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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 AccessibilityNodeObject_h
     30 #define AccessibilityNodeObject_h
     31 
     32 #include "core/accessibility/AccessibilityObject.h"
     33 #include "core/platform/graphics/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 AccessibilityNodeObject : public AccessibilityObject {
     59 protected:
     60     explicit AccessibilityNodeObject(Node*);
     61 
     62 public:
     63     static PassRefPtr<AccessibilityNodeObject> create(Node*);
     64     virtual ~AccessibilityNodeObject();
     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 isARIARange() const;
     86     bool isDescendantOfBarrenParent() const;
     87     // This returns true if it's focusable but it's not content editable and it's not a control or ARIA control.
     88     bool isGenericFocusableElement() const;
     89     HTMLLabelElement* labelForElement(Element*) const;
     90     AccessibilityObject* menuButtonForMenu() const;
     91     Element* menuItemElementForMenu() const;
     92     Element* mouseButtonListener() const;
     93     AccessibilityRole remapAriaRoleDueToParent(AccessibilityRole) const;
     94     bool isNativeCheckboxOrRadio() const;
     95     void setNode(Node*);
     96 
     97     //
     98     // Overridden from AccessibilityObject.
     99     //
    100 
    101     virtual void init() OVERRIDE;
    102     virtual void detach() OVERRIDE;
    103     virtual bool isDetached() const OVERRIDE { return !m_node; }
    104     virtual bool isAccessibilityNodeObject() const OVERRIDE { return true; }
    105 
    106     // Check object role or purpose.
    107     virtual bool isAnchor() const OVERRIDE;
    108     virtual bool isControl() const OVERRIDE;
    109     virtual bool isFieldset() const OVERRIDE;
    110     virtual bool isHeading() const OVERRIDE;
    111     virtual bool isHovered() const OVERRIDE;
    112     virtual bool isImage() const OVERRIDE;
    113     bool isImageButton() const;
    114     virtual bool isInputImage() const OVERRIDE;
    115     virtual bool isLink() const;
    116     virtual bool isMenu() const OVERRIDE;
    117     virtual bool isMenuButton() const OVERRIDE;
    118     virtual bool isMultiSelectable() const OVERRIDE;
    119     bool isNativeImage() const;
    120     virtual bool isNativeTextControl() const OVERRIDE;
    121     virtual bool isNonNativeTextControl() const OVERRIDE;
    122     virtual bool isPasswordField() const OVERRIDE;
    123     virtual bool isProgressIndicator() const OVERRIDE;
    124     virtual bool isSlider() const OVERRIDE;
    125 
    126     // Check object state.
    127     virtual bool isChecked() const OVERRIDE;
    128     virtual bool isEnabled() const OVERRIDE;
    129     virtual bool isIndeterminate() const OVERRIDE;
    130     virtual bool isPressed() const OVERRIDE;
    131     virtual bool isReadOnly() const OVERRIDE;
    132     virtual bool isRequired() const OVERRIDE;
    133 
    134     // Check whether certain properties can be modified.
    135     virtual bool canSetFocusAttribute() const OVERRIDE;
    136 
    137     // Properties of static elements.
    138     virtual bool canvasHasFallbackContent() const OVERRIDE;
    139     virtual int headingLevel() const OVERRIDE;
    140     virtual unsigned hierarchicalLevel() const OVERRIDE;
    141     virtual String text() const OVERRIDE;
    142 
    143     // Properties of interactive elements.
    144     virtual AccessibilityButtonState checkboxOrRadioValue() const OVERRIDE;
    145     virtual void colorValue(int& r, int& g, int& b) const OVERRIDE;
    146     virtual String valueDescription() const OVERRIDE;
    147     virtual float valueForRange() const OVERRIDE;
    148     virtual float maxValueForRange() const OVERRIDE;
    149     virtual float minValueForRange() const OVERRIDE;
    150     virtual String stringValue() const OVERRIDE;
    151 
    152     // ARIA attributes.
    153     virtual String ariaDescribedByAttribute() const;
    154     virtual String ariaLabeledByAttribute() const OVERRIDE;
    155     virtual AccessibilityRole ariaRoleAttribute() const OVERRIDE;
    156 
    157     // Accessibility Text.
    158     virtual void accessibilityText(Vector<AccessibilityText>&) OVERRIDE;
    159     virtual String textUnderElement() const OVERRIDE;
    160 
    161     // Accessibility Text - (To be deprecated).
    162     virtual String accessibilityDescription() const OVERRIDE;
    163     virtual String title() const OVERRIDE;
    164     virtual String helpText() const OVERRIDE;
    165 
    166     // Location and click point in frame-relative coordinates.
    167     virtual LayoutRect elementRect() const OVERRIDE;
    168 
    169     // High-level accessibility tree access.
    170     virtual AccessibilityObject* parentObject() const OVERRIDE;
    171     virtual AccessibilityObject* parentObjectIfExists() const OVERRIDE;
    172 
    173     // Low-level accessibility tree exploration.
    174     virtual AccessibilityObject* firstChild() const OVERRIDE;
    175     virtual AccessibilityObject* nextSibling() const OVERRIDE;
    176     virtual void addChildren() OVERRIDE;
    177     virtual bool canHaveChildren() const OVERRIDE;
    178     void addChild(AccessibilityObject*);
    179     void insertChild(AccessibilityObject*, unsigned index);
    180 
    181     // DOM and Render tree access.
    182     virtual Element* actionElement() const OVERRIDE;
    183     virtual Element* anchorElement() const OVERRIDE;
    184     virtual Document* document() const OVERRIDE;
    185     virtual Node* node() const OVERRIDE { return m_node; }
    186 
    187     // Modify or take an action on an object.
    188     virtual void increment() OVERRIDE;
    189     virtual void decrement() OVERRIDE;
    190 
    191     // Notifications that this object may have changed.
    192     virtual void childrenChanged() OVERRIDE;
    193     virtual void selectionChanged() OVERRIDE;
    194     virtual void textChanged() OVERRIDE;
    195     virtual void updateAccessibilityRole() OVERRIDE;
    196 
    197 private:
    198     Node* m_node;
    199 
    200     String alternativeTextForWebArea() const;
    201     void alternativeText(Vector<AccessibilityText>&) const;
    202     void ariaLabeledByText(Vector<AccessibilityText>&) const;
    203     void changeValueByPercent(float percentChange);
    204     void helpText(Vector<AccessibilityText>&) const;
    205     void titleElementText(Vector<AccessibilityText>&);
    206     void visibleText(Vector<AccessibilityText>&) const;
    207     float stepValueForRange() const;
    208 };
    209 
    210 inline AccessibilityNodeObject* toAccessibilityNodeObject(AccessibilityObject* object)
    211 {
    212     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isAccessibilityNodeObject());
    213     return static_cast<AccessibilityNodeObject*>(object);
    214 }
    215 
    216 inline const AccessibilityNodeObject* toAccessibilityNodeObject(const AccessibilityObject* object)
    217 {
    218     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isAccessibilityNodeObject());
    219     return static_cast<const AccessibilityNodeObject*>(object);
    220 }
    221 
    222 // This will catch anyone doing an unnecessary cast.
    223 void toAccessibilityNodeObject(const AccessibilityNodeObject*);
    224 
    225 } // namespace WebCore
    226 
    227 #endif // AccessibilityNodeObject_h
    228