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
121
122
123
124
125
126
127
128
129
130
131
132
|
//! Parallel iterator types for [results][std::result]
//!
//! You will rarely need to interact with this module directly unless you need
//! to name one of the iterator types.
//!
//! [std::result]: https://doc.rust-lang.org/stable/std/result/
use crate::iter::plumbing::*;
use crate::iter::*;
use std::sync::Mutex;
use crate::option;
/// Parallel iterator over a result
#[derive(Debug, Clone)]
pub struct IntoIter<T: Send> {
inner: option::IntoIter<T>,
}
impl<T: Send, E> IntoParallelIterator for Result<T, E> {
type Item = T;
type Iter = IntoIter<T>;
fn into_par_iter(self) -> Self::Iter {
IntoIter {
inner: self.ok().into_par_iter(),
}
}
}
delegate_indexed_iterator! {
IntoIter<T> => T,
impl<T: Send>
}
/// Parallel iterator over an immutable reference to a result
#[derive(Debug)]
pub struct Iter<'a, T: Sync> {
inner: option::IntoIter<&'a T>,
}
impl<'a, T: Sync> Clone for Iter<'a, T> {
fn clone(&self) -> Self {
Iter {
inner: self.inner.clone(),
}
}
}
impl<'a, T: Sync, E> IntoParallelIterator for &'a Result<T, E> {
type Item = &'a T;
type Iter = Iter<'a, T>;
fn into_par_iter(self) -> Self::Iter {
Iter {
inner: self.as_ref().ok().into_par_iter(),
}
}
}
delegate_indexed_iterator! {
Iter<'a, T> => &'a T,
impl<'a, T: Sync + 'a>
}
/// Parallel iterator over a mutable reference to a result
#[derive(Debug)]
pub struct IterMut<'a, T: Send> {
inner: option::IntoIter<&'a mut T>,
}
impl<'a, T: Send, E> IntoParallelIterator for &'a mut Result<T, E> {
type Item = &'a mut T;
type Iter = IterMut<'a, T>;
fn into_par_iter(self) -> Self::Iter {
IterMut {
inner: self.as_mut().ok().into_par_iter(),
}
}
}
delegate_indexed_iterator! {
IterMut<'a, T> => &'a mut T,
impl<'a, T: Send + 'a>
}
/// Collect an arbitrary `Result`-wrapped collection.
///
/// If any item is `Err`, then all previous `Ok` items collected are
/// discarded, and it returns that error. If there are multiple errors, the
/// one returned is not deterministic.
impl<C, T, E> FromParallelIterator<Result<T, E>> for Result<C, E>
where
C: FromParallelIterator<T>,
T: Send,
E: Send,
{
fn from_par_iter<I>(par_iter: I) -> Self
where
I: IntoParallelIterator<Item = Result<T, E>>,
{
fn ok<T, E>(saved: &Mutex<Option<E>>) -> impl Fn(Result<T, E>) -> Option<T> + '_ {
move |item| match item {
Ok(item) => Some(item),
Err(error) => {
// We don't need a blocking `lock()`, as anybody
// else holding the lock will also be writing
// `Some(error)`, and then ours is irrelevant.
if let Ok(mut guard) = saved.try_lock() {
if guard.is_none() {
*guard = Some(error);
}
}
None
}
}
}
let saved_error = Mutex::new(None);
let collection = par_iter
.into_par_iter()
.map(ok(&saved_error))
.while_some()
.collect();
match saved_error.into_inner().unwrap() {
Some(error) => Err(error),
None => Ok(collection),
}
}
}
|
