/*

 * Copyright (C) 2008 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 COMPUTER, 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 COMPUTER, 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 "DOMTimer.h"

#include "InspectorTimelineAgent.h"

#include "ScheduledAction.h"

#include "ScriptExecutionContext.h"

#include <wtf/HashSet.h>

#include <wtf/StdLibExtras.h>

using namespace std;

namespace WebCore {

static const int maxTimerNestingLevel = 5;

static const double oneMillisecond = 0.001;

double DOMTimer::s_minTimerInterval = 0.010; // 10 milliseconds

static int timerNestingLevel = 0;

DOMTimer::DOMTimer(ScriptExecutionContext* context, PassOwnPtr<ScheduledAction> action, int timeout, bool singleShot)

    : SuspendableTimer(context)

    , m_action(action)

{

    static int lastUsedTimeoutId = 0;

    ++lastUsedTimeoutId;

    // Avoid wraparound going negative on us.

    if (lastUsedTimeoutId <= 0)

        lastUsedTimeoutId = 1;

    m_timeoutId = lastUsedTimeoutId;

    m_nestingLevel = timerNestingLevel + 1;

    scriptExecutionContext()->addTimeout(m_timeoutId, this);

    double intervalMilliseconds = max(oneMillisecond, timeout * oneMillisecond);

    // Use a minimum interval of 10 ms to match other browsers, but only once we've

    // nested enough to notice that we're repeating.

    // Faster timers might be "better", but they're incompatible.

    if (intervalMilliseconds < s_minTimerInterval && m_nestingLevel >= maxTimerNestingLevel)

        intervalMilliseconds = s_minTimerInterval;

    if (singleShot)

        startOneShot(intervalMilliseconds);

    else

        startRepeating(intervalMilliseconds);

}

DOMTimer::~DOMTimer()

{

    if (scriptExecutionContext())

        scriptExecutionContext()->removeTimeout(m_timeoutId);

}

int DOMTimer::install(ScriptExecutionContext* context, PassOwnPtr<ScheduledAction> action, int timeout, bool singleShot)

{

    // DOMTimer constructor links the new timer into a list of ActiveDOMObjects held by the 'context'.

    // The timer is deleted when context is deleted (DOMTimer::contextDestroyed) or explicitly via DOMTimer::removeById(),

    // or if it is a one-time timer and it has fired (DOMTimer::fired).

    DOMTimer* timer = new DOMTimer(context, action, timeout, singleShot);

#if ENABLE(INSPECTOR)

    if (InspectorTimelineAgent* timelineAgent = InspectorTimelineAgent::retrieve(context))

        timelineAgent->didInstallTimer(timer->m_timeoutId, timeout, singleShot);

#endif    

    return timer->m_timeoutId;

}

void DOMTimer::removeById(ScriptExecutionContext* context, int timeoutId)

{

    // timeout IDs have to be positive, and 0 and -1 are unsafe to

    // even look up since they are the empty and deleted value

    // respectively

    if (timeoutId <= 0)

        return;

#if ENABLE(INSPECTOR)

    if (InspectorTimelineAgent* timelineAgent = InspectorTimelineAgent::retrieve(context))

        timelineAgent->didRemoveTimer(timeoutId);

#endif

    delete context->findTimeout(timeoutId);

}

void DOMTimer::fired()

{

    ScriptExecutionContext* context = scriptExecutionContext();

    timerNestingLevel = m_nestingLevel;

#if ENABLE(INSPECTOR)

    if (InspectorTimelineAgent* timelineAgent = InspectorTimelineAgent::retrieve(context))

        timelineAgent->willFireTimer(m_timeoutId);

#endif

    // Simple case for non-one-shot timers.

    if (isActive()) {

        if (repeatInterval() && repeatInterval() < s_minTimerInterval) {

            m_nestingLevel++;

            if (m_nestingLevel >= maxTimerNestingLevel)

                augmentRepeatInterval(s_minTimerInterval - repeatInterval());

        }

        // No access to member variables after this point, it can delete the timer.

        m_action->execute(context);

#if ENABLE(INSPECTOR)

        if (InspectorTimelineAgent* timelineAgent = InspectorTimelineAgent::retrieve(context))

            timelineAgent->didFireTimer();

#endif

        return;

    }

    // Delete timer before executing the action for one-shot timers.

    OwnPtr<ScheduledAction> action = m_action.release();

    // No access to member variables after this point.

    delete this;

    action->execute(context);

#if ENABLE(INSPECTOR)

    if (InspectorTimelineAgent* timelineAgent = InspectorTimelineAgent::retrieve(context))

        timelineAgent->didFireTimer();

#endif

    timerNestingLevel = 0;

}

void DOMTimer::contextDestroyed()

{

    SuspendableTimer::contextDestroyed();

    delete this;

}

void DOMTimer::stop()

{

    SuspendableTimer::stop();

    // Need to release JS objects potentially protected by ScheduledAction

    // because they can form circular references back to the ScriptExecutionContext

    // which will cause a memory leak.

    m_action.clear();

}

} // namespace WebCore