rocketmq-runtime 1.0.0

// Copyright 2023 The RocketMQ Rust Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::time::Duration;
use std::time::Instant;

/// Monotonic time source used by rate and queue-age budgets.
///
/// Production code normally uses [`SystemMonotonicClock`]. Tests can inject a
/// deterministic clock without sleeping or changing wall-clock time.
pub trait MonotonicClock: Send + Sync + 'static {
    /// Returns the now.
    fn now(&self) -> Duration;
}

/// Represents system monotonic clock.
#[derive(Debug)]
pub struct SystemMonotonicClock {
    origin: Instant,
}

impl SystemMonotonicClock {
    #[must_use]
    /// Creates a new `SystemMonotonicClock`.
    pub fn new() -> Self {
        Self { origin: Instant::now() }
    }
}

impl Default for SystemMonotonicClock {
    fn default() -> Self {
        Self::new()
    }
}

impl MonotonicClock for SystemMonotonicClock {
    fn now(&self) -> Duration {
        self.origin.elapsed()
    }
}