92 lines
2.5 KiB
Rust
92 lines
2.5 KiB
Rust
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use std::time::{Duration, Instant};
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/// Keeps track of the elapsed time since the moment the polling started.
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pub struct PollTimeout {
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timeout: Option<Duration>,
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start: Instant,
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}
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impl PollTimeout {
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/// Constructs a new `PollTimeout` with the given optional `Duration`.
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pub fn new(timeout: Option<Duration>) -> PollTimeout {
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PollTimeout {
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timeout,
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start: Instant::now(),
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}
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}
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/// Returns whether the timeout has elapsed.
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///
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/// It always returns `false` if the initial timeout was set to `None`.
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pub fn elapsed(&self) -> bool {
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self.timeout
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.map(|timeout| self.start.elapsed() >= timeout)
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.unwrap_or(false)
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}
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/// Returns the timeout leftover (initial timeout duration - elapsed duration).
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pub fn leftover(&self) -> Option<Duration> {
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self.timeout.map(|timeout| {
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let elapsed = self.start.elapsed();
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if elapsed >= timeout {
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Duration::from_secs(0)
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} else {
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timeout - elapsed
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}
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})
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}
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}
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#[cfg(test)]
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mod tests {
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use std::time::{Duration, Instant};
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use super::PollTimeout;
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#[test]
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pub fn test_timeout_without_duration_does_not_have_leftover() {
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let timeout = PollTimeout::new(None);
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assert_eq!(timeout.leftover(), None)
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}
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#[test]
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pub fn test_timeout_without_duration_never_elapses() {
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let timeout = PollTimeout::new(None);
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assert!(!timeout.elapsed());
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}
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#[test]
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pub fn test_timeout_elapses() {
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const TIMEOUT_MILLIS: u64 = 100;
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let timeout = PollTimeout {
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timeout: Some(Duration::from_millis(TIMEOUT_MILLIS)),
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start: Instant::now() - Duration::from_millis(2 * TIMEOUT_MILLIS),
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};
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assert!(timeout.elapsed());
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}
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#[test]
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pub fn test_elapsed_timeout_has_zero_leftover() {
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const TIMEOUT_MILLIS: u64 = 100;
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let timeout = PollTimeout {
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timeout: Some(Duration::from_millis(TIMEOUT_MILLIS)),
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start: Instant::now() - Duration::from_millis(2 * TIMEOUT_MILLIS),
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};
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assert!(timeout.elapsed());
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assert_eq!(timeout.leftover(), Some(Duration::from_millis(0)));
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}
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#[test]
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pub fn test_not_elapsed_timeout_has_positive_leftover() {
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let timeout = PollTimeout::new(Some(Duration::from_secs(60)));
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assert!(!timeout.elapsed());
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assert!(timeout.leftover().unwrap() > Duration::from_secs(0));
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}
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}
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