MutationObserverRegistration.cpp   [plain text]

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#include "config.h"

#include "MutationObserverRegistration.h"

#include "Document.h"
#include "QualifiedName.h"

namespace WebCore {

MutationObserverRegistration::MutationObserverRegistration(PassRefPtr<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()
{
    clearTransientRegistrations();
    m_observer->observationEnded(*this);
}

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 = std::make_unique<NodeHashSet>();

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

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

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

    m_transientRegistrationNodes = nullptr;

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

void MutationObserverRegistration::unregisterAndDelete(MutationObserverRegistration* registry)
{
    RefPtr<Node> registrationNode(registry->m_registrationNode);
    registrationNode->unregisterMutationObserver(registry);
    // The above line will cause registry to be deleted, so don't do any more in this function.
}

bool MutationObserverRegistration::shouldReceiveMutationFrom(Node* node, MutationObserver::MutationType type, const QualifiedName* attributeName) const
{
    ASSERT((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(HashSet<Node*>& nodes) const
{
    nodes.add(m_registrationNode);
    if (!m_transientRegistrationNodes)
        return;
    for (auto& node : *m_transientRegistrationNodes)
        nodes.add(node.get());
}

} // namespace WebCore