text: /*
   * Copyright (C) 2011 Google Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   *     * Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above
   * copyright notice, this list of conditions and the following disclaimer
   * in the documentation and/or other materials provided with the
   * distribution.
   *     * Neither the name of Google Inc. nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "config.h"
  #include "core/dom/MutationObserver.h"
  
  #include "bindings/core/v8/ExceptionState.h"
  #include "core/dom/ExceptionCode.h"
  #include "core/dom/Microtask.h"
  #include "core/dom/MutationCallback.h"
  #include "core/dom/MutationObserverInit.h"
  #include "core/dom/MutationObserverRegistration.h"
  #include "core/dom/MutationRecord.h"
  #include "core/dom/Node.h"
  #include "core/inspector/InspectorInstrumentation.h"
  #include "wtf/MainThread.h"
  #include <algorithm>
  
  namespace blink {
  
  static unsigned s_observerPriority = 0;
  
  struct MutationObserver::ObserverLessThan {
      bool operator()(const RefPtrWillBeMember<MutationObserver>& lhs, const RefPtrWillBeMember<MutationObserver>& rhs)
      {
          return lhs->m_priority < rhs->m_priority;
      }
  };
  
  PassRefPtrWillBeRawPtr<MutationObserver> MutationObserver::create(PassOwnPtr<MutationCallback> callback)
  {
      ASSERT(isMainThread());
      return adoptRefWillBeNoop(new MutationObserver(callback));
  }
  
  MutationObserver::MutationObserver(PassOwnPtr<MutationCallback> callback)
      : m_callback(callback)
      , m_priority(s_observerPriority++)
  {
  }
  
  MutationObserver::~MutationObserver()
  {
  #if !ENABLE(OILPAN)
      ASSERT(m_registrations.isEmpty());
  #endif
      if (!m_records.isEmpty())
          InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
  }
  
  void MutationObserver::observe(Node* node, const MutationObserverInit& observerInit, ExceptionState& exceptionState)
  {
      if (!node) {
          exceptionState.throwDOMException(NotFoundError, "The provided node was null.");
          return;
      }
  
      MutationObserverOptions options = 0;
  
      if (observerInit.hasAttributeOldValue() && observerInit.attributeOldValue())
          options |= AttributeOldValue;
  
      HashSet<AtomicString> attributeFilter;
      if (observerInit.hasAttributeFilter()) {
          const Vector<String>& sequence = observerInit.attributeFilter();
          for (unsigned i = 0; i < sequence.size(); ++i)
              attributeFilter.add(AtomicString(sequence[i]));
          options |= AttributeFilter;
      }
  
      bool attributes = observerInit.hasAttributes() && observerInit.attributes();
      if (attributes || (!observerInit.hasAttributes() && (observerInit.hasAttributeOldValue() || observerInit.hasAttributeFilter())))
          options |= Attributes;
  
      if (observerInit.hasCharacterDataOldValue() && observerInit.characterDataOldValue())
          options |= CharacterDataOldValue;
  
      bool characterData = observerInit.hasCharacterData() && observerInit.characterData();
      if (characterData || (!observerInit.hasCharacterData() && observerInit.hasCharacterDataOldValue()))
          options |= CharacterData;
  
      if (observerInit.childList())
          options |= ChildList;
  
      if (observerInit.subtree())
          options |= Subtree;
  
      if (!(options & Attributes)) {
          if (options & AttributeOldValue) {
              exceptionState.throwTypeError("The options object may only set 'attributeOldValue' to true when 'attributes' is true or not present.");
              return;
          }
          if (options & AttributeFilter) {
              exceptionState.throwTypeError("The options object may only set 'attributeFilter' when 'attributes' is true or not present.");
              return;
          }
      }
      if (!((options & CharacterData) || !(options & CharacterDataOldValue))) {
          exceptionState.throwTypeError("The options object may only set 'characterDataOldValue' to true when 'characterData' is true or not present.");
          return;
      }
  
      if (!(options & (Attributes | CharacterData | ChildList))) {
          exceptionState.throwTypeError("The options object must set at least one of 'attributes', 'characterData', or 'childList' to true.");
          return;
      }
  
      node->registerMutationObserver(*this, options, attributeFilter);
  }
  
  MutationRecordVector MutationObserver::takeRecords()
  {
      MutationRecordVector records;
      records.swap(m_records);
      InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
      return records;
  }
  
  void MutationObserver::disconnect()
  {
      m_records.clear();
      InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
      MutationObserverRegistrationSet registrations(m_registrations);
      for (MutationObserverRegistrationSet::iterator iter = registrations.begin(); iter != registrations.end(); ++iter)
          (*iter)->unregister();
      ASSERT(m_registrations.isEmpty());
  }
  
  void MutationObserver::observationStarted(MutationObserverRegistration* registration)
  {
      ASSERT(!m_registrations.contains(registration));
      m_registrations.add(registration);
  }
  
  void MutationObserver::observationEnded(MutationObserverRegistration* registration)
  {
      ASSERT(m_registrations.contains(registration));
      m_registrations.remove(registration);
  }
  
  static MutationObserverSet& activeMutationObservers()
  {
      DEFINE_STATIC_LOCAL(OwnPtrWillBePersistent<MutationObserverSet>, activeObservers, (adoptPtrWillBeNoop(new MutationObserverSet())));
      return *activeObservers;
  }
  
  static MutationObserverSet& suspendedMutationObservers()
  {
      DEFINE_STATIC_LOCAL(OwnPtrWillBePersistent<MutationObserverSet>, suspendedObservers, (adoptPtrWillBeNoop(new MutationObserverSet())));
      return *suspendedObservers;
  }
  
  static void activateObserver(PassRefPtrWillBeRawPtr<MutationObserver> observer)
  {
      if (activeMutationObservers().isEmpty())
          Microtask::enqueueMicrotask(WTF::bind(&MutationObserver::deliverMutations));
  
      activeMutationObservers().add(observer);
  }
  
  void MutationObserver::enqueueMutationRecord(PassRefPtrWillBeRawPtr<MutationRecord> mutation)
  {
      ASSERT(isMainThread());
      m_records.append(mutation);
      activateObserver(this);
      InspectorInstrumentation::didEnqueueMutationRecord(m_callback->executionContext(), this);
  }
  
  void MutationObserver::setHasTransientRegistration()
  {
      ASSERT(isMainThread());
      activateObserver(this);
  }
  
  WillBeHeapHashSet<RawPtrWillBeMember<Node> > MutationObserver::getObservedNodes() const
  {
      WillBeHeapHashSet<RawPtrWillBeMember<Node> > observedNodes;
      for (MutationObserverRegistrationSet::const_iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter)
          (*iter)->addRegistrationNodesToSet(observedNodes);
      return observedNodes;
  }
  
  bool MutationObserver::canDeliver()
  {
      return !m_callback->executionContext()->activeDOMObjectsAreSuspended();
  }
  
  void MutationObserver::deliver()
  {
      ASSERT(canDeliver());
  
      // Calling clearTransientRegistrations() can modify m_registrations, so it's necessary
      // to make a copy of the transient registrations before operating on them.
      WillBeHeapVector<RawPtrWillBeMember<MutationObserverRegistration>, 1> transientRegistrations;
      for (MutationObserverRegistrationSet::iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter) {
          if ((*iter)->hasTransientRegistrations())
              transientRegistrations.append(*iter);
      }
      for (size_t i = 0; i < transientRegistrations.size(); ++i)
          transientRegistrations[i]->clearTransientRegistrations();
  
      if (m_records.isEmpty())
          return;
  
      MutationRecordVector records;
      records.swap(m_records);
  
      InspectorInstrumentation::willDeliverMutationRecords(m_callback->executionContext(), this);
      m_callback->call(records, this);
      InspectorInstrumentation::didDeliverMutationRecords(m_callback->executionContext());
  }
  
  void MutationObserver::resumeSuspendedObservers()
  {
      ASSERT(isMainThread());
      if (suspendedMutationObservers().isEmpty())
          return;
  
      MutationObserverVector suspended;
      copyToVector(suspendedMutationObservers(), suspended);
      for (size_t i = 0; i < suspended.size(); ++i) {
          if (suspended[i]->canDeliver()) {
              suspendedMutationObservers().remove(suspended[i]);
              activateObserver(suspended[i]);
          }
      }
  }
  
  void MutationObserver::deliverMutations()
  {
      ASSERT(isMainThread());
      MutationObserverVector observers;
      copyToVector(activeMutationObservers(), observers);
      activeMutationObservers().clear();
      std::sort(observers.begin(), observers.end(), ObserverLessThan());
      for (size_t i = 0; i < observers.size(); ++i) {
          if (observers[i]->canDeliver())
              observers[i]->deliver();
          else
              suspendedMutationObservers().add(observers[i]);
      }
  }
  
  void MutationObserver::trace(Visitor* visitor)
  {
  #if ENABLE(OILPAN)
      visitor->trace(m_records);
      visitor->trace(m_registrations);
  #endif
  }
  
  } // namespace blink
  