radicle_node/
deserializer.rs

1use std::io;
2use std::marker::PhantomData;
3
4use crate::bounded;
5use crate::prelude::BoundedVec;
6use crate::service::message::Message;
7use crate::wire;
8
9/// Message stream deserializer.
10///
11/// Used to for example turn a byte stream into network messages.
12#[derive(Debug)]
13pub struct Deserializer<const B: usize, D = Message> {
14    unparsed: BoundedVec<u8, B>,
15    item: PhantomData<D>,
16}
17
18impl<const B: usize, D: wire::Decode> Default for Deserializer<B, D> {
19    fn default() -> Self {
20        Self::new(wire::Size::MAX as usize + 1)
21    }
22}
23
24impl<const B: usize, D> TryFrom<Vec<u8>> for Deserializer<B, D> {
25    type Error = bounded::Error;
26
27    fn try_from(unparsed: Vec<u8>) -> Result<Self, Self::Error> {
28        BoundedVec::try_from(unparsed).map(|unparsed| Self {
29            unparsed,
30            item: PhantomData,
31        })
32    }
33}
34
35impl<const B: usize, D: wire::Decode> Deserializer<B, D> {
36    /// Create a new stream decoder.
37    pub fn new(capacity: usize) -> Self {
38        Self {
39            unparsed: BoundedVec::with_capacity(capacity)
40                .expect("Deserializer::new: capacity exceeds maximum"),
41            item: PhantomData,
42        }
43    }
44
45    /// Input bytes into the decoder.
46    pub fn input(&mut self, bytes: &[u8]) -> Result<(), bounded::Error> {
47        self.unparsed.extend_from_slice(bytes)
48    }
49
50    /// Decode and return the next message. Returns [`None`] if nothing was decoded.
51    pub fn deserialize_next(&mut self) -> Result<Option<D>, wire::Error> {
52        let mut reader = io::Cursor::new(self.unparsed.as_slice());
53
54        match D::decode(&mut reader) {
55            Ok(msg) => {
56                let pos = reader.position() as usize;
57                self.unparsed.drain(..pos);
58
59                Ok(Some(msg))
60            }
61            Err(err) if err.is_eof() => Ok(None),
62            Err(err) => Err(err),
63        }
64    }
65
66    /// Drain the unparsed buffer.
67    pub fn unparsed(&mut self) -> impl ExactSizeIterator<Item = u8> + '_ {
68        self.unparsed.drain(..)
69    }
70
71    /// Return whether there are unparsed bytes.
72    pub fn is_empty(&self) -> bool {
73        self.unparsed.is_empty()
74    }
75
76    /// Return the size of the unparsed data.
77    pub fn len(&self) -> usize {
78        self.unparsed.len()
79    }
80}
81
82impl<const B: usize, D: wire::Decode> io::Write for Deserializer<B, D> {
83    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
84        self.input(buf).map_err(|_| io::ErrorKind::OutOfMemory)?;
85
86        Ok(buf.len())
87    }
88
89    fn flush(&mut self) -> io::Result<()> {
90        Ok(())
91    }
92}
93
94impl<const B: usize, D: wire::Decode> Iterator for Deserializer<B, D> {
95    type Item = Result<D, wire::Error>;
96
97    fn next(&mut self) -> Option<Self::Item> {
98        self.deserialize_next().transpose()
99    }
100}
101
102#[cfg(test)]
103mod test {
104    use super::*;
105    use qcheck_macros::quickcheck;
106
107    use crate::test::assert_matches;
108
109    const MSG_HELLO: &[u8] = &[5, b'h', b'e', b'l', b'l', b'o'];
110    const MSG_BYE: &[u8] = &[3, b'b', b'y', b'e'];
111
112    #[test]
113    fn test_decode_next() {
114        let mut decoder = Deserializer::<1024, String>::new(8);
115
116        decoder.input(&[3, b'b']).unwrap();
117        assert_matches!(decoder.deserialize_next(), Ok(None));
118        assert_eq!(decoder.unparsed.len(), 2);
119
120        decoder.input(&[b'y']).unwrap();
121        assert_matches!(decoder.deserialize_next(), Ok(None));
122        assert_eq!(decoder.unparsed.len(), 3);
123
124        decoder.input(&[b'e']).unwrap();
125        assert_matches!(decoder.deserialize_next(), Ok(Some(s)) if s.as_str() == "bye");
126        assert_eq!(decoder.unparsed.len(), 0);
127        assert!(decoder.is_empty());
128    }
129
130    #[test]
131    fn test_unparsed() {
132        let mut decoder = Deserializer::<1024, String>::new(8);
133
134        decoder.input(&[3, b'b', b'y']).unwrap();
135        assert_eq!(decoder.unparsed().collect::<Vec<_>>(), vec![3, b'b', b'y']);
136        assert!(decoder.is_empty());
137    }
138
139    #[quickcheck]
140    fn prop_decode_next(chunk_size: usize) {
141        let mut bytes = vec![];
142        let mut msgs = vec![];
143        let mut decoder = Deserializer::<1024, String>::new(8);
144
145        let chunk_size = 1 + chunk_size % MSG_HELLO.len() + MSG_BYE.len();
146
147        bytes.extend_from_slice(MSG_HELLO);
148        bytes.extend_from_slice(MSG_BYE);
149
150        for chunk in bytes.as_slice().chunks(chunk_size) {
151            decoder.input(chunk).unwrap();
152
153            while let Some(msg) = decoder.deserialize_next().unwrap() {
154                msgs.push(msg);
155            }
156        }
157
158        assert_eq!(decoder.unparsed.len(), 0);
159        assert_eq!(msgs.len(), 2);
160        assert_eq!(msgs[0], String::from("hello"));
161        assert_eq!(msgs[1], String::from("bye"));
162    }
163}
radicle_node/deserializer.rs

radicle_node/
deserializer.rs
