| use super::plumbing::*; |
| use super::ParallelIterator; |
| use super::Try; |
| |
| use std::ops::ControlFlow::{self, Break, Continue}; |
| use std::sync::atomic::{AtomicBool, Ordering}; |
| |
| pub(super) fn try_reduce_with<PI, R, T>(pi: PI, reduce_op: R) -> Option<T> |
| where |
| PI: ParallelIterator<Item = T>, |
| R: Fn(T::Output, T::Output) -> T + Sync, |
| T: Try + Send, |
| { |
| let full = AtomicBool::new(false); |
| let consumer = TryReduceWithConsumer { |
| reduce_op: &reduce_op, |
| full: &full, |
| }; |
| pi.drive_unindexed(consumer) |
| } |
| |
| struct TryReduceWithConsumer<'r, R> { |
| reduce_op: &'r R, |
| full: &'r AtomicBool, |
| } |
| |
| impl<'r, R> Copy for TryReduceWithConsumer<'r, R> {} |
| |
| impl<'r, R> Clone for TryReduceWithConsumer<'r, R> { |
| fn clone(&self) -> Self { |
| *self |
| } |
| } |
| |
| impl<'r, R, T> Consumer<T> for TryReduceWithConsumer<'r, R> |
| where |
| R: Fn(T::Output, T::Output) -> T + Sync, |
| T: Try + Send, |
| { |
| type Folder = TryReduceWithFolder<'r, R, T>; |
| type Reducer = Self; |
| type Result = Option<T>; |
| |
| fn split_at(self, _index: usize) -> (Self, Self, Self) { |
| (self, self, self) |
| } |
| |
| fn into_folder(self) -> Self::Folder { |
| TryReduceWithFolder { |
| reduce_op: self.reduce_op, |
| opt_control: None, |
| full: self.full, |
| } |
| } |
| |
| fn full(&self) -> bool { |
| self.full.load(Ordering::Relaxed) |
| } |
| } |
| |
| impl<'r, R, T> UnindexedConsumer<T> for TryReduceWithConsumer<'r, R> |
| where |
| R: Fn(T::Output, T::Output) -> T + Sync, |
| T: Try + Send, |
| { |
| fn split_off_left(&self) -> Self { |
| *self |
| } |
| |
| fn to_reducer(&self) -> Self::Reducer { |
| *self |
| } |
| } |
| |
| impl<'r, R, T> Reducer<Option<T>> for TryReduceWithConsumer<'r, R> |
| where |
| R: Fn(T::Output, T::Output) -> T + Sync, |
| T: Try, |
| { |
| fn reduce(self, left: Option<T>, right: Option<T>) -> Option<T> { |
| let reduce_op = self.reduce_op; |
| match (left, right) { |
| (Some(left), Some(right)) => match (left.branch(), right.branch()) { |
| (Continue(left), Continue(right)) => Some(reduce_op(left, right)), |
| (Break(r), _) | (_, Break(r)) => Some(T::from_residual(r)), |
| }, |
| (None, x) | (x, None) => x, |
| } |
| } |
| } |
| |
| struct TryReduceWithFolder<'r, R, T: Try> { |
| reduce_op: &'r R, |
| opt_control: Option<ControlFlow<T::Residual, T::Output>>, |
| full: &'r AtomicBool, |
| } |
| |
| impl<'r, R, T> Folder<T> for TryReduceWithFolder<'r, R, T> |
| where |
| R: Fn(T::Output, T::Output) -> T, |
| T: Try, |
| { |
| type Result = Option<T>; |
| |
| fn consume(mut self, item: T) -> Self { |
| let reduce_op = self.reduce_op; |
| let control = match (self.opt_control, item.branch()) { |
| (Some(Continue(left)), Continue(right)) => reduce_op(left, right).branch(), |
| (Some(control @ Break(_)), _) | (_, control) => control, |
| }; |
| if let Break(_) = control { |
| self.full.store(true, Ordering::Relaxed) |
| } |
| self.opt_control = Some(control); |
| self |
| } |
| |
| fn complete(self) -> Option<T> { |
| match self.opt_control { |
| Some(Continue(c)) => Some(T::from_output(c)), |
| Some(Break(r)) => Some(T::from_residual(r)), |
| None => None, |
| } |
| } |
| |
| fn full(&self) -> bool { |
| match self.opt_control { |
| Some(Break(_)) => true, |
| _ => self.full.load(Ordering::Relaxed), |
| } |
| } |
| } |