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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 #include "core/dom/MutationObserver.h"
     33 
     34 #include <algorithm>
     35 #include "bindings/v8/Dictionary.h"
     36 #include "bindings/v8/ExceptionState.h"
     37 #include "core/dom/Document.h"
     38 #include "core/dom/ExceptionCode.h"
     39 #include "core/dom/MutationCallback.h"
     40 #include "core/dom/MutationObserverRegistration.h"
     41 #include "core/dom/MutationRecord.h"
     42 #include "core/dom/Node.h"
     43 #include "wtf/MainThread.h"
     44 
     45 namespace WebCore {
     46 
     47 static unsigned s_observerPriority = 0;
     48 
     49 struct MutationObserver::ObserverLessThan {
     50     bool operator()(const RefPtr<MutationObserver>& lhs, const RefPtr<MutationObserver>& rhs)
     51     {
     52         return lhs->m_priority < rhs->m_priority;
     53     }
     54 };
     55 
     56 PassRefPtr<MutationObserver> MutationObserver::create(PassOwnPtr<MutationCallback> callback)
     57 {
     58     ASSERT(isMainThread());
     59     return adoptRef(new MutationObserver(callback));
     60 }
     61 
     62 MutationObserver::MutationObserver(PassOwnPtr<MutationCallback> callback)
     63     : m_callback(callback)
     64     , m_priority(s_observerPriority++)
     65 {
     66     ScriptWrappable::init(this);
     67 }
     68 
     69 MutationObserver::~MutationObserver()
     70 {
     71     ASSERT(m_registrations.isEmpty());
     72 }
     73 
     74 void MutationObserver::observe(Node* node, const Dictionary& optionsDictionary, ExceptionState& exceptionState)
     75 {
     76     if (!node) {
     77         exceptionState.throwDOMException(NotFoundError, "The provided node was null.");
     78         return;
     79     }
     80 
     81     MutationObserverOptions options = 0;
     82 
     83     bool attributeOldValue = false;
     84     bool attributeOldValuePresent = optionsDictionary.get("attributeOldValue", attributeOldValue);
     85     if (attributeOldValue)
     86         options |= AttributeOldValue;
     87 
     88     HashSet<AtomicString> attributeFilter;
     89     bool attributeFilterPresent = optionsDictionary.get("attributeFilter", attributeFilter);
     90     if (attributeFilterPresent)
     91         options |= AttributeFilter;
     92 
     93     bool attributes = false;
     94     bool attributesPresent = optionsDictionary.get("attributes", attributes);
     95     if (attributes || (!attributesPresent && (attributeOldValuePresent || attributeFilterPresent)))
     96         options |= Attributes;
     97 
     98     bool characterDataOldValue = false;
     99     bool characterDataOldValuePresent = optionsDictionary.get("characterDataOldValue", characterDataOldValue);
    100     if (characterDataOldValue)
    101         options |= CharacterDataOldValue;
    102 
    103     bool characterData = false;
    104     bool characterDataPresent = optionsDictionary.get("characterData", characterData);
    105     if (characterData || (!characterDataPresent && characterDataOldValuePresent))
    106         options |= CharacterData;
    107 
    108     bool childListValue = false;
    109     if (optionsDictionary.get("childList", childListValue) && childListValue)
    110         options |= ChildList;
    111 
    112     bool subtreeValue = false;
    113     if (optionsDictionary.get("subtree", subtreeValue) && subtreeValue)
    114         options |= Subtree;
    115 
    116     if (!(options & Attributes)) {
    117         if (options & AttributeOldValue) {
    118             exceptionState.throwDOMException(TypeError, "The options object may only set 'attributeOldValue' to true when 'attributes' is true or not present.");
    119             return;
    120         }
    121         if (options & AttributeFilter) {
    122             exceptionState.throwDOMException(TypeError, "The options object may only set 'attributeFilter' when 'attributes' is true or not present.");
    123             return;
    124         }
    125     }
    126     if (!((options & CharacterData) || !(options & CharacterDataOldValue))) {
    127         exceptionState.throwDOMException(TypeError, "The options object may only set 'characterDataOldValue' to true when 'characterData' is true or not present.");
    128         return;
    129     }
    130 
    131     if (!(options & (Attributes | CharacterData | ChildList))) {
    132         exceptionState.throwDOMException(TypeError, "The options object must set at least one of 'attributes', 'characterData', or 'childList' to true.");
    133         return;
    134     }
    135 
    136     node->registerMutationObserver(this, options, attributeFilter);
    137 }
    138 
    139 Vector<RefPtr<MutationRecord> > MutationObserver::takeRecords()
    140 {
    141     Vector<RefPtr<MutationRecord> > records;
    142     records.swap(m_records);
    143     return records;
    144 }
    145 
    146 void MutationObserver::disconnect()
    147 {
    148     m_records.clear();
    149     HashSet<MutationObserverRegistration*> registrations(m_registrations);
    150     for (HashSet<MutationObserverRegistration*>::iterator iter = registrations.begin(); iter != registrations.end(); ++iter)
    151         (*iter)->unregister();
    152 }
    153 
    154 void MutationObserver::observationStarted(MutationObserverRegistration* registration)
    155 {
    156     ASSERT(!m_registrations.contains(registration));
    157     m_registrations.add(registration);
    158 }
    159 
    160 void MutationObserver::observationEnded(MutationObserverRegistration* registration)
    161 {
    162     ASSERT(m_registrations.contains(registration));
    163     m_registrations.remove(registration);
    164 }
    165 
    166 typedef HashSet<RefPtr<MutationObserver> > MutationObserverSet;
    167 
    168 static MutationObserverSet& activeMutationObservers()
    169 {
    170     DEFINE_STATIC_LOCAL(MutationObserverSet, activeObservers, ());
    171     return activeObservers;
    172 }
    173 
    174 static MutationObserverSet& suspendedMutationObservers()
    175 {
    176     DEFINE_STATIC_LOCAL(MutationObserverSet, suspendedObservers, ());
    177     return suspendedObservers;
    178 }
    179 
    180 void MutationObserver::enqueueMutationRecord(PassRefPtr<MutationRecord> mutation)
    181 {
    182     ASSERT(isMainThread());
    183     m_records.append(mutation);
    184     activeMutationObservers().add(this);
    185 }
    186 
    187 void MutationObserver::setHasTransientRegistration()
    188 {
    189     ASSERT(isMainThread());
    190     activeMutationObservers().add(this);
    191 }
    192 
    193 HashSet<Node*> MutationObserver::getObservedNodes() const
    194 {
    195     HashSet<Node*> observedNodes;
    196     for (HashSet<MutationObserverRegistration*>::const_iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter)
    197         (*iter)->addRegistrationNodesToSet(observedNodes);
    198     return observedNodes;
    199 }
    200 
    201 bool MutationObserver::canDeliver()
    202 {
    203     return !m_callback->executionContext()->activeDOMObjectsAreSuspended();
    204 }
    205 
    206 void MutationObserver::deliver()
    207 {
    208     ASSERT(canDeliver());
    209 
    210     // Calling clearTransientRegistrations() can modify m_registrations, so it's necessary
    211     // to make a copy of the transient registrations before operating on them.
    212     Vector<MutationObserverRegistration*, 1> transientRegistrations;
    213     for (HashSet<MutationObserverRegistration*>::iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter) {
    214         if ((*iter)->hasTransientRegistrations())
    215             transientRegistrations.append(*iter);
    216     }
    217     for (size_t i = 0; i < transientRegistrations.size(); ++i)
    218         transientRegistrations[i]->clearTransientRegistrations();
    219 
    220     if (m_records.isEmpty())
    221         return;
    222 
    223     Vector<RefPtr<MutationRecord> > records;
    224     records.swap(m_records);
    225 
    226     m_callback->call(records, this);
    227 }
    228 
    229 void MutationObserver::deliverAllMutations()
    230 {
    231     ASSERT(isMainThread());
    232     static bool deliveryInProgress = false;
    233     if (deliveryInProgress)
    234         return;
    235     deliveryInProgress = true;
    236 
    237     if (!suspendedMutationObservers().isEmpty()) {
    238         Vector<RefPtr<MutationObserver> > suspended;
    239         copyToVector(suspendedMutationObservers(), suspended);
    240         for (size_t i = 0; i < suspended.size(); ++i) {
    241             if (!suspended[i]->canDeliver())
    242                 continue;
    243 
    244             suspendedMutationObservers().remove(suspended[i]);
    245             activeMutationObservers().add(suspended[i]);
    246         }
    247     }
    248 
    249     while (!activeMutationObservers().isEmpty()) {
    250         Vector<RefPtr<MutationObserver> > observers;
    251         copyToVector(activeMutationObservers(), observers);
    252         activeMutationObservers().clear();
    253         std::sort(observers.begin(), observers.end(), ObserverLessThan());
    254         for (size_t i = 0; i < observers.size(); ++i) {
    255             if (observers[i]->canDeliver())
    256                 observers[i]->deliver();
    257             else
    258                 suspendedMutationObservers().add(observers[i]);
    259         }
    260     }
    261 
    262     deliveryInProgress = false;
    263 }
    264 
    265 } // namespace WebCore
    266