previewgeneratorqueue.h

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// -*- Mode: c++ -*-
#ifndef PREVIEW_GENERATOR_QUEUE_H
#define PREVIEW_GENERATOR_QUEUE_H
 
#include <QStringList>
#include <QDateTime>
#include <QMutex>
#include <QMap>
#include <QSet>
 
#include "libmythbase/mthread.h"
 
#include "previewgenerator.h"
#include "mythtvexp.h"
 
class ProgramInfo;
class QSize;
 
class PreviewGenState
{
  public:
    PreviewGenState() = default;
 
    PreviewGenerator *m_gen           {nullptr};
 
    bool              m_genStarted    {false};
 
    uint              m_attempts      {0};
 
    std::chrono::seconds m_lastBlockTime {0s};
 
    QDateTime         m_blockRetryUntil;
 
    QSet<QString>     m_tokens;
};
using PreviewMap = QMap<QString,PreviewGenState>;
 
class MTV_PUBLIC PreviewGeneratorQueue : public QObject, public MThread
{
    Q_OBJECT
 
  public:
    static void CreatePreviewGeneratorQueue(
        PreviewGenerator::Mode mode,
        uint maxAttempts, std::chrono::seconds minBlockSeconds);
    static void TeardownPreviewGeneratorQueue();
 
    static void GetPreviewImage(const ProgramInfo &pginfo, const QString& token)
    {
        GetPreviewImage(pginfo, QSize(0,0), "", -1s, -1, token);
    }
    static void GetPreviewImage(const ProgramInfo &pginfo, QSize outputsize,
                                const QString &outputfile,
                                std::chrono::seconds time, long long frame,
                                const QString& token);
    static void AddListener(QObject *listener);
    static void RemoveListener(QObject *listener);
 
  private:
    PreviewGeneratorQueue(PreviewGenerator::Mode mode,
                          uint maxAttempts, std::chrono::seconds minBlockSeconds);
    ~PreviewGeneratorQueue() override;
 
    QString GeneratePreviewImage(ProgramInfo &pginfo, QSize size,
                                 const QString &outputfile,
                                 std::chrono::seconds time, long long frame,
                                 const QString& token);
 
    void GetInfo(const QString &key, uint &queue_depth, uint &token_cnt);
    void SetPreviewGenerator(const QString &key, PreviewGenerator *g);
    void IncPreviewGeneratorPriority(const QString &key, const QString& token);
    void UpdatePreviewGeneratorThreads(void);
    bool IsGeneratingPreview(const QString &key) const;
    uint IncPreviewGeneratorAttempts(const QString &key);
    void ClearPreviewGeneratorAttempts(const QString &key);
 
    bool event(QEvent *e) override; // QObject
 
    void SendEvent(const ProgramInfo &pginfo,
                   const QString     &eventname,
                   const QString     &filename,
                   const QString     &token,
                   const QString     &msg,
                   const QDateTime   &dt);
 
  private:
    static PreviewGeneratorQueue *s_pgq;
    QSet<QObject*> m_listeners;
    mutable QMutex         m_lock;
    PreviewGenerator::Mode m_mode;
    PreviewMap             m_previewMap;
    QMap<QString,QString>  m_tokenToKeyMap;
    QStringList            m_queue;
    uint                   m_running    {0};
    uint                   m_maxThreads {2};
    uint                   m_maxAttempts;
    std::chrono::seconds   m_minBlockSeconds;
};
 
#endif // PREVIEW_GENERATOR_QUEUE_H