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      1 /*
      2  * Copyright (C) 2011 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 are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 
     33 #include "core/dom/MutationObserverRegistration.h"
     34 
     35 #include "core/dom/Node.h"
     36 #include "core/dom/QualifiedName.h"
     37 
     38 namespace WebCore {
     39 
     40 PassOwnPtr<MutationObserverRegistration> MutationObserverRegistration::create(PassRefPtr<MutationObserver> observer, Node* registrationNode, MutationObserverOptions options, const HashSet<AtomicString>& attributeFilter)
     41 {
     42     return adoptPtr(new MutationObserverRegistration(observer, registrationNode, options, attributeFilter));
     43 }
     44 
     45 MutationObserverRegistration::MutationObserverRegistration(PassRefPtr<MutationObserver> observer, Node* registrationNode, MutationObserverOptions options, const HashSet<AtomicString>& attributeFilter)
     46     : m_observer(observer)
     47     , m_registrationNode(registrationNode)
     48     , m_options(options)
     49     , m_attributeFilter(attributeFilter)
     50 {
     51     m_observer->observationStarted(this);
     52 }
     53 
     54 MutationObserverRegistration::~MutationObserverRegistration()
     55 {
     56     clearTransientRegistrations();
     57     m_observer->observationEnded(this);
     58 }
     59 
     60 void MutationObserverRegistration::resetObservation(MutationObserverOptions options, const HashSet<AtomicString>& attributeFilter)
     61 {
     62     clearTransientRegistrations();
     63     m_options = options;
     64     m_attributeFilter = attributeFilter;
     65 }
     66 
     67 void MutationObserverRegistration::observedSubtreeNodeWillDetach(Node* node)
     68 {
     69     if (!isSubtree())
     70         return;
     71 
     72     node->registerTransientMutationObserver(this);
     73     m_observer->setHasTransientRegistration();
     74 
     75     if (!m_transientRegistrationNodes) {
     76         m_transientRegistrationNodes = adoptPtr(new NodeHashSet);
     77 
     78         ASSERT(!m_registrationNodeKeepAlive);
     79         m_registrationNodeKeepAlive = m_registrationNode; // Balanced in clearTransientRegistrations.
     80     }
     81     m_transientRegistrationNodes->add(node);
     82 }
     83 
     84 void MutationObserverRegistration::clearTransientRegistrations()
     85 {
     86     if (!m_transientRegistrationNodes) {
     87         ASSERT(!m_registrationNodeKeepAlive);
     88         return;
     89     }
     90 
     91     for (NodeHashSet::iterator iter = m_transientRegistrationNodes->begin(); iter != m_transientRegistrationNodes->end(); ++iter)
     92         (*iter)->unregisterTransientMutationObserver(this);
     93 
     94     m_transientRegistrationNodes.clear();
     95 
     96     ASSERT(m_registrationNodeKeepAlive);
     97     m_registrationNodeKeepAlive = 0; // Balanced in observeSubtreeNodeWillDetach.
     98 }
     99 
    100 void MutationObserverRegistration::unregister()
    101 {
    102     m_registrationNode->unregisterMutationObserver(this);
    103     // The above line will cause this object to be deleted, so don't do any more in this function.
    104 }
    105 
    106 bool MutationObserverRegistration::shouldReceiveMutationFrom(Node* node, MutationObserver::MutationType type, const QualifiedName* attributeName) const
    107 {
    108     ASSERT((type == MutationObserver::Attributes && attributeName) || !attributeName);
    109     if (!(m_options & type))
    110         return false;
    111 
    112     if (m_registrationNode != node && !isSubtree())
    113         return false;
    114 
    115     if (type != MutationObserver::Attributes || !(m_options & MutationObserver::AttributeFilter))
    116         return true;
    117 
    118     if (!attributeName->namespaceURI().isNull())
    119         return false;
    120 
    121     return m_attributeFilter.contains(attributeName->localName());
    122 }
    123 
    124 void MutationObserverRegistration::addRegistrationNodesToSet(HashSet<Node*>& nodes) const
    125 {
    126     nodes.add(m_registrationNode);
    127     if (!m_transientRegistrationNodes)
    128         return;
    129     for (NodeHashSet::const_iterator iter = m_transientRegistrationNodes->begin(); iter != m_transientRegistrationNodes->end(); ++iter)
    130         nodes.add(iter->get());
    131 }
    132 
    133 } // namespace WebCore
    134