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/platform/external/webkit/WebCore/accessibility/AXObjectCache.cpp

https://github.com/aharish/totoro-gb-opensource-update2
C++ | 524 lines | 380 code | 93 blank | 51 comment | 101 complexity | 5cbec6ea68474d8d3eb97664ad1813c6 MD5 | raw file
  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 *
  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#include "config.h"
 30#include "AXObjectCache.h"
 31
 32#include "AccessibilityARIAGrid.h"
 33#include "AccessibilityARIAGridCell.h"
 34#include "AccessibilityARIAGridRow.h"
 35#include "AccessibilityImageMapLink.h"
 36#include "AccessibilityList.h"
 37#include "AccessibilityListBox.h"
 38#include "AccessibilityListBoxOption.h"
 39#include "AccessibilityMediaControls.h"
 40#include "AccessibilityMenuList.h"
 41#include "AccessibilityMenuListPopup.h"
 42#include "AccessibilityMenuListOption.h"
 43#include "AccessibilityRenderObject.h"
 44#include "AccessibilityScrollbar.h"
 45#include "AccessibilitySlider.h"
 46#include "AccessibilityTable.h"
 47#include "AccessibilityTableCell.h"
 48#include "AccessibilityTableColumn.h"
 49#include "AccessibilityTableHeaderContainer.h"
 50#include "AccessibilityTableRow.h"
 51#include "FocusController.h"
 52#include "Frame.h"
 53#include "HTMLAreaElement.h"
 54#include "HTMLImageElement.h"
 55#include "HTMLNames.h"
 56#if ENABLE(VIDEO)
 57#include "MediaControlElements.h"
 58#endif
 59#include "InputElement.h"
 60#include "Page.h"
 61#include "RenderObject.h"
 62#include "RenderView.h"
 63
 64#include <wtf/PassRefPtr.h>
 65
 66namespace WebCore {
 67
 68using namespace HTMLNames;
 69    
 70bool AXObjectCache::gAccessibilityEnabled = false;
 71bool AXObjectCache::gAccessibilityEnhancedUserInterfaceEnabled = false;
 72
 73AXObjectCache::AXObjectCache()
 74    : m_notificationPostTimer(this, &AXObjectCache::notificationPostTimerFired)
 75{
 76}
 77
 78AXObjectCache::~AXObjectCache()
 79{
 80    HashMap<AXID, RefPtr<AccessibilityObject> >::iterator end = m_objects.end();
 81    for (HashMap<AXID, RefPtr<AccessibilityObject> >::iterator it = m_objects.begin(); it != end; ++it) {
 82        AccessibilityObject* obj = (*it).second.get();
 83        detachWrapper(obj);
 84        obj->detach();
 85        removeAXID(obj);
 86    }
 87}
 88
 89AccessibilityObject* AXObjectCache::focusedImageMapUIElement(HTMLAreaElement* areaElement)
 90{
 91    // Find the corresponding accessibility object for the HTMLAreaElement. This should be
 92    // in the list of children for its corresponding image.
 93    if (!areaElement)
 94        return 0;
 95    
 96    HTMLImageElement* imageElement = areaElement->imageElement();
 97    if (!imageElement)
 98        return 0;
 99    
100    AccessibilityObject* axRenderImage = areaElement->document()->axObjectCache()->getOrCreate(imageElement->renderer());
101    if (!axRenderImage)
102        return 0;
103    
104    AccessibilityObject::AccessibilityChildrenVector imageChildren = axRenderImage->children();
105    unsigned count = imageChildren.size();
106    for (unsigned k = 0; k < count; ++k) {
107        AccessibilityObject* child = imageChildren[k].get();
108        if (!child->isImageMapLink())
109            continue;
110        
111        if (static_cast<AccessibilityImageMapLink*>(child)->areaElement() == areaElement)
112            return child;
113    }    
114    
115    return 0;
116}
117    
118AccessibilityObject* AXObjectCache::focusedUIElementForPage(const Page* page)
119{
120    // get the focused node in the page
121    Document* focusedDocument = page->focusController()->focusedOrMainFrame()->document();
122    Node* focusedNode = focusedDocument->focusedNode();
123    if (!focusedNode)
124        focusedNode = focusedDocument;
125
126    if (focusedNode->hasTagName(areaTag))
127        return focusedImageMapUIElement(static_cast<HTMLAreaElement*>(focusedNode));
128    
129    RenderObject* focusedNodeRenderer = focusedNode->renderer();
130    if (!focusedNodeRenderer)
131        return 0;
132
133    AccessibilityObject* obj = focusedNodeRenderer->document()->axObjectCache()->getOrCreate(focusedNodeRenderer);
134
135    if (obj->shouldFocusActiveDescendant()) {
136        if (AccessibilityObject* descendant = obj->activeDescendant())
137            obj = descendant;
138    }
139
140    // the HTML element, for example, is focusable but has an AX object that is ignored
141    if (obj->accessibilityIsIgnored())
142        obj = obj->parentObjectUnignored();
143
144    return obj;
145}
146
147AccessibilityObject* AXObjectCache::get(RenderObject* renderer)
148{
149    if (!renderer)
150        return 0;
151    
152    AccessibilityObject* obj = 0;
153    AXID axID = m_renderObjectMapping.get(renderer);
154    ASSERT(!HashTraits<AXID>::isDeletedValue(axID));
155
156    if (axID)
157        obj = m_objects.get(axID).get();
158    
159    return obj;
160}
161    
162bool AXObjectCache::nodeIsAriaType(Node* node, String role)
163{
164    if (!node || !node->isElementNode())
165        return false;
166    
167    return equalIgnoringCase(static_cast<Element*>(node)->getAttribute(roleAttr), role);
168}
169
170AccessibilityObject* AXObjectCache::getOrCreate(RenderObject* renderer)
171{
172    if (!renderer)
173        return 0;
174    
175    AccessibilityObject* obj = get(renderer);
176
177    if (!obj) {
178        Node* node = renderer->node();
179        RefPtr<AccessibilityObject> newObj = 0;
180        if (renderer->isListBox())
181            newObj = AccessibilityListBox::create(renderer);
182        else if (renderer->isMenuList())
183            newObj = AccessibilityMenuList::create(renderer);
184
185        // If the node is aria role="list" or the aria role is empty and its a ul/ol/dl type (it shouldn't be a list if aria says otherwise). 
186        else if (node && ((nodeIsAriaType(node, "list") || nodeIsAriaType(node, "directory"))
187                          || (nodeIsAriaType(node, nullAtom) && (node->hasTagName(ulTag) || node->hasTagName(olTag) || node->hasTagName(dlTag)))))
188            newObj = AccessibilityList::create(renderer);
189        
190        // aria tables
191        else if (nodeIsAriaType(node, "grid") || nodeIsAriaType(node, "treegrid"))
192            newObj = AccessibilityARIAGrid::create(renderer);
193        else if (nodeIsAriaType(node, "row"))
194            newObj = AccessibilityARIAGridRow::create(renderer);
195        else if (nodeIsAriaType(node, "gridcell") || nodeIsAriaType(node, "columnheader") || nodeIsAriaType(node, "rowheader"))
196            newObj = AccessibilityARIAGridCell::create(renderer);
197
198        // standard tables
199        else if (renderer->isTable())
200            newObj = AccessibilityTable::create(renderer);
201        else if (renderer->isTableRow())
202            newObj = AccessibilityTableRow::create(renderer);
203        else if (renderer->isTableCell())
204            newObj = AccessibilityTableCell::create(renderer);
205
206#if ENABLE(VIDEO)
207        // media controls
208        else if (renderer->node() && renderer->node()->isMediaControlElement())
209            newObj = AccessibilityMediaControl::create(renderer);
210#endif
211
212        // input type=range
213        else if (renderer->isSlider())
214            newObj = AccessibilitySlider::create(renderer);
215
216        else
217            newObj = AccessibilityRenderObject::create(renderer);
218        
219        obj = newObj.get();
220        
221        getAXID(obj);
222        
223        m_renderObjectMapping.set(renderer, obj->axObjectID());
224        m_objects.set(obj->axObjectID(), obj);    
225        attachWrapper(obj);
226    }
227    
228    return obj;
229}
230
231AccessibilityObject* AXObjectCache::getOrCreate(AccessibilityRole role)
232{
233    RefPtr<AccessibilityObject> obj = 0;
234    
235    // will be filled in...
236    switch (role) {
237    case ListBoxOptionRole:
238        obj = AccessibilityListBoxOption::create();
239        break;
240    case ImageMapLinkRole:
241        obj = AccessibilityImageMapLink::create();
242        break;
243    case ColumnRole:
244        obj = AccessibilityTableColumn::create();
245        break;            
246    case TableHeaderContainerRole:
247        obj = AccessibilityTableHeaderContainer::create();
248        break;   
249    case SliderThumbRole:
250        obj = AccessibilitySliderThumb::create();
251        break;
252    case MenuListPopupRole:
253        obj = AccessibilityMenuListPopup::create();
254        break;
255    case MenuListOptionRole:
256        obj = AccessibilityMenuListOption::create();
257        break;
258    case ScrollBarRole:
259        obj = AccessibilityScrollbar::create();
260        break;
261    default:
262        obj = 0;
263    }
264    
265    if (obj)
266        getAXID(obj.get());
267    else
268        return 0;
269
270    m_objects.set(obj->axObjectID(), obj);    
271    attachWrapper(obj.get());
272    return obj.get();
273}
274
275void AXObjectCache::remove(AXID axID)
276{
277    if (!axID)
278        return;
279    
280    // first fetch object to operate some cleanup functions on it 
281    AccessibilityObject* obj = m_objects.get(axID).get();
282    if (!obj)
283        return;
284    
285    detachWrapper(obj);
286    obj->detach();
287    removeAXID(obj);
288    
289    // finally remove the object
290    if (!m_objects.take(axID))
291        return;
292    
293    ASSERT(m_objects.size() >= m_idsInUse.size());    
294}
295    
296void AXObjectCache::remove(RenderObject* renderer)
297{
298    if (!renderer)
299        return;
300    
301    AXID axID = m_renderObjectMapping.get(renderer);
302    remove(axID);
303    m_renderObjectMapping.remove(renderer);
304}
305
306#if !PLATFORM(WIN)
307AXID AXObjectCache::platformGenerateAXID() const
308{
309    static AXID lastUsedID = 0;
310
311    // Generate a new ID.
312    AXID objID = lastUsedID;
313    do {
314        ++objID;
315    } while (!objID || HashTraits<AXID>::isDeletedValue(objID) || m_idsInUse.contains(objID));
316
317    lastUsedID = objID;
318
319    return objID;
320}
321#endif
322
323AXID AXObjectCache::getAXID(AccessibilityObject* obj)
324{
325    // check for already-assigned ID
326    AXID objID = obj->axObjectID();
327    if (objID) {
328        ASSERT(m_idsInUse.contains(objID));
329        return objID;
330    }
331
332    objID = platformGenerateAXID();
333
334    m_idsInUse.add(objID);
335    obj->setAXObjectID(objID);
336    
337    return objID;
338}
339
340void AXObjectCache::removeAXID(AccessibilityObject* object)
341{
342    if (!object)
343        return;
344    
345    AXID objID = object->axObjectID();
346    if (!objID)
347        return;
348    ASSERT(!HashTraits<AXID>::isDeletedValue(objID));
349    ASSERT(m_idsInUse.contains(objID));
350    object->setAXObjectID(0);
351    m_idsInUse.remove(objID);
352}
353
354#if HAVE(ACCESSIBILITY)
355void AXObjectCache::contentChanged(RenderObject* renderer)
356{
357    AccessibilityObject* object = getOrCreate(renderer);
358    if (object)
359        object->contentChanged(); 
360}
361#endif
362
363void AXObjectCache::childrenChanged(RenderObject* renderer)
364{
365    if (!renderer)
366        return;
367 
368    AXID axID = m_renderObjectMapping.get(renderer);
369    if (!axID)
370        return;
371    
372    AccessibilityObject* obj = m_objects.get(axID).get();
373    if (obj)
374        obj->childrenChanged();
375}
376    
377void AXObjectCache::notificationPostTimerFired(Timer<AXObjectCache>*)
378{
379    m_notificationPostTimer.stop();
380
381    unsigned i = 0, count = m_notificationsToPost.size();
382    for (i = 0; i < count; ++i) {
383        AccessibilityObject* obj = m_notificationsToPost[i].first.get();
384#ifndef NDEBUG
385        // Make sure none of the render views are in the process of being layed out.
386        // Notifications should only be sent after the renderer has finished
387        if (obj->isAccessibilityRenderObject()) {
388            AccessibilityRenderObject* renderObj = static_cast<AccessibilityRenderObject*>(obj);
389            RenderObject* renderer = renderObj->renderer();
390            if (renderer && renderer->view())
391                ASSERT(!renderer->view()->layoutState());
392        }
393#endif
394        
395        postPlatformNotification(obj, m_notificationsToPost[i].second);
396    }
397    
398    m_notificationsToPost.clear();
399}
400    
401#if HAVE(ACCESSIBILITY)
402void AXObjectCache::postNotification(RenderObject* renderer, AXNotification notification, bool postToElement, PostType postType)
403{
404    // Notifications for text input objects are sent to that object.
405    // All others are sent to the top WebArea.
406    if (!renderer)
407        return;
408    
409    // Get an accessibility object that already exists. One should not be created here
410    // because a render update may be in progress and creating an AX object can re-trigger a layout
411    RefPtr<AccessibilityObject> object = get(renderer);
412    while (!object && renderer) {
413        renderer = renderer->parent();
414        object = get(renderer); 
415    }
416    
417    if (!renderer)
418        return;
419    
420    postNotification(object.get(), renderer->document(), notification, postToElement, postType);
421}
422
423void AXObjectCache::postNotification(AccessibilityObject* object, Document* document, AXNotification notification, bool postToElement, PostType postType)
424{
425    if (object && !postToElement)
426        object = object->observableObject();
427
428    if (!object && document)
429        object = get(document->renderer());
430
431    if (!object)
432        return;
433
434    if (postType == PostAsynchronously) {
435        m_notificationsToPost.append(make_pair(object, notification));
436        if (!m_notificationPostTimer.isActive())
437            m_notificationPostTimer.startOneShot(0);
438    } else
439        postPlatformNotification(object, notification);
440}
441
442void AXObjectCache::selectedChildrenChanged(RenderObject* renderer)
443{
444    postNotification(renderer, AXSelectedChildrenChanged, true);
445}
446#endif
447
448#if HAVE(ACCESSIBILITY)
449void AXObjectCache::handleActiveDescendantChanged(RenderObject* renderer)
450{
451    if (!renderer)
452        return;
453    AccessibilityObject* obj = getOrCreate(renderer);
454    if (obj)
455        obj->handleActiveDescendantChanged();
456}
457
458void AXObjectCache::handleAriaRoleChanged(RenderObject* renderer)
459{
460    if (!renderer)
461        return;
462    AccessibilityObject* obj = getOrCreate(renderer);
463    if (obj && obj->isAccessibilityRenderObject())
464        static_cast<AccessibilityRenderObject*>(obj)->updateAccessibilityRole();
465}
466#endif
467    
468VisiblePosition AXObjectCache::visiblePositionForTextMarkerData(TextMarkerData& textMarkerData)
469{
470    VisiblePosition visiblePos = VisiblePosition(textMarkerData.node, textMarkerData.offset, textMarkerData.affinity);
471    Position deepPos = visiblePos.deepEquivalent();
472    if (deepPos.isNull())
473        return VisiblePosition();
474    
475    RenderObject* renderer = deepPos.node()->renderer();
476    if (!renderer)
477        return VisiblePosition();
478    
479    AXObjectCache* cache = renderer->document()->axObjectCache();
480    if (!cache->isIDinUse(textMarkerData.axID))
481        return VisiblePosition();
482    
483    if (deepPos.node() != textMarkerData.node || deepPos.deprecatedEditingOffset() != textMarkerData.offset)
484        return VisiblePosition();
485    
486    return visiblePos;
487}
488
489void AXObjectCache::textMarkerDataForVisiblePosition(TextMarkerData& textMarkerData, const VisiblePosition& visiblePos)
490{
491    // This memory must be bzero'd so instances of TextMarkerData can be tested for byte-equivalence.
492    // This also allows callers to check for failure by looking at textMarkerData upon return.
493    memset(&textMarkerData, 0, sizeof(TextMarkerData));
494    
495    if (visiblePos.isNull())
496        return;
497    
498    Position deepPos = visiblePos.deepEquivalent();
499    Node* domNode = deepPos.node();
500    ASSERT(domNode);
501    if (!domNode)
502        return;
503    
504    if (domNode->isHTMLElement()) {
505        InputElement* inputElement = toInputElement(static_cast<Element*>(domNode));
506        if (inputElement && inputElement->isPasswordField())
507            return;
508    }
509    
510    // locate the renderer, which must exist for a visible dom node
511    RenderObject* renderer = domNode->renderer();
512    ASSERT(renderer);
513    
514    // find or create an accessibility object for this renderer
515    AXObjectCache* cache = renderer->document()->axObjectCache();
516    RefPtr<AccessibilityObject> obj = cache->getOrCreate(renderer);
517    
518    textMarkerData.axID = obj.get()->axObjectID();
519    textMarkerData.node = domNode;
520    textMarkerData.offset = deepPos.deprecatedEditingOffset();
521    textMarkerData.affinity = visiblePos.affinity();    
522}
523    
524} // namespace WebCore