/*

 * Copyright (C) 2010 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:

 *

 *     * Redistributions of source code must retain the above copyright

 * notice, this list of conditions and the following disclaimer.

 *     * 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.

 *     * Neither the name of Google Inc. nor the names of its

 * contributors may be used to endorse or promote products derived from

 * this software without specific prior written permission.

 *

 * 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 "Timing.h"

#if ENABLE(WEB_TIMING)

#include "DocumentLoader.h"

#include "Frame.h"

#include "ResourceLoadTiming.h"

#include "ResourceResponse.h"

namespace WebCore {

static unsigned long long toIntegerMilliseconds(double seconds)

{

    ASSERT(seconds >= 0);

    return static_cast<unsigned long long>(seconds * 1000.0);

}

static double getPossiblySkewedTimeInKnownRange(double skewedTime, double lowerBound, double upperBound)

{

#if PLATFORM(CHROMIUM)

    // The chromium port's currentTime() implementation only syncs with the

    // system clock every 60 seconds. So it is possible for timing marks

    // collected in different threads or processes to have a small skew.

    // FIXME: It may be possible to add a currentTimeFromSystemTime() method

    // that eliminates the skew.

    if (skewedTime <= lowerBound)

        return lowerBound;

    if (skewedTime >= upperBound)

        return upperBound;

#else

    ASSERT_UNUSED(lowerBound, skewedTime >= lowerBound);

    ASSERT_UNUSED(upperBound, skewedTime <= upperBound);

#endif

    return skewedTime;

}

Timing::Timing(Frame* frame)

    : m_frame(frame)

{

}

Frame* Timing::frame() const

{

    return m_frame;

}

void Timing::disconnectFrame()

{

    m_frame = 0;

}

unsigned long long Timing::navigationStart() const

{

    DocumentLoadTiming* timing = documentLoadTiming();

    if (!timing)

        return 0;

    return toIntegerMilliseconds(timing->navigationStart);

}

unsigned long long Timing::unloadEventEnd() const

{

    DocumentLoadTiming* timing = documentLoadTiming();

    if (!timing)

        return 0;

    return toIntegerMilliseconds(timing->unloadEventEnd);

}

unsigned long long Timing::redirectStart() const

{

    DocumentLoadTiming* timing = documentLoadTiming();

    if (!timing)

        return 0;

    return toIntegerMilliseconds(timing->redirectStart);

}

unsigned long long Timing::redirectEnd() const

{

    DocumentLoadTiming* timing = documentLoadTiming();

    if (!timing)

        return 0;

    return toIntegerMilliseconds(timing->redirectEnd);

}

unsigned long long Timing::fetchStart() const

{

    DocumentLoadTiming* timing = documentLoadTiming();

    if (!timing)

        return 0;

    return toIntegerMilliseconds(timing->fetchStart);

}

unsigned long long Timing::domainLookupStart() const

{

    ResourceLoadTiming* timing = resourceLoadTiming();

    if (!timing)

        return 0;

    // This will be -1 when a DNS request is not performed.

    // Rather than exposing a special value that indicates no DNS, we "backfill" with fetchStart.

    int dnsStart = timing->dnsStart;

    if (dnsStart < 0)

        return fetchStart();

    return resourceLoadTimeRelativeToAbsolute(dnsStart);

}

unsigned long long Timing::domainLookupEnd() const

{

    ResourceLoadTiming* timing = resourceLoadTiming();

    if (!timing)

        return 0;

    // This will be -1 when a DNS request is not performed.

    // Rather than exposing a special value that indicates no DNS, we "backfill" with domainLookupStart.

    int dnsEnd = timing->dnsEnd;

    if (dnsEnd < 0)

        return domainLookupStart();

    return resourceLoadTimeRelativeToAbsolute(dnsEnd);

}

unsigned long long Timing::connectStart() const

{

    ResourceLoadTiming* timing = resourceLoadTiming();

    if (!timing)

        return 0;

    // This will be -1 when a new connection is not established.

    // Rather than exposing a special value that indicates no new connection, we "backfill" with domainLookupEnd.

    int connectStart = timing->connectStart;

    if (connectStart < 0)

        return domainLookupEnd();

    return resourceLoadTimeRelativeToAbsolute(connectStart);

}

unsigned long long Timing::connectEnd() const

{

    ResourceLoadTiming* timing = resourceLoadTiming();

    if (!timing)

        return 0;

    // This will be -1 when a new connection is not established.

    // Rather than exposing a special value that indicates no new connection, we "backfill" with connectStart.

    int connectEnd = timing->connectEnd;

    if (connectEnd < 0)

        return connectStart();

    return resourceLoadTimeRelativeToAbsolute(connectEnd);

}

unsigned long long Timing::requestStart() const

{

    ResourceLoadTiming* timing = resourceLoadTiming();

    if (!timing)

        return 0;

    ASSERT(timing->sendStart >= 0);

    return resourceLoadTimeRelativeToAbsolute(timing->sendStart);

}

unsigned long long Timing::requestEnd() const

{

    ResourceLoadTiming* timing = resourceLoadTiming();

    if (!timing)

        return 0;

    ASSERT(timing->sendEnd >= 0);

    return resourceLoadTimeRelativeToAbsolute(timing->sendEnd);

}

unsigned long long Timing::responseStart() const

{

    ResourceLoadTiming* timing = resourceLoadTiming();

    if (!timing)

        return 0;

    // FIXME: Response start needs to be the time of the first received byte.

    // However, the ResourceLoadTiming API currently only supports the time

    // the last header byte was received. For many responses with reasonable

    // sized cookies, the HTTP headers fit into a single packet so this time

    // is basically equivalent. But for some responses, particularly those with

    // headers larger than a single packet, this time will be too late.

    ASSERT(timing->receiveHeadersEnd >= 0);

    return resourceLoadTimeRelativeToAbsolute(timing->receiveHeadersEnd);

}

unsigned long long Timing::responseEnd() const

{

    DocumentLoadTiming* timing = documentLoadTiming();

    if (!timing)

        return 0;

    return toIntegerMilliseconds(timing->responseEnd);

}

unsigned long long Timing::loadEventStart() const

{

    DocumentLoadTiming* timing = documentLoadTiming();

    if (!timing)

        return 0;

    return toIntegerMilliseconds(timing->loadEventStart);

}

unsigned long long Timing::loadEventEnd() const

{

    DocumentLoadTiming* timing = documentLoadTiming();

    if (!timing)

        return 0;

    return toIntegerMilliseconds(timing->loadEventEnd);

}

DocumentLoader* Timing::documentLoader() const

{

    if (!m_frame)

        return 0;

    return m_frame->loader()->documentLoader();

}

DocumentLoadTiming* Timing::documentLoadTiming() const

{

    DocumentLoader* loader = documentLoader();

    if (!loader)

        return 0;

    return loader->timing();

}

ResourceLoadTiming* Timing::resourceLoadTiming() const

{

    DocumentLoader* loader = documentLoader();

    if (!loader)

        return 0;

    return loader->response().resourceLoadTiming();

}

unsigned long long Timing::resourceLoadTimeRelativeToAbsolute(int relativeSeconds) const

{

    ASSERT(relativeSeconds >= 0);

    ResourceLoadTiming* resourceTiming = resourceLoadTiming();

    ASSERT(resourceTiming);

    DocumentLoadTiming* documentTiming = documentLoadTiming();

    ASSERT(documentTiming);

    // The ResourceLoadTiming API's requestTime is the base time to which all

    // other marks are relative. So to get an absolute time, we must add it to

    // the relative marks.

    //

    // Since ResourceLoadTimings came from the network platform layer, we must

    // check them for skew because they may be from another thread/process.

    double baseTime = getPossiblySkewedTimeInKnownRange(resourceTiming->requestTime, documentTiming->fetchStart, documentTiming->responseEnd - (resourceTiming->receiveHeadersEnd / 1000.0));

    return toIntegerMilliseconds(baseTime) + relativeSeconds;

}

} // namespace WebCore

#endif // ENABLE(WEB_TIMING)