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use core::ops::{Deref, DerefMut};
#[cfg(any(feature = "use_std", feature = "use_alloc"))]
use core::borrow::BorrowMut;
use core::fmt;
#[cfg(feature = "use_std")]
use std::boxed::Box;
#[cfg(feature = "use_alloc")]
use alloc::boxed::Box;
#[cfg(feature = "use_std")]
use std::vec::Vec;
pub enum Managed<'a, T: 'a + ?Sized> {
Borrowed(&'a mut T),
#[cfg(any(feature = "use_std", feature = "use_alloc"))]
Owned(Box<BorrowMut<T>>)
}
impl<'a, T: 'a + fmt::Debug + ?Sized> fmt::Debug for Managed<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "Managed::from({:?})", self.deref())
}
}
impl<'a, T: 'a + ?Sized> From<&'a mut T> for Managed<'a, T> {
fn from(value: &'a mut T) -> Self {
Managed::Borrowed(value)
}
}
#[cfg(any(feature = "use_std", feature = "use_alloc"))]
impl<T, U: BorrowMut<T> + 'static> From<Box<U>> for Managed<'static, T> {
fn from(value: Box<U>) -> Self {
Managed::Owned(value)
}
}
#[cfg(feature = "use_std")]
impl<T: 'static> From<Vec<T>> for Managed<'static, [T]> {
fn from(mut value: Vec<T>) -> Self {
value.shrink_to_fit();
Managed::Owned(Box::new(value))
}
}
impl<'a, T: 'a + ?Sized> Deref for Managed<'a, T> {
type Target = T;
fn deref(&self) -> &Self::Target {
match self {
&Managed::Borrowed(ref value) => value,
#[cfg(any(feature = "use_std", feature = "use_alloc"))]
&Managed::Owned(ref value) => (**value).borrow()
}
}
}
impl<'a, T: 'a + ?Sized> DerefMut for Managed<'a, T> {
fn deref_mut(&mut self) -> &mut Self::Target {
match self {
&mut Managed::Borrowed(ref mut value) => value,
#[cfg(any(feature = "use_std", feature = "use_alloc"))]
&mut Managed::Owned(ref mut value) => (**value).borrow_mut()
}
}
}