src/third_party/WebKit/Source/core/dom/MutationObserver.cpp

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   9  * notice, this list of conditions and the following disclaimer.
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  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
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  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/Microtask.h"
  40 #include "core/dom/MutationCallback.h"
  41 #include "core/dom/MutationObserverRegistration.h"
  42 #include "core/dom/MutationRecord.h"
  43 #include "core/dom/Node.h"
  44 #include "core/inspector/InspectorInstrumentation.h"
  45 #include "wtf/MainThread.h"
  46
  47 namespace WebCore {
  48
  49 static unsigned s_observerPriority = 0;
  50
  51 struct MutationObserver::ObserverLessThan {
  52     bool operator()(const RefPtr<MutationObserver>& lhs, const RefPtr<MutationObserver>& rhs)
  53     {
  54         return lhs->m_priority < rhs->m_priority;
  55     }
  56 };
  57
  58 PassRefPtr<MutationObserver> MutationObserver::create(PassOwnPtr<MutationCallback> callback)
  59 {
  60     ASSERT(isMainThread());
  61     return adoptRef(new MutationObserver(callback));
  62 }
  63
  64 MutationObserver::MutationObserver(PassOwnPtr<MutationCallback> callback)
  65     : m_callback(callback)
  66     , m_priority(s_observerPriority++)
  67 {
  68     ScriptWrappable::init(this);
  69 }
  70
  71 MutationObserver::~MutationObserver()
  72 {
  73     ASSERT(m_registrations.isEmpty());
  74     if (!m_records.isEmpty())
  75         InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
  76 }
  77
  78 void MutationObserver::observe(Node* node, const Dictionary& optionsDictionary, ExceptionState& exceptionState)
  79 {
  80     if (!node) {
  81         exceptionState.throwDOMException(NotFoundError, "The provided node was null.");
  82         return;
  83     }
  84
  85     MutationObserverOptions options = 0;
  86
  87     bool attributeOldValue = false;
  88     bool attributeOldValuePresent = optionsDictionary.get("attributeOldValue", attributeOldValue);
  89     if (attributeOldValue)
  90         options |= AttributeOldValue;
  91
  92     HashSet<AtomicString> attributeFilter;
  93     bool attributeFilterPresent = optionsDictionary.get("attributeFilter", attributeFilter);
  94     if (attributeFilterPresent)
  95         options |= AttributeFilter;
  96
  97     bool attributes = false;
  98     bool attributesPresent = optionsDictionary.get("attributes", attributes);
  99     if (attributes || (!attributesPresent && (attributeOldValuePresent || attributeFilterPresent)))
 100         options |= Attributes;
 101
 102     bool characterDataOldValue = false;
 103     bool characterDataOldValuePresent = optionsDictionary.get("characterDataOldValue", characterDataOldValue);
 104     if (characterDataOldValue)
 105         options |= CharacterDataOldValue;
 106
 107     bool characterData = false;
 108     bool characterDataPresent = optionsDictionary.get("characterData", characterData);
 109     if (characterData || (!characterDataPresent && characterDataOldValuePresent))
 110         options |= CharacterData;
 111
 112     bool childListValue = false;
 113     if (optionsDictionary.get("childList", childListValue) && childListValue)
 114         options |= ChildList;
 115
 116     bool subtreeValue = false;
 117     if (optionsDictionary.get("subtree", subtreeValue) && subtreeValue)
 118         options |= Subtree;
 119
 120     if (!(options & Attributes)) {
 121         if (options & AttributeOldValue) {
 122             exceptionState.throwDOMException(TypeError, "The options object may only set 'attributeOldValue' to true when 'attributes' is true or not present.");
 123             return;
 124         }
 125         if (options & AttributeFilter) {
 126             exceptionState.throwDOMException(TypeError, "The options object may only set 'attributeFilter' when 'attributes' is true or not present.");
 127             return;
 128         }
 129     }
 130     if (!((options & CharacterData) || !(options & CharacterDataOldValue))) {
 131         exceptionState.throwDOMException(TypeError, "The options object may only set 'characterDataOldValue' to true when 'characterData' is true or not present.");
 132         return;
 133     }
 134
 135     if (!(options & (Attributes | CharacterData | ChildList))) {
 136         exceptionState.throwDOMException(TypeError, "The options object must set at least one of 'attributes', 'characterData', or 'childList' to true.");
 137         return;
 138     }
 139
 140     node->registerMutationObserver(this, options, attributeFilter);
 141 }
 142
 143 Vector<RefPtr<MutationRecord> > MutationObserver::takeRecords()
 144 {
 145     Vector<RefPtr<MutationRecord> > records;
 146     records.swap(m_records);
 147     InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
 148     return records;
 149 }
 150
 151 void MutationObserver::disconnect()
 152 {
 153     m_records.clear();
 154     InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
 155     HashSet<MutationObserverRegistration*> registrations(m_registrations);
 156     for (HashSet<MutationObserverRegistration*>::iterator iter = registrations.begin(); iter != registrations.end(); ++iter)
 157         (*iter)->unregister();
 158 }
 159
 160 void MutationObserver::observationStarted(MutationObserverRegistration* registration)
 161 {
 162     ASSERT(!m_registrations.contains(registration));
 163     m_registrations.add(registration);
 164 }
 165
 166 void MutationObserver::observationEnded(MutationObserverRegistration* registration)
 167 {
 168     ASSERT(m_registrations.contains(registration));
 169     m_registrations.remove(registration);
 170 }
 171
 172 typedef HashSet<RefPtr<MutationObserver> > MutationObserverSet;
 173
 174 static MutationObserverSet& activeMutationObservers()
 175 {
 176     DEFINE_STATIC_LOCAL(MutationObserverSet, activeObservers, ());
 177     return activeObservers;
 178 }
 179
 180 static MutationObserverSet& suspendedMutationObservers()
 181 {
 182     DEFINE_STATIC_LOCAL(MutationObserverSet, suspendedObservers, ());
 183     return suspendedObservers;
 184 }
 185
 186 static void activateObserver(PassRefPtr<MutationObserver> observer)
 187 {
 188     if (activeMutationObservers().isEmpty())
 189         Microtask::enqueueMicrotask(&MutationObserver::deliverMutations);
 190
 191     activeMutationObservers().add(observer);
 192 }
 193
 194 void MutationObserver::enqueueMutationRecord(PassRefPtr<MutationRecord> mutation)
 195 {
 196     ASSERT(isMainThread());
 197     m_records.append(mutation);
 198     activateObserver(this);
 199     InspectorInstrumentation::didEnqueueMutationRecord(m_callback->executionContext(), this);
 200 }
 201
 202 void MutationObserver::setHasTransientRegistration()
 203 {
 204     ASSERT(isMainThread());
 205     activateObserver(this);
 206 }
 207
 208 HashSet<Node*> MutationObserver::getObservedNodes() const
 209 {
 210     HashSet<Node*> observedNodes;
 211     for (HashSet<MutationObserverRegistration*>::const_iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter)
 212         (*iter)->addRegistrationNodesToSet(observedNodes);
 213     return observedNodes;
 214 }
 215
 216 bool MutationObserver::canDeliver()
 217 {
 218     return !m_callback->executionContext()->activeDOMObjectsAreSuspended();
 219 }
 220
 221 void MutationObserver::deliver()
 222 {
 223     ASSERT(canDeliver());
 224
 225     // Calling clearTransientRegistrations() can modify m_registrations, so it's necessary
 226     // to make a copy of the transient registrations before operating on them.
 227     Vector<MutationObserverRegistration*, 1> transientRegistrations;
 228     for (HashSet<MutationObserverRegistration*>::iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter) {
 229         if ((*iter)->hasTransientRegistrations())
 230             transientRegistrations.append(*iter);
 231     }
 232     for (size_t i = 0; i < transientRegistrations.size(); ++i)
 233         transientRegistrations[i]->clearTransientRegistrations();
 234
 235     if (m_records.isEmpty())
 236         return;
 237
 238     Vector<RefPtr<MutationRecord> > records;
 239     records.swap(m_records);
 240
 241     InspectorInstrumentation::willDeliverMutationRecords(m_callback->executionContext(), this);
 242     m_callback->call(records, this);
 243     InspectorInstrumentation::didDeliverMutationRecords(m_callback->executionContext());
 244 }
 245
 246 void MutationObserver::resumeSuspendedObservers()
 247 {
 248     ASSERT(isMainThread());
 249     if (suspendedMutationObservers().isEmpty())
 250         return;
 251
 252     Vector<RefPtr<MutationObserver> > suspended;
 253     copyToVector(suspendedMutationObservers(), suspended);
 254     for (size_t i = 0; i < suspended.size(); ++i) {
 255         if (suspended[i]->canDeliver()) {
 256             suspendedMutationObservers().remove(suspended[i]);
 257             activateObserver(suspended[i]);
 258         }
 259     }
 260 }
 261
 262 void MutationObserver::deliverMutations()
 263 {
 264     ASSERT(isMainThread());
 265     Vector<RefPtr<MutationObserver> > observers;
 266     copyToVector(activeMutationObservers(), observers);
 267     activeMutationObservers().clear();
 268     std::sort(observers.begin(), observers.end(), ObserverLessThan());
 269     for (size_t i = 0; i < observers.size(); ++i) {
 270         if (observers[i]->canDeliver())
 271             observers[i]->deliver();
 272         else
 273             suspendedMutationObservers().add(observers[i]);
 274     }
 275 }
 276
 277 } // namespace WebCore