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

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

/// `Flatten` turns each element to a parallel iterator, then flattens these iterators
/// together. This struct is created by the [`flatten()`] method on [`ParallelIterator`].
///
/// [`flatten()`]: ParallelIterator::flatten()
#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
#[derive(Debug, Clone)]
pub struct Flatten<I> {
    base: I,
}

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

impl<I> ParallelIterator for Flatten<I>
where
    I: ParallelIterator<Item: IntoParallelIterator>,
{
    type Item = <I::Item as IntoParallelIterator>::Item;

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

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

struct FlattenConsumer<C> {
    base: C,
}

impl<C> FlattenConsumer<C> {
    fn new(base: C) -> Self {
        FlattenConsumer { base }
    }
}

impl<T, C> Consumer<T> for FlattenConsumer<C>
where
    C: UnindexedConsumer<T::Item>,
    T: IntoParallelIterator,
{
    type Folder = FlattenFolder<C, C::Result>;
    type Reducer = C::Reducer;
    type Result = C::Result;

    fn split_at(self, index: usize) -> (Self, Self, C::Reducer) {
        let (left, right, reducer) = self.base.split_at(index);
        (
            FlattenConsumer::new(left),
            FlattenConsumer::new(right),
            reducer,
        )
    }

    fn into_folder(self) -> Self::Folder {
        FlattenFolder {
            base: self.base,
            previous: None,
        }
    }

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

impl<T, C> UnindexedConsumer<T> for FlattenConsumer<C>
where
    C: UnindexedConsumer<T::Item>,
    T: IntoParallelIterator,
{
    fn split_off_left(&self) -> Self {
        FlattenConsumer::new(self.base.split_off_left())
    }

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

struct FlattenFolder<C, R> {
    base: C,
    previous: Option<R>,
}

impl<T, C> Folder<T> for FlattenFolder<C, C::Result>
where
    C: UnindexedConsumer<T::Item>,
    T: IntoParallelIterator,
{
    type Result = C::Result;

    fn consume(self, item: T) -> Self {
        let par_iter = item.into_par_iter();
        let consumer = self.base.split_off_left();
        let result = par_iter.drive_unindexed(consumer);

        let previous = match self.previous {
            None => Some(result),
            Some(previous) => {
                let reducer = self.base.to_reducer();
                Some(reducer.reduce(previous, result))
            }
        };

        FlattenFolder {
            base: self.base,
            previous,
        }
    }

    fn complete(self) -> Self::Result {
        match self.previous {
            Some(previous) => previous,
            None => self.base.into_folder().complete(),
        }
    }

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

Line	Count	Source
1		use super::plumbing::*;
2		use super::*;
3
4		/// `Flatten` turns each element to a parallel iterator, then flattens these iterators
5		/// together. This struct is created by the [`flatten()`] method on [`ParallelIterator`].
6		///
7		/// [`flatten()`]: ParallelIterator::flatten()
8		#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
9		#[derive(Debug, Clone)]
10		pub struct Flatten<I> {
11		base: I,
12		}
13
14		impl<I> Flatten<I> {
15		/// Creates a new `Flatten` iterator.
16	0	pub(super) fn new(base: I) -> Self {
17	0	Flatten { base }
18	0	}
19		}
20
21		impl<I> ParallelIterator for Flatten<I>
22		where
23		I: ParallelIterator<Item: IntoParallelIterator>,
24		{
25		type Item = <I::Item as IntoParallelIterator>::Item;
26
27	0	fn drive_unindexed<C>(self, consumer: C) -> C::Result
28	0	where
29	0	C: UnindexedConsumer<Self::Item>,
30		{
31	0	let consumer = FlattenConsumer::new(consumer);
32	0	self.base.drive_unindexed(consumer)
33	0	}
34		}
35
36		// ////////////////////////////////////////////////////////////////////////
37		// Consumer implementation
38
39		struct FlattenConsumer<C> {
40		base: C,
41		}
42
43		impl<C> FlattenConsumer<C> {
44	0	fn new(base: C) -> Self {
45	0	FlattenConsumer { base }
46	0	}
47		}
48
49		impl<T, C> Consumer<T> for FlattenConsumer<C>
50		where
51		C: UnindexedConsumer<T::Item>,
52		T: IntoParallelIterator,
53		{
54		type Folder = FlattenFolder<C, C::Result>;
55		type Reducer = C::Reducer;
56		type Result = C::Result;
57
58	0	fn split_at(self, index: usize) -> (Self, Self, C::Reducer) {
59	0	let (left, right, reducer) = self.base.split_at(index);
60	0	(
61	0	FlattenConsumer::new(left),
62	0	FlattenConsumer::new(right),
63	0	reducer,
64	0	)
65	0	}
66
67	0	fn into_folder(self) -> Self::Folder {
68	0	FlattenFolder {
69	0	base: self.base,
70	0	previous: None,
71	0	}
72	0	}
73
74	0	fn full(&self) -> bool {
75	0	self.base.full()
76	0	}
77		}
78
79		impl<T, C> UnindexedConsumer<T> for FlattenConsumer<C>
80		where
81		C: UnindexedConsumer<T::Item>,
82		T: IntoParallelIterator,
83		{
84	0	fn split_off_left(&self) -> Self {
85	0	FlattenConsumer::new(self.base.split_off_left())
86	0	}
87
88	0	fn to_reducer(&self) -> Self::Reducer {
89	0	self.base.to_reducer()
90	0	}
91		}
92
93		struct FlattenFolder<C, R> {
94		base: C,
95		previous: Option<R>,
96		}
97
98		impl<T, C> Folder<T> for FlattenFolder<C, C::Result>
99		where
100		C: UnindexedConsumer<T::Item>,
101		T: IntoParallelIterator,
102		{
103		type Result = C::Result;
104
105	0	fn consume(self, item: T) -> Self {
106	0	let par_iter = item.into_par_iter();
107	0	let consumer = self.base.split_off_left();
108	0	let result = par_iter.drive_unindexed(consumer);
109
110	0	let previous = match self.previous {
111	0	None => Some(result),
112	0	Some(previous) => {
113	0	let reducer = self.base.to_reducer();
114	0	Some(reducer.reduce(previous, result))
115		}
116		};
117
118	0	FlattenFolder {
119	0	base: self.base,
120	0	previous,
121	0	}
122	0	}
123
124	0	fn complete(self) -> Self::Result {
125	0	match self.previous {
126	0	Some(previous) => previous,
127	0	None => self.base.into_folder().complete(),
128		}
129	0	}
130
131	0	fn full(&self) -> bool {
132	0	self.base.full()
133	0	}
134		}

Coverage Report

Created: 2025-12-05 07:37