115 lines
4.3 KiB
Rust
115 lines
4.3 KiB
Rust
use core::time;
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use std::sync::{Arc, Mutex};
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use chrono::NaiveDateTime;
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use once_cell::sync::{Lazy, OnceCell};
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use thiserror::Error;
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const HAIL_PERIOD_START: Lazy<i64> = Lazy::new(|| {
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crate::time::date(2022, 2, 22)
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.map(|d| d.and_hms_opt(22, 22, 22))
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.flatten()
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.map(|dt| crate::time::attach_asia_shanghai(dt))
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.map(|dt| dt.timestamp())
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.unwrap_or_else(|| NaiveDateTime::MIN.timestamp())
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});
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type TimestampValidator = fn(i64) -> bool;
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type TimestampGenerator = fn() -> i64;
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static INSTANCE: OnceCell<HailSerialCodeAlgorithm> = OnceCell::new();
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#[derive(Debug, Error)]
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pub enum HailSerialCodeAlgorithmError {
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#[error("Algorithm is already initialized")]
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AlgorithmAlreadyInitialized,
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}
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/// 冰雹序列ID算法。
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/// 缩减了时间戳的位数，相比雪花算法可以额外支持近40年。
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pub struct HailSerialCodeAlgorithm {
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validator: Option<TimestampValidator>,
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generator: Option<TimestampGenerator>,
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host_id: i64,
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last_timestamp: Arc<Mutex<i64>>,
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counter: Arc<Mutex<i64>>,
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}
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impl HailSerialCodeAlgorithm {
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/// 获取一个算法实例用于获取序列ID。
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pub fn get() -> &'static Self {
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INSTANCE.get().unwrap()
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}
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/// 初始化整个序列ID算法。
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/// ! 注意，如果选择使用内置的主机独立时间戳生成器和验证器，那么将不能保证多主机状态下的序列ID一致性。可能会存在个别主机时间回拨现象。
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///
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/// - `host_id`：主机ID，取值范围为0~65535。
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/// - `timestamp_generator`：时间戳生成器，用于生成时间戳。如果不提供，则使用算法内置的主机独立时间戳生成器。
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/// - `timestamp_validatoe`：时间戳验证器，用于验证时间戳是否有效。如果不提供，则使用算法内置的主机独立时间戳验证器。
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pub fn initialize_algorithm(
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host_id: i64,
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timestamp_generator: Option<TimestampGenerator>,
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timestamp_validatoe: Option<TimestampValidator>,
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) -> Result<(), HailSerialCodeAlgorithmError> {
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let algorithm = HailSerialCodeAlgorithm {
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validator: timestamp_validatoe,
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generator: timestamp_generator,
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host_id,
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last_timestamp: Arc::new(Mutex::new(0)),
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counter: Arc::new(Mutex::new(0)),
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};
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INSTANCE
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.set(algorithm)
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.map_err(|_| HailSerialCodeAlgorithmError::AlgorithmAlreadyInitialized)
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}
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/// 生成一个自计时起点以来的时间戳。
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fn generate_timestamp(&self) -> i64 {
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let current_time = crate::time::now_asia_shanghai().timestamp();
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current_time - *HAIL_PERIOD_START
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}
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/// 生成一个64位长整型序列ID。
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pub fn generate_serial(&self) -> i64 {
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let last_timestamp = self.last_timestamp.clone();
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let mut last_timestamp = last_timestamp.lock().unwrap();
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let counter = self.counter.clone();
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let mut counter = counter.lock().unwrap();
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loop {
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let timestamp = if let Some(generator) = self.generator {
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generator()
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} else {
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self.generate_timestamp()
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};
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if let Some(validator) = self.validator {
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if !validator(timestamp) {
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std::thread::sleep(time::Duration::from_secs(1));
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continue;
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}
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} else if timestamp < *last_timestamp {
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std::thread::sleep(time::Duration::from_secs(1));
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continue;
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}
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if *last_timestamp < timestamp {
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// 对齐时间戳并重置序列计数器
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*last_timestamp = timestamp;
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*counter = 0;
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}
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*counter += 1;
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return (timestamp << 20) | ((self.host_id & 0xFFFF) << 16) | (*counter & 0xFFFF_FFFF);
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}
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}
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/// 生成一个17位长前补零的序列ID字符串。
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pub fn generate_string_serial(&self) -> String {
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let serial = self.generate_serial();
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format!("{:017}", serial)
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}
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/// 生成一个带字符串前缀17位长前补零的序列ID字符串。
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pub fn generate_prefixed_string_serial(&self, prefix: &str) -> String {
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let serial = self.generate_serial();
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format!("{}{:017}", prefix, serial)
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}
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}
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