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db620b42ec
Currently, the timer uses a `Now` trait to abstract the source of time. This allows time to be mocked out. However, the current implementation has a number of limitations as represented by #288 and #296. The main issues are that `Now` requires `&mut self` which prevents a value from being easily used in a concurrent environment. Also, when wanting to write code that is abstract over the source of time, generics get out of hand. This patch provides an alternate solution. A new type, `Clock` is provided which defaults to `Instant::now` as the source of time, but allows configuring the actual source using a new iteration of the `Now` trait. This time, `Now` is `Send + Sync + 'static`. Internally, `Clock` stores the now value in an `Arc<Now>` value, which introduces dynamism and allows `Clock` values to be cloned and be `Sync`. Also, the current clock can be set for the current execution context using the `with_default` pattern. Because using the `Instant::now` will be the most common case by far, it is special cased in order to avoid the need to allocate an `Arc` and use dynamic dispatch.
52 lines
901 B
Rust
52 lines
901 B
Rust
extern crate tokio_executor;
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extern crate tokio_timer;
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use tokio_timer::clock;
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use tokio_timer::clock::*;
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use std::time::Instant;
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struct ConstNow(Instant);
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impl Now for ConstNow {
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fn now(&self) -> Instant {
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self.0
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}
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}
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#[test]
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fn default_clock() {
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let a = Instant::now();
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let b = clock::now();
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let c = Clock::new().now();
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assert!(a <= b);
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assert!(b <= c);
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}
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#[test]
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fn custom_clock() {
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let now = ConstNow(Instant::now());
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let clock = Clock::new_with_now(now);
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let a = Instant::now();
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let b = clock.now();
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assert!(b <= a);
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}
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#[test]
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fn execution_context() {
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let now = ConstNow(Instant::now());
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let clock = Clock::new_with_now(now);
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let mut enter = tokio_executor::enter().unwrap();
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with_default(&clock, &mut enter, |_| {
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let a = Instant::now();
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let b = clock::now();
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assert!(b <= a);
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});
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}
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