squire 0.0.1-alpha.7

Safe and idiomatic SQLite bindings
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 core::{
    ffi::CStr,
    fmt,
    marker::PhantomData,
    ops::{Deref, DerefMut},
};

pub struct Pointer<'a, T: Pointee + ?Sized> {
    target: *const T,
    _value: PhantomData<fn() -> &'a T>,
}

impl<'a, T: Pointee + ?Sized> Pointer<'a, T> {
    /// Create a [`Pointer`] from a raw pointer.
    ///
    /// # Safety
    ///
    /// `target` must be [convertible to `&'a T`][safety].
    ///
    /// [safety]: https://doc.rust-lang.org/std/ptr/index.html#pointer-to-reference-conversion
    pub const unsafe fn new(target: *const T) -> Option<Self> {
        if !target.is_null() {
            Some(Self {
                target,
                _value: PhantomData,
            })
        } else {
            None
        }
    }

    pub const fn of(value: &'a T) -> Self {
        Self {
            target: value,
            _value: PhantomData,
        }
    }
}

impl<T: Pointee + ?Sized> Deref for Pointer<'_, T> {
    type Target = T;

    fn deref(&self) -> &T {
        // SAFETY: guaranteed by `new` / `of` constructors
        unsafe { &*self.target }
    }
}

impl<T: Pointee + ?Sized> AsRef<T> for Pointer<'_, T> {
    fn as_ref(&self) -> &T {
        self
    }
}

impl<T: Pointee + fmt::Debug + ?Sized> fmt::Debug for Pointer<'_, T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Pointer")
            .field("type", &T::TYPE)
            .field("ptr", &self.target)
            .finish()
    }
}

pub struct PointerMut<'a, T: Pointee + ?Sized> {
    target: *mut T,
    _value: PhantomData<fn() -> &'a mut T>,
}

impl<'a, T: Pointee + ?Sized> PointerMut<'a, T> {
    /// Create a [`PointerMut`] from a raw pointer.
    ///
    /// # Safety
    ///
    /// `target` must be [convertible to a `&'a mut T`][safety].
    ///
    /// [safety]: https://doc.rust-lang.org/std/ptr/index.html#pointer-to-reference-conversion
    pub const unsafe fn new(target: *mut T) -> Option<Self> {
        if !target.is_null() {
            Some(Self {
                target,
                _value: PhantomData,
            })
        } else {
            None
        }
    }

    pub const fn of(value: &'a mut T) -> Self {
        Self {
            target: value,
            _value: PhantomData,
        }
    }
}

impl<T: Pointee + ?Sized> Deref for PointerMut<'_, T> {
    type Target = T;

    fn deref(&self) -> &T {
        // SAFETY: guaranteed by `new` / `of` constructors
        unsafe { &*self.target }
    }
}

impl<T: Pointee + ?Sized> DerefMut for PointerMut<'_, T> {
    fn deref_mut(&mut self) -> &mut T {
        // SAFETY: guaranteed by `new` / `of` constructors
        unsafe { &mut *self.target }
    }
}

impl<T: Pointee + ?Sized> AsRef<T> for PointerMut<'_, T> {
    fn as_ref(&self) -> &T {
        self
    }
}

impl<T: Pointee + fmt::Debug + ?Sized> fmt::Debug for PointerMut<'_, T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("PointerMut")
            .field("type", &T::TYPE)
            .field("ptr", &self.target)
            .finish()
    }
}

/// A type that can use the SQLite [pointer passing interface][].
///
/// [pointer passing interface]: https://sqlite.org/bindptr.html
pub trait Pointee {
    const TYPE: &'static CStr;
}