C++ TextTrack::setSourceBuffer方法代码示例

void MediaSource::removeSourceBuffer(SourceBuffer& buffer, ExceptionCode& ec)
{
    LOG(MediaSource, "MediaSource::removeSourceBuffer() %p", this);
    Ref<SourceBuffer> protect(buffer);

    // 2. If sourceBuffer specifies an object that is not in sourceBuffers then
    // throw a NOT_FOUND_ERR exception and abort these steps.
    if (!m_sourceBuffers->length() || !m_sourceBuffers->contains(buffer)) {
        ec = NOT_FOUND_ERR;
        return;
    }

    // 3. If the sourceBuffer.updating attribute equals true, then run the following steps: ...
    buffer.abortIfUpdating();

    // 4. Let SourceBuffer audioTracks list equal the AudioTrackList object returned by sourceBuffer.audioTracks.
    RefPtr<AudioTrackList> audioTracks = buffer.audioTracks();

    // 5. If the SourceBuffer audioTracks list is not empty, then run the following steps:
    if (audioTracks->length()) {
        // 5.1 Let HTMLMediaElement audioTracks list equal the AudioTrackList object returned by the audioTracks
        // attribute on the HTMLMediaElement.
        // 5.2 Let the removed enabled audio track flag equal false.
        bool removedEnabledAudioTrack = false;

        // 5.3 For each AudioTrack object in the SourceBuffer audioTracks list, run the following steps:
        while (audioTracks->length()) {
            AudioTrack* track = audioTracks->lastItem();

            // 5.3.1 Set the sourceBuffer attribute on the AudioTrack object to null.
            track->setSourceBuffer(nullptr);

            // 5.3.2 If the enabled attribute on the AudioTrack object is true, then set the removed enabled
            // audio track flag to true.
            if (track->enabled())
                removedEnabledAudioTrack = true;

            // 5.3.3 Remove the AudioTrack object from the HTMLMediaElement audioTracks list.
            // 5.3.4 Queue a task to fire a trusted event named removetrack, that does not bubble and is not
            // cancelable, and that uses the TrackEvent interface, at the HTMLMediaElement audioTracks list.
            if (mediaElement())
                mediaElement()->removeAudioTrack(track);

            // 5.3.5 Remove the AudioTrack object from the SourceBuffer audioTracks list.
            // 5.3.6 Queue a task to fire a trusted event named removetrack, that does not bubble and is not
            // cancelable, and that uses the TrackEvent interface, at the SourceBuffer audioTracks list.
            audioTracks->remove(track);
        }

        // 5.4 If the removed enabled audio track flag equals true, then queue a task to fire a simple event
        // named change at the HTMLMediaElement audioTracks list.
        if (removedEnabledAudioTrack)
            mediaElement()->audioTracks()->scheduleChangeEvent();
    }

    // 6. Let SourceBuffer videoTracks list equal the VideoTrackList object returned by sourceBuffer.videoTracks.
    RefPtr<VideoTrackList> videoTracks = buffer.videoTracks();

    // 7. If the SourceBuffer videoTracks list is not empty, then run the following steps:
    if (videoTracks->length()) {
        // 7.1 Let HTMLMediaElement videoTracks list equal the VideoTrackList object returned by the videoTracks
        // attribute on the HTMLMediaElement.
        // 7.2 Let the removed selected video track flag equal false.
        bool removedSelectedVideoTrack = false;

        // 7.3 For each VideoTrack object in the SourceBuffer videoTracks list, run the following steps:
        while (videoTracks->length()) {
            VideoTrack* track = videoTracks->lastItem();

            // 7.3.1 Set the sourceBuffer attribute on the VideoTrack object to null.
            track->setSourceBuffer(nullptr);

            // 7.3.2 If the selected attribute on the VideoTrack object is true, then set the removed selected
            // video track flag to true.
            if (track->selected())
                removedSelectedVideoTrack = true;

            // 7.3.3 Remove the VideoTrack object from the HTMLMediaElement videoTracks list.
            // 7.3.4 Queue a task to fire a trusted event named removetrack, that does not bubble and is not
            // cancelable, and that uses the TrackEvent interface, at the HTMLMediaElement videoTracks list.
            if (mediaElement())
                mediaElement()->removeVideoTrack(track);

            // 7.3.5 Remove the VideoTrack object from the SourceBuffer videoTracks list.
            // 7.3.6 Queue a task to fire a trusted event named removetrack, that does not bubble and is not
            // cancelable, and that uses the TrackEvent interface, at the SourceBuffer videoTracks list.
            videoTracks->remove(track);
        }

        // 7.4 If the removed selected video track flag equals true, then queue a task to fire a simple event
        // named change at the HTMLMediaElement videoTracks list.
        if (removedSelectedVideoTrack)
            mediaElement()->videoTracks()->scheduleChangeEvent();
    }

    // 8. Let SourceBuffer textTracks list equal the TextTrackList object returned by sourceBuffer.textTracks.
    RefPtr<TextTrackList> textTracks = buffer.textTracks();

    // 9. If the SourceBuffer textTracks list is not empty, then run the following steps:
    if (textTracks->length()) {
//.........这里部分代码省略.........