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

/*
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#include "core/dom/MutationObserverRegistration.h"

#include "core/dom/Node.h"
#include "core/dom/QualifiedName.h"

namespace blink {

MutationObserverRegistration* MutationObserverRegistration::create(
    MutationObserver& observer,
    Node* registrationNode,
    MutationObserverOptions options,
    const HashSet<AtomicString>& attributeFilter) {
  return new MutationObserverRegistration(observer, registrationNode, options,
                                          attributeFilter);
}

MutationObserverRegistration::MutationObserverRegistration(
    MutationObserver& observer,
    Node* registrationNode,
    MutationObserverOptions options,
    const HashSet<AtomicString>& attributeFilter)
    : m_observer(this, &observer),
      m_registrationNode(registrationNode),
      m_options(options),
      m_attributeFilter(attributeFilter) {
  m_observer->observationStarted(this);
}

MutationObserverRegistration::~MutationObserverRegistration() {}

void MutationObserverRegistration::dispose() {
  clearTransientRegistrations();
  m_observer->observationEnded(this);
  m_observer.clear();
}

void MutationObserverRegistration::resetObservation(
    MutationObserverOptions options,
    const HashSet<AtomicString>& attributeFilter) {
  clearTransientRegistrations();
  m_options = options;
  m_attributeFilter = attributeFilter;
}

void MutationObserverRegistration::observedSubtreeNodeWillDetach(Node& node) {
  if (!isSubtree())
    return;

  node.registerTransientMutationObserver(this);
  m_observer->setHasTransientRegistration();

  if (!m_transientRegistrationNodes) {
    m_transientRegistrationNodes = new NodeHashSet;

    DCHECK(m_registrationNode);
    DCHECK(!m_registrationNodeKeepAlive);
    m_registrationNodeKeepAlive =
        m_registrationNode.get();  // Balanced in clearTransientRegistrations.
  }
  m_transientRegistrationNodes->add(&node);
}

void MutationObserverRegistration::clearTransientRegistrations() {
  if (!m_transientRegistrationNodes) {
    DCHECK(!m_registrationNodeKeepAlive);
    return;
  }

  for (auto& node : *m_transientRegistrationNodes)
    node->unregisterTransientMutationObserver(this);

  m_transientRegistrationNodes.clear();

  DCHECK(m_registrationNodeKeepAlive);
  m_registrationNodeKeepAlive =
      nullptr;  // Balanced in observeSubtreeNodeWillDetach.
}

void MutationObserverRegistration::unregister() {
  DCHECK(m_registrationNode);
  m_registrationNode->unregisterMutationObserver(this);
  // The above line will cause this object to be deleted, so don't do any more
  // in this function.
}

bool MutationObserverRegistration::shouldReceiveMutationFrom(
    Node& node,
    MutationObserver::MutationType type,
    const QualifiedName* attributeName) const {
  DCHECK((type == MutationObserver::Attributes && attributeName) ||
         !attributeName);
  if (!(m_options & type))
    return false;

  if (m_registrationNode != &node && !isSubtree())
    return false;

  if (type != MutationObserver::Attributes ||
      !(m_options & MutationObserver::AttributeFilter))
    return true;

  if (!attributeName->namespaceURI().isNull())
    return false;

  return m_attributeFilter.contains(attributeName->localName());
}

void MutationObserverRegistration::addRegistrationNodesToSet(
    HeapHashSet<Member<Node>>& nodes) const {
  DCHECK(m_registrationNode);
  nodes.add(m_registrationNode.get());
  if (!m_transientRegistrationNodes)
    return;
  for (NodeHashSet::const_iterator iter = m_transientRegistrationNodes->begin();
       iter != m_transientRegistrationNodes->end(); ++iter)
    nodes.add(iter->get());
}

DEFINE_TRACE(MutationObserverRegistration) {
  visitor->trace(m_observer);
  visitor->trace(m_registrationNode);
  visitor->trace(m_registrationNodeKeepAlive);
  visitor->trace(m_transientRegistrationNodes);
}

DEFINE_TRACE_WRAPPERS(MutationObserverRegistration) {
  visitor->traceWrappers(m_observer);
}

}  // namespace blink