comparison base/FileReadThread.h @ 95:040a151d0897

* Add file reader thread, and make the matrix file code use it to preload
  fft cache data without glitching

+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    This file copyright 2006 Chris Cannam.
+    
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef _FILE_READ_THREAD_H_
+#define _FILE_READ_THREAD_H_
+
+#include <QThread>
+#include <QMutex>
+#include <QWaitCondition>
+
+#include <map>
+#include <set>
+
+#include <stdint.h>
+
+class FileReadThread : public QThread
+{
+    Q_OBJECT
+
+public:
+    FileReadThread();
+
+    virtual void run();
+    virtual void finish();
+
+    struct Request {
+        int fd;
+        QMutex *mutex; // used to synchronise access to fd; may be null
+        off_t start;
+        size_t size;
+        char *data; // caller is responsible for allocating and deallocating
+    };
+    
+    virtual int request(const Request &request);
+    virtual void cancel(int token);
+
+    virtual bool isReady(int token);
+    virtual bool isCancelled(int token); // and safe to delete
+    virtual bool getRequest(int token, Request &request);
+    virtual void done(int token);
+
+signals:
+    void ready(int token, bool successful); 
+    void cancelled(int token);
+    
+protected:
+    int m_nextToken;
+    bool m_exiting;
+    
+    typedef std::map<int, Request> RequestQueue;
+    RequestQueue m_queue;
+    RequestQueue m_cancelledRequests;
+    RequestQueue m_readyRequests;
+    std::set<int> m_newlyCancelled;
+
+    QMutex m_mutex;
+    QWaitCondition m_condition;
+
+    void process();
+    void notifyCancelled();
+};
+
+#endif