QMediaPlayer(1)

QMediaPlayer

QMediaPlayer의 기본 구조는 아래 그림 정도가 될것 같습니다. 

이제 생성자 소스를 보겠습니다. 

QMediaPlayer::QMediaPlayer(QObject *parent, QMediaPlayer::Flags flags):
    QMediaObject(*new QMediaPlayerPrivate,
                 parent,
                 playerService(flags))
{
    Q_D(QMediaPlayer);

    d->provider = QMediaServiceProvider::defaultServiceProvider();
    if (d->service == 0) {
        d->error = ServiceMissingError;
    } else {
        d->control = qobject_cast<QMediaPlayerControl*>(d->service->requestControl(QMediaPlayerControl_iid));
        d->networkAccessControl = qobject_cast<QMediaNetworkAccessControl*>(d->service->requestControl(QMediaNetworkAccessControl_iid));
        if (d->control != 0) {
            connect(d->control, SIGNAL(mediaChanged(QMediaContent)), SLOT(_q_handleMediaChanged(QMediaContent)));
            connect(d->control, SIGNAL(stateChanged(QMediaPlayer::State)), SLOT(_q_stateChanged(QMediaPlayer::State)));
            connect(d->control, SIGNAL(mediaStatusChanged(QMediaPlayer::MediaStatus)),
                    SLOT(_q_mediaStatusChanged(QMediaPlayer::MediaStatus)));
            connect(d->control, SIGNAL(error(int,QString)), SLOT(_q_error(int,QString)));

            connect(d->control, SIGNAL(durationChanged(qint64)), SIGNAL(durationChanged(qint64)));
            connect(d->control, SIGNAL(positionChanged(qint64)), SIGNAL(positionChanged(qint64)));
            connect(d->control, SIGNAL(audioAvailableChanged(bool)), SIGNAL(audioAvailableChanged(bool)));
            connect(d->control, SIGNAL(videoAvailableChanged(bool)), SIGNAL(videoAvailableChanged(bool)));
            connect(d->control, SIGNAL(volumeChanged(int)), SIGNAL(volumeChanged(int)));
            connect(d->control, SIGNAL(mutedChanged(bool)), SIGNAL(mutedChanged(bool)));
            connect(d->control, SIGNAL(seekableChanged(bool)), SIGNAL(seekableChanged(bool)));
            connect(d->control, SIGNAL(playbackRateChanged(qreal)), SIGNAL(playbackRateChanged(qreal)));
            connect(d->control, SIGNAL(bufferStatusChanged(int)), SIGNAL(bufferStatusChanged(int)));

            d->state = d->control->state();
            d->status = d->control->mediaStatus();

            if (d->state == PlayingState)
                addPropertyWatch("position");

            if (d->status == StalledMedia || d->status == BufferingMedia)
                addPropertyWatch("bufferStatus");

            d->hasStreamPlaybackFeature = d->provider->supportedFeatures(d->service).testFlag(QMediaServiceProviderHint::StreamPlayback);

            d->audioRoleControl = qobject_cast<QAudioRoleControl*>(d->service->requestControl(QAudioRoleControl_iid));
            if (d->audioRoleControl) {
                connect(d->audioRoleControl, &QAudioRoleControl::audioRoleChanged,
                        this, &QMediaPlayer::audioRoleChanged);
            }
        }
        if (d->networkAccessControl != 0) {
            connect(d->networkAccessControl, SIGNAL(configurationChanged(QNetworkConfiguration)),
            this, SIGNAL(networkConfigurationChanged(QNetworkConfiguration)));
        }
    }
}

생성자의 첫부분 부터 보겠습니다.

QMediaPlayer::QMediaPlayer(QObject *parent, QMediaPlayer::Flags flags):
    QMediaObject(*new QMediaPlayerPrivate,
                 parent,
                 playerService(flags))

QMediaObject::QMediaObject(QMediaObjectPrivate &dd, QObject *parent,
                                            QMediaService *service):
    QObject(parent),
    d_ptr(&dd)
{
    Q_D(QMediaObject);
    d->q_ptr = this;

    d->notifyTimer = new QTimer(this);
    d->notifyTimer->setInterval(1000);
    connect(d->notifyTimer, SIGNAL(timeout()), SLOT(_q_notify()));

    d->service = service;

    setupControls();
}

소스에서 보면 

QMediaPlayer::QMediaPlayer(QObject *parent, QMediaPlayer::Flags flags):
    QMediaObject(*new QMediaPlayerPrivate,
                 parent,
                 playerService(flags))

에서 부모 QMediaObject 를 초기화 해 줍니다. 

첫번째 인자 부터 알아 보겠습니다. 

*new QMediaPlayerPrivate 는 

QMediaObject::QMediaObject(QMediaObjectPrivate &dd, QObject *parent,
                                            QMediaService *service):
    QObject(parent),
    d_ptr(&dd)

해당 생성자를 초기화 할때 

d_ptr(&dd) 로 넘겨 줍니다. 

class QMediaPlayerPrivate : public QMediaObjectPrivate
{
    Q_DECLARE_NON_CONST_PUBLIC(QMediaPlayer)

public:
    QMediaPlayerPrivate()
        : provider(0)
        , control(0)
        , audioRoleControl(0)
        , state(QMediaPlayer::StoppedState)
        , status(QMediaPlayer::UnknownMediaStatus)
        , error(QMediaPlayer::NoError)
        , ignoreNextStatusChange(-1)
        , playlist(0)
        , networkAccessControl(0)
        , hasStreamPlaybackFeature(false)
        , nestedPlaylists(0)
    {}

    QMediaServiceProvider *provider;
    QMediaPlayerControl* control;
    QAudioRoleControl *audioRoleControl;
    QMediaPlayer::State state;
    QMediaPlayer::MediaStatus status;
    QMediaPlayer::Error error;
    QString errorString;
    int ignoreNextStatusChange;

    QPointer<QObject> videoOutput;
    QMediaPlaylist *playlist;
    QMediaNetworkAccessControl *networkAccessControl;
    QVideoSurfaceOutput surfaceOutput;
    bool hasStreamPlaybackFeature;
    QMediaContent qrcMedia;
    QScopedPointer<QFile> qrcFile;

    QMediaContent rootMedia;
    QMediaContent pendingPlaylist;
    QMediaPlaylist *parentPlaylist(QMediaPlaylist *pls);
    bool isInChain(QUrl url);
    int nestedPlaylists;

    void setMedia(const QMediaContent &media, QIODevice *stream = 0);

    void setPlaylist(QMediaPlaylist *playlist);
    void setPlaylistMedia();
    void loadPlaylist();
    void disconnectPlaylist();
    void connectPlaylist();

    void _q_stateChanged(QMediaPlayer::State state);
    void _q_mediaStatusChanged(QMediaPlayer::MediaStatus status);
    void _q_error(int error, const QString &errorString);
    void _q_updateMedia(const QMediaContent&);
    void _q_playlistDestroyed();
    void _q_handleMediaChanged(const QMediaContent&);
    void _q_handlePlaylistLoaded();
    void _q_handlePlaylistLoadFailed();
};

QMediaServiceProvider 이것이 무엇인지 알보겠습니다. 

그뒤에 다시 private 로 돌아 와야 할것 같습니다.