crossfire 3.1.8

channels for async and threads
Documentation 
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

use super::{FlavorBounded, FlavorImpl, FlavorSelect, Queue, Token};
use crate::crossbeam::array_queue_mpsc::ArrayQueueMpsc;
use std::mem::MaybeUninit;

/// Simplified ArrayQueue tweaks for MPSC
///
/// Push and pop fast path reduced one atomic ops compared to its MPMC version (only 3 ops instead
/// of 4),
/// and it's faster to detect the empty / full condition (2 ops instead of 3).
pub struct ArrayMpsc<T>(ArrayQueueMpsc<T>);

impl<T> ArrayMpsc<T> {
    pub fn new(mut bound: usize) -> Self {
        assert!(bound <= u32::MAX as usize);
        if bound == 0 {
            bound = 1;
        }
        Self(ArrayQueueMpsc::<T>::new(bound))
    }
}

impl<T> Queue for ArrayMpsc<T> {
    type Item = T;

    #[inline(always)]
    fn pop(&self) -> Option<T>
    where
        T: Send,
    {
        self.0.pop(true)
    }

    #[inline(always)]
    fn push(&self, item: T) -> Result<(), T>
    where
        T: Send,
    {
        let _item = MaybeUninit::new(item);
        if unsafe { self.0.push_with_ptr(_item.as_ptr()) } {
            Ok(())
        } else {
            Err(unsafe { _item.assume_init_read() })
        }
    }

    #[inline(always)]
    fn is_full(&self) -> bool {
        self.0.is_full()
    }

    #[inline(always)]
    fn is_empty(&self) -> bool {
        self.0.is_empty()
    }

    #[inline(always)]
    fn len(&self) -> usize {
        self.0.len()
    }

    #[inline(always)]
    fn capacity(&self) -> Option<usize> {
        Some(self.0.capacity())
    }
}

impl<T> FlavorImpl for ArrayMpsc<T> {
    #[inline(always)]
    fn try_send(&self, item: &MaybeUninit<T>) -> bool {
        unsafe { self.0.push_with_ptr(item.as_ptr()) }
    }

    #[inline(always)]
    fn try_send_oneshot(&self, item: *const T) -> Option<bool> {
        unsafe { self.0.try_push_oneshot(item) }
    }

    #[inline(always)]
    fn try_recv_cached(&self) -> Option<T> {
        self.0.pop_cached()
    }

    #[inline]
    fn try_recv(&self) -> Option<T> {
        self.0.pop(false)
    }

    #[inline]
    fn try_recv_final(&self) -> Option<T> {
        self.0.pop(true)
    }

    #[inline]
    fn backoff_limit(&self) -> u16 {
        if self.0.capacity() > 10 {
            crate::backoff::DEFAULT_LIMIT
        } else {
            #[cfg(target_arch = "x86_64")]
            {
                crate::backoff::DEFAULT_LIMIT
            }
            #[cfg(not(target_arch = "x86_64"))]
            {
                crate::backoff::MAX_LIMIT
            }
        }
    }

    #[inline]
    fn may_direct_copy(&self) -> bool {
        true
    }
}

impl<T> FlavorSelect for ArrayMpsc<T> {
    #[inline]
    fn try_select(&self, final_check: bool) -> Option<Token> {
        self.0.start_read(final_check)
    }

    #[inline(always)]
    fn read_with_token(&self, token: Token) -> T {
        self.0.read(token)
    }
}

impl<T> FlavorBounded for ArrayMpsc<T> {
    #[inline(always)]
    fn new_with_bound(size: usize) -> Self {
        Self::new(size)
    }
}