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//! The implementation for Version 6 UUIDs.
//!
//! Note that you need to enable the `v6` Cargo feature
//! in order to use this module.
use crate::{Builder, Timestamp, Uuid};
impl Uuid {
/// Create a new version 6 UUID using the current system time and node ID.
///
/// This method is only available if the `std` feature is enabled.
///
/// This method is a convenient alternative to [`Uuid::new_v6`] that uses the current system time
/// as the source timestamp.
///
/// Note that usage of this method requires the `v6`, `std`, and `rng` features of this crate
/// to be enabled.
#[cfg(all(feature = "std", feature = "rng"))]
pub fn now_v6(node_id: &[u8; 6]) -> Self {
let ts = Timestamp::now(crate::timestamp::context::shared_context());
Self::new_v6(ts, node_id)
}
/// Create a new version 6 UUID using the given timestamp and a node ID.
///
/// This is similar to version 1 UUIDs, except that it is lexicographically sortable by timestamp.
///
/// Also see [`Uuid::now_v6`] for a convenient way to generate version 6
/// UUIDs using the current system time.
///
/// When generating [`Timestamp`]s using a [`ClockSequence`], this function
/// is only guaranteed to produce unique values if the following conditions
/// hold:
///
/// 1. The *node ID* is unique for this process,
/// 2. The *context* is shared across all threads which are generating version 6
/// UUIDs,
/// 3. The [`ClockSequence`] implementation reliably returns unique
/// clock sequences (this crate provides [`Context`] for this
/// purpose. However you can create your own [`ClockSequence`]
/// implementation, if [`Context`] does not meet your needs).
///
/// The NodeID must be exactly 6 bytes long.
///
/// Note that usage of this method requires the `v6` feature of this crate
/// to be enabled.
///
/// # Examples
///
/// A UUID can be created from a unix [`Timestamp`] with a
/// [`ClockSequence`]. RFC4122 requires the clock sequence
/// is seeded with a random value:
///
/// ```rust
/// # use uuid::{Uuid, Timestamp, Context};
/// # fn random_seed() -> u16 { 42 }
/// let context = Context::new(random_seed());
/// let ts = Timestamp::from_unix(context, 1497624119, 1234);
///
/// let uuid = Uuid::new_v6(ts, &[1, 2, 3, 4, 5, 6]);
///
/// assert_eq!(
/// uuid.hyphenated().to_string(),
/// "1e752a1f-3b49-658c-802a-010203040506"
/// );
/// ```
///
/// The timestamp can also be created manually as per RFC4122:
///
/// ```
/// # use uuid::{Uuid, Timestamp, Context, ClockSequence};
/// # fn random_seed() -> u16 { 42 }
/// let context = Context::new(random_seed());
/// let ts = Timestamp::from_rfc4122(14976241191231231313, context.generate_sequence(0, 0) );
///
/// let uuid = Uuid::new_v6(ts, &[1, 2, 3, 4, 5, 6]);
///
/// assert_eq!(
/// uuid.hyphenated().to_string(),
/// "fd64c041-1e91-6551-802a-010203040506"
/// );
/// ```
///
/// # References
///
/// * [Version 6 UUIDs in Draft RFC: New UUID Formats, Version 4](https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format-04#section-5.1)
///
/// [`Timestamp`]: v1/struct.Timestamp.html
/// [`ClockSequence`]: v1/trait.ClockSequence.html
/// [`Context`]: v1/struct.Context.html
pub fn new_v6(ts: Timestamp, node_id: &[u8; 6]) -> Self {
let (ticks, counter) = ts.to_rfc4122();
Builder::from_sorted_rfc4122_timestamp(ticks, counter, node_id).into_uuid()
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{Context, Variant, Version};
use std::string::ToString;
#[cfg(all(
target_arch = "wasm32",
target_vendor = "unknown",
target_os = "unknown"
))]
use wasm_bindgen_test::*;
#[test]
#[cfg_attr(
all(
target_arch = "wasm32",
target_vendor = "unknown",
target_os = "unknown"
),
wasm_bindgen_test
)]
fn test_new() {
let time: u64 = 1_496_854_535;
let time_fraction: u32 = 812_946_000;
let node = [1, 2, 3, 4, 5, 6];
let context = Context::new(0);
let uuid = Uuid::new_v6(Timestamp::from_unix(context, time, time_fraction), &node);
assert_eq!(uuid.get_version(), Some(Version::SortMac));
assert_eq!(uuid.get_variant(), Variant::RFC4122);
assert_eq!(
uuid.hyphenated().to_string(),
"1e74ba22-0616-6934-8000-010203040506"
);
let ts = uuid.get_timestamp().unwrap().to_rfc4122();
assert_eq!(ts.0 - 0x01B2_1DD2_1381_4000, 14_968_545_358_129_460);
// Ensure parsing the same UUID produces the same timestamp
let parsed = Uuid::parse_str("1e74ba22-0616-6934-8000-010203040506").unwrap();
assert_eq!(
uuid.get_timestamp().unwrap(),
parsed.get_timestamp().unwrap()
);
}
#[test]
#[cfg_attr(
all(
target_arch = "wasm32",
target_vendor = "unknown",
target_os = "unknown"
),
wasm_bindgen_test
)]
#[cfg(all(feature = "std", feature = "rng"))]
fn test_now() {
let node = [1, 2, 3, 4, 5, 6];
let uuid = Uuid::now_v6(&node);
assert_eq!(uuid.get_version(), Some(Version::SortMac));
assert_eq!(uuid.get_variant(), Variant::RFC4122);
}
#[test]
#[cfg_attr(
all(
target_arch = "wasm32",
target_vendor = "unknown",
target_os = "unknown"
),
wasm_bindgen_test
)]
fn test_new_context() {
let time: u64 = 1_496_854_535;
let time_fraction: u32 = 812_946_000;
let node = [1, 2, 3, 4, 5, 6];
// This context will wrap
let context = Context::new(u16::MAX >> 2);
let uuid1 = Uuid::new_v6(Timestamp::from_unix(&context, time, time_fraction), &node);
let time: u64 = 1_496_854_536;
let uuid2 = Uuid::new_v6(Timestamp::from_unix(&context, time, time_fraction), &node);
assert_eq!(uuid1.get_timestamp().unwrap().to_rfc4122().1, 16383);
assert_eq!(uuid2.get_timestamp().unwrap().to_rfc4122().1, 0);
let time = 1_496_854_535;
let uuid3 = Uuid::new_v6(Timestamp::from_unix(&context, time, time_fraction), &node);
let uuid4 = Uuid::new_v6(Timestamp::from_unix(&context, time, time_fraction), &node);
assert_eq!(uuid3.get_timestamp().unwrap().counter, 1);
assert_eq!(uuid4.get_timestamp().unwrap().counter, 2);
}
}