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(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