class InputStreamFileWriter

class InputStreamFileWriter implements InputStreamFileWriterInterface {
    
    /**
     * Creates a new InputStreamFileUploader.
     */
    public function __construct(FileSystemInterface $fileSystem) {
    }
    
    /**
     * {@inheritdoc}
     */
    public function writeStreamToFile(string $stream = self::DEFAULT_STREAM, int $bytesToRead = self::DEFAULT_BYTES_TO_READ) : string {
        // 'rb' is needed so reading works correctly on Windows environments too.
        $fileData = fopen($stream, 'rb');
        $tempFilePath = $this->fileSystem
            ->tempnam('temporary://', 'file');
        $tempFile = fopen($tempFilePath, 'wb');
        if ($tempFile) {
            while (!feof($fileData)) {
                $read = fread($fileData, $bytesToRead);
                if ($read === FALSE) {
                    // Close the file streams.
                    fclose($tempFile);
                    fclose($fileData);
                    throw new UploadException('Input file data could not be read');
                }
                if (fwrite($tempFile, $read) === FALSE) {
                    // Close the file streams.
                    fclose($tempFile);
                    fclose($fileData);
                    throw new CannotWriteFileException(sprintf('Temporary file data for "%s" could not be written', $tempFilePath));
                }
            }
            // Close the temp file stream.
            fclose($tempFile);
        }
        else {
            // Close the input file stream since we can't proceed with the upload.
            // Don't try to close $tempFile since it's FALSE at this point.
            fclose($fileData);
            throw new NoFileException(sprintf('Temporary file "%s" could not be opened for file upload', $tempFilePath));
        }
        // Close the input stream.
        fclose($fileData);
        return $tempFilePath;
    }

}