html/track/TextTrack.cpp

/*
 * Copyright (C) 2011 Google Inc.  All rights reserved.
 * Copyright (C) 2011, 2012, 2013 Apple Inc.  All rights reserved.
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 * modification, are permitted provided that the following conditions are
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#include "config.h"
#include "core/html/track/TextTrack.h"

#include "bindings/v8/ExceptionStatePlaceholder.h"
#include "core/dom/ExceptionCode.h"
#include "core/html/HTMLMediaElement.h"
#include "core/html/track/TextTrackCueList.h"
#include "core/html/track/TextTrackList.h"
#include "core/html/track/TextTrackRegion.h"
#include "core/html/track/TextTrackRegionList.h"

namespace WebCore {

static const int invalidTrackIndex = -1;

const AtomicString& TextTrack::subtitlesKeyword()
{
    DEFINE_STATIC_LOCAL(const AtomicString, subtitles, ("subtitles", AtomicString::ConstructFromLiteral));
    return subtitles;
}

const AtomicString& TextTrack::captionsKeyword()
{
    DEFINE_STATIC_LOCAL(const AtomicString, captions, ("captions", AtomicString::ConstructFromLiteral));
    return captions;
}

const AtomicString& TextTrack::descriptionsKeyword()
{
    DEFINE_STATIC_LOCAL(const AtomicString, descriptions, ("descriptions", AtomicString::ConstructFromLiteral));
    return descriptions;
}

const AtomicString& TextTrack::chaptersKeyword()
{
    DEFINE_STATIC_LOCAL(const AtomicString, chapters, ("chapters", AtomicString::ConstructFromLiteral));
    return chapters;
}

const AtomicString& TextTrack::metadataKeyword()
{
    DEFINE_STATIC_LOCAL(const AtomicString, metadata, ("metadata", AtomicString::ConstructFromLiteral));
    return metadata;
}

const AtomicString& TextTrack::disabledKeyword()
{
    DEFINE_STATIC_LOCAL(const AtomicString, open, ("disabled", AtomicString::ConstructFromLiteral));
    return open;
}

const AtomicString& TextTrack::hiddenKeyword()
{
    DEFINE_STATIC_LOCAL(const AtomicString, closed, ("hidden", AtomicString::ConstructFromLiteral));
    return closed;
}

const AtomicString& TextTrack::showingKeyword()
{
    DEFINE_STATIC_LOCAL(const AtomicString, ended, ("showing", AtomicString::ConstructFromLiteral));
    return ended;
}

TextTrack::TextTrack(ScriptExecutionContext* context, TextTrackClient* client, const AtomicString& kind, const AtomicString& label, const AtomicString& language, TextTrackType type)
    : TrackBase(context, TrackBase::TextTrack)
    , m_cues(0)
#if ENABLE(WEBVTT_REGIONS)
    , m_regions(0)
#endif
    , m_mediaElement(0)
    , m_label(label)
    , m_language(language)
    , m_mode(disabledKeyword().string())
    , m_client(client)
    , m_trackType(type)
    , m_readinessState(NotLoaded)
    , m_trackIndex(invalidTrackIndex)
    , m_renderedTrackIndex(invalidTrackIndex)
    , m_hasBeenConfigured(false)
{
    ScriptWrappable::init(this);
    setKind(kind);
}

TextTrack::~TextTrack()
{
    if (m_cues) {
        if (m_client)
            m_client->textTrackRemoveCues(this, m_cues.get());

        for (size_t i = 0; i < m_cues->length(); ++i)
            m_cues->item(i)->setTrack(0);
    }

#if ENABLE(WEBVTT_REGIONS)
    if (m_regions) {
        for (size_t i = 0; i < m_regions->length(); ++i)
            m_regions->item(i)->setTrack(0);
    }
#endif
    clearClient();
}

bool TextTrack::isValidKindKeyword(const AtomicString& value)
{
    if (value == subtitlesKeyword())
        return true;
    if (value == captionsKeyword())
        return true;
    if (value == descriptionsKeyword())
        return true;
    if (value == chaptersKeyword())
        return true;
    if (value == metadataKeyword())
        return true;

    return false;
}

void TextTrack::setKind(const AtomicString& kind)
{
    String oldKind = m_kind;

    if (isValidKindKeyword(kind))
        m_kind = kind;
    else
        m_kind = subtitlesKeyword();

    if (m_client && oldKind != m_kind)
        m_client->textTrackKindChanged(this);
}

void TextTrack::setMode(const AtomicString& mode)
{
    // On setting, if the new value isn't equal to what the attribute would currently
    // return, the new value must be processed as follows ...
    if (mode != disabledKeyword() && mode != hiddenKeyword() && mode != showingKeyword())
        return;

    if (m_mode == mode)
        return;

    // If mode changes to disabled, remove this track's cues from the client
    // because they will no longer be accessible from the cues() function.
    if (mode == disabledKeyword() && m_client && m_cues)
        m_client->textTrackRemoveCues(this, m_cues.get());

    if (mode != showingKeyword() && m_cues)
        for (size_t i = 0; i < m_cues->length(); ++i)
            m_cues->item(i)->removeDisplayTree();

    m_mode = mode;

    if (m_client)
        m_client->textTrackModeChanged(this);
}

TextTrackCueList* TextTrack::cues()
{
    // 4.8.10.12.5 If the text track mode ... is not the text track disabled mode,
    // then the cues attribute must return a live TextTrackCueList object ...
    // Otherwise, it must return null. When an object is returned, the
    // same object must be returned each time.
    // http://www.whatwg.org/specs/web-apps/current-work/#dom-texttrack-cues
    if (m_mode != disabledKeyword())
        return ensureTextTrackCueList();
    return 0;
}

void TextTrack::removeAllCues()
{
    if (!m_cues)
        return;

    if (m_client)
        m_client->textTrackRemoveCues(this, m_cues.get());

    for (size_t i = 0; i < m_cues->length(); ++i)
        m_cues->item(i)->setTrack(0);

    m_cues = 0;
}

TextTrackCueList* TextTrack::activeCues() const
{
    // 4.8.10.12.5 If the text track mode ... is not the text track disabled mode,
    // then the activeCues attribute must return a live TextTrackCueList object ...
    // ... whose active flag was set when the script started, in text track cue
    // order. Otherwise, it must return null. When an object is returned, the
    // same object must be returned each time.
    // http://www.whatwg.org/specs/web-apps/current-work/#dom-texttrack-activecues
    if (m_cues && m_mode != disabledKeyword())
        return m_cues->activeCues();
    return 0;
}

void TextTrack::addCue(PassRefPtr<TextTrackCue> prpCue)
{
    if (!prpCue)
        return;

    RefPtr<TextTrackCue> cue = prpCue;

    // TODO(93143): Add spec-compliant behavior for negative time values.
    if (std::isnan(cue->startTime()) || std::isnan(cue->endTime()) || cue->startTime() < 0 || cue->endTime() < 0)
        return;

    // 4.8.10.12.5 Text track API

    // The addCue(cue) method of TextTrack objects, when invoked, must run the following steps:

    // 1. If the given cue is in a text track list of cues, then remove cue from that text track
    // list of cues.
    TextTrack* cueTrack = cue->track();
    if (cueTrack && cueTrack != this)
        cueTrack->removeCue(cue.get(), ASSERT_NO_EXCEPTION);

    // 2. Add cue to the method's TextTrack object's text track's text track list of cues.
    cue->setTrack(this);
    ensureTextTrackCueList()->add(cue);

    if (m_client)
        m_client->textTrackAddCue(this, cue.get());
}

void TextTrack::removeCue(TextTrackCue* cue, ExceptionState& es)
{
    if (!cue)
        return;

    // 4.8.10.12.5 Text track API

    // The removeCue(cue) method of TextTrack objects, when invoked, must run the following steps:

    // 1. If the given cue is not currently listed in the method's TextTrack
    // object's text track's text track list of cues, then throw a NotFoundError exception.
    if (cue->track() != this) {
        es.throwDOMException(NotFoundError);
        return;
    }

    // 2. Remove cue from the method's TextTrack object's text track's text track list of cues.
    if (!m_cues || !m_cues->remove(cue)) {
        es.throwDOMException(InvalidStateError);
        return;
    }

    cue->setTrack(0);
    if (m_client)
        m_client->textTrackRemoveCue(this, cue);
}

#if ENABLE(WEBVTT_REGIONS)
TextTrackRegionList* TextTrack::regionList()
{
    return ensureTextTrackRegionList();
}

TextTrackRegionList* TextTrack::ensureTextTrackRegionList()
{
    if (!m_regions)
        m_regions = TextTrackRegionList::create();

    return m_regions.get();
}

TextTrackRegionList* TextTrack::regions()
{
    // If the text track mode of the text track that the TextTrack object
    // represents is not the text track disabled mode, then the regions
    // attribute must return a live TextTrackRegionList object that represents
    // the text track list of regions of the text track. Otherwise, it must
    // return null. When an object is returned, the same object must be returned
    // each time.
    if (m_mode != disabledKeyword())
        return ensureTextTrackRegionList();

    return 0;
}

void TextTrack::addRegion(PassRefPtr<TextTrackRegion> prpRegion)
{
    if (!prpRegion)
        return;

    RefPtr<TextTrackRegion> region = prpRegion;
    TextTrackRegionList* regionList = ensureTextTrackRegionList();

    // 1. If the given region is in a text track list of regions, then remove
    // region from that text track list of regions.
    TextTrack* regionTrack = region->track();
    if (regionTrack && regionTrack != this)
        regionTrack->removeRegion(region.get(), ASSERT_NO_EXCEPTION);

    // 2. If the method's TextTrack object's text track list of regions contains
    // a region with the same identifier as region replace the values of that
    // region's width, height, anchor point, viewport anchor point and scroll
    // attributes with those of region.
    TextTrackRegion* existingRegion = regionList->getRegionById(region->id());
    if (existingRegion) {
        existingRegion->updateParametersFromRegion(region.get());
        return;
    }

    // Otherwise: add region to the method's TextTrack object's text track
    // list of regions.
    region->setTrack(this);
    regionList->add(region);
}

void TextTrack::removeRegion(TextTrackRegion* region, ExceptionState &es)
{
    if (!region)
        return;

    // 1. If the given region is not currently listed in the method's TextTrack
    // object's text track list of regions, then throw a NotFoundError exception.
    if (region->track() != this) {
        es.throwDOMException(NotFoundError);
        return;
    }

    if (!m_regions || !m_regions->remove(region)) {
        es.throwDOMException(InvalidStateError);
        return;
    }

    region->setTrack(0);
}
#endif

void TextTrack::cueWillChange(TextTrackCue* cue)
{
    if (!m_client)
        return;

    // The cue may need to be repositioned in the media element's interval tree, may need to
    // be re-rendered, etc, so remove it before the modification...
    m_client->textTrackRemoveCue(this, cue);
}

void TextTrack::cueDidChange(TextTrackCue* cue)
{
    if (!m_client)
        return;

    // Make sure the TextTrackCueList order is up-to-date.
    ensureTextTrackCueList()->updateCueIndex(cue);

    // ... and add it back again.
    m_client->textTrackAddCue(this, cue);
}

int TextTrack::trackIndex()
{
    ASSERT(m_mediaElement);

    if (m_trackIndex == invalidTrackIndex)
        m_trackIndex = m_mediaElement->textTracks()->getTrackIndex(this);

    return m_trackIndex;
}

void TextTrack::invalidateTrackIndex()
{
    m_trackIndex = invalidTrackIndex;
    m_renderedTrackIndex = invalidTrackIndex;
}

bool TextTrack::isRendered()
{
    if (m_kind != captionsKeyword() && m_kind != subtitlesKeyword())
        return false;

    if (m_mode != showingKeyword())
        return false;

    return true;
}

TextTrackCueList* TextTrack::ensureTextTrackCueList()
{
    if (!m_cues)
        m_cues = TextTrackCueList::create();

    return m_cues.get();
}

int TextTrack::trackIndexRelativeToRenderedTracks()
{
    ASSERT(m_mediaElement);

    if (m_renderedTrackIndex == invalidTrackIndex)
        m_renderedTrackIndex = m_mediaElement->textTracks()->getTrackIndexRelativeToRenderedTracks(this);

    return m_renderedTrackIndex;
}

bool TextTrack::hasCue(TextTrackCue* cue)
{
    if (cue->startTime() < 0 || cue->endTime() < 0)
        return false;

    if (!m_cues || !m_cues->length())
        return false;

    size_t searchStart = 0;
    size_t searchEnd = m_cues->length();

    while (1) {
        ASSERT(searchStart <= m_cues->length());
        ASSERT(searchEnd <= m_cues->length());

        TextTrackCue* existingCue;

        // Cues in the TextTrackCueList are maintained in start time order.
        if (searchStart == searchEnd) {
            if (!searchStart)
                return false;

            // If there is more than one cue with the same start time, back up to first one so we
            // consider all of them.
            while (searchStart >= 2 && cue->startTime() == m_cues->item(searchStart - 2)->startTime())
                --searchStart;

            bool firstCompare = true;
            while (1) {
                if (!firstCompare)
                    ++searchStart;
                firstCompare = false;
                if (searchStart > m_cues->length())
                    return false;

                existingCue = m_cues->item(searchStart - 1);
                if (!existingCue || cue->startTime() > existingCue->startTime())
                    return false;

                if (*existingCue != *cue)
                    continue;

                return true;
            }
        }

        size_t index = (searchStart + searchEnd) / 2;
        existingCue = m_cues->item(index);
        if (cue->startTime() < existingCue->startTime() || (cue->startTime() == existingCue->startTime() && cue->endTime() > existingCue->endTime()))
            searchEnd = index;
        else
            searchStart = index + 1;
    }

    ASSERT_NOT_REACHED();
    return false;
}

bool TextTrack::isMainProgramContent() const
{
    // "Main program" content is intrinsic to the presentation of the media file, regardless of locale. Content such as
    // directors commentary is not "main program" because it is not essential for the presentation. HTML5 doesn't have
    // a way to express this in a machine-reable form, it is typically done with the track label, so we assume that caption
    // tracks are main content and all other track types are not.
    return m_kind == captionsKeyword();
}

} // namespace WebCore