diff options
Diffstat (limited to 'vendor/rayon/src/result.rs')
-rw-r--r-- | vendor/rayon/src/result.rs | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/vendor/rayon/src/result.rs b/vendor/rayon/src/result.rs new file mode 100644 index 0000000..43685ca --- /dev/null +++ b/vendor/rayon/src/result.rs @@ -0,0 +1,132 @@ +//! Parallel iterator types for [results][std::result] +//! +//! You will rarely need to interact with this module directly unless you need +//! to name one of the iterator types. +//! +//! [std::result]: https://doc.rust-lang.org/stable/std/result/ + +use crate::iter::plumbing::*; +use crate::iter::*; +use std::sync::Mutex; + +use crate::option; + +/// Parallel iterator over a result +#[derive(Debug, Clone)] +pub struct IntoIter<T: Send> { + inner: option::IntoIter<T>, +} + +impl<T: Send, E> IntoParallelIterator for Result<T, E> { + type Item = T; + type Iter = IntoIter<T>; + + fn into_par_iter(self) -> Self::Iter { + IntoIter { + inner: self.ok().into_par_iter(), + } + } +} + +delegate_indexed_iterator! { + IntoIter<T> => T, + impl<T: Send> +} + +/// Parallel iterator over an immutable reference to a result +#[derive(Debug)] +pub struct Iter<'a, T: Sync> { + inner: option::IntoIter<&'a T>, +} + +impl<'a, T: Sync> Clone for Iter<'a, T> { + fn clone(&self) -> Self { + Iter { + inner: self.inner.clone(), + } + } +} + +impl<'a, T: Sync, E> IntoParallelIterator for &'a Result<T, E> { + type Item = &'a T; + type Iter = Iter<'a, T>; + + fn into_par_iter(self) -> Self::Iter { + Iter { + inner: self.as_ref().ok().into_par_iter(), + } + } +} + +delegate_indexed_iterator! { + Iter<'a, T> => &'a T, + impl<'a, T: Sync + 'a> +} + +/// Parallel iterator over a mutable reference to a result +#[derive(Debug)] +pub struct IterMut<'a, T: Send> { + inner: option::IntoIter<&'a mut T>, +} + +impl<'a, T: Send, E> IntoParallelIterator for &'a mut Result<T, E> { + type Item = &'a mut T; + type Iter = IterMut<'a, T>; + + fn into_par_iter(self) -> Self::Iter { + IterMut { + inner: self.as_mut().ok().into_par_iter(), + } + } +} + +delegate_indexed_iterator! { + IterMut<'a, T> => &'a mut T, + impl<'a, T: Send + 'a> +} + +/// Collect an arbitrary `Result`-wrapped collection. +/// +/// If any item is `Err`, then all previous `Ok` items collected are +/// discarded, and it returns that error. If there are multiple errors, the +/// one returned is not deterministic. +impl<C, T, E> FromParallelIterator<Result<T, E>> for Result<C, E> +where + C: FromParallelIterator<T>, + T: Send, + E: Send, +{ + fn from_par_iter<I>(par_iter: I) -> Self + where + I: IntoParallelIterator<Item = Result<T, E>>, + { + fn ok<T, E>(saved: &Mutex<Option<E>>) -> impl Fn(Result<T, E>) -> Option<T> + '_ { + move |item| match item { + Ok(item) => Some(item), + Err(error) => { + // We don't need a blocking `lock()`, as anybody + // else holding the lock will also be writing + // `Some(error)`, and then ours is irrelevant. + if let Ok(mut guard) = saved.try_lock() { + if guard.is_none() { + *guard = Some(error); + } + } + None + } + } + } + + let saved_error = Mutex::new(None); + let collection = par_iter + .into_par_iter() + .map(ok(&saved_error)) + .while_some() + .collect(); + + match saved_error.into_inner().unwrap() { + Some(error) => Err(error), + None => Ok(collection), + } + } +} |