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minimize moves by introducing
WeakVec
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,67 @@ | ||
| //! Module containing the [`WeakVec`] API. | ||
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| use std::sync::Weak; | ||
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| /// A container that holds Weak references of T. | ||
| /// | ||
| /// On `push` it scans its contents for weak references with no strong references still alive and drops them. | ||
| #[derive(Debug)] | ||
| pub(crate) struct WeakVec<T> { | ||
| inner: Vec<Option<Weak<T>>>, | ||
| } | ||
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| impl<T> Default for WeakVec<T> { | ||
| fn default() -> Self { | ||
| Self { | ||
| inner: Default::default(), | ||
| } | ||
| } | ||
| } | ||
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| impl<T> WeakVec<T> { | ||
| pub(crate) fn new() -> Self { | ||
| Self { inner: Vec::new() } | ||
| } | ||
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| /// Pushes a new element to this collection, dropping older elements that no longer have | ||
| /// a strong reference to them. | ||
| /// | ||
| /// NOTE: The length and capacity of this collection do not change when old elements are | ||
| /// dropped. | ||
| pub(crate) fn push(&mut self, value: Weak<T>) { | ||
| let mut to_insert = Some(value); | ||
| for slot in &mut self.inner { | ||
| if let Some(w) = slot { | ||
| if w.strong_count() == 0 { | ||
| *slot = to_insert.take(); | ||
| } | ||
| } else { | ||
| *slot = to_insert.take(); | ||
| } | ||
| } | ||
| if let Some(to_insert) = to_insert { | ||
| self.inner.push(Some(to_insert)); | ||
| } | ||
| } | ||
| } | ||
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| pub(crate) struct WeakVecIter<T> { | ||
| inner: std::iter::Flatten<std::vec::IntoIter<Option<Weak<T>>>>, | ||
| } | ||
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| impl<T> Iterator for WeakVecIter<T> { | ||
| type Item = Weak<T>; | ||
| fn next(&mut self) -> Option<Self::Item> { | ||
| self.inner.next() | ||
| } | ||
| } | ||
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| impl<T> IntoIterator for WeakVec<T> { | ||
| type Item = Weak<T>; | ||
| type IntoIter = WeakVecIter<T>; | ||
| fn into_iter(self) -> Self::IntoIter { | ||
| WeakVecIter { | ||
| inner: self.inner.into_iter().flatten(), | ||
| } | ||
| } | ||
| } |