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// SPDX-License-Identifier: GPL-2.0
//! Extensions to [`Vec`] for fallible allocations.
use alloc::{collections::TryReserveError, vec::Vec};
use core::result::Result;
/// Extensions to [`Vec`].
pub trait VecExt<T>: Sized {
/// Creates a new [`Vec`] instance with at least the given capacity.
fn try_with_capacity(capacity: usize) -> Result<Self, TryReserveError>;
/// Appends an element to the back of the [`Vec`] instance.
fn try_push(&mut self, v: T) -> Result<(), TryReserveError>;
/// Pushes clones of the elements of slice into the [`Vec`] instance.
fn try_extend_from_slice(&mut self, other: &[T]) -> Result<(), TryReserveError>
where
T: Clone;
}
impl<T> VecExt<T> for Vec<T> {
fn try_with_capacity(capacity: usize) -> Result<Self, TryReserveError> {
let mut v = Vec::new();
v.try_reserve(capacity)?;
Ok(v)
}
fn try_push(&mut self, v: T) -> Result<(), TryReserveError> {
if let Err(retry) = self.push_within_capacity(v) {
self.try_reserve(1)?;
let _ = self.push_within_capacity(retry);
}
Ok(())
}
fn try_extend_from_slice(&mut self, other: &[T]) -> Result<(), TryReserveError>
where
T: Clone,
{
self.try_reserve(other.len())?;
for item in other {
self.try_push(item.clone())?;
}
Ok(())
}
}
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