annotate base/TempDirectory.h @ 1727:8efce64dd85e

Fix potential deadlock when notifying a handler that more models are [not] available

/* -*- 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 SV_TEMP_DIRECTORY_H
#define SV_TEMP_DIRECTORY_H

#include <QString>
#include <QMutex>

#include <exception>

/**
 * A class that manages the creation and removal of a temporary
 * directory tree to store data during the program run.  There is one
 * root temporary directory for the program, created on demand and
 * deleted when the program exits.
 *
 * This class is thread safe.
 */

class TempDirectory
{
public:
    static TempDirectory *getInstance();
    
    virtual ~TempDirectory();

    /**
     * Return the path of the directory in which the temporary
     * directory has been or will be created.  This directory is
     * particular to this application, although not to this instance
     * of it, and it will not be removed when the application exits.
     * Persistent cache data or similar may be placed in this
     * directory or other, non-temporary subdirectories of it.
     *
     * If this directory does not exist, it will be created.  Throw
     * DirectoryCreationFailed if the directory cannot be created.
     */
    QString getContainingPath();

    /**
     * Create the root temporary directory if necessary, and return
     * its path.  This directory will be removed when the application
     * exits.
     *
     * Throw DirectoryCreationFailed if the directory cannot be
     * created.
     */
    QString getPath();

    /** 
     * Create an immediate subdirectory of the root temporary
     * directory of the given name, if it doesn't already exist, and
     * return its path.  This directory will be removed when the
     * application exits.
     * 
     * Throw DirectoryCreationFailed if the directory cannot be
     * created.
     */
    QString getSubDirectoryPath(QString subdir);

    /**
     * Delete the temporary directory (before exiting).
     */
    void cleanup();

protected:
    TempDirectory();

    QString createTempDirectoryIn(QString inDir);
    void cleanupDirectory(QString tmpDir);
    void cleanupAbandonedDirectories(QString svDir);

    QString m_tmpdir;
    QMutex m_mutex;

    static TempDirectory *m_instance;
};


#endif