/*
 * Copyright (C) 2007, 2008, 2009, 2010 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"

#if ENABLE(VIDEO)
#include "HTMLMediaElement.h"

#include "Chrome.h"
#include "ChromeClient.h"
#include "ClientRect.h"
#include "ClientRectList.h"
#include "CSSHelper.h"
#include "CSSPropertyNames.h"
#include "CSSValueKeywords.h"
#include "ContentType.h"
#include "DocLoader.h"
#include "Event.h"
#include "EventNames.h"
#include "ExceptionCode.h"
#include "Frame.h"
#include "FrameLoader.h"
#include "FrameLoaderClient.h"
#include "FrameView.h"
#include "HTMLDocument.h"
#include "HTMLNames.h"
#include "HTMLSourceElement.h"
#include "HTMLVideoElement.h"
#include "MIMETypeRegistry.h"
#include "MappedAttribute.h"
#include "MediaDocument.h"
#include "MediaError.h"
#include "MediaList.h"
#include "MediaPlayer.h"
#include "MediaQueryEvaluator.h"
#include "Page.h"
#include "RenderVideo.h"
#include "RenderView.h"
#include "ScriptEventListener.h"
#include "Settings.h"
#include "TimeRanges.h"
#include <limits>
#include <wtf/CurrentTime.h>
#include <wtf/MathExtras.h>

#if USE(ACCELERATED_COMPOSITING)
#include "RenderView.h"
#include "RenderLayerCompositor.h"
#endif

#if ENABLE(PLUGIN_PROXY_FOR_VIDEO)
#include "RenderEmbeddedObject.h"
#include "Widget.h"
#endif

using namespace std;

namespace WebCore {

using namespace HTMLNames;

HTMLMediaElement::HTMLMediaElement(const QualifiedName& tagName, Document* doc)
    : HTMLElement(tagName, doc)
    , m_loadTimer(this, &HTMLMediaElement::loadTimerFired)
    , m_asyncEventTimer(this, &HTMLMediaElement::asyncEventTimerFired)
    , m_progressEventTimer(this, &HTMLMediaElement::progressEventTimerFired)
    , m_playbackProgressTimer(this, &HTMLMediaElement::playbackProgressTimerFired)
    , m_playedTimeRanges()
    , m_playbackRate(1.0f)
    , m_defaultPlaybackRate(1.0f)
    , m_webkitPreservesPitch(true)
    , m_networkState(NETWORK_EMPTY)
    , m_readyState(HAVE_NOTHING)
    , m_volume(1.0f)
    , m_lastSeekTime(0)
    , m_previousProgress(0)
    , m_previousProgressTime(numeric_limits<double>::max())
    , m_lastTimeUpdateEventWallTime(0)
    , m_lastTimeUpdateEventMovieTime(numeric_limits<float>::max())
    , m_loadState(WaitingForSource)
    , m_currentSourceNode(0)
    , m_player(0)
    , m_restrictions(NoRestrictions)
    , m_preload(MediaPlayer::Auto)
    , m_playing(false)
    , m_processingMediaPlayerCallback(0)
    , m_isWaitingUntilMediaCanStart(false)
    , m_processingLoad(false)
    , m_delayingTheLoadEvent(false)
    , m_haveFiredLoadedData(false)
    , m_inActiveDocument(true)
    , m_autoplaying(true)
    , m_muted(false)
    , m_paused(true)
    , m_seeking(false)
    , m_sentStalledEvent(false)
    , m_sentEndEvent(false)
    , m_pausedInternal(false)
    , m_sendProgressEvents(true)
    , m_isFullscreen(false)
    , m_closedCaptionsVisible(false)
#if ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    , m_needWidgetUpdate(false)
#endif
    , m_dispatchingCanPlayEvent(false)
{
    document()->registerForDocumentActivationCallbacks(this);
    document()->registerForMediaVolumeCallbacks(this);
}

HTMLMediaElement::~HTMLMediaElement()
{
    if (m_isWaitingUntilMediaCanStart) {
        if (Page* page = document()->page())
            page->removeMediaCanStartListener(this);
    }

    document()->unregisterForDocumentActivationCallbacks(this);
    document()->unregisterForMediaVolumeCallbacks(this);
}

void HTMLMediaElement::willMoveToNewOwnerDocument()
{
    document()->unregisterForDocumentActivationCallbacks(this);
    document()->unregisterForMediaVolumeCallbacks(this);
    HTMLElement::willMoveToNewOwnerDocument();
}

void HTMLMediaElement::didMoveToNewOwnerDocument()
{
    document()->registerForDocumentActivationCallbacks(this);
    document()->registerForMediaVolumeCallbacks(this);
    HTMLElement::didMoveToNewOwnerDocument();
}


bool HTMLMediaElement::checkDTD(const Node* newChild)
{
    return newChild->hasTagName(sourceTag) || HTMLElement::checkDTD(newChild);
}

void HTMLMediaElement::attributeChanged(Attribute* attr, bool preserveDecls)
{
    HTMLElement::attributeChanged(attr, preserveDecls);

    const QualifiedName& attrName = attr->name();
    if (attrName == srcAttr) {
        // don't have a src or any <source> children, trigger load
        if (inDocument() && m_loadState == WaitingForSource)
            scheduleLoad();
    } 
#if !ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    else if (attrName == controlsAttr) {
        if (!isVideo() && attached() && (controls() != (renderer() != 0))) {
            detach();
            attach();
        }
        if (renderer())
            renderer()->updateFromElement();
    }
#endif
}

void HTMLMediaElement::parseMappedAttribute(MappedAttribute* attr)
{
    const QualifiedName& attrName = attr->name();

    if (attrName == preloadAttr) {
        String value = attr->value();

        if (equalIgnoringCase(value, "none"))
            m_preload = MediaPlayer::None;
        else if (equalIgnoringCase(value, "metadata"))
            m_preload = MediaPlayer::MetaData;
        else {
            // The spec does not define an "invalid value default" but "auto" is suggested as the
            // "missing value default", so use it for everything except "none" and "metadata"
            m_preload = MediaPlayer::Auto;
        }

        // The attribute must be ignored if the autoplay attribute is present
        if (!autoplay() && m_player)
            m_player->setPreload(m_preload);

    } else if (attrName == onabortAttr)
        setAttributeEventListener(eventNames().abortEvent, createAttributeEventListener(this, attr));
    else if (attrName == onbeforeloadAttr)
        setAttributeEventListener(eventNames().beforeloadEvent, createAttributeEventListener(this, attr));
    else if (attrName == oncanplayAttr)
        setAttributeEventListener(eventNames().canplayEvent, createAttributeEventListener(this, attr));
    else if (attrName == oncanplaythroughAttr)
        setAttributeEventListener(eventNames().canplaythroughEvent, createAttributeEventListener(this, attr));
    else if (attrName == ondurationchangeAttr)
        setAttributeEventListener(eventNames().durationchangeEvent, createAttributeEventListener(this, attr));
    else if (attrName == onemptiedAttr)
        setAttributeEventListener(eventNames().emptiedEvent, createAttributeEventListener(this, attr));
    else if (attrName == onendedAttr)
        setAttributeEventListener(eventNames().endedEvent, createAttributeEventListener(this, attr));
    else if (attrName == onerrorAttr)
        setAttributeEventListener(eventNames().errorEvent, createAttributeEventListener(this, attr));
    else if (attrName == onloadAttr)
        setAttributeEventListener(eventNames().loadEvent, createAttributeEventListener(this, attr));
    else if (attrName == onloadeddataAttr)
        setAttributeEventListener(eventNames().loadeddataEvent, createAttributeEventListener(this, attr));
    else if (attrName == onloadedmetadataAttr)
        setAttributeEventListener(eventNames().loadedmetadataEvent, createAttributeEventListener(this, attr));
    else if (attrName == onloadstartAttr)
        setAttributeEventListener(eventNames().loadstartEvent, createAttributeEventListener(this, attr));
    else if (attrName == onpauseAttr)
        setAttributeEventListener(eventNames().pauseEvent, createAttributeEventListener(this, attr));
    else if (attrName == onplayAttr)
        setAttributeEventListener(eventNames().playEvent, createAttributeEventListener(this, attr));
    else if (attrName == onplayingAttr)
        setAttributeEventListener(eventNames().playingEvent, createAttributeEventListener(this, attr));
    else if (attrName == onprogressAttr)
        setAttributeEventListener(eventNames().progressEvent, createAttributeEventListener(this, attr));
    else if (attrName == onratechangeAttr)
        setAttributeEventListener(eventNames().ratechangeEvent, createAttributeEventListener(this, attr));
    else if (attrName == onseekedAttr)
        setAttributeEventListener(eventNames().seekedEvent, createAttributeEventListener(this, attr));
    else if (attrName == onseekingAttr)
        setAttributeEventListener(eventNames().seekingEvent, createAttributeEventListener(this, attr));
    else if (attrName == onstalledAttr)
        setAttributeEventListener(eventNames().stalledEvent, createAttributeEventListener(this, attr));
    else if (attrName == onsuspendAttr)
        setAttributeEventListener(eventNames().suspendEvent, createAttributeEventListener(this, attr));
    else if (attrName == ontimeupdateAttr)
        setAttributeEventListener(eventNames().timeupdateEvent, createAttributeEventListener(this, attr));
    else if (attrName == onvolumechangeAttr)
        setAttributeEventListener(eventNames().volumechangeEvent, createAttributeEventListener(this, attr));
    else if (attrName == onwaitingAttr)
        setAttributeEventListener(eventNames().waitingEvent, createAttributeEventListener(this, attr));
    else if (attrName == onwebkitbeginfullscreenAttr)
        setAttributeEventListener(eventNames().webkitbeginfullscreenEvent, createAttributeEventListener(this, attr));
    else if (attrName == onwebkitendfullscreenAttr)
        setAttributeEventListener(eventNames().webkitendfullscreenEvent, createAttributeEventListener(this, attr));
    else
        HTMLElement::parseMappedAttribute(attr);
}

bool HTMLMediaElement::rendererIsNeeded(RenderStyle* style)
{
#if ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    UNUSED_PARAM(style);
    Frame* frame = document()->frame();
    if (!frame)
        return false;

    return true;
#else
    return controls() ? HTMLElement::rendererIsNeeded(style) : false;
#endif
}

RenderObject* HTMLMediaElement::createRenderer(RenderArena* arena, RenderStyle*)
{
#if ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    return new (arena) RenderEmbeddedObject(this);
#else
    return new (arena) RenderMedia(this);
#endif
}
 
void HTMLMediaElement::insertedIntoDocument()
{
    HTMLElement::insertedIntoDocument();
    if (!src().isEmpty() && m_networkState == NETWORK_EMPTY)
        scheduleLoad();
}

void HTMLMediaElement::removedFromDocument()
{
    if (m_networkState > NETWORK_EMPTY)
        pause(processingUserGesture());
    if (m_isFullscreen)
        exitFullscreen();
    HTMLElement::removedFromDocument();
}

void HTMLMediaElement::attach()
{
    ASSERT(!attached());

#if ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    m_needWidgetUpdate = true;
#endif

    HTMLElement::attach();

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::recalcStyle(StyleChange change)
{
    HTMLElement::recalcStyle(change);

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::scheduleLoad()
{
    if (m_loadTimer.isActive())
        return;
    prepareForLoad();
    m_loadTimer.startOneShot(0);
}

void HTMLMediaElement::scheduleNextSourceChild()
{
    // Schedule the timer to try the next <source> element WITHOUT resetting state ala prepareForLoad.
    m_loadTimer.startOneShot(0);
}

void HTMLMediaElement::scheduleEvent(const AtomicString& eventName)
{
    m_pendingEvents.append(Event::create(eventName, false, true));
    if (!m_asyncEventTimer.isActive())
        m_asyncEventTimer.startOneShot(0);
}

void HTMLMediaElement::asyncEventTimerFired(Timer<HTMLMediaElement>*)
{
    Vector<RefPtr<Event> > pendingEvents;
    ExceptionCode ec = 0;

    m_pendingEvents.swap(pendingEvents);
    unsigned count = pendingEvents.size();
    for (unsigned ndx = 0; ndx < count; ++ndx) {
        if (pendingEvents[ndx]->type() == eventNames().canplayEvent) {
            m_dispatchingCanPlayEvent = true;
            dispatchEvent(pendingEvents[ndx].release(), ec);
            m_dispatchingCanPlayEvent = false;
        } else
            dispatchEvent(pendingEvents[ndx].release(), ec);
    }
}

void HTMLMediaElement::loadTimerFired(Timer<HTMLMediaElement>*)
{
    if (m_loadState == LoadingFromSourceElement)
        loadNextSourceChild();
    else
        loadInternal();
}

static String serializeTimeOffset(float time)
{
    String timeString = String::number(time);
    // FIXME serialize time offset values properly (format not specified yet)
    timeString.append("s");
    return timeString;
}

static float parseTimeOffset(const String& timeString, bool* ok = 0)
{
    const UChar* characters = timeString.characters();
    unsigned length = timeString.length();
    
    if (length && characters[length - 1] == 's')
        length--;
    
    // FIXME parse time offset values (format not specified yet)
    float val = charactersToFloat(characters, length, ok);
    return val;
}

float HTMLMediaElement::getTimeOffsetAttribute(const QualifiedName& name, float valueOnError) const
{
    bool ok;
    String timeString = getAttribute(name);
    float result = parseTimeOffset(timeString, &ok);
    if (ok)
        return result;
    return valueOnError;
}

void HTMLMediaElement::setTimeOffsetAttribute(const QualifiedName& name, float value)
{
    setAttribute(name, serializeTimeOffset(value));
}

PassRefPtr<MediaError> HTMLMediaElement::error() const 
{
    return m_error;
}

KURL HTMLMediaElement::src() const
{
    return document()->completeURL(getAttribute(srcAttr));
}

void HTMLMediaElement::setSrc(const String& url)
{
    setAttribute(srcAttr, url);
}

String HTMLMediaElement::currentSrc() const
{
    return m_currentSrc;
}

HTMLMediaElement::NetworkState HTMLMediaElement::networkState() const
{
    return m_networkState;
}

String HTMLMediaElement::canPlayType(const String& mimeType) const
{
    MediaPlayer::SupportsType support = MediaPlayer::supportsType(ContentType(mimeType));
    String canPlay;

    // 4.8.10.3
    switch (support)
    {
        case MediaPlayer::IsNotSupported:
            canPlay = "";
            break;
        case MediaPlayer::MayBeSupported:
            canPlay = "maybe";
            break;
        case MediaPlayer::IsSupported:
            canPlay = "probably";
            break;
    }
    
    return canPlay;
}

void HTMLMediaElement::load(bool isUserGesture, ExceptionCode& ec)
{
    if (m_restrictions & RequireUserGestureForLoadRestriction && !isUserGesture)
        ec = INVALID_STATE_ERR;
    else {
        prepareForLoad();
        loadInternal();
    }
}

void HTMLMediaElement::prepareForLoad()
{
    // Perform the cleanup required for the resource load algorithm to run.
    stopPeriodicTimers();
    m_loadTimer.stop();
    m_sentStalledEvent = false;
    m_haveFiredLoadedData = false;

    // 2 - Abort any already-running instance of the resource selection algorithm for this element.
    m_currentSourceNode = 0;

    // 3 - If there are any tasks from the media element's media element event task source in 
    // one of the task queues, then remove those tasks.
    cancelPendingEventsAndCallbacks();
}

void HTMLMediaElement::loadInternal()
{
    // If we can't start a load right away, start it later.
    Page* page = document()->page();
    if (page && !page->canStartMedia()) {
        if (m_isWaitingUntilMediaCanStart)
            return;
        page->addMediaCanStartListener(this);
        m_isWaitingUntilMediaCanStart = true;
        return;
    }

    // If the load() method for this element is already being invoked, then abort these steps.
    if (m_processingLoad)
        return;
    m_processingLoad = true;
    
    // Steps 1 and 2 were done in prepareForLoad()

    // 3 - If the media element's networkState is set to NETWORK_LOADING or NETWORK_IDLE, queue
    // a task to fire a simple event named abort at the media element.
    if (m_networkState == NETWORK_LOADING || m_networkState == NETWORK_IDLE)
        scheduleEvent(eventNames().abortEvent);

    // 4
    if (m_networkState != NETWORK_EMPTY) {
        m_networkState = NETWORK_EMPTY;
        m_readyState = HAVE_NOTHING;
        m_paused = true;
        m_seeking = false;
        if (m_player) {
            m_player->pause();
            m_playing = false;
            m_player->seek(0);
        }
        scheduleEvent(eventNames().emptiedEvent);
    }

    // 5 - Set the playbackRate attribute to the value of the defaultPlaybackRate attribute.
    setPlaybackRate(defaultPlaybackRate());

    // 6 - Set the error attribute to null and the autoplaying flag to true.
    m_error = 0;
    m_autoplaying = true;

    m_playedTimeRanges = TimeRanges::create();
    m_lastSeekTime = 0;
    m_closedCaptionsVisible = false;

    // 7 - Invoke the media element's resource selection algorithm.
    selectMediaResource();
    m_processingLoad = false;
}

void HTMLMediaElement::selectMediaResource()
{
    // 1 - Set the networkState to NETWORK_NO_SOURCE
    m_networkState = NETWORK_NO_SOURCE;

    // 2 - Asynchronously await a stable state.

    // 3 - ... the media element has neither a src attribute ...
    String mediaSrc = getAttribute(srcAttr);
    if (!mediaSrc) {
        // ... nor a source element child: ...
        Node* node;
        for (node = firstChild(); node; node = node->nextSibling()) {
            if (node->hasTagName(sourceTag))
                break;
        }

        if (!node) {
            m_loadState = WaitingForSource;

            // ... set the networkState to NETWORK_EMPTY, and abort these steps
            m_networkState = NETWORK_EMPTY;
            ASSERT(!m_delayingTheLoadEvent);
            return;
        }
    }

    // 4
    m_delayingTheLoadEvent = true;
    m_networkState = NETWORK_LOADING;

    // 5
    scheduleEvent(eventNames().loadstartEvent);

    // 6 - If the media element has a src attribute, then run these substeps
    ContentType contentType("");
    if (!mediaSrc.isNull()) {
        KURL mediaURL = document()->completeURL(mediaSrc);
        if (isSafeToLoadURL(mediaURL, Complain) && dispatchBeforeLoadEvent(mediaURL.string())) {
            m_loadState = LoadingFromSrcAttr;
            loadResource(mediaURL, contentType);
        } else 
            noneSupported();

        return;
    }

    // Otherwise, the source elements will be used
    m_currentSourceNode = 0;
    loadNextSourceChild();
}

void HTMLMediaElement::loadNextSourceChild()
{
    ContentType contentType("");
    KURL mediaURL = selectNextSourceChild(&contentType, Complain);
    if (!mediaURL.isValid()) {
        waitForSourceChange();
        return;
    }

    m_loadState = LoadingFromSourceElement;
    loadResource(mediaURL, contentType);
}

void HTMLMediaElement::loadResource(const KURL& initialURL, ContentType& contentType)
{
    ASSERT(isSafeToLoadURL(initialURL, Complain));

    Frame* frame = document()->frame();
    if (!frame)
        return;
    FrameLoader* loader = frame->loader();
    if (!loader)
        return;

    KURL url(initialURL);
    if (!loader->willLoadMediaElementURL(url))
        return;

    // The resource fetch algorithm 
    m_networkState = NETWORK_LOADING;

    m_currentSrc = url;

    if (m_sendProgressEvents) 
        startProgressEventTimer();

#if !ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    m_player = MediaPlayer::create(this);
#else
    if (!m_player)
        m_player = MediaPlayer::create(this);
#endif

    if (!autoplay())
        m_player->setPreload(m_preload);
    m_player->setPreservesPitch(m_webkitPreservesPitch);
    updateVolume();

    m_player->load(m_currentSrc, contentType);

    if (isVideo() && m_player->canLoadPoster()) {
        KURL posterUrl = static_cast<HTMLVideoElement*>(this)->poster();
        if (!posterUrl.isEmpty())
            m_player->setPoster(posterUrl);
    }

    if (renderer())
        renderer()->updateFromElement();
}

bool HTMLMediaElement::isSafeToLoadURL(const KURL& url, InvalidSourceAction actionIfInvalid)
{
    Frame* frame = document()->frame();
    FrameLoader* loader = frame ? frame->loader() : 0;

    // don't allow remote to local urls, and check with the frame loader client.
    if (!loader || !SecurityOrigin::canLoad(url, String(), document())) {
        if (actionIfInvalid == Complain)
            FrameLoader::reportLocalLoadFailed(frame, url.string());
        return false;
    }
    
    return true;
}

void HTMLMediaElement::startProgressEventTimer()
{
    if (m_progressEventTimer.isActive())
        return;

    m_previousProgressTime = WTF::currentTime();
    m_previousProgress = 0;
    // 350ms is not magic, it is in the spec!
    m_progressEventTimer.startRepeating(0.350);
}

void HTMLMediaElement::waitForSourceChange()
{
    stopPeriodicTimers();
    m_loadState = WaitingForSource;

    // 6.17 - Waiting: Set the element's networkState attribute to the NETWORK_NO_SOURCE value
    m_networkState = NETWORK_NO_SOURCE;

    // 6.18 - Set the element's delaying-the-load-event flag to false. This stops delaying the load event.
    m_delayingTheLoadEvent = false;
}

void HTMLMediaElement::noneSupported()
{
    stopPeriodicTimers();
    m_loadState = WaitingForSource;
    m_currentSourceNode = 0;

    // 5 - Reaching this step indicates that either the URL failed to resolve, or the media
    // resource failed to load. Set the error attribute to a new MediaError object whose
    // code attribute is set to MEDIA_ERR_SRC_NOT_SUPPORTED.
    m_error = MediaError::create(MediaError::MEDIA_ERR_SRC_NOT_SUPPORTED);

    // 6 - Set the element's networkState attribute to the NETWORK_NO_SOURCE value.
    m_networkState = NETWORK_NO_SOURCE;

    // 7 - Queue a task to fire a progress event called error at the media element, in
    // the context of the fetching process that was used to try to obtain the media
    // resource in the resource fetch algorithm.
    scheduleEvent(eventNames().errorEvent);

    // 8 - Set the element's delaying-the-load-event flag to false. This stops delaying the load event.
    m_delayingTheLoadEvent = false;

    // 9 -Abort these steps. Until the load() method is invoked, the element won't attempt to load another resource.

    updatePosterImage();

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::mediaEngineError(PassRefPtr<MediaError> err)
{
    // 1 - The user agent should cancel the fetching process.
    stopPeriodicTimers();
    m_loadState = WaitingForSource;

    // 2 - Set the error attribute to a new MediaError object whose code attribute is 
    // set to MEDIA_ERR_NETWORK/MEDIA_ERR_DECODE.
    m_error = err;

    // 3 - Queue a task to fire a progress event called error at the media element, in
    // the context of the fetching process started by this instance of this algorithm.
    scheduleEvent(eventNames().errorEvent);

    // 4 - Set the element's networkState attribute to the NETWORK_EMPTY value and queue a
    // task to fire a simple event called emptied at the element.
    m_networkState = NETWORK_EMPTY;
    scheduleEvent(eventNames().emptiedEvent);

    // 5 - Set the element's delaying-the-load-event flag to false. This stops delaying the load event.
    m_delayingTheLoadEvent = false;

    // 6 - Abort the overall resource selection algorithm.
    m_currentSourceNode = 0;
}

void HTMLMediaElement::cancelPendingEventsAndCallbacks()
{
    m_pendingEvents.clear();

    for (Node* node = firstChild(); node; node = node->nextSibling()) {
        if (node->hasTagName(sourceTag))
            static_cast<HTMLSourceElement*>(node)->cancelPendingErrorEvent();
    }
}

Document* HTMLMediaElement::mediaPlayerOwningDocument()
{
    Document* d = document();
    
    if (!d)
        d = ownerDocument();
    
    return d;
}

void HTMLMediaElement::mediaPlayerNetworkStateChanged(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();
    setNetworkState(m_player->networkState());
    endProcessingMediaPlayerCallback();
}

void HTMLMediaElement::setNetworkState(MediaPlayer::NetworkState state)
{
    if (state == MediaPlayer::Empty) {
        // just update the cached state and leave, we can't do anything 
        m_networkState = NETWORK_EMPTY;
        return;
    }

    if (state == MediaPlayer::FormatError || state == MediaPlayer::NetworkError || state == MediaPlayer::DecodeError) {
        stopPeriodicTimers();

        // If we failed while trying to load a <source> element, the movie was never parsed, and there are more
        // <source> children, schedule the next one
        if (m_readyState < HAVE_METADATA && m_loadState == LoadingFromSourceElement) {
            m_currentSourceNode->scheduleErrorEvent();
            if (havePotentialSourceChild())
                scheduleNextSourceChild();
            else
                waitForSourceChange();

            return;
        }

        if (state == MediaPlayer::NetworkError)
            mediaEngineError(MediaError::create(MediaError::MEDIA_ERR_NETWORK));
        else if (state == MediaPlayer::DecodeError)
            mediaEngineError(MediaError::create(MediaError::MEDIA_ERR_DECODE));
        else if (state == MediaPlayer::FormatError && m_loadState == LoadingFromSrcAttr)
            noneSupported();

        updatePosterImage();
        return;
    }

    if (state == MediaPlayer::Idle) {
        if (m_networkState > NETWORK_IDLE) {
            stopPeriodicTimers();
            scheduleEvent(eventNames().suspendEvent);
        }
        m_networkState = NETWORK_IDLE;
    }

    if (state == MediaPlayer::Loading) {
        if (m_networkState < NETWORK_LOADING || m_networkState == NETWORK_NO_SOURCE)
            startProgressEventTimer();
        m_networkState = NETWORK_LOADING;
    }

    if (state == MediaPlayer::Loaded) {
        NetworkState oldState = m_networkState;

        m_networkState = NETWORK_LOADED;
        if (oldState < NETWORK_LOADED || oldState == NETWORK_NO_SOURCE) {
            m_progressEventTimer.stop();

            // Schedule one last progress event so we guarantee that at least one is fired
            // for files that load very quickly.
            scheduleEvent(eventNames().progressEvent);

            // Check to see if readyState changes need to be dealt with before sending the 
            // 'load' event so we report 'canplaythrough' first. This is necessary because a
            //  media engine reports readyState and networkState changes separately
            MediaPlayer::ReadyState currentState = m_player->readyState();
            if (static_cast<ReadyState>(currentState) != m_readyState)
                setReadyState(currentState);

            scheduleEvent(eventNames().loadEvent);
        }
    }
}

void HTMLMediaElement::mediaPlayerReadyStateChanged(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();

    setReadyState(m_player->readyState());

    endProcessingMediaPlayerCallback();
}

void HTMLMediaElement::setReadyState(MediaPlayer::ReadyState state)
{
    // Set "wasPotentiallyPlaying" BEFORE updating m_readyState, potentiallyPlaying() uses it
    bool wasPotentiallyPlaying = potentiallyPlaying();

    ReadyState oldState = m_readyState;
    m_readyState = static_cast<ReadyState>(state);

    if (m_readyState == oldState)
        return;
    
    if (m_networkState == NETWORK_EMPTY)
        return;

    if (m_seeking) {
        // 4.8.10.10, step 8
        if (wasPotentiallyPlaying && m_readyState < HAVE_FUTURE_DATA)
            scheduleEvent(eventNames().waitingEvent);

        // 4.8.10.10, step 9
        if (m_readyState < HAVE_CURRENT_DATA) {
            if (oldState >= HAVE_CURRENT_DATA)
                scheduleEvent(eventNames().seekingEvent);
        } else {
            // 4.8.10.10 step 12 & 13.
            finishSeek();
        }

    } else {
        if (wasPotentiallyPlaying && m_readyState < HAVE_FUTURE_DATA) {
            // 4.8.10.9
            scheduleTimeupdateEvent(false);
            scheduleEvent(eventNames().waitingEvent);
        }
    }

    if (m_readyState >= HAVE_METADATA && oldState < HAVE_METADATA) {
        scheduleEvent(eventNames().durationchangeEvent);
        scheduleEvent(eventNames().loadedmetadataEvent);

#if !ENABLE(PLUGIN_PROXY_FOR_VIDEO)
        if (renderer() && renderer()->isVideo()) {
            toRenderVideo(renderer())->videoSizeChanged();
        }
#endif        
        m_delayingTheLoadEvent = false;
        m_player->seek(0);
    }

    bool shouldUpdatePosterImage = false;

    // 4.8.10.7 says loadeddata is sent only when the new state *is* HAVE_CURRENT_DATA: "If the
    // previous ready state was HAVE_METADATA and the new ready state is HAVE_CURRENT_DATA", 
    // but the event table at the end of the spec says it is sent when: "readyState newly 
    // increased to HAVE_CURRENT_DATA  or greater for the first time"
    // We go with the later because it seems useful to count on getting this event
    if (m_readyState >= HAVE_CURRENT_DATA && oldState < HAVE_CURRENT_DATA && !m_haveFiredLoadedData) {
        m_haveFiredLoadedData = true;
        shouldUpdatePosterImage = true;
        scheduleEvent(eventNames().loadeddataEvent);
    }

    bool isPotentiallyPlaying = potentiallyPlaying();
    if (m_readyState == HAVE_FUTURE_DATA && oldState <= HAVE_CURRENT_DATA) {
        scheduleEvent(eventNames().canplayEvent);
        if (isPotentiallyPlaying)
            scheduleEvent(eventNames().playingEvent);
        shouldUpdatePosterImage = true;
    }

    if (m_readyState == HAVE_ENOUGH_DATA && oldState < HAVE_ENOUGH_DATA) {
        if (oldState <= HAVE_CURRENT_DATA)
            scheduleEvent(eventNames().canplayEvent);

        scheduleEvent(eventNames().canplaythroughEvent);

        if (isPotentiallyPlaying && oldState <= HAVE_CURRENT_DATA)
            scheduleEvent(eventNames().playingEvent);

        if (m_autoplaying && m_paused && autoplay()) {
            m_paused = false;
            scheduleEvent(eventNames().playEvent);
            scheduleEvent(eventNames().playingEvent);
        }

        shouldUpdatePosterImage = true;
    }

    if (shouldUpdatePosterImage)
        updatePosterImage();

    updatePlayState();
}

void HTMLMediaElement::progressEventTimerFired(Timer<HTMLMediaElement>*)
{
    ASSERT(m_player);
    if (m_networkState == NETWORK_EMPTY || m_networkState >= NETWORK_LOADED)
        return;

    unsigned progress = m_player->bytesLoaded();
    double time = WTF::currentTime();
    double timedelta = time - m_previousProgressTime;

    if (progress == m_previousProgress) {
        if (timedelta > 3.0 && !m_sentStalledEvent) {
            scheduleEvent(eventNames().stalledEvent);
            m_sentStalledEvent = true;
        }
    } else {
        scheduleEvent(eventNames().progressEvent);
        m_previousProgress = progress;
        m_previousProgressTime = time;
        m_sentStalledEvent = false;
        if (renderer())
            renderer()->updateFromElement();
    }
}

void HTMLMediaElement::rewind(float timeDelta)
{
    ExceptionCode e;
    setCurrentTime(max(currentTime() - timeDelta, minTimeSeekable()), e);
}

void HTMLMediaElement::returnToRealtime()
{
    ExceptionCode e;
    setCurrentTime(maxTimeSeekable(), e);
}  

void HTMLMediaElement::addPlayedRange(float start, float end)
{
    if (!m_playedTimeRanges)
        m_playedTimeRanges = TimeRanges::create();
    m_playedTimeRanges->add(start, end);
}  

bool HTMLMediaElement::supportsSave() const
{
    return m_player ? m_player->supportsSave() : false;
}
    
void HTMLMediaElement::seek(float time, ExceptionCode& ec)
{
    // 4.8.10.10. Seeking
    // 1
    if (m_readyState == HAVE_NOTHING || !m_player) {
        ec = INVALID_STATE_ERR;
        return;
    }

    // 2
    time = min(time, duration());

    // 3
    time = max(time, 0.0f);

    // 4
    RefPtr<TimeRanges> seekableRanges = seekable();
    if (!seekableRanges->contain(time)) {
        ec = INDEX_SIZE_ERR;
        return;
    }
    
    // avoid generating events when the time won't actually change
    float now = currentTime();
    if (time == now)
        return;

    // 5
    if (m_playing) {
        if (m_lastSeekTime < now)
            addPlayedRange(m_lastSeekTime, now);
    }
    m_lastSeekTime = time;

    // 6 - set the seeking flag, it will be cleared when the engine tells is the time has actually changed
    m_seeking = true;

    // 7
    scheduleTimeupdateEvent(false);

    // 8 - this is covered, if necessary, when the engine signals a readystate change

    // 10
    m_player->seek(time);
    m_sentEndEvent = false;
}

void HTMLMediaElement::finishSeek()
{
    // 4.8.10.10 Seeking step 12
    m_seeking = false;

    // 4.8.10.10 Seeking step 13
    scheduleEvent(eventNames().seekedEvent);
}

HTMLMediaElement::ReadyState HTMLMediaElement::readyState() const
{
    return m_readyState;
}

MediaPlayer::MovieLoadType HTMLMediaElement::movieLoadType() const
{
    return m_player ? m_player->movieLoadType() : MediaPlayer::Unknown;
}

bool HTMLMediaElement::hasAudio() const
{
    return m_player ? m_player->hasAudio() : false;
}

bool HTMLMediaElement::seeking() const
{
    return m_seeking;
}

// playback state
float HTMLMediaElement::currentTime() const
{
    if (!m_player)
        return 0;
    if (m_seeking)
        return m_lastSeekTime;
    return m_player->currentTime();
}

void HTMLMediaElement::setCurrentTime(float time, ExceptionCode& ec)
{
    seek(time, ec);
}

float HTMLMediaElement::startTime() const
{
    if (!m_player)
        return 0;
    return m_player->startTime();
}

float HTMLMediaElement::duration() const
{
    if (m_player && m_readyState >= HAVE_METADATA)
        return m_player->duration();

    return numeric_limits<float>::quiet_NaN();
}

bool HTMLMediaElement::paused() const
{
    return m_paused;
}

float HTMLMediaElement::defaultPlaybackRate() const
{
    return m_defaultPlaybackRate;
}

void HTMLMediaElement::setDefaultPlaybackRate(float rate)
{
    if (m_defaultPlaybackRate != rate) {
        m_defaultPlaybackRate = rate;
        scheduleEvent(eventNames().ratechangeEvent);
    }
}

float HTMLMediaElement::playbackRate() const
{
    return m_player ? m_player->rate() : 0;
}

void HTMLMediaElement::setPlaybackRate(float rate)
{
    if (m_playbackRate != rate) {
        m_playbackRate = rate;
        scheduleEvent(eventNames().ratechangeEvent);
    }
    if (m_player && potentiallyPlaying() && m_player->rate() != rate)
        m_player->setRate(rate);
}

bool HTMLMediaElement::webkitPreservesPitch() const
{
    return m_webkitPreservesPitch;
}

void HTMLMediaElement::setWebkitPreservesPitch(bool preservesPitch)
{
    m_webkitPreservesPitch = preservesPitch;
    
    if (!m_player)
        return;

    m_player->setPreservesPitch(preservesPitch);
}

bool HTMLMediaElement::ended() const
{
    // 4.8.10.8 Playing the media resource
    // The ended attribute must return true if the media element has ended 
    // playback and the direction of playback is forwards, and false otherwise.
    return endedPlayback() && m_playbackRate > 0;
}

bool HTMLMediaElement::autoplay() const
{
    return hasAttribute(autoplayAttr);
}

void HTMLMediaElement::setAutoplay(bool b)
{
    setBooleanAttribute(autoplayAttr, b);
}

String HTMLMediaElement::preload() const
{
    switch (m_preload) {
    case MediaPlayer::None:
        return "none";
        break;
    case MediaPlayer::MetaData:
        return "metadata";
        break;
    case MediaPlayer::Auto:
        return "auto";
        break;
    }

    ASSERT_NOT_REACHED();
    return String();
}

void HTMLMediaElement::setPreload(const String& preload)
{
    setAttribute(preloadAttr, preload);
}

void HTMLMediaElement::play(bool isUserGesture)
{
    if (m_restrictions & RequireUserGestureForRateChangeRestriction && !isUserGesture)
        return;

    Document* doc = document();
    Settings* settings = doc->settings();
    if (settings && settings->needsSiteSpecificQuirks() && m_dispatchingCanPlayEvent) {
        // It should be impossible to be processing the canplay event while handling a user gesture
        // since it is dispatched asynchronously.
        ASSERT(!isUserGesture);
        String host = doc->baseURL().host();
        if (host.endsWith(".npr.org", false) || equalIgnoringCase(host, "npr.org"))
            return;
    }
    
    playInternal();
}

void HTMLMediaElement::playInternal()
{
    // 4.8.10.9. Playing the media resource
    if (!m_player || m_networkState == NETWORK_EMPTY)
        scheduleLoad();

    if (endedPlayback()) {
        ExceptionCode unused;
        seek(0, unused);
    }
    
    setPlaybackRate(defaultPlaybackRate());
    
    if (m_paused) {
        m_paused = false;
        scheduleEvent(eventNames().playEvent);

        if (m_readyState <= HAVE_CURRENT_DATA)
            scheduleEvent(eventNames().waitingEvent);
        else if (m_readyState >= HAVE_FUTURE_DATA)
            scheduleEvent(eventNames().playingEvent);
    }
    m_autoplaying = false;

    updatePlayState();
}

void HTMLMediaElement::pause(bool isUserGesture)
{
    if (m_restrictions & RequireUserGestureForRateChangeRestriction && !isUserGesture)
        return;

    pauseInternal();
}


void HTMLMediaElement::pauseInternal()
{
    // 4.8.10.9. Playing the media resource
    if (!m_player || m_networkState == NETWORK_EMPTY)
        scheduleLoad();

    m_autoplaying = false;
    
    if (!m_paused) {
        m_paused = true;
        scheduleTimeupdateEvent(false);
        scheduleEvent(eventNames().pauseEvent);
    }

    updatePlayState();
}

bool HTMLMediaElement::loop() const
{
    return hasAttribute(loopAttr);
}

void HTMLMediaElement::setLoop(bool b)
{
    setBooleanAttribute(loopAttr, b);
}

bool HTMLMediaElement::controls() const
{
    Frame* frame = document()->frame();

    // always show controls when scripting is disabled
    if (frame && !frame->script()->canExecuteScripts(NotAboutToExecuteScript))
        return true;

    return hasAttribute(controlsAttr);
}

void HTMLMediaElement::setControls(bool b)
{
    setBooleanAttribute(controlsAttr, b);
}

float HTMLMediaElement::volume() const
{
    return m_volume;
}

void HTMLMediaElement::setVolume(float vol, ExceptionCode& ec)
{
    if (vol < 0.0f || vol > 1.0f) {
        ec = INDEX_SIZE_ERR;
        return;
    }
    
    if (m_volume != vol) {
        m_volume = vol;
        updateVolume();
        scheduleEvent(eventNames().volumechangeEvent);
    }
}

bool HTMLMediaElement::muted() const
{
    return m_muted;
}

void HTMLMediaElement::setMuted(bool muted)
{
    if (m_muted != muted) {
        m_muted = muted;
        // Avoid recursion when the player reports volume changes.
        if (!processingMediaPlayerCallback()) {
            if (m_player) {
                m_player->setMuted(m_muted);
                if (renderer())
                    renderer()->updateFromElement();
            } else
                updateVolume();
        }
        scheduleEvent(eventNames().volumechangeEvent);
    }
}

void HTMLMediaElement::togglePlayState()
{
    // We can safely call the internal play/pause methods, which don't check restrictions, because
    // this method is only called from the built-in media controller
    if (canPlay())
        playInternal();
    else 
        pauseInternal();
}

void HTMLMediaElement::beginScrubbing()
{
    if (!paused()) {
        if (ended()) {
            // Because a media element stays in non-paused state when it reaches end, playback resumes 
            // when the slider is dragged from the end to another position unless we pause first. Do 
            // a "hard pause" so an event is generated, since we want to stay paused after scrubbing finishes.
            pause(processingUserGesture());
        } else {
            // Not at the end but we still want to pause playback so the media engine doesn't try to
            // continue playing during scrubbing. Pause without generating an event as we will 
            // unpause after scrubbing finishes.
            setPausedInternal(true);
        }
    }
}

void HTMLMediaElement::endScrubbing()
{
    if (m_pausedInternal)
        setPausedInternal(false);
}

// The spec says to fire periodic timeupdate events (those sent while playing) every
// "15 to 250ms", we choose the slowest frequency
static const double maxTimeupdateEventFrequency = 0.25;

void HTMLMediaElement::startPlaybackProgressTimer()
{
    if (m_playbackProgressTimer.isActive())
        return;

    m_previousProgressTime = WTF::currentTime();
    m_previousProgress = 0;
    m_playbackProgressTimer.startRepeating(maxTimeupdateEventFrequency);
}

void HTMLMediaElement::playbackProgressTimerFired(Timer<HTMLMediaElement>*)
{
    ASSERT(m_player);
    if (!m_playbackRate)
        return;

    scheduleTimeupdateEvent(true);
    
    // FIXME: deal with cue ranges here
}

void HTMLMediaElement::scheduleTimeupdateEvent(bool periodicEvent)
{
    double now = WTF::currentTime();
    double timedelta = now - m_lastTimeUpdateEventWallTime;

    // throttle the periodic events
    if (periodicEvent && timedelta < maxTimeupdateEventFrequency)
        return;

    // Some media engines make multiple "time changed" callbacks at the same time, but we only want one
    // event at a given time so filter here
    float movieTime = m_player ? m_player->currentTime() : 0;
    if (movieTime != m_lastTimeUpdateEventMovieTime) {
        scheduleEvent(eventNames().timeupdateEvent);
        m_lastTimeUpdateEventWallTime = now;
        m_lastTimeUpdateEventMovieTime = movieTime;
    }
}

bool HTMLMediaElement::canPlay() const
{
    return paused() || ended() || m_readyState < HAVE_METADATA;
}

float HTMLMediaElement::percentLoaded() const
{
    if (!m_player)
        return 0;
    float duration = m_player->duration();

    if (!duration || isinf(duration))
        return 0;

    float buffered = 0;
    RefPtr<TimeRanges> timeRanges = m_player->buffered();
    for (unsigned i = 0; i < timeRanges->length(); ++i) {
        ExceptionCode ignoredException;
        float start = timeRanges->start(i, ignoredException);
        float end = timeRanges->end(i, ignoredException);
        buffered += end - start;
    }
    return buffered / duration;
}

bool HTMLMediaElement::havePotentialSourceChild()
{
    // Stash the current <source> node so we can restore it after checking
    // to see there is another potential
    HTMLSourceElement* currentSourceNode = m_currentSourceNode;
    KURL nextURL = selectNextSourceChild(0, DoNothing);
    m_currentSourceNode = currentSourceNode;

    return nextURL.isValid();
}

KURL HTMLMediaElement::selectNextSourceChild(ContentType *contentType, InvalidSourceAction actionIfInvalid)
{
    KURL mediaURL;
    Node* node;
    bool lookingForPreviousNode = m_currentSourceNode;
    bool canUse = false;

    for (node = firstChild(); !canUse && node; node = node->nextSibling()) {
        if (!node->hasTagName(sourceTag))
            continue;

        if (lookingForPreviousNode) {
            if (m_currentSourceNode == static_cast<HTMLSourceElement*>(node))
                lookingForPreviousNode = false;
            continue;
        }

        HTMLSourceElement* source = static_cast<HTMLSourceElement*>(node);
        if (!source->hasAttribute(srcAttr))
            goto check_again; 

        if (source->hasAttribute(mediaAttr)) {
            MediaQueryEvaluator screenEval("screen", document()->frame(), renderer() ? renderer()->style() : 0);
            RefPtr<MediaList> media = MediaList::createAllowingDescriptionSyntax(source->media());
            if (!screenEval.eval(media.get())) 
                goto check_again;
        }

        if (source->hasAttribute(typeAttr)) {
            if (!MediaPlayer::supportsType(ContentType(source->type())))
                goto check_again;
        }

        // Is it safe to load this url?
        mediaURL = source->src();
        if (!mediaURL.isValid() || !isSafeToLoadURL(mediaURL, actionIfInvalid) || !dispatchBeforeLoadEvent(mediaURL.string()))
            goto check_again;

        // Making it this far means the <source> looks reasonable
        canUse = true;
        if (contentType)
            *contentType = ContentType(source->type());

check_again:
        if (!canUse && actionIfInvalid == Complain)
            source->scheduleErrorEvent();
        m_currentSourceNode = static_cast<HTMLSourceElement*>(node);
    }

    if (!canUse)
        m_currentSourceNode = 0;
    return canUse ? mediaURL : KURL();
}

void HTMLMediaElement::mediaPlayerTimeChanged(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();

    // Always call scheduleTimeupdateEvent when the media engine reports a time discontinuity, 
    // it will only queue a 'timeupdate' event if we haven't already posted one at the current
    // movie time.
    scheduleTimeupdateEvent(false);

    // 4.8.10.10 step 12 & 13.  Needed if no ReadyState change is associated with the seek.
    if (m_readyState >= HAVE_CURRENT_DATA && m_seeking)
        finishSeek();
    
    float now = currentTime();
    float dur = duration();
    if (!isnan(dur) && dur && now >= dur) {
        if (loop()) {
            ExceptionCode ignoredException;
            m_sentEndEvent = false;
            seek(0, ignoredException);
        } else {
            if (!m_sentEndEvent) {
                m_sentEndEvent = true;
                scheduleEvent(eventNames().endedEvent);
            }
        }
    }
    else
        m_sentEndEvent = false;

    updatePlayState();
    endProcessingMediaPlayerCallback();
}

void HTMLMediaElement::mediaPlayerVolumeChanged(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();
    if (m_player)
        m_volume = m_player->volume();
    updateVolume();
    endProcessingMediaPlayerCallback();
}

void HTMLMediaElement::mediaPlayerMuteChanged(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();
    if (m_player)
        setMuted(m_player->muted());
    endProcessingMediaPlayerCallback();
}

void HTMLMediaElement::mediaPlayerDurationChanged(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();
    scheduleEvent(eventNames().durationchangeEvent);
#if !ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    if (renderer()) {
        renderer()->updateFromElement();
        if (renderer()->isVideo())
            toRenderVideo(renderer())->videoSizeChanged();
    }
#endif        
    endProcessingMediaPlayerCallback();
}

void HTMLMediaElement::mediaPlayerRateChanged(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();
    // Stash the rate in case the one we tried to set isn't what the engine is
    // using (eg. it can't handle the rate we set)
    m_playbackRate = m_player->rate();
    endProcessingMediaPlayerCallback();
}

void HTMLMediaElement::mediaPlayerSawUnsupportedTracks(MediaPlayer*)
{
    // The MediaPlayer came across content it cannot completely handle.
    // This is normally acceptable except when we are in a standalone
    // MediaDocument. If so, tell the document what has happened.
    if (ownerDocument()->isMediaDocument()) {
        MediaDocument* mediaDocument = static_cast<MediaDocument*>(ownerDocument());
        mediaDocument->mediaElementSawUnsupportedTracks();
    }
}

// MediaPlayerPresentation methods
void HTMLMediaElement::mediaPlayerRepaint(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();
    if (renderer())
        renderer()->repaint();

    updatePosterImage();
    endProcessingMediaPlayerCallback();
}

void HTMLMediaElement::mediaPlayerSizeChanged(MediaPlayer*)
{
    beginProcessingMediaPlayerCallback();
#if !ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    if (renderer() && renderer()->isVideo())
        toRenderVideo(renderer())->videoSizeChanged();
#endif        
    endProcessingMediaPlayerCallback();
}

#if USE(ACCELERATED_COMPOSITING)
bool HTMLMediaElement::mediaPlayerRenderingCanBeAccelerated(MediaPlayer*)
{
    if (renderer() && renderer()->isVideo()) {
        ASSERT(renderer()->view());
        return renderer()->view()->compositor()->canAccelerateVideoRendering(toRenderVideo(renderer()));
    }
    return false;
}

void HTMLMediaElement::mediaPlayerRenderingModeChanged(MediaPlayer*)
{
    // Kick off a fake recalcStyle that will update the compositing tree.
    setNeedsStyleRecalc(SyntheticStyleChange);
}
#endif

PassRefPtr<TimeRanges> HTMLMediaElement::buffered() const
{
    if (!m_player)
        return TimeRanges::create();
    return m_player->buffered();
}

PassRefPtr<TimeRanges> HTMLMediaElement::played()
{
    if (m_playing) {
        float time = currentTime();
        if (time > m_lastSeekTime)
            addPlayedRange(m_lastSeekTime, time);
    }

    if (!m_playedTimeRanges)
        m_playedTimeRanges = TimeRanges::create();

    return m_playedTimeRanges->copy();
}

PassRefPtr<TimeRanges> HTMLMediaElement::seekable() const
{
    // FIXME real ranges support
    if (!maxTimeSeekable())
        return TimeRanges::create();
    return TimeRanges::create(minTimeSeekable(), maxTimeSeekable());
}

bool HTMLMediaElement::potentiallyPlaying() const
{
    return m_readyState >= HAVE_FUTURE_DATA && couldPlayIfEnoughData();
}

bool HTMLMediaElement::couldPlayIfEnoughData() const
{
    return !paused() && !endedPlayback() && !stoppedDueToErrors() && !pausedForUserInteraction();
}

bool HTMLMediaElement::endedPlayback() const
{
    float dur = duration();
    if (!m_player || isnan(dur))
        return false;

    // 4.8.10.8 Playing the media resource

    // A media element is said to have ended playback when the element's 
    // readyState attribute is HAVE_METADATA or greater, 
    if (m_readyState < HAVE_METADATA)
        return false;
    
    // and the current playback position is the end of the media resource and the direction 
    // of playback is forwards and the media element does not have a loop attribute specified,
    float now = currentTime();
    if (m_playbackRate > 0)
        return now >= dur && !loop();
    
    // or the current playback position is the earliest possible position and the direction 
    // of playback is backwards
    if (m_playbackRate < 0)
        return now <= 0;

    return false;
}

bool HTMLMediaElement::stoppedDueToErrors() const
{
    if (m_readyState >= HAVE_METADATA && m_error) {
        RefPtr<TimeRanges> seekableRanges = seekable();
        if (!seekableRanges->contain(currentTime()))
            return true;
    }
    
    return false;
}

bool HTMLMediaElement::pausedForUserInteraction() const
{
//    return !paused() && m_readyState >= HAVE_FUTURE_DATA && [UA requires a decitions from the user]
    return false;
}

float HTMLMediaElement::minTimeSeekable() const
{
    return 0;
}

float HTMLMediaElement::maxTimeSeekable() const
{
    return m_player ? m_player->maxTimeSeekable() : 0;
}
    
void HTMLMediaElement::updateVolume()
{
    if (!m_player)
        return;

    // Avoid recursion when the player reports volume changes.
    if (!processingMediaPlayerCallback()) {
        Page* page = document()->page();
        float volumeMultiplier = page ? page->mediaVolume() : 1;
    
        m_player->setMuted(m_muted);
        m_player->setVolume(m_volume * volumeMultiplier);
    }
    
    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::updatePlayState()
{
    if (!m_player)
        return;

    if (m_pausedInternal) {
        if (!m_player->paused())
            m_player->pause();
        m_playbackProgressTimer.stop();
        return;
    }
    
    bool shouldBePlaying = potentiallyPlaying();
    bool playerPaused = m_player->paused();
    if (shouldBePlaying && playerPaused) {
        // Set rate before calling play in case the rate was set before the media engine wasn't setup.
        // The media engine should just stash the rate since it isn't already playing.
        m_player->setRate(m_playbackRate);
        m_player->play();
        startPlaybackProgressTimer();
        m_playing = true;
    } else if (!shouldBePlaying && !playerPaused) {
        m_player->pause();
        m_playbackProgressTimer.stop();
        m_playing = false;
        float time = currentTime();
        if (time > m_lastSeekTime)
            addPlayedRange(m_lastSeekTime, time);
    } else if (couldPlayIfEnoughData() && playerPaused)
        m_player->prepareToPlay();
    
    if (renderer())
        renderer()->updateFromElement();
}
    
void HTMLMediaElement::setPausedInternal(bool b)
{
    m_pausedInternal = b;
    updatePlayState();
}

void HTMLMediaElement::stopPeriodicTimers()
{
    m_progressEventTimer.stop();
    m_playbackProgressTimer.stop();
}

void HTMLMediaElement::userCancelledLoad()
{
    if (m_networkState == NETWORK_EMPTY || m_networkState >= NETWORK_LOADED)
        return;

    // If the media data fetching process is aborted by the user:

    // 1 - The user agent should cancel the fetching process.
#if !ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    m_player.clear();
#endif
    stopPeriodicTimers();

    // 2 - Set the error attribute to a new MediaError object whose code attribute is set to MEDIA_ERR_ABORTED.
    m_error = MediaError::create(MediaError::MEDIA_ERR_ABORTED);

    // 3 - Queue a task to fire a progress event called abort at the media element, in the context
    // of the fetching process started by this instance of this algorithm.
    scheduleEvent(eventNames().abortEvent);

    // 5 - If the media element's readyState attribute has a value equal to HAVE_NOTHING, set the
    // element's networkState attribute to the NETWORK_EMPTY value and queue a task to fire a
    // simple event called emptied at the element. Otherwise, set set the element's networkState
    // attribute to the NETWORK_IDLE value.
    if (m_readyState == HAVE_NOTHING) {
        m_networkState = NETWORK_EMPTY;
        scheduleEvent(eventNames().emptiedEvent);
    }
    else
        m_networkState = NETWORK_IDLE;

    // 6 - Set the element's delaying-the-load-event flag to false. This stops delaying the load event.
    m_delayingTheLoadEvent = false;

    // 7 - Abort the overall resource selection algorithm.
    m_currentSourceNode = 0;

    // Reset m_readyState since m_player is gone.
    m_readyState = HAVE_NOTHING;
}

void HTMLMediaElement::documentWillBecomeInactive()
{
    if (m_isFullscreen)
        exitFullscreen();

    m_inActiveDocument = false;
    userCancelledLoad();

    // Stop the playback without generating events
    setPausedInternal(true);

    if (renderer())
        renderer()->updateFromElement();

    stopPeriodicTimers();
    cancelPendingEventsAndCallbacks();
}

void HTMLMediaElement::documentDidBecomeActive()
{
    m_inActiveDocument = true;
    setPausedInternal(false);

    if (m_error && m_error->code() == MediaError::MEDIA_ERR_ABORTED) {
        // Restart the load if it was aborted in the middle by moving the document to the page cache.
        // m_error is only left at MEDIA_ERR_ABORTED when the document becomes inactive (it is set to
        //  MEDIA_ERR_ABORTED while the abortEvent is being sent, but cleared immediately afterwards).
        // This behavior is not specified but it seems like a sensible thing to do.
        ExceptionCode ec;
        load(processingUserGesture(), ec);
    }

    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::mediaVolumeDidChange()
{
    updateVolume();
}

IntRect HTMLMediaElement::screenRect()
{
    if (!renderer())
        return IntRect();
    return renderer()->view()->frameView()->contentsToScreen(renderer()->absoluteBoundingBoxRect());
}
    
void HTMLMediaElement::defaultEventHandler(Event* event)
{
#if ENABLE(PLUGIN_PROXY_FOR_VIDEO)
    RenderObject* r = renderer();
    if (!r || !r->isWidget())
        return;

    Widget* widget = toRenderWidget(r)->widget();
    if (widget)
        widget->handleEvent(event);
#else
    if (renderer() && renderer()->isMedia())
        toRenderMedia(renderer())->forwardEvent(event);
    if (event->defaultHandled())
        return;
    HTMLElement::defaultEventHandler(event);
#endif
}

bool HTMLMediaElement::processingUserGesture() const
{
    Frame* frame = document()->frame();
    FrameLoader* loader = frame ? frame->loader() : 0;

    // return 'true' for safety if we don't know the answer 
    return loader ? loader->isProcessingUserGesture() : true;
}

#if ENABLE(PLUGIN_PROXY_FOR_VIDEO)

void HTMLMediaElement::deliverNotification(MediaPlayerProxyNotificationType notification)
{
    if (notification == MediaPlayerNotificationPlayPauseButtonPressed) {
        togglePlayState();
        return;
    }

    if (m_player)
        m_player->deliverNotification(notification);
}

void HTMLMediaElement::setMediaPlayerProxy(WebMediaPlayerProxy* proxy)
{
    if (m_player)
        m_player->setMediaPlayerProxy(proxy);
}

String HTMLMediaElement::initialURL()
{
    KURL initialSrc = document()->completeURL(getAttribute(srcAttr));
    
    if (!initialSrc.isValid())
        initialSrc = selectNextSourceChild(0, DoNothing);

    m_currentSrc = initialSrc.string();

    return initialSrc;
}

void HTMLMediaElement::finishParsingChildren()
{
    HTMLElement::finishParsingChildren();
    if (!m_player)
        m_player = MediaPlayer::create(this);
    
    document()->updateStyleIfNeeded();
    if (m_needWidgetUpdate && renderer())
        toRenderEmbeddedObject(renderer())->updateWidget(true);
}

#endif

void HTMLMediaElement::enterFullscreen()
{
    ASSERT(!m_isFullscreen);
    if (document() && document()->page()) {
        document()->page()->chrome()->client()->enterFullscreenForNode(this);
        scheduleEvent(eventNames().webkitbeginfullscreenEvent);
        m_isFullscreen = true;
    }
}

void HTMLMediaElement::exitFullscreen()
{
    ASSERT(m_isFullscreen);
    if (document() && document()->page()) {
        document()->page()->chrome()->client()->exitFullscreenForNode(this);
        scheduleEvent(eventNames().webkitendfullscreenEvent);
    }
    m_isFullscreen = false;
}

PlatformMedia HTMLMediaElement::platformMedia() const
{
    return m_player ? m_player->platformMedia() : NoPlatformMedia;
}

#if USE(ACCELERATED_COMPOSITING)
PlatformLayer* HTMLMediaElement::platformLayer() const
{
    return m_player ? m_player->platformLayer() : 0;
}
#endif

bool HTMLMediaElement::hasClosedCaptions() const
{
    return m_player && m_player->hasClosedCaptions();
}

bool HTMLMediaElement::closedCaptionsVisible() const
{
    return m_closedCaptionsVisible;
}

void HTMLMediaElement::setClosedCaptionsVisible(bool closedCaptionVisible)
{
    if (!m_player ||!hasClosedCaptions())
        return;

    m_closedCaptionsVisible = closedCaptionVisible;
    m_player->setClosedCaptionsVisible(closedCaptionVisible);
    if (renderer())
        renderer()->updateFromElement();
}

void HTMLMediaElement::setWebkitClosedCaptionsVisible(bool visible)
{
    setClosedCaptionsVisible(visible);
}

bool HTMLMediaElement::webkitClosedCaptionsVisible() const
{
    return closedCaptionsVisible();
}


bool HTMLMediaElement::webkitHasClosedCaptions() const
{
    return hasClosedCaptions();
}

void HTMLMediaElement::mediaCanStart()
{
    ASSERT(m_isWaitingUntilMediaCanStart);
    m_isWaitingUntilMediaCanStart = false;
    loadInternal();
}

}

#endif