summaryrefslogtreecommitdiffstats
path: root/third_party/rust/rayon/src/collections/binary_heap.rs
blob: fa903121af5907c6963aa3efd9b8a13d24e63252 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
//! This module contains the parallel iterator types for heaps
//! (`BinaryHeap<T>`). You will rarely need to interact with it directly
//! unless you have need to name one of the iterator types.

use std::collections::BinaryHeap;

use crate::iter::plumbing::*;
use crate::iter::*;

use crate::vec;

/// Parallel iterator over a binary heap
#[derive(Debug, Clone)]
pub struct IntoIter<T: Ord + Send> {
    inner: vec::IntoIter<T>,
}

impl<T: Ord + Send> IntoParallelIterator for BinaryHeap<T> {
    type Item = T;
    type Iter = IntoIter<T>;

    fn into_par_iter(self) -> Self::Iter {
        IntoIter {
            inner: Vec::from(self).into_par_iter(),
        }
    }
}

delegate_indexed_iterator! {
    IntoIter<T> => T,
    impl<T: Ord + Send>
}

/// Parallel iterator over an immutable reference to a binary heap
#[derive(Debug)]
pub struct Iter<'a, T: Ord + Sync> {
    inner: vec::IntoIter<&'a T>,
}

impl<'a, T: Ord + Sync> Clone for Iter<'a, T> {
    fn clone(&self) -> Self {
        Iter {
            inner: self.inner.clone(),
        }
    }
}

into_par_vec! {
    &'a BinaryHeap<T> => Iter<'a, T>,
    impl<'a, T: Ord + Sync>
}

delegate_indexed_iterator! {
    Iter<'a, T> => &'a T,
    impl<'a, T: Ord + Sync + 'a>
}

// `BinaryHeap` doesn't have a mutable `Iterator`

/// Draining parallel iterator that moves out of a binary heap,
/// but keeps the total capacity.
#[derive(Debug)]
pub struct Drain<'a, T: Ord + Send> {
    heap: &'a mut BinaryHeap<T>,
}

impl<'a, T: Ord + Send> ParallelDrainFull for &'a mut BinaryHeap<T> {
    type Iter = Drain<'a, T>;
    type Item = T;

    fn par_drain(self) -> Self::Iter {
        Drain { heap: self }
    }
}

impl<'a, T: Ord + Send> ParallelIterator for Drain<'a, T> {
    type Item = T;

    fn drive_unindexed<C>(self, consumer: C) -> C::Result
    where
        C: UnindexedConsumer<Self::Item>,
    {
        bridge(self, consumer)
    }

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

impl<'a, T: Ord + Send> IndexedParallelIterator for Drain<'a, T> {
    fn drive<C>(self, consumer: C) -> C::Result
    where
        C: Consumer<Self::Item>,
    {
        bridge(self, consumer)
    }

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

    fn with_producer<CB>(self, callback: CB) -> CB::Output
    where
        CB: ProducerCallback<Self::Item>,
    {
        super::DrainGuard::new(self.heap)
            .par_drain(..)
            .with_producer(callback)
    }
}

impl<'a, T: Ord + Send> Drop for Drain<'a, T> {
    fn drop(&mut self) {
        if !self.heap.is_empty() {
            // We must not have produced, so just call a normal drain to remove the items.
            self.heap.drain();
        }
    }
}