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use super::plumbing::*;
use super::ParallelIterator;
use super::Try;
use std::fmt::{self, Debug};
use std::marker::PhantomData;
use std::ops::ControlFlow::{self, Break, Continue};
impl<U, I, ID, F> TryFold<I, U, ID, F>
where
I: ParallelIterator,
F: Fn(U::Output, I::Item) -> U + Sync + Send,
ID: Fn() -> U::Output + Sync + Send,
U: Try + Send,
{
pub(super) fn new(base: I, identity: ID, fold_op: F) -> Self {
TryFold {
base,
identity,
fold_op,
marker: PhantomData,
}
}
}
/// `TryFold` is an iterator that applies a function over an iterator producing a single value.
/// This struct is created by the [`try_fold()`] method on [`ParallelIterator`]
///
/// [`try_fold()`]: trait.ParallelIterator.html#method.try_fold
/// [`ParallelIterator`]: trait.ParallelIterator.html
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Clone)]
pub struct TryFold<I, U, ID, F> {
base: I,
identity: ID,
fold_op: F,
marker: PhantomData<U>,
}
impl<U, I: ParallelIterator + Debug, ID, F> Debug for TryFold<I, U, ID, F> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("TryFold").field("base", &self.base).finish()
}
}
impl<U, I, ID, F> ParallelIterator for TryFold<I, U, ID, F>
where
I: ParallelIterator,
F: Fn(U::Output, I::Item) -> U + Sync + Send,
ID: Fn() -> U::Output + Sync + Send,
U: Try + Send,
{
type Item = U;
fn drive_unindexed<C>(self, consumer: C) -> C::Result
where
C: UnindexedConsumer<Self::Item>,
{
let consumer1 = TryFoldConsumer {
base: consumer,
identity: &self.identity,
fold_op: &self.fold_op,
marker: PhantomData,
};
self.base.drive_unindexed(consumer1)
}
}
struct TryFoldConsumer<'c, U, C, ID, F> {
base: C,
identity: &'c ID,
fold_op: &'c F,
marker: PhantomData<U>,
}
impl<'r, U, T, C, ID, F> Consumer<T> for TryFoldConsumer<'r, U, C, ID, F>
where
C: Consumer<U>,
F: Fn(U::Output, T) -> U + Sync,
ID: Fn() -> U::Output + Sync,
U: Try + Send,
{
type Folder = TryFoldFolder<'r, C::Folder, U, F>;
type Reducer = C::Reducer;
type Result = C::Result;
fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
let (left, right, reducer) = self.base.split_at(index);
(
TryFoldConsumer { base: left, ..self },
TryFoldConsumer {
base: right,
..self
},
reducer,
)
}
fn into_folder(self) -> Self::Folder {
TryFoldFolder {
base: self.base.into_folder(),
control: Continue((self.identity)()),
fold_op: self.fold_op,
}
}
fn full(&self) -> bool {
self.base.full()
}
}
impl<'r, U, T, C, ID, F> UnindexedConsumer<T> for TryFoldConsumer<'r, U, C, ID, F>
where
C: UnindexedConsumer<U>,
F: Fn(U::Output, T) -> U + Sync,
ID: Fn() -> U::Output + Sync,
U: Try + Send,
{
fn split_off_left(&self) -> Self {
TryFoldConsumer {
base: self.base.split_off_left(),
..*self
}
}
fn to_reducer(&self) -> Self::Reducer {
self.base.to_reducer()
}
}
struct TryFoldFolder<'r, C, U: Try, F> {
base: C,
fold_op: &'r F,
control: ControlFlow<U::Residual, U::Output>,
}
impl<'r, C, U, F, T> Folder<T> for TryFoldFolder<'r, C, U, F>
where
C: Folder<U>,
F: Fn(U::Output, T) -> U + Sync,
U: Try,
{
type Result = C::Result;
fn consume(mut self, item: T) -> Self {
let fold_op = self.fold_op;
if let Continue(acc) = self.control {
self.control = fold_op(acc, item).branch();
}
self
}
fn complete(self) -> C::Result {
let item = match self.control {
Continue(c) => U::from_output(c),
Break(r) => U::from_residual(r),
};
self.base.consume(item).complete()
}
fn full(&self) -> bool {
match self.control {
Break(_) => true,
_ => self.base.full(),
}
}
}
// ///////////////////////////////////////////////////////////////////////////
impl<U, I, F> TryFoldWith<I, U, F>
where
I: ParallelIterator,
F: Fn(U::Output, I::Item) -> U + Sync,
U: Try + Send,
U::Output: Clone + Send,
{
pub(super) fn new(base: I, item: U::Output, fold_op: F) -> Self {
TryFoldWith {
base,
item,
fold_op,
}
}
}
/// `TryFoldWith` is an iterator that applies a function over an iterator producing a single value.
/// This struct is created by the [`try_fold_with()`] method on [`ParallelIterator`]
///
/// [`try_fold_with()`]: trait.ParallelIterator.html#method.try_fold_with
/// [`ParallelIterator`]: trait.ParallelIterator.html
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Clone)]
pub struct TryFoldWith<I, U: Try, F> {
base: I,
item: U::Output,
fold_op: F,
}
impl<I: ParallelIterator + Debug, U: Try, F> Debug for TryFoldWith<I, U, F>
where
U::Output: Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("TryFoldWith")
.field("base", &self.base)
.field("item", &self.item)
.finish()
}
}
impl<U, I, F> ParallelIterator for TryFoldWith<I, U, F>
where
I: ParallelIterator,
F: Fn(U::Output, I::Item) -> U + Sync + Send,
U: Try + Send,
U::Output: Clone + Send,
{
type Item = U;
fn drive_unindexed<C>(self, consumer: C) -> C::Result
where
C: UnindexedConsumer<Self::Item>,
{
let consumer1 = TryFoldWithConsumer {
base: consumer,
item: self.item,
fold_op: &self.fold_op,
};
self.base.drive_unindexed(consumer1)
}
}
struct TryFoldWithConsumer<'c, C, U: Try, F> {
base: C,
item: U::Output,
fold_op: &'c F,
}
impl<'r, U, T, C, F> Consumer<T> for TryFoldWithConsumer<'r, C, U, F>
where
C: Consumer<U>,
F: Fn(U::Output, T) -> U + Sync,
U: Try + Send,
U::Output: Clone + Send,
{
type Folder = TryFoldFolder<'r, C::Folder, U, F>;
type Reducer = C::Reducer;
type Result = C::Result;
fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
let (left, right, reducer) = self.base.split_at(index);
(
TryFoldWithConsumer {
base: left,
item: self.item.clone(),
..self
},
TryFoldWithConsumer {
base: right,
..self
},
reducer,
)
}
fn into_folder(self) -> Self::Folder {
TryFoldFolder {
base: self.base.into_folder(),
control: Continue(self.item),
fold_op: self.fold_op,
}
}
fn full(&self) -> bool {
self.base.full()
}
}
impl<'r, U, T, C, F> UnindexedConsumer<T> for TryFoldWithConsumer<'r, C, U, F>
where
C: UnindexedConsumer<U>,
F: Fn(U::Output, T) -> U + Sync,
U: Try + Send,
U::Output: Clone + Send,
{
fn split_off_left(&self) -> Self {
TryFoldWithConsumer {
base: self.base.split_off_left(),
item: self.item.clone(),
..*self
}
}
fn to_reducer(&self) -> Self::Reducer {
self.base.to_reducer()
}
}