musli 0.1.5

Müsli is a flexible and efficient serialization framework.
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

//! Mutation fuzzing: encode a valid value, corrupt it, and make sure decoding
//! only ever errors rather than panicking.

use std::collections::HashMap;

use musli::alloc::Global;
use musli::value::Value;
use musli::{Decode, Encode};

#[derive(Debug, PartialEq, Encode, Decode)]
struct Inner {
    a: u32,
    b: String,
    c: Vec<u8>,
}

#[derive(Debug, PartialEq, Encode, Decode)]
enum En {
    Unit,
    Newtype(u32),
    Tuple(u32, String),
    Struct { x: i64, y: Option<u8> },
}

#[derive(Debug, PartialEq, Encode, Decode)]
struct Outer {
    inner: Inner,
    list: Vec<En>,
    opt: Option<Inner>,
    tup: (u8, i16, f64),
    map: HashMap<String, u32>,
    ch: char,
    flag: bool,
}

struct Rng(u64);

impl Rng {
    fn next(&mut self) -> u64 {
        let mut x = self.0;
        x ^= x << 13;
        x ^= x >> 7;
        x ^= x << 17;
        self.0 = x;
        x
    }

    fn below(&mut self, n: usize) -> usize {
        (self.next() % n as u64) as usize
    }
}

fn sample() -> Outer {
    let mut map = HashMap::new();
    map.insert("key".to_string(), 7u32);

    Outer {
        inner: Inner {
            a: 5,
            b: "hello".into(),
            c: vec![1, 2, 3, 4],
        },
        list: vec![
            En::Unit,
            En::Newtype(3),
            En::Tuple(1, "t".into()),
            En::Struct { x: -2, y: Some(4) },
        ],
        opt: Some(Inner {
            a: 0,
            b: String::new(),
            c: Vec::new(),
        }),
        tup: (1, -2, 3.5),
        map,
        ch: '\u{1f600}',
        flag: true,
    }
}

fn mutate(rng: &mut Rng, original: &[u8]) -> Vec<u8> {
    let mut bytes = original.to_vec();

    for _ in 0..rng.below(6) + 1 {
        if bytes.is_empty() {
            bytes.push((rng.next() & 0xFF) as u8);
            continue;
        }

        let at = rng.below(bytes.len());

        match rng.below(4) {
            0 => bytes[at] ^= 1u8 << rng.below(8),
            1 => bytes[at] = (rng.next() & 0xFF) as u8,
            2 => bytes.truncate(at),
            _ => bytes.insert(at, (rng.next() & 0xFF) as u8),
        }
    }

    bytes
}

macro_rules! fuzz {
    ($module:ident, $seed:expr) => {{
        let value = sample();
        let original = musli::$module::to_vec(&value).unwrap();
        let mut rng = Rng($seed);

        for _ in 0..50000 {
            let bytes = mutate(&mut rng, &original);

            // Only errors or values are acceptable, never a panic.
            let _ = musli::$module::from_slice::<Outer>(&bytes);
            let _ = musli::$module::from_slice::<Inner>(&bytes);
            let _ = musli::$module::from_slice::<Vec<En>>(&bytes);
            let _ = musli::$module::from_slice::<u64>(&bytes);
            let _ = musli::$module::from_slice::<String>(&bytes);
        }
    }};
}

#[test]
fn fuzz_storage() {
    fuzz!(storage, 0x1111);
}

#[test]
fn fuzz_wire() {
    fuzz!(wire, 0x2222);
}

#[test]
fn fuzz_descriptive() {
    fuzz!(descriptive, 0x3333);
}

#[test]
fn fuzz_json() {
    fuzz!(json, 0x4444);
}

#[test]
fn fuzz_descriptive_into_value() {
    let value = sample();
    let original = musli::descriptive::to_vec(&value).unwrap();
    let mut rng = Rng(0x5555);

    for _ in 0..50000 {
        let bytes = mutate(&mut rng, &original);
        let _ = musli::descriptive::from_slice::<Value<Global>>(&bytes);
    }
}