module net import strings const ( crlf = '\r\n' msg_peek = 0x02 max_read = 400 max_read_line_len = 1048576 ) // 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 return a line, ending with LF, or just '', on EOF. // Note: 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 { return con.read_line_max(net.max_read_line_len) } // read_line_max is a *simple*, *non customizable*, blocking line reader. // It will return a line, ending with LF, '' on EOF. // It stops reading, when the result line length exceeds max_line_len. [manualfree] pub fn (mut con TcpConn) read_line_max(max_line_len int) string { if !con.is_blocking { con.set_blocking(true) or {} } mut buf := [net.max_read]u8{} // where C.recv will store the network data mut res := strings.new_builder(net.max_read) // The final result, including the ending \n. defer { unsafe { res.free() } } bstart := unsafe { &buf[0] } for { n := C.recv(con.sock.handle, bstart, net.max_read - 1, net.msg_peek | msg_nosignal) if n <= 0 { return res.str() } buf[n] = `\0` mut eol_idx := -1 mut lend := n for i in 0 .. n { if buf[i] == `\n` { eol_idx = i lend = i + 1 buf[lend] = `\0` break } } 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, bstart, lend, msg_nosignal) unsafe { res.write_ptr(bstart, lend) } break } // recv returned a buffer without \n in it, just store it for now: C.recv(con.sock.handle, bstart, n, msg_nosignal) unsafe { res.write_ptr(bstart, lend) } if res.len > max_line_len { break } } return res.str() }