view base/TempWriteFile.cpp @ 1752:6d09d68165a4 by-id

Further review of ById: make IDs only available when adding a model to the ById store, not by querying the item directly. This means any id encountered in the wild must have been added to the store at some point (even if later released), which simplifies reasoning about lifecycles

/* -*- 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 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.
*/

#include "TempWriteFile.h"

#include "Exceptions.h"

#include <QTemporaryFile>
#include <QDir>
#include <iostream>

TempWriteFile::TempWriteFile(QString target) :
    m_target(target)
{
    QTemporaryFile temp(m_target + ".");
    temp.setAutoRemove(false);
    temp.open(); // creates the file and opens it atomically
    if (temp.error()) {
        SVCERR << "TempWriteFile: Failed to create temporary file in directory of " << m_target << ": " << temp.errorString() << endl;
        throw FileOperationFailed(temp.fileName(), "creation");
    }
    
    m_temp = temp.fileName();
    temp.close(); // does not remove the file
}

TempWriteFile::~TempWriteFile()
{
    if (m_temp != "") {
        QDir dir(QFileInfo(m_temp).dir());
        dir.remove(m_temp);
    }
}

QString
TempWriteFile::getTemporaryFilename()
{
    return m_temp;
}

void
TempWriteFile::moveToTarget()
{
    if (m_temp == "") return;

    QFile tempFile(m_temp);
    QFile targetFile(m_target);
    
    if (targetFile.exists()) {
        if (!targetFile.remove()) {
            SVCERR << "TempWriteFile: WARNING: Failed to remove existing target file " << m_target << " prior to moving temporary file " << m_temp << " to it" << endl;
        }
    }
    
    if (!tempFile.rename(m_target)) {
        SVCERR << "TempWriteFile: Failed to rename temporary file " << m_temp << " to target " << m_target << endl;
        throw FileOperationFailed(m_temp, "rename");
    }

    m_temp = "";
}