| 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<PI, R, ID, T>(pi: PI, identity: ID, reduce_op: R) -> T |
| where |
| PI: ParallelIterator<Item = T>, |
| R: Fn(T::Output, T::Output) -> T + Sync, |
| ID: Fn() -> T::Output + Sync, |
| T: Try + Send, |
| { |
| let full = AtomicBool::new(false); |
| let consumer = TryReduceConsumer { |
| identity: &identity, |
| reduce_op: &reduce_op, |
| full: &full, |
| }; |
| pi.drive_unindexed(consumer) |
| } |
| |
| struct TryReduceConsumer<'r, R, ID> { |
| identity: &'r ID, |
| reduce_op: &'r R, |
| full: &'r AtomicBool, |
| } |
| |
| impl<'r, R, ID> Copy for TryReduceConsumer<'r, R, ID> {} |
| |
| impl<'r, R, ID> Clone for TryReduceConsumer<'r, R, ID> { |
| fn clone(&self) -> Self { |
| *self |
| } |
| } |
| |
| impl<'r, R, ID, T> Consumer<T> for TryReduceConsumer<'r, R, ID> |
| where |
| R: Fn(T::Output, T::Output) -> T + Sync, |
| ID: Fn() -> T::Output + Sync, |
| T: Try + Send, |
| { |
| type Folder = TryReduceFolder<'r, R, T>; |
| type Reducer = Self; |
| type Result = T; |
| |
| fn split_at(self, _index: usize) -> (Self, Self, Self) { |
| (self, self, self) |
| } |
| |
| fn into_folder(self) -> Self::Folder { |
| TryReduceFolder { |
| reduce_op: self.reduce_op, |
| control: Continue((self.identity)()), |
| full: self.full, |
| } |
| } |
| |
| fn full(&self) -> bool { |
| self.full.load(Ordering::Relaxed) |
| } |
| } |
| |
| impl<'r, R, ID, T> UnindexedConsumer<T> for TryReduceConsumer<'r, R, ID> |
| where |
| R: Fn(T::Output, T::Output) -> T + Sync, |
| ID: Fn() -> T::Output + Sync, |
| T: Try + Send, |
| { |
| fn split_off_left(&self) -> Self { |
| *self |
| } |
| |
| fn to_reducer(&self) -> Self::Reducer { |
| *self |
| } |
| } |
| |
| impl<'r, R, ID, T> Reducer<T> for TryReduceConsumer<'r, R, ID> |
| where |
| R: Fn(T::Output, T::Output) -> T + Sync, |
| T: Try, |
| { |
| fn reduce(self, left: T, right: T) -> T { |
| match (left.branch(), right.branch()) { |
| (Continue(left), Continue(right)) => (self.reduce_op)(left, right), |
| (Break(r), _) | (_, Break(r)) => T::from_residual(r), |
| } |
| } |
| } |
| |
| struct TryReduceFolder<'r, R, T: Try> { |
| reduce_op: &'r R, |
| control: ControlFlow<T::Residual, T::Output>, |
| full: &'r AtomicBool, |
| } |
| |
| impl<'r, R, T> Folder<T> for TryReduceFolder<'r, R, T> |
| where |
| R: Fn(T::Output, T::Output) -> T, |
| T: Try, |
| { |
| type Result = T; |
| |
| fn consume(mut self, item: T) -> Self { |
| let reduce_op = self.reduce_op; |
| self.control = match (self.control, item.branch()) { |
| (Continue(left), Continue(right)) => reduce_op(left, right).branch(), |
| (control @ Break(_), _) | (_, control @ Break(_)) => control, |
| }; |
| if let Break(_) = self.control { |
| self.full.store(true, Ordering::Relaxed); |
| } |
| self |
| } |
| |
| fn complete(self) -> T { |
| match self.control { |
| Continue(c) => T::from_output(c), |
| Break(r) => T::from_residual(r), |
| } |
| } |
| |
| fn full(&self) -> bool { |
| match self.control { |
| Break(_) => true, |
| _ => self.full.load(Ordering::Relaxed), |
| } |
| } |
| } |