Carla/source/modules/water/files/TemporaryFile.cpp

/*
  ==============================================================================

   This file is part of the Water library.
   Copyright (c) 2016 ROLI Ltd.
   Copyright (C) 2017 Filipe Coelho <falktx@falktx.com>

   Permission is granted to use this software under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license/

   Permission to use, copy, modify, and/or distribute this software for any
   purpose with or without fee is hereby granted, provided that the above
   copyright notice and this permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
   OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
   USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
   TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
   OF THIS SOFTWARE.

  ==============================================================================
*/

#include "TemporaryFile.h"
#include "../maths/Random.h"

namespace water {

static File createTempFile (const File& parentDirectory, String name,
                            const String& suffix, const int optionFlags)
{
    if ((optionFlags & TemporaryFile::useHiddenFile) != 0)
        name = "." + name;

    return parentDirectory.getNonexistentChildFile (name, suffix, (optionFlags & TemporaryFile::putNumbersInBrackets) != 0);
}

TemporaryFile::TemporaryFile (const String& suffix, const int optionFlags)
    : temporaryFile (createTempFile (File::getSpecialLocation (File::tempDirectory),
                                     "temp_" + String::toHexString (Random::getSystemRandom().nextInt()),
                                     suffix, optionFlags))
{
}

TemporaryFile::TemporaryFile (const File& target, const int optionFlags)
    : temporaryFile (createTempFile (target.getParentDirectory(),
                                     target.getFileNameWithoutExtension()
                                       + "_temp" + String::toHexString (Random::getSystemRandom().nextInt()),
                                     target.getFileExtension(), optionFlags)),
      targetFile (target)
{
    // If you use this constructor, you need to give it a valid target file!
    wassert (targetFile != File());
}

TemporaryFile::TemporaryFile (const File& target, const File& temporary)
    : temporaryFile (temporary), targetFile (target)
{
}

TemporaryFile::~TemporaryFile()
{
    if (! deleteTemporaryFile())
    {
        /* Failed to delete our temporary file! The most likely reason for this would be
           that you've not closed an output stream that was being used to write to file.

           If you find that something beyond your control is changing permissions on
           your temporary files and preventing them from being deleted, you may want to
           call TemporaryFile::deleteTemporaryFile() to detect those error cases and
           handle them appropriately.
        */
        wassertfalse;
    }
}

//==============================================================================
bool TemporaryFile::overwriteTargetFileWithTemporary() const
{
    // This method only works if you created this object with the constructor
    // that takes a target file!
    wassert (targetFile != File());

    if (temporaryFile.exists())
    {
        // Have a few attempts at overwriting the file before giving up..
        for (int i = 5; --i >= 0;)
        {
            if (temporaryFile.replaceFileIn (targetFile))
                return true;

            carla_msleep (100);
        }
    }
    else
    {
        // There's no temporary file to use. If your write failed, you should
        // probably check, and not bother calling this method.
        wassertfalse;
    }

    return false;
}

bool TemporaryFile::deleteTemporaryFile() const
{
    // Have a few attempts at deleting the file before giving up..
    for (int i = 5; --i >= 0;)
    {
        if (temporaryFile.deleteFile())
            return true;

        carla_msleep (50);
    }

    return false;
}

}