1use crate::Uuid;
2
3impl Uuid {
4 /// Creates a random UUID.
5 ///
6 /// This uses the [`getrandom`] crate to utilise the operating system's RNG
7 /// as the source of random numbers. If you'd like to use a custom
8 /// generator, don't use this method: generate random bytes using your
9 /// custom generator and pass them to the
10 /// [`uuid::Builder::from_random_bytes`][from_random_bytes] function
11 /// instead.
12 ///
13 /// Note that usage of this method requires the `v4` feature of this crate
14 /// to be enabled.
15 ///
16 /// # Examples
17 ///
18 /// Basic usage:
19 ///
20 /// ```
21 /// # use uuid::{Uuid, Version};
22 /// let uuid = Uuid::new_v4();
23 ///
24 /// assert_eq!(Some(Version::Random), uuid.get_version());
25 /// ```
26 ///
27 /// # References
28 ///
29 /// * [UUID Version 4 in RFC 9562](https://www.ietf.org/rfc/rfc9562.html#section-5.4)
30 ///
31 /// [`getrandom`]: https://crates.io/crates/getrandom
32 /// [from_random_bytes]: struct.Builder.html#method.from_random_bytes
33 pub fn new_v4() -> Uuid {
34 // This is an optimized method for generating random UUIDs that just masks
35 // out the bits for the version and variant and sets them both together
36 Uuid::from_u128(
37 crate::rng::u128() & 0xFFFFFFFFFFFF4FFFBFFFFFFFFFFFFFFF | 0x40008000000000000000,
38 )
39 }
40}
41
42#[cfg(test)]
43mod tests {
44 use super::*;
45 use crate::{Variant, Version};
46
47 #[cfg(all(
48 target_arch = "wasm32",
49 target_vendor = "unknown",
50 target_os = "unknown"
51 ))]
52 use wasm_bindgen_test::*;
53
54 #[test]
55 #[cfg_attr(
56 all(
57 target_arch = "wasm32",
58 target_vendor = "unknown",
59 target_os = "unknown"
60 ),
61 wasm_bindgen_test
62 )]
63 fn test_new() {
64 let uuid = Uuid::new_v4();
65
66 assert_eq!(uuid.get_version(), Some(Version::Random));
67 assert_eq!(uuid.get_variant(), Variant::RFC4122);
68 }
69
70 #[test]
71 #[cfg_attr(
72 all(
73 target_arch = "wasm32",
74 target_vendor = "unknown",
75 target_os = "unknown"
76 ),
77 wasm_bindgen_test
78 )]
79 fn test_get_version() {
80 let uuid = Uuid::new_v4();
81
82 assert_eq!(uuid.get_version(), Some(Version::Random));
83 assert_eq!(uuid.get_version_num(), 4)
84 }
85}
86