70 lines
2.1 KiB
Rust
70 lines
2.1 KiB
Rust
/*
|
|
* Copyright (c) 2023 Stalwart Labs Ltd.
|
|
*
|
|
* This file is part of Stalwart Mail Server.
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU Affero General Public License as
|
|
* published by the Free Software Foundation, either version 3 of
|
|
* the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU Affero General Public License for more details.
|
|
* in the LICENSE file at the top-level directory of this distribution.
|
|
* You should have received a copy of the GNU Affero General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
* You can be released from the requirements of the AGPLv3 license by
|
|
* purchasing a commercial license. Please contact licensing@stalw.art
|
|
* for more details.
|
|
*/
|
|
|
|
use std::{
|
|
sync::atomic::{AtomicU64, Ordering},
|
|
time::{Duration, SystemTime},
|
|
};
|
|
|
|
pub struct SnowflakeIdGenerator {
|
|
epoch: SystemTime,
|
|
node_id: u64,
|
|
sequence: AtomicU64,
|
|
}
|
|
|
|
const SEQUENCE_LEN: u64 = 12;
|
|
const NODE_ID_LEN: u64 = 9;
|
|
|
|
const SEQUENCE_MASK: u64 = (1 << SEQUENCE_LEN) - 1;
|
|
const NODE_ID_MASK: u64 = (1 << NODE_ID_LEN) - 1;
|
|
|
|
impl SnowflakeIdGenerator {
|
|
pub fn new() -> Self {
|
|
Self::with_node_id(rand::random::<u64>())
|
|
}
|
|
|
|
pub fn with_node_id(node_id: u64) -> Self {
|
|
Self {
|
|
epoch: SystemTime::UNIX_EPOCH + Duration::from_secs(1632280000), // 52 years after UNIX_EPOCH
|
|
node_id,
|
|
sequence: 0.into(),
|
|
}
|
|
}
|
|
|
|
pub fn generate(&self) -> Option<u64> {
|
|
let elapsed = self.epoch.elapsed().ok()?.as_millis() as u64;
|
|
let sequence = self.sequence.fetch_add(1, Ordering::Relaxed);
|
|
|
|
(elapsed << (SEQUENCE_LEN + NODE_ID_LEN)
|
|
| (self.node_id & NODE_ID_MASK) << SEQUENCE_LEN
|
|
| (sequence & SEQUENCE_MASK))
|
|
.into()
|
|
}
|
|
}
|
|
|
|
impl Default for SnowflakeIdGenerator {
|
|
fn default() -> Self {
|
|
Self::new()
|
|
}
|
|
}
|