name : LazyOpenStream.php <?php declare(strict_types=1); namespace GuzzleHttp\Psr7; use Psr\Http\Message\StreamInterface; /** * Lazily reads or writes to a file that is opened only after an IO operation * take place on the stream. */ final class LazyOpenStream implements StreamInterface { use StreamDecoratorTrait; /** @var string */ private $filename; /** @var string */ private $mode; /** * @var StreamInterface */ private $stream; /** * @param string $filename File to lazily open * @param string $mode fopen mode to use when opening the stream */ public function __construct(string $filename, string $mode) { $this->filename = $filename; $this->mode = $mode; // unsetting the property forces the first access to go through // __get(). unset($this->stream); } /** * Creates the underlying stream lazily when required. */ protected function createStream(): StreamInterface { return Utils::streamFor(Utils::tryFopen($this->filename, $this->mode)); } }