Source/WebCore/dom/MutationObserverRegistration.cpp

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
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 * in the documentation and/or other materials provided with the
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 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#include "config.h"

#include "MutationObserverRegistration.h"

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

namespace WebCore {

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

MutationObserverRegistration::~MutationObserverRegistration()
{
    takeTransientRegistrations();
    m_observer->observationEnded(*this);
}

void MutationObserverRegistration::resetObservation(MutationObserverOptions options, const HashSet<AtomString>& attributeFilter)
{
    takeTransientRegistrations();
    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 = makeUnique<HashSet<GCReachableRef<Node>>>();

        ASSERT(!m_nodeKeptAlive);
        m_nodeKeptAlive = &m_node; // Balanced in takeTransientRegistrations.
    }
    m_transientRegistrationNodes->add(node);
}

std::unique_ptr<HashSet<GCReachableRef<Node>>> MutationObserverRegistration::takeTransientRegistrations()
{
    if (!m_transientRegistrationNodes) {
        ASSERT(!m_nodeKeptAlive);
        return nullptr;
    }

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

    auto returnValue = WTFMove(m_transientRegistrationNodes);

    ASSERT(m_nodeKeptAlive);
    m_nodeKeptAlive = nullptr; // Balanced in observeSubtreeNodeWillDetach.

    return returnValue;
}

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_node != &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_node);
    if (!m_transientRegistrationNodes)
        return;
    for (auto& node : *m_transientRegistrationNodes)
        nodes.add(node.ptr());
}

} // namespace WebCore