decoder.h

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// -*- Mode: c++ -*-
 
#ifndef DECODER_H_
#define DECODER_H_
 
// Qt
#include <QCoreApplication>
#include <QEvent>
#include <QMutex>
#include <QStringList>
#include <QWaitCondition>
 
// MythTV
#include <libmythbase/mthread.h>
#include <libmythbase/mythobservable.h>
 
class MusicMetadata;
class MetaIO;
class Decoder;
class DecoderFactory;
 
class QObject;
class QIODevice;
class OutputEvent;
 
class Buffer;
class AudioOutput;
 
class DecoderEvent : public MythEvent
{
  public:
    explicit DecoderEvent(Type type) : MythEvent(type) { ; }
    explicit DecoderEvent(QString *e) : MythEvent(kError), m_errorMsg(e) { ; }
 
    ~DecoderEvent() override
    {
        delete m_errorMsg;
    }
 
    const QString *errorMessage() const { return m_errorMsg; }
 
    MythEvent *clone(void) const override // MythEvent
        { return new DecoderEvent(*this); }
 
    static const Type kDecoding;
    static const Type kStopped;
    static const Type kFinished;
    static const Type kError;
 
  private:
    DecoderEvent(const DecoderEvent &o) : MythEvent(o)
    {
        if (o.m_errorMsg)
        {
            m_errorMsg = new QString(*o.m_errorMsg);
        }
    }
 
  // No implicit copying.
  protected:
    DecoderEvent &operator=(const DecoderEvent &other) = default;
  public:
    DecoderEvent(DecoderEvent &&) = delete;
    DecoderEvent &operator=(DecoderEvent &&) = delete;
 
  private:
    QString *m_errorMsg {nullptr};
};
 
class Decoder : public MThread, public MythObservable
{
  public:
    ~Decoder() override;
 
    virtual bool initialize() = 0;
    virtual void seek(double) = 0;
    virtual void stop() = 0;
 
    DecoderFactory *factory() const { return m_fctry; }
 
    AudioOutput *output() { return m_out; }
    void setOutput(AudioOutput *o);
    void setURL(const QString &url) { m_url = url; }
 
    virtual void lock(void) { m_mtx.lock(); }
    virtual void unlock(void) { m_mtx.unlock(); }
    virtual bool tryLock(void) { return m_mtx.tryLock(); }
 
    QWaitCondition *cond() { return &m_cnd; }
 
    QString getURL(void) const { return m_url; }
 
    // static methods
    static QStringList all();
    static bool supports(const QString &source);
    static void registerFactory(DecoderFactory *fact);
    static Decoder *create(const QString &source, AudioOutput *output, bool deletable = false);
 
  protected:
    Decoder(DecoderFactory *d, AudioOutput *o)
        : MThread("MythMusicDecoder"), m_fctry(d), m_out(o) {}
    QMutex* getMutex(void) { return &m_mtx; }
    void error(const QString &e);
 
    QString m_url;
 
  private:
    DecoderFactory *m_fctry {nullptr};
 
    AudioOutput *m_out {nullptr};
 
    QMutex m_mtx;
    QWaitCondition m_cnd;
 
};
 
class DecoderFactory
{
public:
    virtual bool supports(const QString &source) const = 0;
    virtual const QString &extension() const = 0; // file extension, ie. ".mp3" or ".ogg"
    virtual const QString &description() const = 0; // file type, ie. "MPEG Audio Files"
    virtual Decoder *create(const QString &source, AudioOutput *output, bool deletable) = 0;
    virtual ~DecoderFactory() = default;
};
 
class CdDecoderFactory : public DecoderFactory
{
    Q_DECLARE_TR_FUNCTIONS(CdDecoderFactory);
 
public:
    bool supports(const QString &source) const override; // DecoderFactory
    const QString &extension() const override; // DecoderFactory
    const QString &description() const override; // DecoderFactory
    Decoder *create(const QString &file, AudioOutput *output, bool deletable) override; // DecoderFactory
};
 
class avfDecoderFactory : public DecoderFactory
{
    Q_DECLARE_TR_FUNCTIONS(avfDecoderFactory);
 
public:
    bool supports(const QString &source) const override; // DecoderFactory
    const QString &extension() const override; // DecoderFactory
    const QString &description() const override; // DecoderFactory
    Decoder *create(const QString &file, AudioOutput *output, bool deletable) override; // DecoderFactory
};
 
#endif