thinnable 0.3.3

Thin references to unsized types.
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
133
134
135
136
137
138
139

use core::{
    borrow::{Borrow, BorrowMut},
    cmp,
    convert::TryInto,
    fmt,
    hash::{Hash, Hasher},
    ops::{Deref, DerefMut},
};

use crate::{Fake, Metadata};

/// A "thin" exclusive DST reference, analogue of `&mut U` (but only one
/// pointer-width in size).
pub struct ThinMut<'a, U: ?Sized, M = Metadata<U>>(&'a mut Fake<U, M>);

impl<'a, U, M> ThinMut<'a, U, M>
where
    U: ?Sized,
{
    pub(crate) fn new(r: &'a mut Fake<U, M>) -> Self {
        Self(r)
    }
}

impl<U, M> BorrowMut<U> for ThinMut<'_, U, M>
where
    U: ?Sized,
    M: Copy + TryInto<Metadata<U>>,
{
    #[inline(always)]
    fn borrow_mut(&mut self) -> &mut U {
        self.0
    }
}

impl<U, M> DerefMut for ThinMut<'_, U, M>
where
    U: ?Sized,
    M: Copy + TryInto<Metadata<U>>,
{
    #[inline(always)]
    fn deref_mut(&mut self) -> &mut U {
        self.borrow_mut()
    }
}

delegate! {
    for ThinMut {
        #[cfg(any(feature = "fn-refs", doc))]
        #[doc(cfg(feature = "fn-refs"))]
        FnMut<Args> {
            extern "rust-call" fn call_mut(&mut self, args: Args) -> U::Output;
        }

        fmt::Write {
            fn write_str(&mut self, s: &str) -> fmt::Result;
            fn write_char(&mut self, c: char) -> fmt::Result;
            fn write_fmt(&mut self, args: fmt::Arguments<'_>) -> fmt::Result;
        }

        Iterator {
            type Item;
            fn next(&mut self) -> Option<U::Item>;
            fn size_hint(&self) -> (usize, Option<usize>);
            fn nth(&mut self, n: usize) -> Option<Self::Item>;
        }
        DoubleEndedIterator {
            fn next_back(&mut self) -> Option<U::Item>;
            fn nth_back(&mut self, n: usize) -> Option<U::Item>;
        }
        ExactSizeIterator {}
        core::iter::FusedIterator {}

        #[cfg(any(feature = "std", doc))]
        #[doc(cfg(feature = "std"))]
        std::io::Write {
            fn write(&mut self, buf: &[u8]) -> std::io::Result<usize>;
            fn write_vectored(&mut self, bufs: &[std::io::IoSlice<'_>]) -> std::io::Result<usize>;
            fn flush(&mut self) -> std::io::Result<()>;
            fn write_all(&mut self, buf: &[u8]) -> std::io::Result<()>;
            fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> std::io::Result<()>;
        }

        #[cfg(any(feature = "std", doc))]
        #[doc(cfg(feature = "std"))]
        std::io::Read {
            fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize>;
            fn read_vectored(&mut self, bufs: &mut [std::io::IoSliceMut<'_>]) -> std::io::Result<usize>;
            fn read_to_end(&mut self, buf: &mut Vec<u8>) -> std::io::Result<usize>;
            fn read_to_string(&mut self, buf: &mut String) -> std::io::Result<usize>;
            fn read_exact(&mut self, buf: &mut [u8]) -> std::io::Result<()>;
        }

        #[cfg(any(feature = "std", doc))]
        #[doc(cfg(feature = "std"))]
        std::io::Seek {
            fn seek(&mut self, pos: std::io::SeekFrom) -> std::io::Result<u64>;
            fn rewind(&mut self) -> std::io::Result<()>;
            fn stream_position(&mut self) -> std::io::Result<u64>;
        }

        #[cfg(any(feature = "std", doc))]
        #[doc(cfg(feature = "std"))]
        std::io::BufRead {
            fn fill_buf(&mut self) -> std::io::Result<&[u8]>;
            fn consume(&mut self, amt: usize);
            fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> std::io::Result<usize>;
            fn read_line(&mut self, buf: &mut String) -> std::io::Result<usize>;
        }
    }
}

impl<T, U, M> AsMut<T> for ThinMut<'_, U, M>
where
    T: ?Sized,
    U: ?Sized + AsMut<T>,
    M: Copy + TryInto<Metadata<U>>,
{
    #[inline(always)]
    fn as_mut(&mut self) -> &mut T {
        (**self).as_mut()
    }
}

#[cfg(any(feature = "fn-refs", doc))]
#[doc(cfg(feature = "fn-refs"))]
impl<Args, U, M> FnOnce<Args> for ThinMut<'_, U, M>
where
    U: ?Sized + FnMut<Args>,
    M: Copy + TryInto<Metadata<U>>,
{
    type Output = U::Output;
    #[inline(always)]
    extern "rust-call" fn call_once(mut self, args: Args) -> U::Output {
        (&mut *self).call_mut(args)
    }
}

impl_common_ref_traits_for!(ThinMut);