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 "MutationObserver.h"
  
  #include "Dictionary.h"
  #include "Document.h"
  #include "ExceptionCode.h"
  #include "MutationCallback.h"
  #include "MutationObserverRegistration.h"
  #include "MutationRecord.h"
  #include "Node.h"
  #include <algorithm>
  #include <wtf/HashSet.h>
  #include <wtf/MainThread.h>
  #include <wtf/Vector.h>
  
  namespace WebCore {
  
  static unsigned s_observerPriority = 0;
  
  struct MutationObserver::ObserverLessThan {
      bool operator()(const RefPtr<MutationObserver>& lhs, const RefPtr<MutationObserver>& rhs)
      {
          return lhs->m_priority < rhs->m_priority;
      }
  };
  
  PassRefPtr<MutationObserver> MutationObserver::create(PassRefPtr<MutationCallback> callback)
  {
      ASSERT(isMainThread());
      return adoptRef(new MutationObserver(callback));
  }
  
  MutationObserver::MutationObserver(PassRefPtr<MutationCallback> callback)
      : m_callback(callback)
      , m_priority(s_observerPriority++)
  {
  }
  
  MutationObserver::~MutationObserver()
  {
      ASSERT(m_registrations.isEmpty());
  }
  
  bool MutationObserver::validateOptions(MutationObserverOptions options)
  {
      return (options & (Attributes | CharacterData | ChildList))
          && ((options & Attributes) || !(options & AttributeOldValue))
          && ((options & Attributes) || !(options & AttributeFilter))
          && ((options & CharacterData) || !(options & CharacterDataOldValue));
  }
  
  void MutationObserver::observe(Node* node, const Dictionary& optionsDictionary, ExceptionCode& ec)
  {
      if (!node) {
          ec = NOT_FOUND_ERR;
          return;
      }
  
      static const struct {
          const char* name;
          MutationObserverOptions value;
      } booleanOptions[] = {
          { "childList", ChildList },
          { "attributes", Attributes },
          { "characterData", CharacterData },
          { "subtree", Subtree },
          { "attributeOldValue", AttributeOldValue },
          { "characterDataOldValue", CharacterDataOldValue }
      };
      MutationObserverOptions options = 0;
      for (unsigned i = 0; i < sizeof(booleanOptions) / sizeof(booleanOptions[0]); ++i) {
          bool value = false;
          if (optionsDictionary.get(booleanOptions[i].name, value) && value)
              options |= booleanOptions[i].value;
      }
  
      HashSet<AtomicString> attributeFilter;
      if (optionsDictionary.get("attributeFilter", attributeFilter))
          options |= AttributeFilter;
  
      if (!validateOptions(options)) {
          ec = SYNTAX_ERR;
          return;
      }
  
      node->registerMutationObserver(this, options, attributeFilter);
  }
  
  Vector<RefPtr<MutationRecord> > MutationObserver::takeRecords()
  {
      Vector<RefPtr<MutationRecord> > records;
      records.swap(m_records);
      return records;
  }
  
  void MutationObserver::disconnect()
  {
      m_records.clear();
      HashSet<MutationObserverRegistration*> registrations(m_registrations);
      for (HashSet<MutationObserverRegistration*>::iterator iter = registrations.begin(); iter != registrations.end(); ++iter)
          MutationObserverRegistration::unregisterAndDelete(*iter);
  }
  
  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);
  }
  
  typedef HashSet<RefPtr<MutationObserver> > MutationObserverSet;
  
  static MutationObserverSet& activeMutationObservers()
  {
      DEFINE_STATIC_LOCAL(MutationObserverSet, activeObservers, ());
      return activeObservers;
  }
  
  static MutationObserverSet& suspendedMutationObservers()
  {
      DEFINE_STATIC_LOCAL(MutationObserverSet, suspendedObservers, ());
      return suspendedObservers;
  }
  
  void MutationObserver::enqueueMutationRecord(PassRefPtr<MutationRecord> mutation)
  {
      ASSERT(isMainThread());
      m_records.append(mutation);
      activeMutationObservers().add(this);
  }
  
  void MutationObserver::setHasTransientRegistration()
  {
      ASSERT(isMainThread());
      activeMutationObservers().add(this);
  }
  
  HashSet<Node*> MutationObserver::getObservedNodes() const
  {
      HashSet<Node*> observedNodes;
      for (HashSet<MutationObserverRegistration*>::const_iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter)
          (*iter)->addRegistrationNodesToSet(observedNodes);
      return observedNodes;
  }
  
  bool MutationObserver::canDeliver()
  {
      return !m_callback->scriptExecutionContext()->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.
      Vector<MutationObserverRegistration*, 1> transientRegistrations;
      for (HashSet<MutationObserverRegistration*>::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;
  
      Vector<RefPtr<MutationRecord> > records;
      records.swap(m_records);
  
      m_callback->call(records, this);
  }
  
  void MutationObserver::deliverAllMutations()
  {
      ASSERT(isMainThread());
      static bool deliveryInProgress = false;
      if (deliveryInProgress)
          return;
      deliveryInProgress = true;
  
      if (!suspendedMutationObservers().isEmpty()) {
          Vector<RefPtr<MutationObserver> > suspended;
          copyToVector(suspendedMutationObservers(), suspended);
          for (size_t i = 0; i < suspended.size(); ++i) {
              if (!suspended[i]->canDeliver())
                  continue;
  
              suspendedMutationObservers().remove(suspended[i]);
              activeMutationObservers().add(suspended[i]);
          }
      }
  
      while (!activeMutationObservers().isEmpty()) {
          Vector<RefPtr<MutationObserver> > 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]);
          }
      }
  
      deliveryInProgress = false;
  }
  
  } // namespace WebCore
  