PHPDaemon\FS\File::sendfile PHP 메소드

    public function sendfile($outfd, $cb, $startCb = null, $offset = 0, $length = null, $pri = EIO_PRI_DEFAULT)
    {
        $cb = CallbackWrapper::forceWrap($cb);
        if (!$this->fd) {
            if ($cb) {
                $cb($this, false);
            }
            return false;
        }
        if (!FileSystem::$supported) {
            if ($cb) {
                $cb($this, false);
            }
            return false;
        }
        static $chunkSize = 1024;
        $ret = true;
        $handler = function ($file, $sent = -1) use(&$ret, $outfd, $cb, &$handler, &$offset, &$length, $pri, $chunkSize) {
            if ($outfd instanceof IOStream) {
                if ($outfd->isFreed()) {
                    $cb($file, false);
                    return;
                }
                $ofd = $outfd->getFd();
            } else {
                $ofd = $outfd;
            }
            if (!$ret) {
                $cb($file, false);
                return;
            }
            if ($sent === -1) {
                $sent = 0;
            }
            $offset += $sent;
            $length -= $sent;
            if ($length <= 0) {
                $cb($file, true);
                return;
            }
            if (!$ofd) {
                $cb($file, false);
                return;
            }
            $c = min($chunkSize, $length);
            $ret = eio_sendfile($ofd, $file->fd, $offset, $c, $pri, $handler, $file);
        };
        if ($length !== null) {
            if ($startCb !== null) {
                if (!$startCb($this, $length, $handler)) {
                    $handler($this);
                }
            } else {
                $handler($this);
            }
            return true;
        }
        $this->statRefresh(function ($file, $stat) use($startCb, $handler, &$length) {
            $length = $stat['size'];
            if ($startCb !== null) {
                if (!$startCb($file, $length, $handler)) {
                    $handler($file);
                }
            } else {
                $handler($file);
            }
        }, $pri);
        return true;
    }