Source/WebCore/dom/MutationObserverInterestGroup.cpp

/*
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#include "config.h"

#include "MutationObserverInterestGroup.h"

#include "MutationObserverRegistration.h"
#include "MutationRecord.h"

namespace WebCore {

std::unique_ptr<MutationObserverInterestGroup> MutationObserverInterestGroup::createIfNeeded(Node& target, MutationObserver::MutationType type, MutationRecordDeliveryOptions oldValueFlag, const QualifiedName* attributeName)
{
    ASSERT((type == MutationObserver::Attributes && attributeName) || !attributeName);
    HashMap<MutationObserver*, MutationRecordDeliveryOptions> observers;
    target.getRegisteredMutationObserversOfType(observers, type, attributeName);
    if (observers.isEmpty())
        return nullptr;

    return std::make_unique<MutationObserverInterestGroup>(observers, oldValueFlag);
}

MutationObserverInterestGroup::MutationObserverInterestGroup(HashMap<MutationObserver*, MutationRecordDeliveryOptions>& observers, MutationRecordDeliveryOptions oldValueFlag)
    : m_oldValueFlag(oldValueFlag)
{
    ASSERT(!observers.isEmpty());
    m_observers.swap(observers);
}

bool MutationObserverInterestGroup::isOldValueRequested()
{
    for (auto options : m_observers.values()) {
        if (hasOldValue(options))
            return true;
    }
    return false;
}

void MutationObserverInterestGroup::enqueueMutationRecord(PassRefPtr<MutationRecord> prpMutation)
{
    RefPtr<MutationRecord> mutation = prpMutation;
    RefPtr<MutationRecord> mutationWithNullOldValue;
    for (auto& observerOptionsPair : m_observers) {
        MutationObserver* observer = observerOptionsPair.key;
        if (hasOldValue(observerOptionsPair.value)) {
            observer->enqueueMutationRecord(mutation);
            continue;
        }
        if (!mutationWithNullOldValue) {
            if (mutation->oldValue().isNull())
                mutationWithNullOldValue = mutation;
            else
                mutationWithNullOldValue = MutationRecord::createWithNullOldValue(mutation).get();
        }
        observer->enqueueMutationRecord(mutationWithNullOldValue);
    }
}

} // namespace WebCore