1 files changed, 90 insertions, 0 deletions
diff --git a/v_windows/v/vlib/net/tcp_read_line.v b/v_windows/v/vlib/net/tcp_read_line.v
new file mode 100644
index 0000000..ec4a18e
--- /dev/null
+++ b/v_windows/v/vlib/net/tcp_read_line.v
@@ -0,0 +1,90 @@
+module net
+
+const (
+	crlf     = '\r\n'
+	msg_peek = 0x02
+	max_read = 400
+)
+
+// get_blocking returns whether the connection is in a blocking state,
+// that is calls to .read_line, C.recv etc will block till there is new
+// data arrived, instead of returning immediately.
+pub fn (mut con TcpConn) get_blocking() bool {
+	// flags := C.fcntl(con.sock.handle, C.F_GETFL, 0)
+	// return 0 == flags & C.O_NONBLOCK
+	return con.is_blocking
+}
+
+// set_blocking will change the state of the connection to either blocking,
+// when state is true, or non blocking (false).
+// The default for `net` tcp connections is the non blocking mode.
+// Calling .read_line will set the connection to blocking mode.
+pub fn (mut con TcpConn) set_blocking(state bool) ? {
+	con.is_blocking = state
+	$if windows {
+		mut t := u32(0)
+		if !con.is_blocking {
+			t = 1
+		}
+		socket_error(C.ioctlsocket(con.sock.handle, fionbio, &t)) ?
+	} $else {
+		mut flags := C.fcntl(con.sock.handle, C.F_GETFL, 0)
+		if state {
+			flags &= ~C.O_NONBLOCK
+		} else {
+			flags |= C.O_NONBLOCK
+		}
+		socket_error(C.fcntl(con.sock.handle, C.F_SETFL, flags)) ?
+	}
+}
+
+// read_line is a *simple*, *non customizable*, blocking line reader.
+// It will *always* return a line, ending with CRLF, or just '', on EOF.
+// NB: if you want more control over the buffer, please use a buffered IO
+// reader instead: `io.new_buffered_reader({reader: io.make_reader(con)})`
+pub fn (mut con TcpConn) read_line() string {
+	mut buf := [net.max_read]byte{} // where C.recv will store the network data
+	mut res := '' // The final result, including the ending \n.
+	if !con.is_blocking {
+		con.set_blocking(true) or {}
+	}
+	for {
+		mut line := '' // The current line. Can be a partial without \n in it.
+		n := C.recv(con.sock.handle, &buf[0], net.max_read - 1, net.msg_peek | msg_nosignal)
+		if n == -1 {
+			return res
+		}
+		if n == 0 {
+			return res
+		}
+		buf[n] = `\0`
+		mut eol_idx := -1
+		for i in 0 .. n {
+			if int(buf[i]) == `\n` {
+				eol_idx = i
+				// Ensure that tos_clone(buf) later,
+				// will return *only* the first line (including \n),
+				// and ignore the rest
+				buf[i + 1] = `\0`
+				break
+			}
+		}
+		line = unsafe { tos_clone(&buf[0]) }
+		if eol_idx > 0 {
+			// At this point, we are sure that recv returned valid data,
+			// that contains *at least* one line.
+			// Ensure that the block till the first \n (including it)
+			// is removed from the socket's receive queue, so that it does
+			// not get read again.
+			C.recv(con.sock.handle, &buf[0], eol_idx + 1, msg_nosignal)
+			res += line
+			break
+		}
+		// recv returned a buffer without \n in it .
+		C.recv(con.sock.handle, &buf[0], n, msg_nosignal)
+		res += line
+		res += net.crlf
+		break
+	}
+	return res
+}