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v/vlib/net/tcp_read_line.v

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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 {}
}
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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()
}