Method findDeletedFiles

/**
 * Compares two "files" entries to find deleted files/folders
 *
 * @param   array  $oldFiles  An array of \SimpleXMLElement objects that are the old files
 * @param   array  $newFiles  An array of \SimpleXMLElement objects that are the new files
 *
 * @return  array  An array with the delete files and folders in findDeletedFiles[files] and findDeletedFiles[folders] respectively
 *
 * @since   3.1
 */
public function findDeletedFiles($oldFiles, $newFiles)
{
    // The magic find deleted files function!
    // The files that are new
    $files = array();
    // The folders that are new
    $folders = array();
    // The folders of the files that are new
    $containers = array();
    // A list of files to delete
    $files_deleted = array();
    // A list of folders to delete
    $folders_deleted = array();
    foreach ($newFiles as $file) {
        switch ($file->getName()) {
            case 'folder':
                // Add any folders to the list
                $folders[] = (string) $file;
                break;
            case 'file':
            default:
                // Add any files to the list
                $files[] = (string) $file;
                // Now handle the folder part of the file to ensure we get any containers
                // Break up the parts of the directory
                $container_parts = explode('/', \dirname((string) $file));
                // Make sure this is clean and empty
                $container = '';
                foreach ($container_parts as $part) {
                    // Iterate through each part
                    // Add a slash if its not empty
                    if (!empty($container)) {
                        $container .= '/';
                    }
                    // Append the folder part
                    $container .= $part;
                    if (!\in_array($container, $containers)) {
                        // Add the container if it doesn't already exist
                        $containers[] = $container;
                    }
                }
                break;
        }
    }
    foreach ($oldFiles as $file) {
        switch ($file->getName()) {
            case 'folder':
                if (!\in_array((string) $file, $folders)) {
                    // See whether the folder exists in the new list
                    if (!\in_array((string) $file, $containers)) {
                        // Check if the folder exists as a container in the new list
                        // If it's not in the new list or a container then delete it
                        $folders_deleted[] = (string) $file;
                    }
                }
                break;
            case 'file':
            default:
                if (!\in_array((string) $file, $files)) {
                    // Look if the file exists in the new list
                    if (!\in_array(\dirname((string) $file), $folders)) {
                        // Look if the file is now potentially in a folder
                        $files_deleted[] = (string) $file;
                    }
                }
                break;
        }
    }
    return array('files' => $files_deleted, 'folders' => $folders_deleted);
}