third_party/WebKit/Source/core/dom/IdTargetObserverRegistry.cpp

/*
 * Copyright (C) 2012 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:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "core/dom/IdTargetObserverRegistry.h"

#include "core/dom/IdTargetObserver.h"

namespace blink {

IdTargetObserverRegistry* IdTargetObserverRegistry::create() {
  return new IdTargetObserverRegistry();
}

DEFINE_TRACE(IdTargetObserverRegistry) {
  visitor->trace(m_registry);
  visitor->trace(m_notifyingObserversInSet);
}

void IdTargetObserverRegistry::addObserver(const AtomicString& id,
                                           IdTargetObserver* observer) {
  if (id.isEmpty())
    return;

  IdToObserverSetMap::AddResult result = m_registry.insert(id.impl(), nullptr);
  if (result.isNewEntry)
    result.storedValue->value = new ObserverSet();

  result.storedValue->value->insert(observer);
}

void IdTargetObserverRegistry::removeObserver(const AtomicString& id,
                                              IdTargetObserver* observer) {
  if (id.isEmpty() || m_registry.isEmpty())
    return;

  IdToObserverSetMap::iterator iter = m_registry.find(id.impl());

  ObserverSet* set = iter->value.get();
  set->erase(observer);
  if (set->isEmpty() && set != m_notifyingObserversInSet)
    m_registry.remove(iter);
}

void IdTargetObserverRegistry::notifyObserversInternal(const AtomicString& id) {
  DCHECK(!id.isEmpty());
  DCHECK(!m_registry.isEmpty());

  m_notifyingObserversInSet = m_registry.at(id.impl());
  if (!m_notifyingObserversInSet)
    return;

  HeapVector<Member<IdTargetObserver>> copy;
  copyToVector(*m_notifyingObserversInSet, copy);
  for (const auto& observer : copy) {
    if (m_notifyingObserversInSet->contains(observer))
      observer->idTargetChanged();
  }

  if (m_notifyingObserversInSet->isEmpty())
    m_registry.erase(id.impl());

  m_notifyingObserversInSet = nullptr;
}

bool IdTargetObserverRegistry::hasObservers(const AtomicString& id) const {
  if (id.isEmpty() || m_registry.isEmpty())
    return false;
  ObserverSet* set = m_registry.at(id.impl());
  return set && !set->isEmpty();
}

}  // namespace blink