/rust/registry/src/index.crates.io-1949cf8c6b5b557f/rayon-1.11.0/src/iter/update.rs

Source
use super::plumbing::*;
use super::*;

use std::fmt::{self, Debug};

/// `Update` is an iterator that mutates the elements of an
/// underlying iterator before they are yielded.
///
/// This struct is created by the [`update()`] method on [`ParallelIterator`]
///
/// [`update()`]: ParallelIterator::update()
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Clone)]
pub struct Update<I, F> {
    base: I,
    update_op: F,
}

impl<I: Debug, F> Debug for Update<I, F> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Update").field("base", &self.base).finish()
    }
}

impl<I, F> Update<I, F> {
    /// Creates a new `Update` iterator.
    pub(super) fn new(base: I, update_op: F) -> Self {
        Update { base, update_op }
    }
}

impl<I, F> ParallelIterator for Update<I, F>
where
    I: ParallelIterator,
    F: Fn(&mut I::Item) + Send + Sync,
{
    type Item = I::Item;

    fn drive_unindexed<C>(self, consumer: C) -> C::Result
    where
        C: UnindexedConsumer<Self::Item>,
    {
        let consumer1 = UpdateConsumer::new(consumer, &self.update_op);
        self.base.drive_unindexed(consumer1)
    }

    fn opt_len(&self) -> Option<usize> {
        self.base.opt_len()
    }
}

impl<I, F> IndexedParallelIterator for Update<I, F>
where
    I: IndexedParallelIterator,
    F: Fn(&mut I::Item) + Send + Sync,
{
    fn drive<C>(self, consumer: C) -> C::Result
    where
        C: Consumer<Self::Item>,
    {
        let consumer1 = UpdateConsumer::new(consumer, &self.update_op);
        self.base.drive(consumer1)
    }

    fn len(&self) -> usize {
        self.base.len()
    }

    fn with_producer<CB>(self, callback: CB) -> CB::Output
    where
        CB: ProducerCallback<Self::Item>,
    {
        return self.base.with_producer(Callback {
            callback,
            update_op: self.update_op,
        });

        struct Callback<CB, F> {
            callback: CB,
            update_op: F,
        }

        impl<T, F, CB> ProducerCallback<T> for Callback<CB, F>
        where
            CB: ProducerCallback<T>,
            F: Fn(&mut T) + Send + Sync,
        {
            type Output = CB::Output;

            fn callback<P>(self, base: P) -> CB::Output
            where
                P: Producer<Item = T>,
            {
                let producer = UpdateProducer {
                    base,
                    update_op: &self.update_op,
                };
                self.callback.callback(producer)
            }
        }
    }
}

// ////////////////////////////////////////////////////////////////////////

struct UpdateProducer<'f, P, F> {
    base: P,
    update_op: &'f F,
}

impl<'f, P, F> Producer for UpdateProducer<'f, P, F>
where
    P: Producer,
    F: Fn(&mut P::Item) + Send + Sync,
{
    type Item = P::Item;
    type IntoIter = UpdateSeq<P::IntoIter, &'f F>;

    fn into_iter(self) -> Self::IntoIter {
        UpdateSeq {
            base: self.base.into_iter(),
            update_op: self.update_op,
        }
    }

    fn min_len(&self) -> usize {
        self.base.min_len()
    }
    fn max_len(&self) -> usize {
        self.base.max_len()
    }

    fn split_at(self, index: usize) -> (Self, Self) {
        let (left, right) = self.base.split_at(index);
        (
            UpdateProducer {
                base: left,
                update_op: self.update_op,
            },
            UpdateProducer {
                base: right,
                update_op: self.update_op,
            },
        )
    }

    fn fold_with<G>(self, folder: G) -> G
    where
        G: Folder<Self::Item>,
    {
        let folder1 = UpdateFolder {
            base: folder,
            update_op: self.update_op,
        };
        self.base.fold_with(folder1).base
    }
}

// ////////////////////////////////////////////////////////////////////////
// Consumer implementation

struct UpdateConsumer<'f, C, F> {
    base: C,
    update_op: &'f F,
}

impl<'f, C, F> UpdateConsumer<'f, C, F> {
    fn new(base: C, update_op: &'f F) -> Self {
        UpdateConsumer { base, update_op }
    }
}

impl<'f, T, C, F> Consumer<T> for UpdateConsumer<'f, C, F>
where
    C: Consumer<T>,
    F: Fn(&mut T) + Send + Sync,
{
    type Folder = UpdateFolder<'f, C::Folder, 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);
        (
            UpdateConsumer::new(left, self.update_op),
            UpdateConsumer::new(right, self.update_op),
            reducer,
        )
    }

    fn into_folder(self) -> Self::Folder {
        UpdateFolder {
            base: self.base.into_folder(),
            update_op: self.update_op,
        }
    }

    fn full(&self) -> bool {
        self.base.full()
    }
}

impl<'f, T, C, F> UnindexedConsumer<T> for UpdateConsumer<'f, C, F>
where
    C: UnindexedConsumer<T>,
    F: Fn(&mut T) + Send + Sync,
{
    fn split_off_left(&self) -> Self {
        UpdateConsumer::new(self.base.split_off_left(), self.update_op)
    }

    fn to_reducer(&self) -> Self::Reducer {
        self.base.to_reducer()
    }
}

struct UpdateFolder<'f, C, F> {
    base: C,
    update_op: &'f F,
}

fn apply<T>(update_op: impl Fn(&mut T)) -> impl Fn(T) -> T {
    move |mut item| {
        update_op(&mut item);
        item
    }
}

impl<'f, T, C, F> Folder<T> for UpdateFolder<'f, C, F>
where
    C: Folder<T>,
    F: Fn(&mut T),
{
    type Result = C::Result;

    fn consume(self, mut item: T) -> Self {
        (self.update_op)(&mut item);

        UpdateFolder {
            base: self.base.consume(item),
            update_op: self.update_op,
        }
    }

    fn consume_iter<I>(mut self, iter: I) -> Self
    where
        I: IntoIterator<Item = T>,
    {
        let update_op = self.update_op;
        self.base = self
            .base
            .consume_iter(iter.into_iter().map(apply(update_op)));
        self
    }

    fn complete(self) -> C::Result {
        self.base.complete()
    }

    fn full(&self) -> bool {
        self.base.full()
    }
}

/// Standard Update adaptor, based on `itertools::adaptors::Update`
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Debug, Clone)]
struct UpdateSeq<I, F> {
    base: I,
    update_op: F,
}

impl<I, F> Iterator for UpdateSeq<I, F>
where
    I: Iterator,
    F: Fn(&mut I::Item),
{
    type Item = I::Item;

    fn next(&mut self) -> Option<Self::Item> {
        let mut v = self.base.next()?;
        (self.update_op)(&mut v);
        Some(v)
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        self.base.size_hint()
    }

    fn fold<Acc, G>(self, init: Acc, g: G) -> Acc
    where
        G: FnMut(Acc, Self::Item) -> Acc,
    {
        self.base.map(apply(self.update_op)).fold(init, g)
    }

    // if possible, re-use inner iterator specializations in collect
    fn collect<C>(self) -> C
    where
        C: ::std::iter::FromIterator<Self::Item>,
    {
        self.base.map(apply(self.update_op)).collect()
    }
}

impl<I, F> ExactSizeIterator for UpdateSeq<I, F>
where
    I: ExactSizeIterator,
    F: Fn(&mut I::Item),
{
}

impl<I, F> DoubleEndedIterator for UpdateSeq<I, F>
where
    I: DoubleEndedIterator,
    F: Fn(&mut I::Item),
{
    fn next_back(&mut self) -> Option<Self::Item> {
        let mut v = self.base.next_back()?;
        (self.update_op)(&mut v);
        Some(v)
    }
}

Coverage Report

Created: 2026-01-09 07:43

Line	Count	Source
1		use super::plumbing::*;
2		use super::*;
3
4		use std::fmt::{self, Debug};
5
6		/// `Update` is an iterator that mutates the elements of an
7		/// underlying iterator before they are yielded.
8		///
9		/// This struct is created by the [`update()`] method on [`ParallelIterator`]
10		///
11		/// [`update()`]: ParallelIterator::update()
12		#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
13		#[derive(Clone)]
14		pub struct Update<I, F> {
15		base: I,
16		update_op: F,
17		}
18
19		impl<I: Debug, F> Debug for Update<I, F> {
20	0	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
21	0	f.debug_struct("Update").field("base", &self.base).finish()
22	0	}
23		}
24
25		impl<I, F> Update<I, F> {
26		/// Creates a new `Update` iterator.
27	0	pub(super) fn new(base: I, update_op: F) -> Self {
28	0	Update { base, update_op }
29	0	}
30		}
31
32		impl<I, F> ParallelIterator for Update<I, F>
33		where
34		I: ParallelIterator,
35		F: Fn(&mut I::Item) + Send + Sync,
36		{
37		type Item = I::Item;
38
39	0	fn drive_unindexed<C>(self, consumer: C) -> C::Result
40	0	where
41	0	C: UnindexedConsumer<Self::Item>,
42		{
43	0	let consumer1 = UpdateConsumer::new(consumer, &self.update_op);
44	0	self.base.drive_unindexed(consumer1)
45	0	}
46
47	0	fn opt_len(&self) -> Option<usize> {
48	0	self.base.opt_len()
49	0	}
50		}
51
52		impl<I, F> IndexedParallelIterator for Update<I, F>
53		where
54		I: IndexedParallelIterator,
55		F: Fn(&mut I::Item) + Send + Sync,
56		{
57	0	fn drive<C>(self, consumer: C) -> C::Result
58	0	where
59	0	C: Consumer<Self::Item>,
60		{
61	0	let consumer1 = UpdateConsumer::new(consumer, &self.update_op);
62	0	self.base.drive(consumer1)
63	0	}
64
65	0	fn len(&self) -> usize {
66	0	self.base.len()
67	0	}
68
69	0	fn with_producer<CB>(self, callback: CB) -> CB::Output
70	0	where
71	0	CB: ProducerCallback<Self::Item>,
72		{
73	0	return self.base.with_producer(Callback {
74	0	callback,
75	0	update_op: self.update_op,
76	0	});
77
78		struct Callback<CB, F> {
79		callback: CB,
80		update_op: F,
81		}
82
83		impl<T, F, CB> ProducerCallback<T> for Callback<CB, F>
84		where
85		CB: ProducerCallback<T>,
86		F: Fn(&mut T) + Send + Sync,
87		{
88		type Output = CB::Output;
89
90	0	fn callback<P>(self, base: P) -> CB::Output
91	0	where
92	0	P: Producer<Item = T>,
93		{
94	0	let producer = UpdateProducer {
95	0	base,
96	0	update_op: &self.update_op,
97	0	};
98	0	self.callback.callback(producer)
99	0	}
100		}
101	0	}
102		}
103
104		// ////////////////////////////////////////////////////////////////////////
105
106		struct UpdateProducer<'f, P, F> {
107		base: P,
108		update_op: &'f F,
109		}
110
111		impl<'f, P, F> Producer for UpdateProducer<'f, P, F>
112		where
113		P: Producer,
114		F: Fn(&mut P::Item) + Send + Sync,
115		{
116		type Item = P::Item;
117		type IntoIter = UpdateSeq<P::IntoIter, &'f F>;
118
119	0	fn into_iter(self) -> Self::IntoIter {
120	0	UpdateSeq {
121	0	base: self.base.into_iter(),
122	0	update_op: self.update_op,
123	0	}
124	0	}
125
126	0	fn min_len(&self) -> usize {
127	0	self.base.min_len()
128	0	}
129	0	fn max_len(&self) -> usize {
130	0	self.base.max_len()
131	0	}
132
133	0	fn split_at(self, index: usize) -> (Self, Self) {
134	0	let (left, right) = self.base.split_at(index);
135	0	(
136	0	UpdateProducer {
137	0	base: left,
138	0	update_op: self.update_op,
139	0	},
140	0	UpdateProducer {
141	0	base: right,
142	0	update_op: self.update_op,
143	0	},
144	0	)
145	0	}
146
147	0	fn fold_with<G>(self, folder: G) -> G
148	0	where
149	0	G: Folder<Self::Item>,
150		{
151	0	let folder1 = UpdateFolder {
152	0	base: folder,
153	0	update_op: self.update_op,
154	0	};
155	0	self.base.fold_with(folder1).base
156	0	}
157		}
158
159		// ////////////////////////////////////////////////////////////////////////
160		// Consumer implementation
161
162		struct UpdateConsumer<'f, C, F> {
163		base: C,
164		update_op: &'f F,
165		}
166
167		impl<'f, C, F> UpdateConsumer<'f, C, F> {
168	0	fn new(base: C, update_op: &'f F) -> Self {
169	0	UpdateConsumer { base, update_op }
170	0	}
171		}
172
173		impl<'f, T, C, F> Consumer<T> for UpdateConsumer<'f, C, F>
174		where
175		C: Consumer<T>,
176		F: Fn(&mut T) + Send + Sync,
177		{
178		type Folder = UpdateFolder<'f, C::Folder, F>;
179		type Reducer = C::Reducer;
180		type Result = C::Result;
181
182	0	fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
183	0	let (left, right, reducer) = self.base.split_at(index);
184	0	(
185	0	UpdateConsumer::new(left, self.update_op),
186	0	UpdateConsumer::new(right, self.update_op),
187	0	reducer,
188	0	)
189	0	}
190
191	0	fn into_folder(self) -> Self::Folder {
192	0	UpdateFolder {
193	0	base: self.base.into_folder(),
194	0	update_op: self.update_op,
195	0	}
196	0	}
197
198	0	fn full(&self) -> bool {
199	0	self.base.full()
200	0	}
201		}
202
203		impl<'f, T, C, F> UnindexedConsumer<T> for UpdateConsumer<'f, C, F>
204		where
205		C: UnindexedConsumer<T>,
206		F: Fn(&mut T) + Send + Sync,
207		{
208	0	fn split_off_left(&self) -> Self {
209	0	UpdateConsumer::new(self.base.split_off_left(), self.update_op)
210	0	}
211
212	0	fn to_reducer(&self) -> Self::Reducer {
213	0	self.base.to_reducer()
214	0	}
215		}
216
217		struct UpdateFolder<'f, C, F> {
218		base: C,
219		update_op: &'f F,
220		}
221
222	0	fn apply<T>(update_op: impl Fn(&mut T)) -> impl Fn(T) -> T {
223	0	move \|mut item\| {
224	0	update_op(&mut item);
225	0	item
226	0	}
227	0	}
228
229		impl<'f, T, C, F> Folder<T> for UpdateFolder<'f, C, F>
230		where
231		C: Folder<T>,
232		F: Fn(&mut T),
233		{
234		type Result = C::Result;
235
236	0	fn consume(self, mut item: T) -> Self {
237	0	(self.update_op)(&mut item);
238
239	0	UpdateFolder {
240	0	base: self.base.consume(item),
241	0	update_op: self.update_op,
242	0	}
243	0	}
244
245	0	fn consume_iter<I>(mut self, iter: I) -> Self
246	0	where
247	0	I: IntoIterator<Item = T>,
248		{
249	0	let update_op = self.update_op;
250	0	self.base = self
251	0	.base
252	0	.consume_iter(iter.into_iter().map(apply(update_op)));
253	0	self
254	0	}
255
256	0	fn complete(self) -> C::Result {
257	0	self.base.complete()
258	0	}
259
260	0	fn full(&self) -> bool {
261	0	self.base.full()
262	0	}
263		}
264
265		/// Standard Update adaptor, based on `itertools::adaptors::Update`
266		#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
267		#[derive(Debug, Clone)]
268		struct UpdateSeq<I, F> {
269		base: I,
270		update_op: F,
271		}
272
273		impl<I, F> Iterator for UpdateSeq<I, F>
274		where
275		I: Iterator,
276		F: Fn(&mut I::Item),
277		{
278		type Item = I::Item;
279
280	0	fn next(&mut self) -> Option<Self::Item> {
281	0	let mut v = self.base.next()?;
282	0	(self.update_op)(&mut v);
283	0	Some(v)
284	0	}
285
286	0	fn size_hint(&self) -> (usize, Option<usize>) {
287	0	self.base.size_hint()
288	0	}
289
290	0	fn fold<Acc, G>(self, init: Acc, g: G) -> Acc
291	0	where
292	0	G: FnMut(Acc, Self::Item) -> Acc,
293		{
294	0	self.base.map(apply(self.update_op)).fold(init, g)
295	0	}
296
297		// if possible, re-use inner iterator specializations in collect
298	0	fn collect<C>(self) -> C
299	0	where
300	0	C: ::std::iter::FromIterator<Self::Item>,
301		{
302	0	self.base.map(apply(self.update_op)).collect()
303	0	}
304		}
305
306		impl<I, F> ExactSizeIterator for UpdateSeq<I, F>
307		where
308		I: ExactSizeIterator,
309		F: Fn(&mut I::Item),
310		{
311		}
312
313		impl<I, F> DoubleEndedIterator for UpdateSeq<I, F>
314		where
315		I: DoubleEndedIterator,
316		F: Fn(&mut I::Item),
317		{
318	0	fn next_back(&mut self) -> Option<Self::Item> {
319	0	let mut v = self.base.next_back()?;
320	0	(self.update_op)(&mut v);
321	0	Some(v)
322	0	}
323		}