mqtt/control/variable_header/
connect_ack_flags.rs

1use std::io::{self, Read, Write};
2
3use byteorder::{ReadBytesExt, WriteBytesExt};
4
5use crate::control::variable_header::VariableHeaderError;
6use crate::{Decodable, Encodable};
7
8/// Flags in `CONNACK` packet
9#[derive(Debug, Eq, PartialEq, Copy, Clone)]
10pub struct ConnackFlags {
11    pub session_present: bool,
12}
13
14impl ConnackFlags {
15    pub fn empty() -> ConnackFlags {
16        ConnackFlags { session_present: false }
17    }
18}
19
20impl Encodable for ConnackFlags {
21    fn encode<W: Write>(&self, writer: &mut W) -> Result<(), io::Error> {
22        let code = self.session_present as u8;
23        writer.write_u8(code)
24    }
25
26    fn encoded_length(&self) -> u32 {
27        1
28    }
29}
30
31impl Decodable for ConnackFlags {
32    type Error = VariableHeaderError;
33    type Cond = ();
34
35    fn decode_with<R: Read>(reader: &mut R, _rest: ()) -> Result<ConnackFlags, VariableHeaderError> {
36        let code = reader.read_u8()?;
37        if code & !1 != 0 {
38            return Err(VariableHeaderError::InvalidReservedFlag);
39        }
40
41        Ok(ConnackFlags {
42            session_present: code == 1,
43        })
44    }
45}