ic_agent/agent/
nonce.rs

1use rand::{rngs::OsRng, Rng};
2use std::sync::{
3    atomic::{AtomicU64, Ordering},
4    Arc, Mutex,
5};
6
7/// A Factory for nonce blobs.
8#[derive(Clone)]
9pub struct NonceFactory {
10    inner: Arc<dyn NonceGenerator>,
11}
12
13impl NonceFactory {
14    /// Creates a nonce factory from an iterator over blobs. The iterator is not assumed to be fused.
15    pub fn from_iterator(iter: Box<dyn Iterator<Item = Vec<u8>> + Send>) -> Self {
16        Self {
17            inner: Arc::new(Iter::from(iter)),
18        }
19    }
20
21    /// Creates a nonce factory that generates random blobs using `getrandom`.
22    pub fn random() -> NonceFactory {
23        Self {
24            inner: Arc::new(RandomBlob {}),
25        }
26    }
27
28    /// Creates a nonce factory that returns None every time.
29    pub fn empty() -> NonceFactory {
30        Self {
31            inner: Arc::new(Empty),
32        }
33    }
34
35    /// Creates a nonce factory that generates incrementing blobs.
36    pub fn incrementing() -> NonceFactory {
37        Self {
38            inner: Arc::new(Incrementing::default()),
39        }
40    }
41
42    /// Generates a nonce, if one is available. Otherwise, returns None.
43    pub fn generate(&self) -> Option<Vec<u8>> {
44        NonceGenerator::generate(self)
45    }
46}
47
48impl NonceGenerator for NonceFactory {
49    fn generate(&self) -> Option<Vec<u8>> {
50        self.inner.generate()
51    }
52}
53
54/// An interface for generating nonces.
55pub trait NonceGenerator: Send + Sync {
56    /// Generates a nonce, if one is available. Otherwise, returns None.
57    fn generate(&self) -> Option<Vec<u8>>;
58}
59
60pub struct Func<T>(pub T);
61impl<T: Send + Sync + Fn() -> Option<Vec<u8>>> NonceGenerator for Func<T> {
62    fn generate(&self) -> Option<Vec<u8>> {
63        (self.0)()
64    }
65}
66
67pub struct Iter<T>(Mutex<T>);
68impl<T: Send + Iterator<Item = Vec<u8>>> From<T> for Iter<T> {
69    fn from(val: T) -> Iter<T> {
70        Iter(Mutex::new(val))
71    }
72}
73impl<T: Send + Iterator<Item = Vec<u8>>> NonceGenerator for Iter<T> {
74    fn generate(&self) -> Option<Vec<u8>> {
75        self.0.lock().unwrap().next()
76    }
77}
78
79#[derive(Default)]
80pub struct RandomBlob {}
81impl NonceGenerator for RandomBlob {
82    fn generate(&self) -> Option<Vec<u8>> {
83        Some(OsRng.gen::<[u8; 16]>().to_vec())
84    }
85}
86
87#[derive(Default)]
88pub struct Empty;
89impl NonceGenerator for Empty {
90    fn generate(&self) -> Option<Vec<u8>> {
91        None
92    }
93}
94
95#[derive(Default)]
96pub struct Incrementing {
97    next: AtomicU64,
98}
99impl From<u64> for Incrementing {
100    fn from(val: u64) -> Incrementing {
101        Incrementing {
102            next: AtomicU64::new(val),
103        }
104    }
105}
106impl NonceGenerator for Incrementing {
107    fn generate(&self) -> Option<Vec<u8>> {
108        let val = self.next.fetch_add(1, Ordering::Relaxed);
109        Some(val.to_le_bytes().to_vec())
110    }
111}
112
113impl<N: NonceGenerator + ?Sized> NonceGenerator for Box<N> {
114    fn generate(&self) -> Option<Vec<u8>> {
115        (**self).generate()
116    }
117}
118impl<N: NonceGenerator + ?Sized> NonceGenerator for Arc<N> {
119    fn generate(&self) -> Option<Vec<u8>> {
120        (**self).generate()
121    }
122}
ic_agent/agent/nonce.rs

ic_agent/agent/
nonce.rs
