/*

 * Copyright (C) 2010 Julien Chaffraix <jchaffraix@webkit.org>

 * All right 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "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 THE COPYRIGHT

 * OWNER 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 "XMLHttpRequestProgressEventThrottle.h"

#include "EventTarget.h"

#include "XMLHttpRequestProgressEvent.h"

namespace WebCore {

const double XMLHttpRequestProgressEventThrottle::minimumProgressEventDispatchingIntervalInSeconds = .05; // 50 ms per specification.

XMLHttpRequestProgressEventThrottle::XMLHttpRequestProgressEventThrottle(EventTarget* target)

    : m_target(target)

    , m_loaded(0)

    , m_total(0)

    , m_suspended(false)

{

    ASSERT(target);

}

XMLHttpRequestProgressEventThrottle::~XMLHttpRequestProgressEventThrottle()

{

}

void XMLHttpRequestProgressEventThrottle::dispatchProgressEvent(bool lengthComputable, unsigned loaded, unsigned total)

{

    ASSERT(!suspended());

    if (!isActive()) {

        // The timer is not active so the least frequent event for now is every byte.

        // Just go ahead and dispatch the event.

        // We should not have any pending loaded & total information from a previous run.

        ASSERT(!m_loaded);

        ASSERT(!m_total);

        dispatchEvent(XMLHttpRequestProgressEvent::create(eventNames().progressEvent, lengthComputable, loaded, total));

        startRepeating(minimumProgressEventDispatchingIntervalInSeconds);

        return;

    }

    // The timer is already active so minimumProgressEventDispatchingIntervalInSeconds is the least frequent event.

    m_lengthComputable = lengthComputable;

    m_loaded = loaded;

    m_total = total;

}

void XMLHttpRequestProgressEventThrottle::dispatchEvent(PassRefPtr<Event> event, ProgressEventAction progressEventAction)

{

    ASSERT(!suspended());

    // We should not have any pending events from a previous resume.

    ASSERT(!m_pausedEvent);

    if (progressEventAction == FlushProgressEvent)

        flushProgressEvent();

    m_target->dispatchEvent(event);

}

void XMLHttpRequestProgressEventThrottle::flushProgressEvent()

{

    if (!hasEventToDispatch())

        return;

    PassRefPtr<Event> event = XMLHttpRequestProgressEvent::create(eventNames().progressEvent, m_lengthComputable, m_loaded, m_total);

    m_loaded = 0;

    m_total = 0;

    // We stop the timer as this is called when no more events are supposed to occur.

    stop();

    m_target->dispatchEvent(event);

}

void XMLHttpRequestProgressEventThrottle::dispatchPausedEvent()

{

    ASSERT(!suspended());

    if (!m_pausedEvent)

        return;

    m_target->dispatchEvent(m_pausedEvent);

    m_pausedEvent = 0;

}

void XMLHttpRequestProgressEventThrottle::fired()

{

    ASSERT(isActive());

    ASSERT(!suspended());

    ASSERT(!m_pausedEvent);

    if (!hasEventToDispatch()) {

        // No progress event was queued since the previous dispatch, we can safely stop the timer.

        stop();

        return;

    }

    m_target->dispatchEvent(XMLHttpRequestProgressEvent::create(eventNames().progressEvent, m_lengthComputable, m_loaded, m_total));

    m_total = 0;

    m_loaded = 0;

}

bool XMLHttpRequestProgressEventThrottle::hasEventToDispatch() const

{

    return (m_total || m_loaded) && isActive();

}

void XMLHttpRequestProgressEventThrottle::suspend()

{

    ASSERT(!m_pausedEvent);

    m_suspended = true;

    // If we have a progress event waiting to be dispatched,

    // just queue it.

    if (hasEventToDispatch()) {

        m_pausedEvent = XMLHttpRequestProgressEvent::create(eventNames().progressEvent, m_lengthComputable, m_loaded, m_total);

        m_total = 0;

        m_loaded = 0;

    }

    stop();

}

void XMLHttpRequestProgressEventThrottle::resume()

{

    ASSERT(!m_loaded);

    ASSERT(!m_total);

    m_suspended = false;

    dispatchPausedEvent();

}

} // namespace WebCore