160 lines
3.3 KiB
Rust
160 lines
3.3 KiB
Rust
use std::fmt;
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use std::str::FromStr;
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use std::time::SystemTime;
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use std::time::UNIX_EPOCH;
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use num_traits::Bounded;
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use serde::{Deserialize, Serialize};
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use thiserror::Error;
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use crate::ord::Max;
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use crate::Semilattice as _;
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/// Lamport clock.
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#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
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#[serde(transparent)]
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pub struct Lamport {
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counter: Max<u64>,
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}
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impl Lamport {
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/// Return the clock value.
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pub fn get(&self) -> u64 {
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*self.counter.get()
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}
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/// The initial value of the clock.
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pub fn initial() -> Self {
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Self::default()
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}
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/// Increment clock and return new value.
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/// Must be called before sending a message.
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pub fn tick(&mut self) -> Self {
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self.counter.incr();
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*self
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}
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/// Merge clock with another clock, and increment value.
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/// Must be called whenever a message is received.
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pub fn merge(&mut self, other: Self) -> Self {
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self.counter.merge(other.counter);
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self.tick()
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}
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/// Reset clock to default state.
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pub fn reset(&mut self) {
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self.counter = Max::default();
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}
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}
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impl fmt::Display for Lamport {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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write!(f, "{}", self.get())
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}
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}
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impl From<u64> for Lamport {
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fn from(counter: u64) -> Self {
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Self {
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counter: Max::from(counter),
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}
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}
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}
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impl From<Lamport> for u64 {
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fn from(arg: Lamport) -> Self {
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arg.get()
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}
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}
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/// Error decoding an operation from an entry.
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#[derive(Error, Debug)]
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pub enum LamportError {
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#[error("invalid lamport clock value")]
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Invalid,
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}
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impl FromStr for Lamport {
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type Err = LamportError;
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fn from_str(s: &str) -> Result<Self, Self::Err> {
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Self::try_from(s)
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}
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}
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impl TryFrom<&str> for Lamport {
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type Error = LamportError;
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fn try_from(s: &str) -> Result<Self, Self::Error> {
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let v = s.parse::<u64>().map_err(|_| LamportError::Invalid)?;
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Ok(v.into())
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}
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}
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impl Bounded for Lamport {
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fn min_value() -> Self {
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Self::from(u64::min_value())
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}
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fn max_value() -> Self {
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Self::from(u64::max_value())
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}
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}
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/// Physical clock. Tracks real-time by the second.
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#[derive(Debug, Default, Copy, Clone, PartialOrd, PartialEq, Ord, Eq, Serialize, Deserialize)]
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#[serde(transparent)]
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pub struct Physical {
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seconds: u64,
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}
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impl Physical {
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pub fn new(seconds: u64) -> Self {
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Self { seconds }
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}
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pub fn now() -> Self {
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#[allow(clippy::unwrap_used)] // Safe because Unix was already invented!
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let duration = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
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Self {
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seconds: duration.as_secs(),
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}
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}
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pub fn as_secs(&self) -> u64 {
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self.seconds
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}
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}
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impl From<u64> for Physical {
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fn from(seconds: u64) -> Self {
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Self { seconds }
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}
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}
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impl std::ops::Add<u64> for Physical {
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type Output = Self;
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fn add(self, rhs: u64) -> Self::Output {
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Self {
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seconds: self.seconds + rhs,
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}
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}
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}
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impl Bounded for Physical {
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fn min_value() -> Self {
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Self {
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seconds: u64::min_value(),
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}
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}
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fn max_value() -> Self {
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Self {
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seconds: u64::max_value(),
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}
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}
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}
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