/*
 * Copyright (C) 2012 Google Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "IdTargetObserverRegistry.h"

#include "IdTargetObserver.h"

namespace WebCore {

IdTargetObserverRegistry::IdTargetObserverRegistry() = default;

IdTargetObserverRegistry::~IdTargetObserverRegistry() = default;

void IdTargetObserverRegistry::addObserver(const AtomString& id, IdTargetObserver& observer)
{
    if (id.isEmpty())
        return;
    
    IdToObserverSetMap::AddResult result = m_registry.ensure(id, [] {
        return makeUnique<ObserverSet>();
    });

    result.iterator->value->observers.add(observer);
}

void IdTargetObserverRegistry::removeObserver(const AtomString& id, IdTargetObserver& observer)
{
    if (id.isEmpty() || m_registry.isEmpty())
        return;

    IdToObserverSetMap::iterator iter = m_registry.find(id);

    CheckedPtr set = iter->value.get();
    set->observers.remove(observer);
    if (set->observers.isEmpty() && set != m_notifyingObserversInSet) {
        set = nullptr;
        m_registry.remove(iter);
    }
}

void IdTargetObserverRegistry::notifyObserversInternal(const AtomString& id)
{
    ASSERT(!m_registry.isEmpty());

    m_notifyingObserversInSet = m_registry.get(id);
    if (!m_notifyingObserversInSet)
        return;

    for (auto& observer : copyToVector(m_notifyingObserversInSet->observers)) {
        if (m_notifyingObserversInSet->observers.contains(observer))
            observer->idTargetChanged();
    }

    bool hasRemainingObservers = !m_notifyingObserversInSet->observers.isEmpty();
    m_notifyingObserversInSet = nullptr;

    if (!hasRemainingObservers)
        m_registry.remove(id);
}

IdTargetObserverRegistry::ObserverSet::ObserverSet() = default;

IdTargetObserverRegistry::ObserverSet::~ObserverSet() = default;

} // namespace WebCore
