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.
   */
  
  #ifndef THIRD_PARTY_BLINK_RENDERER_CORE_DOM_MUTATION_OBSERVER_INTEREST_GROUP_H_
  #define THIRD_PARTY_BLINK_RENDERER_CORE_DOM_MUTATION_OBSERVER_INTEREST_GROUP_H_
  
  #include "third_party/blink/renderer/core/dom/document.h"
  #include "third_party/blink/renderer/core/dom/mutation_observer.h"
  #include "third_party/blink/renderer/core/dom/node.h"
  #include "third_party/blink/renderer/core/dom/qualified_name.h"
  #include "third_party/blink/renderer/platform/heap/handle.h"
  #include "third_party/blink/renderer/platform/wtf/hash_map.h"
  
  namespace blink {
  
  class MutationObserverInterestGroup final
      : public GarbageCollected<MutationObserverInterestGroup> {
   public:
    static MutationObserverInterestGroup* CreateForChildListMutation(
        Node& target) {
      if (!target.GetDocument().HasMutationObserversOfType(
              MutationObserver::kChildList))
        return nullptr;
  
      MutationRecordDeliveryOptions old_value_flag = 0;
      return CreateIfNeeded(target, MutationObserver::kChildList, old_value_flag);
    }
  
    static MutationObserverInterestGroup* CreateForCharacterDataMutation(
        Node& target) {
      if (!target.GetDocument().HasMutationObserversOfType(
              MutationObserver::kCharacterData))
        return nullptr;
  
      return CreateIfNeeded(target, MutationObserver::kCharacterData,
                            MutationObserver::kCharacterDataOldValue);
    }
  
    static MutationObserverInterestGroup* CreateForAttributesMutation(
        Node& target,
        const QualifiedName& attribute_name) {
      if (!target.GetDocument().HasMutationObserversOfType(
              MutationObserver::kAttributes))
        return nullptr;
  
      return CreateIfNeeded(target, MutationObserver::kAttributes,
                            MutationObserver::kAttributeOldValue,
                            &attribute_name);
    }
  
    bool IsOldValueRequested();
    void EnqueueMutationRecord(MutationRecord*);
  
    void Trace(blink::Visitor*);
  
   private:
    static MutationObserverInterestGroup* CreateIfNeeded(
        Node& target,
        MutationObserver::MutationType,
        MutationRecordDeliveryOptions old_value_flag,
        const QualifiedName* attribute_name = nullptr);
    MutationObserverInterestGroup(
        HeapHashMap<Member<MutationObserver>, MutationRecordDeliveryOptions>&
            observers,
        MutationRecordDeliveryOptions old_value_flag);
  
    bool HasOldValue(MutationRecordDeliveryOptions options) {
      return options & old_value_flag_;
    }
  
    HeapHashMap<Member<MutationObserver>, MutationRecordDeliveryOptions>
        observers_;
    MutationRecordDeliveryOptions old_value_flag_;
  };
  
  }  // namespace blink
  
  #endif  // THIRD_PARTY_BLINK_RENDERER_CORE_DOM_MUTATION_OBSERVER_INTEREST_GROUP_H_
  