2f54a05705
Some things we definitely don't want to generate every frame, such as relative-time formatted strings, as that would create a heap allocation each frame. Introduce TimeCached<T> which is responsible for updating some state after some expiry. Signed-off-by: William Casarin <jb55@jb55.com>
28 lines
779 B
Rust
28 lines
779 B
Rust
use std::time::{Duration, Instant};
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pub struct TimeCached<T> {
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last_update: Instant,
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expires_in: Duration,
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value: Option<T>,
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refresh: Box<dyn Fn() -> T + 'static>,
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}
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impl<T> TimeCached<T> {
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pub fn new(expires_in: Duration, refresh: Box<dyn Fn() -> T + 'static>) -> Self {
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TimeCached {
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last_update: Instant::now(),
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expires_in,
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value: None,
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refresh,
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}
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}
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pub fn get(&mut self) -> &T {
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if self.value.is_none() || self.last_update.elapsed() > self.expires_in {
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self.last_update = Instant::now();
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self.value = Some((self.refresh)());
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}
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self.value.as_ref().unwrap() // This unwrap is safe because we just set the value if it was None.
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}
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}
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