/*

 * Copyright (C) 2009 Apple 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 "PluginHalter.h"

#include "HaltablePlugin.h"

#include <wtf/CurrentTime.h>

#include <wtf/Vector.h>

using namespace std;

namespace WebCore {

PluginHalter::PluginHalter(PluginHalterClient* client)

    : m_client(client)

    , m_timer(this, &PluginHalter::timerFired)

    , m_pluginAllowedRunTime(numeric_limits<unsigned>::max())

{

    ASSERT_ARG(client, client);

}

void PluginHalter::didStartPlugin(HaltablePlugin* obj)

{

    ASSERT_ARG(obj, obj);

    ASSERT_ARG(obj, !m_plugins.contains(obj));

    if (!m_client->enabled())

        return;

    double currentTime = WTF::currentTime();

    m_plugins.add(obj, currentTime);

    if (m_plugins.size() == 1)

        m_oldestStartTime = currentTime;

    startTimerIfNecessary();

}

void PluginHalter::didStopPlugin(HaltablePlugin* obj)

{

    if (!m_client->enabled())

        return;

    m_plugins.remove(obj);

}

void PluginHalter::timerFired(Timer<PluginHalter>*)

{

    if (m_plugins.isEmpty())

        return;

    Vector<HaltablePlugin*> plugins;

    copyKeysToVector(m_plugins, plugins);

    // Plug-ins older than this are candidates to be halted.

    double pluginCutOffTime = WTF::currentTime() - m_pluginAllowedRunTime;

    m_oldestStartTime = numeric_limits<double>::max();

    for (size_t i = 0; i < plugins.size(); ++i) {

        double thisStartTime = m_plugins.get(plugins[i]);

        if (thisStartTime > pluginCutOffTime) {

            // This plug-in is too young to be halted. We find the oldest

            // plug-in that is not old enough to be halted and use it to set

            // the timer's next fire time.

            if (thisStartTime < m_oldestStartTime)

                m_oldestStartTime = thisStartTime;

            continue;

        }

        if (m_client->shouldHaltPlugin(plugins[i]->node()))

            plugins[i]->halt();

        m_plugins.remove(plugins[i]);

    }

    startTimerIfNecessary();

}

void PluginHalter::startTimerIfNecessary()

{

    if (m_timer.isActive())

        return;

    if (m_plugins.isEmpty())

        return;

    double nextFireInterval = static_cast<double>(m_pluginAllowedRunTime) - (currentTime() - m_oldestStartTime);

    m_timer.startOneShot(nextFireInterval < 0 ? 0 : nextFireInterval);

}

} // namespace WebCore