mutatis 0.5.2

`mutatis` is a library for writing custom, structure-aware test-case mutators for fuzzers in Rust.
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

use super::*;
use core::mem;

/// The default mutator for `BTreeMap<K, V>` values.
///
/// See the [`btree_map()`] function to create new instances and for example
/// usage.
#[derive(Clone, Debug, Default)]
pub struct BTreeMap<KM, VM> {
    key_mutator: KM,
    value_mutator: VM,
}

/// Create a new mutator for `BTreeMap<K, V>` values.
///
/// # Example
///
/// ```
/// # fn foo() -> mutatis::Result<()> {
/// use mutatis::{mutators as m, Mutate, Session};
/// use std::collections::BTreeMap;
///
/// let mut items: BTreeMap<u8, u32> = BTreeMap::new();
///
/// let mut mutator = m::btree_map(m::u8(), m::mrange(100..=199));
///
/// let mut session = Session::new();
/// for _ in 0..5 {
///     session.mutate_with(&mut mutator, &mut items)?;
///     println!("items = {items:?}");
/// }
///
/// // Example output:
/// //
/// //     items = {201: 146}
/// //     items = {201: 194}
/// //     items = {}
/// //     items = {44: 197}
/// //     items = {44: 197, 172: 123}
/// # Ok(()) }
/// # foo().unwrap();
/// ```
pub fn btree_map<KM, VM>(key_mutator: KM, value_mutator: VM) -> BTreeMap<KM, VM> {
    BTreeMap {
        key_mutator,
        value_mutator,
    }
}

impl<KM, VM, K, V> Mutate<alloc::collections::BTreeMap<K, V>> for BTreeMap<KM, VM>
where
    KM: Generate<K>,
    VM: Generate<V> + Mutate<V>,
    K: Ord,
{
    #[inline]
    fn mutation_count(
        &self,
        value: &alloc::collections::BTreeMap<K, V>,
        shrink: bool,
    ) -> core::option::Option<u32> {
        let mut count = 0u32;
        // Add an entry.
        count += !shrink as u32;
        // Remove an entry.
        count += !value.is_empty() as u32;
        for (k, v) in value.iter() {
            // Mutate an existing value.
            count += self.value_mutator.mutation_count(v, shrink)?;
            // Mutate an existing key.
            count += self.key_mutator.mutation_count(k, shrink)?;
        }
        Some(count)
    }

    #[inline]
    fn mutate(
        &mut self,
        c: &mut Candidates,
        value: &mut alloc::collections::BTreeMap<K, V>,
    ) -> Result<()> {
        // Add an entry.
        if !c.shrink() {
            c.mutation(|ctx| {
                let k = self.key_mutator.generate(ctx)?;
                let v = self.value_mutator.generate(ctx)?;
                value.insert(k, v);
                Ok(())
            })?;
        }

        // Remove an entry.
        if !value.is_empty() {
            c.mutation(|ctx| {
                if ctx.rng().gen_bool() {
                    value.pop_first();
                } else {
                    value.pop_last();
                }
                Ok(())
            })?;
        }

        // Mutate an existing value.
        for (_k, v) in value.iter_mut() {
            self.value_mutator.mutate(c, v)?;
        }

        // Mutate an existing key.
        if !value.is_empty() {
            let mut early_exit = None;
            for (mut key, val) in mem::take(value) {
                if early_exit.is_none() {
                    match self.key_mutator.mutate(c, &mut key) {
                        Ok(()) => {}
                        Err(e) if e.is_early_exit() => {
                            early_exit = Some(e);
                        }
                        Err(e) => return Err(e),
                    }
                }

                value.insert(key, val);
            }

            if let Some(e) = early_exit {
                return Err(e);
            }
        }

        Ok(())
    }
}

impl<KM, VM, K, V> Generate<alloc::collections::BTreeMap<K, V>> for BTreeMap<KM, VM>
where
    KM: Generate<K>,
    VM: Generate<V> + Mutate<V>,
    K: Ord,
{
    #[inline]
    fn generate(&mut self, ctx: &mut Context) -> Result<alloc::collections::BTreeMap<K, V>> {
        self.generate_via_mutate(ctx, 1)
    }
}

impl<K, V> DefaultMutate for alloc::collections::BTreeMap<K, V>
where
    K: DefaultMutate + Ord,
    K::DefaultMutate: Generate<K>,
    V: DefaultMutate,
    V::DefaultMutate: Generate<V>,
{
    type DefaultMutate = BTreeMap<K::DefaultMutate, V::DefaultMutate>;
}