Method unpack

/**
 * Unpacks a file and verifies it as a Joomla element package
 * Supports .gz .tar .tar.gz and .zip
 *
 * @param   string   $packageFilename    The uploaded package filename or install directory
 * @param   boolean  $alwaysReturnArray  If should return false (and leave garbage behind) or return $retval['type']=false
 *
 * @return  array|boolean  Array on success or boolean false on failure
 *
 * @since   3.1
 */
public static function unpack($packageFilename, $alwaysReturnArray = false)
{
    // Path to the archive
    $archivename = $packageFilename;
    // Temporary folder to extract the archive into
    $tmpdir = uniqid('install_');
    // Clean the paths to use for archive extraction
    $extractdir = Path::clean(\dirname($packageFilename) . '/' . $tmpdir);
    $archivename = Path::clean($archivename);
    // Do the unpacking of the archive
    try {
        $archive = new Archive(array('tmp_path' => Factory::getApplication()->get('tmp_path')));
        $extract = $archive->extract($archivename, $extractdir);
    } catch (\Exception $e) {
        if ($alwaysReturnArray) {
            return array('extractdir' => null, 'packagefile' => $archivename, 'type' => false);
        }
        return false;
    }
    if (!$extract) {
        if ($alwaysReturnArray) {
            return array('extractdir' => null, 'packagefile' => $archivename, 'type' => false);
        }
        return false;
    }
    /*
     * Let's set the extraction directory and package file in the result array so we can
     * cleanup everything properly later on.
     */
    $retval['extractdir'] = $extractdir;
    $retval['packagefile'] = $archivename;
    /*
     * Try to find the correct install directory.  In case the package is inside a
     * subdirectory detect this and set the install directory to the correct path.
     *
     * List all the items in the installation directory.  If there is only one, and
     * it is a folder, then we will set that folder to be the installation folder.
     */
    $dirList = array_merge((array) Folder::files($extractdir, ''), (array) Folder::folders($extractdir, ''));
    if (\count($dirList) === 1) {
        if (Folder::exists($extractdir . '/' . $dirList[0])) {
            $extractdir = Path::clean($extractdir . '/' . $dirList[0]);
        }
    }
    /*
     * We have found the install directory so lets set it and then move on
     * to detecting the extension type.
     */
    $retval['dir'] = $extractdir;
    /*
     * Get the extension type and return the directory/type array on success or
     * false on fail.
     */
    $retval['type'] = self::detectType($extractdir);
    if ($alwaysReturnArray || $retval['type']) {
        return $retval;
    } else {
        return false;
    }
}