acpi/
managed_slice.rs

1use crate::{AcpiError, AcpiResult};
2use core::{
3    alloc::{Allocator, Layout},
4    mem,
5    ptr::NonNull,
6};
7
8/// Thin wrapper around a regular slice, taking a reference to an allocator for automatic
9/// deallocation when the slice is dropped out of scope.
10#[derive(Debug)]
11pub struct ManagedSlice<'a, T, A>
12where
13    A: Allocator,
14{
15    slice: &'a mut [T],
16    allocator: A,
17}
18
19impl<T, A> ManagedSlice<'_, T, A>
20where
21    A: Allocator,
22{
23    /// Attempt to allocate a new `ManagedSlice` that holds `len` `T`s.
24    pub fn new_in(len: usize, allocator: A) -> AcpiResult<Self> {
25        let layout = Layout::array::<T>(len).map_err(|_| AcpiError::AllocError)?;
26        match allocator.allocate(layout) {
27            Ok(mut ptr) => {
28                let slice = unsafe { core::slice::from_raw_parts_mut(ptr.as_mut().as_mut_ptr().cast(), len) };
29                Ok(ManagedSlice { slice, allocator })
30            }
31            Err(_) => Err(AcpiError::AllocError),
32        }
33    }
34}
35
36#[cfg(feature = "alloc")]
37impl<T> ManagedSlice<'_, T, alloc::alloc::Global> {
38    pub fn new(len: usize) -> AcpiResult<Self> {
39        Self::new_in(len, alloc::alloc::Global)
40    }
41}
42
43impl<T, A> Drop for ManagedSlice<'_, T, A>
44where
45    A: Allocator,
46{
47    fn drop(&mut self) {
48        unsafe {
49            let slice_ptr = NonNull::new_unchecked(self.slice.as_ptr().cast_mut().cast::<u8>());
50            let slice_layout =
51                Layout::from_size_align_unchecked(mem::size_of_val(self.slice), mem::align_of_val(self.slice));
52            self.allocator.deallocate(slice_ptr, slice_layout);
53        }
54    }
55}
56
57impl<T, A> core::ops::Deref for ManagedSlice<'_, T, A>
58where
59    A: Allocator,
60{
61    type Target = [T];
62
63    fn deref(&self) -> &Self::Target {
64        self.slice
65    }
66}
67
68impl<T, A> core::ops::DerefMut for ManagedSlice<'_, T, A>
69where
70    A: Allocator,
71{
72    fn deref_mut(&mut self) -> &mut Self::Target {
73        self.slice
74    }
75}
76
77impl<T: Clone, A: Allocator + Clone> Clone for ManagedSlice<'_, T, A> {
78    fn clone(&self) -> Self {
79        let mut new_managed_slice = ManagedSlice::new_in(self.len(), self.allocator.clone()).unwrap();
80        new_managed_slice.clone_from_slice(self);
81        new_managed_slice
82    }
83}
acpi/managed_slice.rs

acpi/
managed_slice.rs
