Source/WebKit/win/AccessibleBase.cpp - platform/external/webkit - Git at Google

 /*
  * Copyright (C) 2008, 2009, 2010 Apple Inc. All Rights Reserved.
  *
  * 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.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 INC. OR
  * 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.
  */

 #include "config.h"
 #include "WebKitDLL.h"
 #include "AccessibleBase.h"

 #include "AccessibleImage.h"
 #include "WebView.h"
 #include <WebCore/AccessibilityListBox.h>
 #include <WebCore/AccessibilityMenuListPopup.h>
 #include <WebCore/AccessibilityObject.h>
 #include <WebCore/AXObjectCache.h>
 #include <WebCore/BString.h>
 #include <WebCore/Element.h>
 #include <WebCore/EventHandler.h>
 #include <WebCore/FrameView.h>
 #include <WebCore/HostWindow.h>
 #include <WebCore/HTMLNames.h>
 #include <WebCore/HTMLFrameElementBase.h>
 #include <WebCore/HTMLInputElement.h>
 #include <WebCore/IntRect.h>
 #include <WebCore/PlatformKeyboardEvent.h>
 #include <WebCore/RenderFrame.h>
 #include <WebCore/RenderObject.h>
 #include <WebCore/RenderView.h>
 #include <oleacc.h>
 #include <wtf/RefPtr.h>

 using namespace WebCore;

 AccessibleBase::AccessibleBase(AccessibilityObject* obj)
     : AccessibilityObjectWrapper(obj)
     , m_refCount(0)
 {
     ASSERT_ARG(obj, obj);
     m_object->setWrapper(this);
     ++gClassCount;
     gClassNameCount.add("AccessibleBase");
 }

 AccessibleBase::~AccessibleBase()
 {
     --gClassCount;
     gClassNameCount.remove("AccessibleBase");
 }

 AccessibleBase* AccessibleBase::createInstance(AccessibilityObject* obj)
 {
     ASSERT_ARG(obj, obj);

     if (obj->isImage())
         return new AccessibleImage(obj);

     return new AccessibleBase(obj);
 }

 HRESULT AccessibleBase::QueryService(REFGUID guidService, REFIID riid, void **ppvObject)
 {
     if (!IsEqualGUID(guidService, SID_AccessibleComparable)) {
         *ppvObject = 0;
         return E_INVALIDARG;
     }
     return QueryInterface(riid, ppvObject);
 }

 // IUnknown
 HRESULT STDMETHODCALLTYPE AccessibleBase::QueryInterface(REFIID riid, void** ppvObject)
 {
     if (IsEqualGUID(riid, __uuidof(IAccessible)))
         *ppvObject = static_cast<IAccessible*>(this);
     else if (IsEqualGUID(riid, __uuidof(IDispatch)))
         *ppvObject = static_cast<IAccessible*>(this);
     else if (IsEqualGUID(riid, __uuidof(IUnknown)))
         *ppvObject = static_cast<IAccessible*>(this);
     else if (IsEqualGUID(riid, __uuidof(IAccessibleComparable)))
         *ppvObject = static_cast<IAccessibleComparable*>(this);
     else if (IsEqualGUID(riid, __uuidof(IServiceProvider)))
         *ppvObject = static_cast<IServiceProvider*>(this);
     else if (IsEqualGUID(riid, __uuidof(AccessibleBase)))
         *ppvObject = static_cast<AccessibleBase*>(this);
     else {
         *ppvObject = 0;
         return E_NOINTERFACE;
     }
     AddRef();
     return S_OK;
 }

 ULONG STDMETHODCALLTYPE AccessibleBase::Release(void)
 {
     ASSERT(m_refCount > 0);
     if (--m_refCount)
         return m_refCount;
     delete this;
     return 0;
 }

 // IAccessible
 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accParent(IDispatch** parent)
 {
     *parent = 0;

     if (!m_object)
         return E_FAIL;

     AccessibilityObject* parentObject = m_object->parentObjectUnignored();
     if (parentObject) {
         *parent = wrapper(parentObject);
         (*parent)->AddRef();
         return S_OK;
     }

     if (!m_object->topDocumentFrameView())
         return E_FAIL;

     return WebView::AccessibleObjectFromWindow(m_object->topDocumentFrameView()->hostWindow()->platformPageClient(),
         OBJID_WINDOW, __uuidof(IAccessible), reinterpret_cast<void**>(parent));
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accChildCount(long* count)
 {
     if (!m_object)
         return E_FAIL;
     if (!count)
         return E_POINTER;
     *count = static_cast<long>(m_object->children().size());
     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accChild(VARIANT vChild, IDispatch** ppChild)
 {
     if (!ppChild)
         return E_POINTER;

     *ppChild = 0;

     AccessibilityObject* childObj;

     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);
     if (FAILED(hr))
         return hr;

     *ppChild = static_cast<IDispatch*>(wrapper(childObj));
     (*ppChild)->AddRef();
     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accName(VARIANT vChild, BSTR* name)
 {
     if (!name)
         return E_POINTER;

     *name = 0;

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     if (*name = BString(wrapper(childObj)->name()).release())
         return S_OK;
     return S_FALSE;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accValue(VARIANT vChild, BSTR* value)
 {
     if (!value)
         return E_POINTER;

     *value = 0;

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     if (*value = BString(wrapper(childObj)->value()).release())
         return S_OK;
     return S_FALSE;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accDescription(VARIANT vChild, BSTR* description)
 {
     if (!description)
         return E_POINTER;

     *description = 0;

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     if (*description = BString(childObj->descriptionForMSAA()).release())
         return S_OK;

     return S_FALSE;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accRole(VARIANT vChild, VARIANT* pvRole)
 {
     if (!pvRole)
         return E_POINTER;

     ::VariantInit(pvRole);

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     String roleString = childObj->stringRoleForMSAA();
     if (!roleString.isEmpty()) {
         V_VT(pvRole) = VT_BSTR;
         V_BSTR(pvRole) = BString(roleString).release();
         return S_OK;
     }

     pvRole->vt = VT_I4;
     pvRole->lVal = wrapper(childObj)->role();
     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accState(VARIANT vChild, VARIANT* pvState)
 {
     if (!pvState)
         return E_POINTER;

     ::VariantInit(pvState);

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     pvState->vt = VT_I4;
     pvState->lVal = 0;

     if (childObj->isLinked())
         pvState->lVal |= STATE_SYSTEM_LINKED;

     if (childObj->isHovered())
         pvState->lVal |= STATE_SYSTEM_HOTTRACKED;

     if (!childObj->isEnabled())
         pvState->lVal |= STATE_SYSTEM_UNAVAILABLE;

     if (childObj->isReadOnly())
         pvState->lVal |= STATE_SYSTEM_READONLY;

     if (childObj->isOffScreen())
         pvState->lVal |= STATE_SYSTEM_OFFSCREEN;

     if (childObj->isPasswordField())
         pvState->lVal |= STATE_SYSTEM_PROTECTED;

     if (childObj->isIndeterminate())
         pvState->lVal |= STATE_SYSTEM_INDETERMINATE;

     if (childObj->isChecked())
         pvState->lVal |= STATE_SYSTEM_CHECKED;

     if (childObj->isPressed())
         pvState->lVal |= STATE_SYSTEM_PRESSED;

     if (childObj->isFocused())
         pvState->lVal |= STATE_SYSTEM_FOCUSED;

     if (childObj->isVisited())
         pvState->lVal |= STATE_SYSTEM_TRAVERSED;

     if (childObj->canSetFocusAttribute())
         pvState->lVal |= STATE_SYSTEM_FOCUSABLE;

     if (childObj->isSelected())
         pvState->lVal |= STATE_SYSTEM_SELECTED;

     if (childObj->canSetSelectedAttribute())
         pvState->lVal |= STATE_SYSTEM_SELECTABLE;

     if (childObj->isMultiSelectable())
         pvState->lVal |= STATE_SYSTEM_EXTSELECTABLE | STATE_SYSTEM_MULTISELECTABLE;

     if (!childObj->isVisible())
         pvState->lVal |= STATE_SYSTEM_INVISIBLE;

     if (childObj->isCollapsed())
         pvState->lVal |= STATE_SYSTEM_COLLAPSED;

     if (childObj->roleValue() == PopUpButtonRole) {
         pvState->lVal |= STATE_SYSTEM_HASPOPUP;

         if (!childObj->isCollapsed())
             pvState->lVal |= STATE_SYSTEM_EXPANDED;
     }

     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accHelp(VARIANT vChild, BSTR* helpText)
 {
     if (!helpText)
         return E_POINTER;

     *helpText = 0;

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     if (*helpText = BString(childObj->helpText()).release())
         return S_OK;
     return S_FALSE;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accKeyboardShortcut(VARIANT vChild, BSTR* shortcut)
 {
     if (!shortcut)
         return E_POINTER;

     *shortcut = 0;

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     String accessKey = childObj->accessKey();
     if (accessKey.isNull())
         return S_FALSE;

     static String accessKeyModifiers;
     if (accessKeyModifiers.isNull()) {
         unsigned modifiers = EventHandler::accessKeyModifiers();
         // Follow the same order as Mozilla MSAA implementation:
         // Ctrl+Alt+Shift+Meta+key. MSDN states that keyboard shortcut strings
         // should not be localized and defines the separator as "+".
         if (modifiers & PlatformKeyboardEvent::CtrlKey)
             accessKeyModifiers += "Ctrl+";
         if (modifiers & PlatformKeyboardEvent::AltKey)
             accessKeyModifiers += "Alt+";
         if (modifiers & PlatformKeyboardEvent::ShiftKey)
             accessKeyModifiers += "Shift+";
         if (modifiers & PlatformKeyboardEvent::MetaKey)
             accessKeyModifiers += "Win+";
     }
     *shortcut = BString(accessKeyModifiers + accessKey).release();
     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::accSelect(long selectionFlags, VARIANT vChild)
 {
     // According to MSDN, these combinations are invalid.
     if (((selectionFlags & (SELFLAG_ADDSELECTION | SELFLAG_REMOVESELECTION)) == (SELFLAG_ADDSELECTION | SELFLAG_REMOVESELECTION))
         || ((selectionFlags & (SELFLAG_ADDSELECTION | SELFLAG_TAKESELECTION)) == (SELFLAG_ADDSELECTION | SELFLAG_TAKESELECTION))
         || ((selectionFlags & (SELFLAG_REMOVESELECTION | SELFLAG_TAKESELECTION)) == (SELFLAG_REMOVESELECTION | SELFLAG_TAKESELECTION))
         || ((selectionFlags & (SELFLAG_EXTENDSELECTION | SELFLAG_TAKESELECTION)) == (SELFLAG_EXTENDSELECTION | SELFLAG_TAKESELECTION)))
         return E_INVALIDARG;

     AccessibilityObject* childObject;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObject);

     if (FAILED(hr))
         return hr;

     if (selectionFlags & SELFLAG_TAKEFOCUS)
         childObject->setFocused(true);

     AccessibilityObject* parentObject = childObject->parentObject();
     if (!parentObject)
         return E_INVALIDARG;

     if (selectionFlags & SELFLAG_TAKESELECTION) {
         if (parentObject->isListBox()) {
             Vector<RefPtr<AccessibilityObject> > selectedChildren(1);
             selectedChildren[0] = childObject;
             static_cast<AccessibilityListBox*>(parentObject)->setSelectedChildren(selectedChildren);
         } else { // any element may be selectable by virtue of it having the aria-selected property
             ASSERT(!parentObject->isMultiSelectable());
             childObject->setSelected(true);
         }
     }

     // MSDN says that ADD, REMOVE, and EXTENDSELECTION with no other flags are invalid for
     // single-select.
     const long allSELFLAGs = SELFLAG_TAKEFOCUS | SELFLAG_TAKESELECTION | SELFLAG_EXTENDSELECTION | SELFLAG_ADDSELECTION | SELFLAG_REMOVESELECTION;
     if (!parentObject->isMultiSelectable()
         && (((selectionFlags & allSELFLAGs) == SELFLAG_ADDSELECTION)
         || ((selectionFlags & allSELFLAGs) == SELFLAG_REMOVESELECTION)
         || ((selectionFlags & allSELFLAGs) == SELFLAG_EXTENDSELECTION)))
         return E_INVALIDARG;

     if (selectionFlags & SELFLAG_ADDSELECTION)
         childObject->setSelected(true);

     if (selectionFlags & SELFLAG_REMOVESELECTION)
         childObject->setSelected(false);

     // FIXME: Should implement SELFLAG_EXTENDSELECTION. For now, we just return
     // S_OK, matching Firefox.

     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accSelection(VARIANT*)
 {
     return E_NOTIMPL;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accFocus(VARIANT* pvFocusedChild)
 {
     if (!pvFocusedChild)
         return E_POINTER;

     ::VariantInit(pvFocusedChild);

     if (!m_object)
         return E_FAIL;

     AccessibilityObject* focusedObj = m_object->focusedUIElement();
     if (!focusedObj)
         return S_FALSE;

     if (focusedObj == m_object) {
         V_VT(pvFocusedChild) = VT_I4;
         V_I4(pvFocusedChild) = CHILDID_SELF;
         return S_OK;
     }

     V_VT(pvFocusedChild) = VT_DISPATCH;
     V_DISPATCH(pvFocusedChild) = wrapper(focusedObj);
     V_DISPATCH(pvFocusedChild)->AddRef();
     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::get_accDefaultAction(VARIANT vChild, BSTR* action)
 {
     if (!action)
         return E_POINTER;

     *action = 0;

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     if (*action = BString(childObj->actionVerb()).release())
         return S_OK;
     return S_FALSE;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::accLocation(long* left, long* top, long* width, long* height, VARIANT vChild)
 {
     if (!left || !top || !width || !height)
         return E_POINTER;

     *left = *top = *width = *height = 0;

     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     if (!childObj->documentFrameView())
         return E_FAIL;

     IntRect screenRect(childObj->documentFrameView()->contentsToScreen(childObj->elementRect()));
     *left = screenRect.x();
     *top = screenRect.y();
     *width = screenRect.width();
     *height = screenRect.height();
     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::accNavigate(long direction, VARIANT vFromChild, VARIANT* pvNavigatedTo)
 {
     if (!pvNavigatedTo)
         return E_POINTER;

     ::VariantInit(pvNavigatedTo);

     AccessibilityObject* childObj = 0;

     switch (direction) {
         case NAVDIR_DOWN:
         case NAVDIR_UP:
         case NAVDIR_LEFT:
         case NAVDIR_RIGHT:
             // These directions are not implemented, matching Mozilla and IE.
             return E_NOTIMPL;
         case NAVDIR_LASTCHILD:
         case NAVDIR_FIRSTCHILD:
             // MSDN states that navigating to first/last child can only be from self.
             if (vFromChild.lVal != CHILDID_SELF)
                 return E_INVALIDARG;

             if (!m_object)
                 return E_FAIL;

             if (direction == NAVDIR_FIRSTCHILD)
                 childObj = m_object->firstChild();
             else
                 childObj = m_object->lastChild();
             break;
         case NAVDIR_NEXT:
         case NAVDIR_PREVIOUS: {
             // Navigating to next and previous is allowed from self or any of our children.
             HRESULT hr = getAccessibilityObjectForChild(vFromChild, childObj);
             if (FAILED(hr))
                 return hr;

             if (direction == NAVDIR_NEXT)
                 childObj = childObj->nextSibling();
             else
                 childObj = childObj->previousSibling();
             break;
         }
         default:
             ASSERT_NOT_REACHED();
             return E_INVALIDARG;
     }

     if (!childObj)
         return S_FALSE;

     V_VT(pvNavigatedTo) = VT_DISPATCH;
     V_DISPATCH(pvNavigatedTo) = wrapper(childObj);
     V_DISPATCH(pvNavigatedTo)->AddRef();
     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::accHitTest(long x, long y, VARIANT* pvChildAtPoint)
 {
     if (!pvChildAtPoint)
         return E_POINTER;

     ::VariantInit(pvChildAtPoint);

     if (!m_object || !m_object->documentFrameView())
         return E_FAIL;

     IntPoint point = m_object->documentFrameView()->screenToContents(IntPoint(x, y));
     AccessibilityObject* childObj = m_object->accessibilityHitTest(point);

     if (!childObj) {
         // If we did not hit any child objects, test whether the point hit us, and
         // report that.
         if (!m_object->boundingBoxRect().contains(point))
             return S_FALSE;
         childObj = m_object;
     }

     if (childObj == m_object) {
         V_VT(pvChildAtPoint) = VT_I4;
         V_I4(pvChildAtPoint) = CHILDID_SELF;
     } else {
         V_VT(pvChildAtPoint) = VT_DISPATCH;
         V_DISPATCH(pvChildAtPoint) = static_cast<IDispatch*>(wrapper(childObj));
         V_DISPATCH(pvChildAtPoint)->AddRef();
     }
     return S_OK;
 }

 HRESULT STDMETHODCALLTYPE AccessibleBase::accDoDefaultAction(VARIANT vChild)
 {
     AccessibilityObject* childObj;
     HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

     if (FAILED(hr))
         return hr;

     if (!childObj->performDefaultAction())
         return S_FALSE;

     return S_OK;
 }

 // AccessibleBase
 String AccessibleBase::name() const
 {
     return m_object->nameForMSAA();
 }

 String AccessibleBase::value() const
 {
     return m_object->stringValueForMSAA();
 }

 static long MSAARole(AccessibilityRole role)
 {
     switch (role) {
         case WebCore::ButtonRole:
             return ROLE_SYSTEM_PUSHBUTTON;
         case WebCore::RadioButtonRole:
             return ROLE_SYSTEM_RADIOBUTTON;
         case WebCore::CheckBoxRole:
             return ROLE_SYSTEM_CHECKBUTTON;
         case WebCore::SliderRole:
             return ROLE_SYSTEM_SLIDER;
         case WebCore::TabGroupRole:
             return ROLE_SYSTEM_PAGETABLIST;
         case WebCore::TextFieldRole:
         case WebCore::TextAreaRole:
         case WebCore::EditableTextRole:
             return ROLE_SYSTEM_TEXT;
         case WebCore::ListMarkerRole:
         case WebCore::StaticTextRole:
             return ROLE_SYSTEM_STATICTEXT;
         case WebCore::OutlineRole:
             return ROLE_SYSTEM_OUTLINE;
         case WebCore::ColumnRole:
             return ROLE_SYSTEM_COLUMN;
         case WebCore::RowRole:
             return ROLE_SYSTEM_ROW;
         case WebCore::GroupRole:
             return ROLE_SYSTEM_GROUPING;
         case WebCore::ListRole:
         case WebCore::ListBoxRole:
         case WebCore::MenuListPopupRole:
             return ROLE_SYSTEM_LIST;
         case WebCore::TableRole:
             return ROLE_SYSTEM_TABLE;
         case WebCore::LinkRole:
         case WebCore::WebCoreLinkRole:
             return ROLE_SYSTEM_LINK;
         case WebCore::ImageMapRole:
         case WebCore::ImageRole:
             return ROLE_SYSTEM_GRAPHIC;
         case WebCore::MenuListOptionRole:
         case WebCore::ListItemRole:
         case WebCore::ListBoxOptionRole:
             return ROLE_SYSTEM_LISTITEM;
         case WebCore::PopUpButtonRole:
             return ROLE_SYSTEM_COMBOBOX;
         default:
             // This is the default role for MSAA.
             return ROLE_SYSTEM_CLIENT;
     }
 }

 long AccessibleBase::role() const
 {
     return MSAARole(m_object->roleValueForMSAA());
 }

 HRESULT AccessibleBase::getAccessibilityObjectForChild(VARIANT vChild, AccessibilityObject*& childObj) const
 {
     childObj = 0;

     if (!m_object)
         return E_FAIL;

     if (vChild.vt != VT_I4)
         return E_INVALIDARG;

     if (vChild.lVal == CHILDID_SELF)
         childObj = m_object;
     else if (vChild.lVal < 0) {
         // When broadcasting MSAA events, we negate the AXID and pass it as the
         // child ID.
         Document* document = m_object->document();
         if (!document)
             return E_FAIL;

         childObj = document->axObjectCache()->objectFromAXID(-vChild.lVal);
     } else {
         size_t childIndex = static_cast<size_t>(vChild.lVal - 1);

         if (childIndex >= m_object->children().size())
             return E_FAIL;
         childObj = m_object->children().at(childIndex).get();
     }

     if (!childObj)
         return E_FAIL;

     return S_OK;
 }

 AccessibleBase* AccessibleBase::wrapper(AccessibilityObject* obj)
 {
     AccessibleBase* result = static_cast<AccessibleBase*>(obj->wrapper());
     if (!result)
         result = createInstance(obj);
     return result;
 }

 HRESULT AccessibleBase::isSameObject(IAccessibleComparable* other, BOOL* result)
 {
     COMPtr<AccessibleBase> otherAccessibleBase(Query, other);
     *result = (otherAccessibleBase == this || otherAccessibleBase->m_object == m_object);
     return S_OK;
 }
	/*
	* Copyright (C) 2008, 2009, 2010 Apple Inc. All Rights Reserved.
	*
	* 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.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 INC. OR
	* 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.
	*/

	#include "config.h"
	#include "WebKitDLL.h"
	#include "AccessibleBase.h"

	#include "AccessibleImage.h"
	#include "WebView.h"
	#include <WebCore/AccessibilityListBox.h>
	#include <WebCore/AccessibilityMenuListPopup.h>
	#include <WebCore/AccessibilityObject.h>
	#include <WebCore/AXObjectCache.h>
	#include <WebCore/BString.h>
	#include <WebCore/Element.h>
	#include <WebCore/EventHandler.h>
	#include <WebCore/FrameView.h>
	#include <WebCore/HostWindow.h>
	#include <WebCore/HTMLNames.h>
	#include <WebCore/HTMLFrameElementBase.h>
	#include <WebCore/HTMLInputElement.h>
	#include <WebCore/IntRect.h>
	#include <WebCore/PlatformKeyboardEvent.h>
	#include <WebCore/RenderFrame.h>
	#include <WebCore/RenderObject.h>
	#include <WebCore/RenderView.h>
	#include <oleacc.h>
	#include <wtf/RefPtr.h>

	using namespace WebCore;

	AccessibleBase::AccessibleBase(AccessibilityObject* obj)
	: AccessibilityObjectWrapper(obj)
	, m_refCount(0)
	{
	ASSERT_ARG(obj, obj);
	m_object->setWrapper(this);
	++gClassCount;
	gClassNameCount.add("AccessibleBase");
	}

	AccessibleBase::~AccessibleBase()
	{
	--gClassCount;
	gClassNameCount.remove("AccessibleBase");
	}

	AccessibleBase* AccessibleBase::createInstance(AccessibilityObject* obj)
	{
	ASSERT_ARG(obj, obj);

	if (obj->isImage())
	return new AccessibleImage(obj);

	return new AccessibleBase(obj);
	}

	HRESULT AccessibleBase::QueryService(REFGUID guidService, REFIID riid, void **ppvObject)
	{
	if (!IsEqualGUID(guidService, SID_AccessibleComparable)) {
	*ppvObject = 0;
	return E_INVALIDARG;
	}
	return QueryInterface(riid, ppvObject);
	}

	// IUnknown
	HRESULT STDMETHODCALLTYPE AccessibleBase::QueryInterface(REFIID riid, void** ppvObject)
	{
	if (IsEqualGUID(riid, __uuidof(IAccessible)))
	ppvObject = static_cast<IAccessible>(this);
	else if (IsEqualGUID(riid, __uuidof(IDispatch)))
	ppvObject = static_cast<IAccessible>(this);
	else if (IsEqualGUID(riid, __uuidof(IUnknown)))
	ppvObject = static_cast<IAccessible>(this);
	else if (IsEqualGUID(riid, __uuidof(IAccessibleComparable)))
	ppvObject = static_cast<IAccessibleComparable>(this);
	else if (IsEqualGUID(riid, __uuidof(IServiceProvider)))
	ppvObject = static_cast<IServiceProvider>(this);
	else if (IsEqualGUID(riid, __uuidof(AccessibleBase)))
	ppvObject = static_cast<AccessibleBase>(this);
	else {
	*ppvObject = 0;
	return E_NOINTERFACE;
	}
	AddRef();
	return S_OK;
	}

	ULONG STDMETHODCALLTYPE AccessibleBase::Release(void)
	{
	ASSERT(m_refCount > 0);
	if (--m_refCount)
	return m_refCount;
	delete this;
	return 0;
	}

	// IAccessible
	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accParent(IDispatch** parent)
	{
	*parent = 0;

	if (!m_object)
	return E_FAIL;

	AccessibilityObject* parentObject = m_object->parentObjectUnignored();
	if (parentObject) {
	*parent = wrapper(parentObject);
	(*parent)->AddRef();
	return S_OK;
	}

	if (!m_object->topDocumentFrameView())
	return E_FAIL;

	return WebView::AccessibleObjectFromWindow(m_object->topDocumentFrameView()->hostWindow()->platformPageClient(),
	OBJID_WINDOW, __uuidof(IAccessible), reinterpret_cast<void**>(parent));
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accChildCount(long* count)
	{
	if (!m_object)
	return E_FAIL;
	if (!count)
	return E_POINTER;
	*count = static_cast<long>(m_object->children().size());
	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accChild(VARIANT vChild, IDispatch** ppChild)
	{
	if (!ppChild)
	return E_POINTER;

	*ppChild = 0;

	AccessibilityObject* childObj;

	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);
	if (FAILED(hr))
	return hr;

	ppChild = static_cast<IDispatch>(wrapper(childObj));
	(*ppChild)->AddRef();
	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accName(VARIANT vChild, BSTR* name)
	{
	if (!name)
	return E_POINTER;

	*name = 0;

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	if (*name = BString(wrapper(childObj)->name()).release())
	return S_OK;
	return S_FALSE;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accValue(VARIANT vChild, BSTR* value)
	{
	if (!value)
	return E_POINTER;

	*value = 0;

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	if (*value = BString(wrapper(childObj)->value()).release())
	return S_OK;
	return S_FALSE;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accDescription(VARIANT vChild, BSTR* description)
	{
	if (!description)
	return E_POINTER;

	*description = 0;

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	if (*description = BString(childObj->descriptionForMSAA()).release())
	return S_OK;

	return S_FALSE;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accRole(VARIANT vChild, VARIANT* pvRole)
	{
	if (!pvRole)
	return E_POINTER;

	::VariantInit(pvRole);

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	String roleString = childObj->stringRoleForMSAA();
	if (!roleString.isEmpty()) {
	V_VT(pvRole) = VT_BSTR;
	V_BSTR(pvRole) = BString(roleString).release();
	return S_OK;
	}

	pvRole->vt = VT_I4;
	pvRole->lVal = wrapper(childObj)->role();
	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accState(VARIANT vChild, VARIANT* pvState)
	{
	if (!pvState)
	return E_POINTER;

	::VariantInit(pvState);

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	pvState->vt = VT_I4;
	pvState->lVal = 0;

	if (childObj->isLinked())
	pvState->lVal \|= STATE_SYSTEM_LINKED;

	if (childObj->isHovered())
	pvState->lVal \|= STATE_SYSTEM_HOTTRACKED;

	if (!childObj->isEnabled())
	pvState->lVal \|= STATE_SYSTEM_UNAVAILABLE;

	if (childObj->isReadOnly())
	pvState->lVal \|= STATE_SYSTEM_READONLY;

	if (childObj->isOffScreen())
	pvState->lVal \|= STATE_SYSTEM_OFFSCREEN;

	if (childObj->isPasswordField())
	pvState->lVal \|= STATE_SYSTEM_PROTECTED;

	if (childObj->isIndeterminate())
	pvState->lVal \|= STATE_SYSTEM_INDETERMINATE;

	if (childObj->isChecked())
	pvState->lVal \|= STATE_SYSTEM_CHECKED;

	if (childObj->isPressed())
	pvState->lVal \|= STATE_SYSTEM_PRESSED;

	if (childObj->isFocused())
	pvState->lVal \|= STATE_SYSTEM_FOCUSED;

	if (childObj->isVisited())
	pvState->lVal \|= STATE_SYSTEM_TRAVERSED;

	if (childObj->canSetFocusAttribute())
	pvState->lVal \|= STATE_SYSTEM_FOCUSABLE;

	if (childObj->isSelected())
	pvState->lVal \|= STATE_SYSTEM_SELECTED;

	if (childObj->canSetSelectedAttribute())
	pvState->lVal \|= STATE_SYSTEM_SELECTABLE;

	if (childObj->isMultiSelectable())
	pvState->lVal \|= STATE_SYSTEM_EXTSELECTABLE \| STATE_SYSTEM_MULTISELECTABLE;

	if (!childObj->isVisible())
	pvState->lVal \|= STATE_SYSTEM_INVISIBLE;

	if (childObj->isCollapsed())
	pvState->lVal \|= STATE_SYSTEM_COLLAPSED;

	if (childObj->roleValue() == PopUpButtonRole) {
	pvState->lVal \|= STATE_SYSTEM_HASPOPUP;

	if (!childObj->isCollapsed())
	pvState->lVal \|= STATE_SYSTEM_EXPANDED;
	}

	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accHelp(VARIANT vChild, BSTR* helpText)
	{
	if (!helpText)
	return E_POINTER;

	*helpText = 0;

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	if (*helpText = BString(childObj->helpText()).release())
	return S_OK;
	return S_FALSE;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accKeyboardShortcut(VARIANT vChild, BSTR* shortcut)
	{
	if (!shortcut)
	return E_POINTER;

	*shortcut = 0;

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	String accessKey = childObj->accessKey();
	if (accessKey.isNull())
	return S_FALSE;

	static String accessKeyModifiers;
	if (accessKeyModifiers.isNull()) {
	unsigned modifiers = EventHandler::accessKeyModifiers();
	// Follow the same order as Mozilla MSAA implementation:
	// Ctrl+Alt+Shift+Meta+key. MSDN states that keyboard shortcut strings
	// should not be localized and defines the separator as "+".
	if (modifiers & PlatformKeyboardEvent::CtrlKey)
	accessKeyModifiers += "Ctrl+";
	if (modifiers & PlatformKeyboardEvent::AltKey)
	accessKeyModifiers += "Alt+";
	if (modifiers & PlatformKeyboardEvent::ShiftKey)
	accessKeyModifiers += "Shift+";
	if (modifiers & PlatformKeyboardEvent::MetaKey)
	accessKeyModifiers += "Win+";
	}
	*shortcut = BString(accessKeyModifiers + accessKey).release();
	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::accSelect(long selectionFlags, VARIANT vChild)
	{
	// According to MSDN, these combinations are invalid.
	if (((selectionFlags & (SELFLAG_ADDSELECTION \| SELFLAG_REMOVESELECTION)) == (SELFLAG_ADDSELECTION \| SELFLAG_REMOVESELECTION))
	\|\| ((selectionFlags & (SELFLAG_ADDSELECTION \| SELFLAG_TAKESELECTION)) == (SELFLAG_ADDSELECTION \| SELFLAG_TAKESELECTION))
	\|\| ((selectionFlags & (SELFLAG_REMOVESELECTION \| SELFLAG_TAKESELECTION)) == (SELFLAG_REMOVESELECTION \| SELFLAG_TAKESELECTION))
	\|\| ((selectionFlags & (SELFLAG_EXTENDSELECTION \| SELFLAG_TAKESELECTION)) == (SELFLAG_EXTENDSELECTION \| SELFLAG_TAKESELECTION)))
	return E_INVALIDARG;

	AccessibilityObject* childObject;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObject);

	if (FAILED(hr))
	return hr;

	if (selectionFlags & SELFLAG_TAKEFOCUS)
	childObject->setFocused(true);

	AccessibilityObject* parentObject = childObject->parentObject();
	if (!parentObject)
	return E_INVALIDARG;

	if (selectionFlags & SELFLAG_TAKESELECTION) {
	if (parentObject->isListBox()) {
	Vector<RefPtr<AccessibilityObject> > selectedChildren(1);
	selectedChildren[0] = childObject;
	static_cast<AccessibilityListBox*>(parentObject)->setSelectedChildren(selectedChildren);
	} else { // any element may be selectable by virtue of it having the aria-selected property
	ASSERT(!parentObject->isMultiSelectable());
	childObject->setSelected(true);
	}
	}

	// MSDN says that ADD, REMOVE, and EXTENDSELECTION with no other flags are invalid for
	// single-select.
	const long allSELFLAGs = SELFLAG_TAKEFOCUS \| SELFLAG_TAKESELECTION \| SELFLAG_EXTENDSELECTION \| SELFLAG_ADDSELECTION \| SELFLAG_REMOVESELECTION;
	if (!parentObject->isMultiSelectable()
	&& (((selectionFlags & allSELFLAGs) == SELFLAG_ADDSELECTION)
	\|\| ((selectionFlags & allSELFLAGs) == SELFLAG_REMOVESELECTION)
	\|\| ((selectionFlags & allSELFLAGs) == SELFLAG_EXTENDSELECTION)))
	return E_INVALIDARG;

	if (selectionFlags & SELFLAG_ADDSELECTION)
	childObject->setSelected(true);

	if (selectionFlags & SELFLAG_REMOVESELECTION)
	childObject->setSelected(false);

	// FIXME: Should implement SELFLAG_EXTENDSELECTION. For now, we just return
	// S_OK, matching Firefox.

	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accSelection(VARIANT*)
	{
	return E_NOTIMPL;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accFocus(VARIANT* pvFocusedChild)
	{
	if (!pvFocusedChild)
	return E_POINTER;

	::VariantInit(pvFocusedChild);

	if (!m_object)
	return E_FAIL;

	AccessibilityObject* focusedObj = m_object->focusedUIElement();
	if (!focusedObj)
	return S_FALSE;

	if (focusedObj == m_object) {
	V_VT(pvFocusedChild) = VT_I4;
	V_I4(pvFocusedChild) = CHILDID_SELF;
	return S_OK;
	}

	V_VT(pvFocusedChild) = VT_DISPATCH;
	V_DISPATCH(pvFocusedChild) = wrapper(focusedObj);
	V_DISPATCH(pvFocusedChild)->AddRef();
	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::get_accDefaultAction(VARIANT vChild, BSTR* action)
	{
	if (!action)
	return E_POINTER;

	*action = 0;

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	if (*action = BString(childObj->actionVerb()).release())
	return S_OK;
	return S_FALSE;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::accLocation(long* left, long* top, long* width, long* height, VARIANT vChild)
	{
	if (!left \|\| !top \|\| !width \|\| !height)
	return E_POINTER;

	left = top = width = height = 0;

	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	if (!childObj->documentFrameView())
	return E_FAIL;

	IntRect screenRect(childObj->documentFrameView()->contentsToScreen(childObj->elementRect()));
	*left = screenRect.x();
	*top = screenRect.y();
	*width = screenRect.width();
	*height = screenRect.height();
	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::accNavigate(long direction, VARIANT vFromChild, VARIANT* pvNavigatedTo)
	{
	if (!pvNavigatedTo)
	return E_POINTER;

	::VariantInit(pvNavigatedTo);

	AccessibilityObject* childObj = 0;

	switch (direction) {
	case NAVDIR_DOWN:
	case NAVDIR_UP:
	case NAVDIR_LEFT:
	case NAVDIR_RIGHT:
	// These directions are not implemented, matching Mozilla and IE.
	return E_NOTIMPL;
	case NAVDIR_LASTCHILD:
	case NAVDIR_FIRSTCHILD:
	// MSDN states that navigating to first/last child can only be from self.
	if (vFromChild.lVal != CHILDID_SELF)
	return E_INVALIDARG;

	if (!m_object)
	return E_FAIL;

	if (direction == NAVDIR_FIRSTCHILD)
	childObj = m_object->firstChild();
	else
	childObj = m_object->lastChild();
	break;
	case NAVDIR_NEXT:
	case NAVDIR_PREVIOUS: {
	// Navigating to next and previous is allowed from self or any of our children.
	HRESULT hr = getAccessibilityObjectForChild(vFromChild, childObj);
	if (FAILED(hr))
	return hr;

	if (direction == NAVDIR_NEXT)
	childObj = childObj->nextSibling();
	else
	childObj = childObj->previousSibling();
	break;
	}
	default:
	ASSERT_NOT_REACHED();
	return E_INVALIDARG;
	}

	if (!childObj)
	return S_FALSE;

	V_VT(pvNavigatedTo) = VT_DISPATCH;
	V_DISPATCH(pvNavigatedTo) = wrapper(childObj);
	V_DISPATCH(pvNavigatedTo)->AddRef();
	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::accHitTest(long x, long y, VARIANT* pvChildAtPoint)
	{
	if (!pvChildAtPoint)
	return E_POINTER;

	::VariantInit(pvChildAtPoint);

	if (!m_object \|\| !m_object->documentFrameView())
	return E_FAIL;

	IntPoint point = m_object->documentFrameView()->screenToContents(IntPoint(x, y));
	AccessibilityObject* childObj = m_object->accessibilityHitTest(point);

	if (!childObj) {
	// If we did not hit any child objects, test whether the point hit us, and
	// report that.
	if (!m_object->boundingBoxRect().contains(point))
	return S_FALSE;
	childObj = m_object;
	}

	if (childObj == m_object) {
	V_VT(pvChildAtPoint) = VT_I4;
	V_I4(pvChildAtPoint) = CHILDID_SELF;
	} else {
	V_VT(pvChildAtPoint) = VT_DISPATCH;
	V_DISPATCH(pvChildAtPoint) = static_cast<IDispatch*>(wrapper(childObj));
	V_DISPATCH(pvChildAtPoint)->AddRef();
	}
	return S_OK;
	}

	HRESULT STDMETHODCALLTYPE AccessibleBase::accDoDefaultAction(VARIANT vChild)
	{
	AccessibilityObject* childObj;
	HRESULT hr = getAccessibilityObjectForChild(vChild, childObj);

	if (FAILED(hr))
	return hr;

	if (!childObj->performDefaultAction())
	return S_FALSE;

	return S_OK;
	}

	// AccessibleBase
	String AccessibleBase::name() const
	{
	return m_object->nameForMSAA();
	}

	String AccessibleBase::value() const
	{
	return m_object->stringValueForMSAA();
	}

	static long MSAARole(AccessibilityRole role)
	{
	switch (role) {
	case WebCore::ButtonRole:
	return ROLE_SYSTEM_PUSHBUTTON;
	case WebCore::RadioButtonRole:
	return ROLE_SYSTEM_RADIOBUTTON;
	case WebCore::CheckBoxRole:
	return ROLE_SYSTEM_CHECKBUTTON;
	case WebCore::SliderRole:
	return ROLE_SYSTEM_SLIDER;
	case WebCore::TabGroupRole:
	return ROLE_SYSTEM_PAGETABLIST;
	case WebCore::TextFieldRole:
	case WebCore::TextAreaRole:
	case WebCore::EditableTextRole:
	return ROLE_SYSTEM_TEXT;
	case WebCore::ListMarkerRole:
	case WebCore::StaticTextRole:
	return ROLE_SYSTEM_STATICTEXT;
	case WebCore::OutlineRole:
	return ROLE_SYSTEM_OUTLINE;
	case WebCore::ColumnRole:
	return ROLE_SYSTEM_COLUMN;
	case WebCore::RowRole:
	return ROLE_SYSTEM_ROW;
	case WebCore::GroupRole:
	return ROLE_SYSTEM_GROUPING;
	case WebCore::ListRole:
	case WebCore::ListBoxRole:
	case WebCore::MenuListPopupRole:
	return ROLE_SYSTEM_LIST;
	case WebCore::TableRole:
	return ROLE_SYSTEM_TABLE;
	case WebCore::LinkRole:
	case WebCore::WebCoreLinkRole:
	return ROLE_SYSTEM_LINK;
	case WebCore::ImageMapRole:
	case WebCore::ImageRole:
	return ROLE_SYSTEM_GRAPHIC;
	case WebCore::MenuListOptionRole:
	case WebCore::ListItemRole:
	case WebCore::ListBoxOptionRole:
	return ROLE_SYSTEM_LISTITEM;
	case WebCore::PopUpButtonRole:
	return ROLE_SYSTEM_COMBOBOX;
	default:
	// This is the default role for MSAA.
	return ROLE_SYSTEM_CLIENT;
	}
	}

	long AccessibleBase::role() const
	{
	return MSAARole(m_object->roleValueForMSAA());
	}

	HRESULT AccessibleBase::getAccessibilityObjectForChild(VARIANT vChild, AccessibilityObject*& childObj) const
	{
	childObj = 0;

	if (!m_object)
	return E_FAIL;

	if (vChild.vt != VT_I4)
	return E_INVALIDARG;

	if (vChild.lVal == CHILDID_SELF)
	childObj = m_object;
	else if (vChild.lVal < 0) {
	// When broadcasting MSAA events, we negate the AXID and pass it as the
	// child ID.
	Document* document = m_object->document();
	if (!document)
	return E_FAIL;

	childObj = document->axObjectCache()->objectFromAXID(-vChild.lVal);
	} else {
	size_t childIndex = static_cast<size_t>(vChild.lVal - 1);

	if (childIndex >= m_object->children().size())
	return E_FAIL;
	childObj = m_object->children().at(childIndex).get();
	}

	if (!childObj)
	return E_FAIL;

	return S_OK;
	}

	AccessibleBase* AccessibleBase::wrapper(AccessibilityObject* obj)
	{
	AccessibleBase* result = static_cast<AccessibleBase*>(obj->wrapper());
	if (!result)
	result = createInstance(obj);
	return result;
	}

	HRESULT AccessibleBase::isSameObject(IAccessibleComparable* other, BOOL* result)
	{
	COMPtr<AccessibleBase> otherAccessibleBase(Query, other);
	*result = (otherAccessibleBase == this \|\| otherAccessibleBase->m_object == m_object);
	return S_OK;
	}