1 /*

     2  * Copyright (C) 2008, 2009, 2010 Apple 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  * 1. Redistributions of source code must retain the above copyright

     8  *    notice, this list of conditions and the following disclaimer.

     9  * 2. Redistributions in binary form must reproduce the above copyright

    10  *    notice, this list of conditions and the following disclaimer in the

    11  *    documentation and/or other materials provided with the distribution.

    12  *

    13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY

    14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR

    17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

    21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

    24  */

    25 

    26 

    27 #include "config.h"

    28 #include "AXObjectCache.h"

    29 

    30 #include "AccessibilityObject.h"

    31 #include "Chrome.h"

    32 #include "Document.h"

    33 #include "Page.h"

    34 #include "RenderObject.h"

    35 

    36 using namespace std;

    37 

    38 namespace WebCore {

    39 

    40 void AXObjectCache::detachWrapper(AccessibilityObject* obj)

    41 {

    42     // On Windows, AccessibilityObjects are created when get_accChildCount is

    43     // called, but they are not wrapped until get_accChild is called, so this

    44     // object may not have a wrapper.

    45     if (AccessibilityObjectWrapper* wrapper = obj->wrapper())

    46         wrapper->detach();

    47 }

    48 

    49 void AXObjectCache::attachWrapper(AccessibilityObject*)

    50 {

    51     // On Windows, AccessibilityObjects are wrapped when the accessibility

    52     // software requests them via get_accChild.

    53 }

    54 

    55 void AXObjectCache::handleScrolledToAnchor(const Node* anchorNode)

    56 {

    57     // The anchor node may not be accessible. Post the notification for the

    58     // first accessible object.

    59     postPlatformNotification(AccessibilityObject::firstAccessibleObjectFromNode(anchorNode), AXScrolledToAnchor);

    60 }

    61 

    62 void AXObjectCache::postPlatformNotification(AccessibilityObject* obj, AXNotification notification)

    63 {

    64     if (!obj)

    65         return;

    66 

    67     Document* document = obj->document();

    68     if (!document)

    69         return;

    70 

    71     Page* page = document->page();

    72     if (!page || !page->chrome()->platformPageClient())

    73         return;

    74 

    75     DWORD msaaEvent;

    76     switch (notification) {

    77         case AXFocusedUIElementChanged:

    78         case AXActiveDescendantChanged:

    79             msaaEvent = EVENT_OBJECT_FOCUS;

    80             break;

    81 

    82         case AXScrolledToAnchor:

    83             msaaEvent = EVENT_SYSTEM_SCROLLINGSTART;

    84             break;

    85 

    86         case AXValueChanged:

    87         case AXMenuListValueChanged:

    88             msaaEvent = EVENT_OBJECT_VALUECHANGE;

    89             break;

    90 

    91         default:

    92             return;

    93     }

    94 

    95     // Windows will end up calling get_accChild() on the root accessible

    96     // object for the WebView, passing the child ID that we specify below. We

    97     // negate the AXID so we know that the caller is passing the ID of an

    98     // element, not the index of a child element.

    99 

   100     ASSERT(obj->axObjectID() >= 1);

   101     ASSERT(obj->axObjectID() <= numeric_limits<LONG>::max());

   102 

   103     NotifyWinEvent(msaaEvent, page->chrome()->platformPageClient(), OBJID_CLIENT, -static_cast<LONG>(obj->axObjectID()));

   104 }

   105 

   106 AXID AXObjectCache::platformGenerateAXID() const

   107 {

   108     static AXID lastUsedID = 0;

   109 

   110     // Generate a new ID. Windows accessibility relies on a positive AXID,

   111     // ranging from 1 to LONG_MAX.

   112     AXID objID = lastUsedID;

   113     do {

   114         ++objID;

   115         objID %= std::numeric_limits<LONG>::max();

   116     } while (objID == 0 || HashTraits<AXID>::isDeletedValue(objID) || m_idsInUse.contains(objID));

   117 

   118     ASSERT(objID >= 1 && objID <= std::numeric_limits<LONG>::max());

   119 

   120     lastUsedID = objID;

   121 

   122     return objID;

   123 }

   124 

   125 void AXObjectCache::handleFocusedUIElementChanged(RenderObject*, RenderObject* newFocusedRenderer)

   126 {

   127     if (!newFocusedRenderer)

   128         return;

   129 

   130     Page* page = newFocusedRenderer->document()->page();

   131     if (!page || !page->chrome()->platformPageClient())

   132         return;

   133 

   134     AccessibilityObject* focusedObject = focusedUIElementForPage(page);

   135     if (!focusedObject)

   136         return;

   137 

   138     ASSERT(!focusedObject->accessibilityIsIgnored());

   139 

   140     postPlatformNotification(focusedObject, AXFocusedUIElementChanged);

   141 }

   142 

   143 } // namespace WebCore