1 use super::plumbing::*;
2 use super::*;
3 use std::fmt;
4 use std::sync::atomic::{AtomicBool, Ordering};
5
6 /// `TakeAnyWhile` is an iterator that iterates over elements from anywhere in `I`
7 /// until the callback returns `false`.
8 /// This struct is created by the [`take_any_while()`] method on [`ParallelIterator`]
9 ///
10 /// [`take_any_while()`]: trait.ParallelIterator.html#method.take_any_while
11 /// [`ParallelIterator`]: trait.ParallelIterator.html
12 #[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
13 #[derive(Clone)]
14 pub struct TakeAnyWhile<I: ParallelIterator, P> {
15 base: I,
16 predicate: P,
17 }
18
19 impl<I: ParallelIterator + fmt::Debug, P> fmt::Debug for TakeAnyWhile<I, P> {
fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result20 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
21 f.debug_struct("TakeAnyWhile")
22 .field("base", &self.base)
23 .finish()
24 }
25 }
26
27 impl<I, P> TakeAnyWhile<I, P>
28 where
29 I: ParallelIterator,
30 {
31 /// Creates a new `TakeAnyWhile` iterator.
new(base: I, predicate: P) -> Self32 pub(super) fn new(base: I, predicate: P) -> Self {
33 TakeAnyWhile { base, predicate }
34 }
35 }
36
37 impl<I, P> ParallelIterator for TakeAnyWhile<I, P>
38 where
39 I: ParallelIterator,
40 P: Fn(&I::Item) -> bool + Sync + Send,
41 {
42 type Item = I::Item;
43
drive_unindexed<C>(self, consumer: C) -> C::Result where C: UnindexedConsumer<Self::Item>,44 fn drive_unindexed<C>(self, consumer: C) -> C::Result
45 where
46 C: UnindexedConsumer<Self::Item>,
47 {
48 let consumer1 = TakeAnyWhileConsumer {
49 base: consumer,
50 predicate: &self.predicate,
51 taking: &AtomicBool::new(true),
52 };
53 self.base.drive_unindexed(consumer1)
54 }
55 }
56
57 /// ////////////////////////////////////////////////////////////////////////
58 /// Consumer implementation
59
60 struct TakeAnyWhileConsumer<'p, C, P> {
61 base: C,
62 predicate: &'p P,
63 taking: &'p AtomicBool,
64 }
65
66 impl<'p, T, C, P> Consumer<T> for TakeAnyWhileConsumer<'p, C, P>
67 where
68 C: Consumer<T>,
69 P: Fn(&T) -> bool + Sync,
70 {
71 type Folder = TakeAnyWhileFolder<'p, C::Folder, P>;
72 type Reducer = C::Reducer;
73 type Result = C::Result;
74
split_at(self, index: usize) -> (Self, Self, Self::Reducer)75 fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
76 let (left, right, reducer) = self.base.split_at(index);
77 (
78 TakeAnyWhileConsumer { base: left, ..self },
79 TakeAnyWhileConsumer {
80 base: right,
81 ..self
82 },
83 reducer,
84 )
85 }
86
into_folder(self) -> Self::Folder87 fn into_folder(self) -> Self::Folder {
88 TakeAnyWhileFolder {
89 base: self.base.into_folder(),
90 predicate: self.predicate,
91 taking: self.taking,
92 }
93 }
94
full(&self) -> bool95 fn full(&self) -> bool {
96 !self.taking.load(Ordering::Relaxed) || self.base.full()
97 }
98 }
99
100 impl<'p, T, C, P> UnindexedConsumer<T> for TakeAnyWhileConsumer<'p, C, P>
101 where
102 C: UnindexedConsumer<T>,
103 P: Fn(&T) -> bool + Sync,
104 {
split_off_left(&self) -> Self105 fn split_off_left(&self) -> Self {
106 TakeAnyWhileConsumer {
107 base: self.base.split_off_left(),
108 ..*self
109 }
110 }
111
to_reducer(&self) -> Self::Reducer112 fn to_reducer(&self) -> Self::Reducer {
113 self.base.to_reducer()
114 }
115 }
116
117 struct TakeAnyWhileFolder<'p, C, P> {
118 base: C,
119 predicate: &'p P,
120 taking: &'p AtomicBool,
121 }
122
take<T>(item: &T, taking: &AtomicBool, predicate: &impl Fn(&T) -> bool) -> bool123 fn take<T>(item: &T, taking: &AtomicBool, predicate: &impl Fn(&T) -> bool) -> bool {
124 if !taking.load(Ordering::Relaxed) {
125 return false;
126 }
127 if predicate(item) {
128 return true;
129 }
130 taking.store(false, Ordering::Relaxed);
131 false
132 }
133
134 impl<'p, T, C, P> Folder<T> for TakeAnyWhileFolder<'p, C, P>
135 where
136 C: Folder<T>,
137 P: Fn(&T) -> bool + 'p,
138 {
139 type Result = C::Result;
140
consume(mut self, item: T) -> Self141 fn consume(mut self, item: T) -> Self {
142 if take(&item, self.taking, self.predicate) {
143 self.base = self.base.consume(item);
144 }
145 self
146 }
147
consume_iter<I>(mut self, iter: I) -> Self where I: IntoIterator<Item = T>,148 fn consume_iter<I>(mut self, iter: I) -> Self
149 where
150 I: IntoIterator<Item = T>,
151 {
152 self.base = self.base.consume_iter(
153 iter.into_iter()
154 .take_while(move |x| take(x, self.taking, self.predicate)),
155 );
156 self
157 }
158
complete(self) -> C::Result159 fn complete(self) -> C::Result {
160 self.base.complete()
161 }
162
full(&self) -> bool163 fn full(&self) -> bool {
164 !self.taking.load(Ordering::Relaxed) || self.base.full()
165 }
166 }
167