Implement sleep and interval for Yew Platform #2784
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Size Comparison
✅ None of the examples has changed their size significantly. |
# Conflicts: # packages/yew/Cargo.toml # packages/yew/tests/use_reducer.rs
| pub struct Sleep { | ||
| inner: Option<Timeout>, | ||
| dur_left: Option<u128>, | ||
| timeout_registered: Rc<Cell<bool>>, | ||
| } | ||
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| impl Future for Sleep { | ||
| type Output = (); | ||
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| fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { | ||
| static I32_MAX_U128: u128 = 2_147_483_647; | ||
| static I32_MAX_U32: u32 = 2_147_483_647; | ||
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| // If polling before the registered timeout is reached, return Pending. | ||
| if self.timeout_registered.get() { | ||
| return Poll::Pending; | ||
| } | ||
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| // set_timeout can only accept maximum of i32, so we wrap around if it gets longer. | ||
| let next_timeout = match self.dur_left.map(|m| (m, u32::try_from(m))) { | ||
| Some((m_u128, Err(_))) => { | ||
| self.dur_left = Some(m_u128 - I32_MAX_U128); | ||
| I32_MAX_U32 | ||
| } | ||
| Some((m_u128, _)) if m_u128 > I32_MAX_U128 => { | ||
| self.dur_left = Some(m_u128 - I32_MAX_U128); | ||
| I32_MAX_U32 | ||
| } | ||
| Some((_, Ok(m_u32))) => { | ||
| self.dur_left = None; | ||
| m_u32 | ||
| } | ||
| None => return Poll::Ready(()), | ||
| }; | ||
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| let waker = cx.waker().clone(); | ||
| self.timeout_registered.set(true); | ||
| let timeout_registered = self.timeout_registered.clone(); | ||
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| self.inner = Some(Timeout::new(next_timeout, move || { | ||
| timeout_registered.set(false); | ||
| waker.wake(); | ||
| })); | ||
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| Poll::Pending | ||
| } | ||
| } | ||
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| Sleep { | ||
| inner: None, | ||
| dur_left: Some(dur.as_millis()), | ||
| timeout_registered: Cell::new(false).into(), | ||
| } |
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Why implement it here? What's wrong with the gloo implementation? If there's a bug or improvement to be made, I think we should fix it there.
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See: rustwasm/gloo#121
The difficulty of patching it with gloo is due to its callback-first API.
Patching gloo_timers requires recursively calling setTimeout, which is difficult to implement due to ownership rules.
It gets worse with Interval, as we have to implement it with a series of patched Timeout than using setInterval.
At that time, it's simply easier to implement Interval with Stream and make the API future-first.
However, this is a bigger change than it is needed to patch around this behaviour.
I patched it here because we have a future-first API and this have very little impact on code size.
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That makes sense. I'm not sure who actually is using a timer that's over 24 days long but I'm fine with merging this change.
Patching it in Gloo would be needless (and not small) breaking change
Description
This pull request implements
yew::platform::timewhich providessleep()andinterval()support.Checklist