttribute(Vector<Element*>& elements, const QualifiedName&) const;
     84     bool hasContentEditableAttributeSet() const;
     85     bool isDescendantOfBarrenParent() const;
     86     // This returns true if it's focusable but it's not content editable and it's not a control or ARIA control.
     87     bool isGenericFocusableElement() const;
     88     HTMLLabelElement* labelForElement(Element*) const;
     89     AXObject* menuButtonForMenu() const;
     90     Element* menuItemElementForMenu() const;
     91     Element* mouseButtonListener() const;
     92     AccessibilityRole remapAriaRoleDueToParent(AccessibilityRole) const;
     93     bool isNativeCheckboxOrRadio() const;
     94     void setNode(Node*);
     95     AXObject* correspondingControlForLabelElement() const;
     96     HTMLLabelElement* labelElementContainer() const;
     97 
     98     //
     99     // Overridden from AXObject.
    100     //
    101 
    102     virtual void init() OVERRIDE;
    103     virtual void detach() OVERRIDE;
    104     virtual bool isDetached() const OVERRIDE { return !m_node; }
    105     virtual bool isAXNodeObject() const OVERRIDE { return true; }
    106 
    107     // Check object role or purpose.
    108     virtual bool isAnchor() const OVERRIDE;
    109     virtual bool isControl() const OVERRIDE;
    110     virtual bool isFieldset() const OVERRIDE;
    111     virtual bool isHeading() const OVERRIDE;
    112     virtual bool isHovered() const OVERRIDE;
    113     virtual bool isImage() const OVERRIDE;
    114     bool isImageButton() const;
    115     virtual bool isInputImage() const OVERRIDE;
    116     virtual bool isLink() const;
    117     virtual bool isMenu() const OVERRIDE;
    118     virtual bool isMenuButton() const OVERRIDE;
    119     virtual bool isMultiSelectable() const OVERRIDE;
    120     bool isNativeImage() const;
    121     virtual bool isNativeTextControl() const OVERRIDE;
    122     virtual bool isNonNativeTextControl() const OVERRIDE;
    123     virtual bool isPasswordField() const OVERRIDE;
    124     virtual bool isProgressIndicator() const OVERRIDE;
    125     virtual bool isSlider() const OVERRIDE;
    126 
    127     // Check object state.
    128     virtual bool isChecked() const OVERRIDE;
    129     virtual bool isClickable() const OVERRIDE;
    130     virtual bool isEnabled() const OVERRIDE;
    131     virtual bool isIndeterminate() const OVERRIDE;
    132     virtual bool isPressed() const OVERRIDE;
    133     virtual bool isReadOnly() const OVERRIDE;
    134     virtual bool isRequired() const OVERRIDE;
    135 
    136     // Check whether certain properties can be modified.
    137     virtual bool canSetFocusAttribute() const OVERRIDE;
    138     virtual bool canSetValueAttribute() const OVERRIDE;
    139 
    140     // Properties of static elements.
    141     virtual bool canvasHasFallbackContent() const OVERRIDE;
    142     virtual bool exposesTitleUIElement() const OVERRIDE;
    143     virtual int headingLevel() const OVERRIDE;
    144     virtual unsigned hierarchicalLevel() const OVERRIDE;
    145     virtual String text() const OVERRIDE;
    146     virtual AXObject* titleUIElement() const OVERRIDE;
    147 
    148     // Properties of interactive elements.
    149     virtual AccessibilityButtonState checkboxOrRadioValue() const OVERRIDE;
    150     virtual void colorValue(int& r, int& g, int& b) const OVERRIDE;
    151     virtual String valueDescription() const OVERRIDE;
    152     virtual float valueForRange() const OVERRIDE;
    153     virtual float maxValueForRange() const OVERRIDE;
    154     virtual float minValueForRange() const OVERRIDE;
    155     virtual String stringValue() const OVERRIDE;
    156 
    157     // ARIA attributes.
    158     virtual String ariaDescribedByAttribute() const;
    159     virtual String ariaLabeledByAttribute() const OVERRIDE;
    160     virtual AccessibilityRole ariaRoleAttribute() const OVERRIDE;
    161 
    162     // Accessibility Text.
    163     virtual void accessibilityText(Vector<AccessibilityText>&) OVERRIDE;
    164     virtual String textUnderElement() const OVERRIDE;
    165 
    166     // Accessibility Text - (To be deprecated).
    167     virtual String accessibilityDescription() const OVERRIDE;
    168     virtual String title() const OVERRIDE;
    169     virtual String helpText() const OVERRIDE;
    170 
    171     // Location and click point in frame-relative coordinates.
    172     virtual LayoutRect elementRect() const OVERRIDE;
    173 
    174     // High-level accessibility tree access.
    175     virtual AXObject* parentObject() const OVERRIDE;
    176     virtual AXObject* parentObjectIfExists() const OVERRIDE;
    177 
    178     // Low-level accessibility tree exploration.
    179     virtual AXObject* firstChild() const OVERRIDE;
    180     virtual AXObject* nextSibling() const OVERRIDE;
    181     virtual void addChildren() OVERRIDE;
    182     virtual bool canHaveChildren() const OVERRIDE;
    183     void addChild(AXObject*);
    184     void insertChild(AXObject*, unsigned index);
    185 
    186     // DOM and Render tree access.
    187     virtual Element* actionElement() const OVERRIDE;
    188     virtual Element* anchorElement() const OVERRIDE;
    189     virtual Document* document() const OVERRIDE;
    190     virtual Node* node() const OVERRIDE { return m_node; }
    191 
    192     // Modify or take an action on an object.
    193     virtual void setFocused(bool) OVERRIDE;
    194     virtual void increment() OVERRIDE;
    195     virtual void decrement() OVERRIDE;
    196 
    197     // Notifications that this object may have changed.
    198     virtual void childrenChanged() OVERRIDE;
    199     virtual void selectionChanged() OVERRIDE;
    200     virtual void textChanged() OVERRIDE;
    201     virtual void updateAccessibilityRole() OVERRIDE;
    202 
    203 private:
    204     Node* m_node;
    205 
    206     String alternativeTextForWebArea() const;
    207     void alternativeText(Vector<AccessibilityText>&) const;
    208     void ariaLabeledByText(Vector<AccessibilityText>&) const;
    209     void changeValueByPercent(float percentChange);
    210     void helpText(Vector<AccessibilityText>&) const;
    211     void titleElementText(Vector<AccessibilityText>&);
    212     void visibleText(Vector<AccessibilityText>&) const;
    213     float stepValueForRange() const;
    214 };
    215 
    216 DEFINE_AX_OBJECT_TYPE_CASTS(AXNodeObject, isAXNodeObject());
    217 
    218 } // namespace WebCore
    219 
    220 #endif // AXNodeObject_h
    221