anyhow/
ptr.rs

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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
use alloc::boxed::Box;
use core::marker::PhantomData;
use core::ptr::NonNull;

#[repr(transparent)]
pub struct Own<T>
where
    T: ?Sized,
{
    pub ptr: NonNull<T>,
}

unsafe impl<T> Send for Own<T> where T: ?Sized {}

unsafe impl<T> Sync for Own<T> where T: ?Sized {}

impl<T> Copy for Own<T> where T: ?Sized {}

impl<T> Clone for Own<T>
where
    T: ?Sized,
{
    fn clone(&self) -> Self {
        *self
    }
}

impl<T> Own<T>
where
    T: ?Sized,
{
    pub fn new(ptr: Box<T>) -> Self {
        Own {
            ptr: unsafe { NonNull::new_unchecked(Box::into_raw(ptr)) },
        }
    }

    pub fn cast<U: CastTo>(self) -> Own<U::Target> {
        Own {
            ptr: self.ptr.cast(),
        }
    }

    pub unsafe fn boxed(self) -> Box<T> {
        Box::from_raw(self.ptr.as_ptr())
    }

    pub fn by_ref(&self) -> Ref<T> {
        Ref {
            ptr: self.ptr,
            lifetime: PhantomData,
        }
    }

    pub fn by_mut(&mut self) -> Mut<T> {
        Mut {
            ptr: self.ptr,
            lifetime: PhantomData,
        }
    }
}

#[repr(transparent)]
pub struct Ref<'a, T>
where
    T: ?Sized,
{
    pub ptr: NonNull<T>,
    lifetime: PhantomData<&'a T>,
}

impl<'a, T> Copy for Ref<'a, T> where T: ?Sized {}

impl<'a, T> Clone for Ref<'a, T>
where
    T: ?Sized,
{
    fn clone(&self) -> Self {
        *self
    }
}

impl<'a, T> Ref<'a, T>
where
    T: ?Sized,
{
    pub fn new(ptr: &'a T) -> Self {
        Ref {
            ptr: NonNull::from(ptr),
            lifetime: PhantomData,
        }
    }

    #[cfg(not(anyhow_no_ptr_addr_of))]
    pub fn from_raw(ptr: NonNull<T>) -> Self {
        Ref {
            ptr,
            lifetime: PhantomData,
        }
    }

    pub fn cast<U: CastTo>(self) -> Ref<'a, U::Target> {
        Ref {
            ptr: self.ptr.cast(),
            lifetime: PhantomData,
        }
    }

    #[cfg(not(anyhow_no_ptr_addr_of))]
    pub fn by_mut(self) -> Mut<'a, T> {
        Mut {
            ptr: self.ptr,
            lifetime: PhantomData,
        }
    }

    #[cfg(not(anyhow_no_ptr_addr_of))]
    pub fn as_ptr(self) -> *const T {
        self.ptr.as_ptr() as *const T
    }

    pub unsafe fn deref(self) -> &'a T {
        &*self.ptr.as_ptr()
    }
}

#[repr(transparent)]
pub struct Mut<'a, T>
where
    T: ?Sized,
{
    pub ptr: NonNull<T>,
    lifetime: PhantomData<&'a mut T>,
}

impl<'a, T> Copy for Mut<'a, T> where T: ?Sized {}

impl<'a, T> Clone for Mut<'a, T>
where
    T: ?Sized,
{
    fn clone(&self) -> Self {
        *self
    }
}

impl<'a, T> Mut<'a, T>
where
    T: ?Sized,
{
    #[cfg(anyhow_no_ptr_addr_of)]
    pub fn new(ptr: &'a mut T) -> Self {
        Mut {
            ptr: NonNull::from(ptr),
            lifetime: PhantomData,
        }
    }

    pub fn cast<U: CastTo>(self) -> Mut<'a, U::Target> {
        Mut {
            ptr: self.ptr.cast(),
            lifetime: PhantomData,
        }
    }

    #[cfg(not(anyhow_no_ptr_addr_of))]
    pub fn by_ref(self) -> Ref<'a, T> {
        Ref {
            ptr: self.ptr,
            lifetime: PhantomData,
        }
    }

    pub fn extend<'b>(self) -> Mut<'b, T> {
        Mut {
            ptr: self.ptr,
            lifetime: PhantomData,
        }
    }

    pub unsafe fn deref_mut(self) -> &'a mut T {
        &mut *self.ptr.as_ptr()
    }
}

impl<'a, T> Mut<'a, T> {
    pub unsafe fn read(self) -> T {
        self.ptr.as_ptr().read()
    }
}

// Force turbofish on all calls of `.cast::<U>()`.
pub trait CastTo {
    type Target;
}

impl<T> CastTo for T {
    type Target = T;
}