/
slice_container.rs
82 lines (69 loc) · 2.07 KB
/
slice_container.rs
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use std::{mem, ptr};
use ndarray::{ArrayBase, Dimension, OwnedRepr};
use pyo3::pyclass;
/// Utility type to safely store `Box<[_]>` or `Vec<_>` on the Python heap
#[pyclass(frozen)]
#[derive(Debug)]
pub(crate) struct PySliceContainer {
pub(crate) ptr: *mut u8,
pub(crate) len: usize,
cap: usize,
drop: unsafe fn(*mut u8, usize, usize),
}
unsafe impl Send for PySliceContainer {}
impl<T: Send> From<Box<[T]>> for PySliceContainer {
fn from(data: Box<[T]>) -> Self {
unsafe fn drop_boxed_slice<T>(ptr: *mut u8, len: usize, _cap: usize) {
let _ = Box::from_raw(ptr::slice_from_raw_parts_mut(ptr as *mut T, len));
}
// FIXME(adamreichold): Use `Box::into_raw` when
// `*mut [T]::{as_mut_ptr, len}` become stable and compatible with our MSRV.
let mut data = mem::ManuallyDrop::new(data);
let ptr = data.as_mut_ptr() as *mut u8;
let len = data.len();
let cap = 0;
let drop = drop_boxed_slice::<T>;
Self {
ptr,
len,
cap,
drop,
}
}
}
impl<T: Send> From<Vec<T>> for PySliceContainer {
fn from(data: Vec<T>) -> Self {
unsafe fn drop_vec<T>(ptr: *mut u8, len: usize, cap: usize) {
let _ = Vec::from_raw_parts(ptr as *mut T, len, cap);
}
// FIXME(adamreichold): Use `Vec::into_raw_parts`
// when it becomes stable and compatible with our MSRV.
let mut data = mem::ManuallyDrop::new(data);
let ptr = data.as_mut_ptr() as *mut u8;
let len = data.len();
let cap = data.capacity();
let drop = drop_vec::<T>;
Self {
ptr,
len,
cap,
drop,
}
}
}
impl<A, D> From<ArrayBase<OwnedRepr<A>, D>> for PySliceContainer
where
A: Send,
D: Dimension,
{
fn from(data: ArrayBase<OwnedRepr<A>, D>) -> Self {
Self::from(data.into_raw_vec())
}
}
impl Drop for PySliceContainer {
fn drop(&mut self) {
unsafe {
(self.drop)(self.ptr, self.len, self.cap);
}
}
}