romp 0.5.2

STOMP server and WebSockets platform
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171

use crate::body_parser::{BodyParser, ParserState};
use crate::message::stomp_message::StompMessage;

/// STOMP protocol push parser, parses message body.
///
/// readonly bytes pushed in from the network and copied into the message
///
/// State of the Struct

/// state of the loop
#[derive(Debug, PartialEq)]
enum State {
    Start,
    /// expecting trailing \0
    AlmostDone,
    Done,
    Error,
}

/// Body parser for binary data when we know the expected length of the data, content-len: x was provided.
pub struct FixedLengthBodyParser {
    state: State,
    expected_len: usize,
    remaining_len: usize,
}

/// reads up to content-length: xxx bytes
impl FixedLengthBodyParser {
    pub fn new() -> FixedLengthBodyParser {
        FixedLengthBodyParser {
            state: State::Start,
            expected_len: 0,
            remaining_len: 0,
        }
    }

    /// must be called before use
    pub fn reinit(&mut self, expected_len: usize) {
        self.state = State::Start;
        self.remaining_len = expected_len;
        self.expected_len = expected_len;
    }

    pub fn expected_len(&self) -> usize {
        self.expected_len
    }
}

impl BodyParser for FixedLengthBodyParser {

    fn push(&mut self, buffer: &[u8], message: &mut StompMessage) -> Result<usize, ParserState> {

        let len = buffer.len();

        // TODO might not be necessary if ([0..0]) is sane
        if State::AlmostDone == self.state {
            let zero = buffer[0];
            if zero != b'\0' {
                self.state = State::Error;
                return Err(ParserState::InvalidMessage);
            }
            else {
                self.state = State::Done;
                return Ok(1);
            }
        }
        if len < self.remaining_len {
            message.add_body(buffer);
            self.remaining_len -= len;

            return Ok(len);
        }
        else if len == self.remaining_len {
            message.add_body(buffer);
            self.remaining_len -= len;
            self.state = State::AlmostDone;

            return Ok(len);
        }
        else if len > self.remaining_len {
            let to_read = self.remaining_len;
            message.add_body(&buffer[0..to_read]);
            self.remaining_len -= to_read;

            // verify trailing \0 is present
            match buffer[to_read] {
                b'\0' => {
                    self.state = State::Done;
                    return Ok(to_read + 1);
                }
                _ => {
                    self.state = State::Error;
                    return Err(ParserState::InvalidMessage);
                }
            }
        }

        // unreachable
        return Err(ParserState::InvalidMessage);
    }

    fn is_done(&self) -> bool {
        State::Done == self.state
    }
}

#[cfg(test)]
mod tests {
    use crate::message::stomp_message::Ownership;

    use super::*;

    #[test]
    fn test_fixed_length_happy() {
        let mut p = FixedLengthBodyParser::new();
        let mut message = StompMessage::new(Ownership::Session);

        p.reinit(23);

        match p.push(b"abcdefghij", &mut message) {
            Ok(10) => { assert!(!p.is_done()); },
            Err(_) => panic!("parse error"),
            _ => panic!("unexpected")
        }
        match p.push(b"klmnopqrst", &mut message) {
            Ok(10) => { assert!(!p.is_done()); },
            Err(_) => panic!("parse error"),
            _ => panic!("unexpected")
        }
        match p.push(b"uvw\0", &mut message) {
            Ok(4) => { assert!(p.is_done()); },
            Err(_) => panic!("parse error"),
            _ => panic!("unexpected")
        }
    }


    #[test]
    fn test_fixed_length_unhappy() {
        let mut p = FixedLengthBodyParser::new();
        let mut message = StompMessage::new(Ownership::Session);

        p.reinit(22); // <- bug

        match p.push(b"abcdefghij", &mut message) {
            Ok(10) => { assert!(!p.is_done()); },
            Err(_) => panic!("parse error"),
            _ => panic!("unexpected")
        }
        match p.push(b"klmnopqrst", &mut message) {
            Ok(10) => { assert!(!p.is_done()); },
            Err(_) => panic!("parse error"),
            _ => panic!("unexpected")
        }
        match p.push(b"uvw\0", &mut message) {
            Err(ParserState::InvalidMessage) => {
                assert!(! p.is_done());
                match p.state {
                    State::Error => {
                        // all good
                    }
                    _ => {
                        panic!("unexpected parser state")
                    }
                }
            },
            Ok(4) => { panic!("unexpected") },
            _ => panic!("unexpected")
        }
    }
}