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
use crate::utils::take_manuallydrop;
use std_::mem::ManuallyDrop;
#[cfg(test)]
mod tests;
/// A wrapper type that runs a closure at the end of the scope.
///
/// This takes both a value and a closure(that takes the value as a parameter),
/// allowing you to access the value before the closure runs.
///
/// # Example
///
/// ```rust
/// use core_extensions::RunOnDrop;
///
/// fn main() {
/// let mut guard = RunOnDrop::new("Hello".to_string(), |string|{
/// assert_eq!(string, "Hello, world!");
/// });
///
/// assert_eq!(guard.get(), "Hello");
///
/// guard.get_mut().push_str(", world!");
/// }
///
/// ```
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "on_drop")))]
pub struct RunOnDrop<T, F>
where
F: FnOnce(T),
{
value: ManuallyDrop<T>,
function: ManuallyDrop<F>,
}
impl<T, F> RunOnDrop<T, F>
where
F: FnOnce(T),
{
/// Constructs this RunOnDrop.
#[inline(always)]
pub fn new(value: T, function: F) -> Self {
Self {
value: ManuallyDrop::new(value),
function: ManuallyDrop::new(function),
}
}
}
impl<T, F> RunOnDrop<T, F>
where
F: FnOnce(T),
{
/// Reborrows the wrapped value.
#[inline(always)]
pub fn get(&self) -> &T {
&*self.value
}
/// Reborrows the wrapped value mutably.
#[inline(always)]
pub fn get_mut(&mut self) -> &mut T {
&mut *self.value
}
/// Extracts the wrapped value, preventing the closure from running at the end of the scope.
pub fn into_inner(self) -> T {
let mut this = ManuallyDrop::new(self);
unsafe{
let ret = take_manuallydrop(&mut this.value);
ManuallyDrop::drop(&mut this.function);
ret
}
}
}
impl<T, F> Drop for RunOnDrop<T, F>
where
F: FnOnce(T),
{
#[inline(always)]
fn drop(&mut self) {
unsafe {
let value = take_manuallydrop(&mut self.value);
let function = take_manuallydrop(&mut self.function);
function(value);
}
}
}