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fix soundness bug
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@NULLx76
NULLx76 committed Oct 23, 2024
1 parent 75fe4f1 commit aa956bf
Showing 1 changed file with 75 additions and 78 deletions.
153 changes: 75 additions & 78 deletions src/with_const_generics.rs
View file
Original file line number Diff line number Diff line change
@@ -1,8 +1,8 @@
use crate::ringbuffer_trait::{RingBufferIntoIterator, RingBufferIterator, RingBufferMutIterator};
use crate::RingBuffer;
use core::iter::FromIterator;
use core::mem;
use core::mem::MaybeUninit;
use core::mem::{self, ManuallyDrop};
use core::ops::{Index, IndexMut};

/// The `ConstGenericRingBuffer` struct is a `RingBuffer` implementation which does not require `alloc` but
Expand Down Expand Up @@ -42,11 +42,14 @@ pub struct ConstGenericRingBuffer<T, const CAP: usize> {

impl<T, const CAP: usize> From<[T; CAP]> for ConstGenericRingBuffer<T, CAP> {
fn from(value: [T; CAP]) -> Self {
let v = ManuallyDrop::new(value);
Self {
// Safety:
// T has the same layout as MaybeUninit<T>
// [T; N] has the same layout as [MaybeUninit<T>; N]
buf: unsafe { mem::transmute_copy(&value) },
// Without ManuallyDrop this would be unsound as
// transmute_copy doesn't take ownership
buf: unsafe { mem::transmute_copy(&v) },
readptr: 0,
writeptr: CAP,
}
Expand Down Expand Up @@ -183,7 +186,7 @@ impl<T, const CAP: usize> ConstGenericRingBuffer<T, CAP> {
// https://rust-lang.github.io/rust-clippy/master/index.html#uninit_assumed_init
#[allow(clippy::uninit_assumed_init)]
Self {
buf: unsafe { MaybeUninit::uninit().assume_init() },
buf: [const { MaybeUninit::<T>::uninit() }; CAP],
writeptr: 0,
readptr: 0,
}
Expand Down Expand Up @@ -280,7 +283,6 @@ unsafe impl<T, const CAP: usize> RingBuffer<T> for ConstGenericRingBuffer<T, CAP
// make sure we drop whatever is being overwritten
// SAFETY: the buffer is full, so this must be initialized
// : also, index has been masked
// make sure we drop because it won't happen automatically
ret = Some(unsafe { previous_value.assume_init() });
self.readptr += 1;
}
Expand Down Expand Up @@ -360,7 +362,10 @@ impl<T, const CAP: usize> IndexMut<usize> for ConstGenericRingBuffer<T, CAP> {

#[cfg(test)]
mod tests {
use super::*;
use crate::{AllocRingBuffer, ConstGenericRingBuffer, GrowableAllocRingBuffer, RingBuffer};
use alloc::collections::{LinkedList, VecDeque};
use alloc::string::ToString;
use alloc::vec;

#[test]
fn test_not_power_of_two() {
Expand Down Expand Up @@ -428,79 +433,71 @@ mod tests {
}
}

#[cfg(test)]
mod tests {
use crate::{AllocRingBuffer, ConstGenericRingBuffer, GrowableAllocRingBuffer, RingBuffer};
use alloc::collections::{LinkedList, VecDeque};
use alloc::string::ToString;
use alloc::vec;

#[test]
fn from() {
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from([1, 2, 3]).to_vec(),
vec![1, 2, 3]
);

let v: &[i32; 3] = &[1, 2, 3];
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(v).to_vec(),
vec![1, 2, 3]
);

let v: &[i32] = &[1, 2, 3];
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(v).to_vec(),
vec![1, 2, 3]
);

let v: &mut [i32; 3] = &mut [1, 2, 3];
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(v).to_vec(),
vec![1, 2, 3]
);

let v: &mut [i32] = &mut [1, 2, 3];
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(v).to_vec(),
vec![1, 2, 3]
);

assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(vec![1, 2, 3]).to_vec(),
vec![1, 2, 3]
);
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(
vec![1, 2, 3].into_iter().collect::<VecDeque<_>>()
)
.to_vec(),
vec![1, 2, 3]
);
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(
vec![1, 2, 3].into_iter().collect::<LinkedList<_>>()
)
#[test]
fn from() {
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from([1, 2, 3]).to_vec(),
vec![1, 2, 3]
);

let v: &[i32; 3] = &[1, 2, 3];
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(v).to_vec(),
vec![1, 2, 3]
);

let v: &[i32] = &[1, 2, 3];
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(v).to_vec(),
vec![1, 2, 3]
);

let v: &mut [i32; 3] = &mut [1, 2, 3];
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(v).to_vec(),
vec![1, 2, 3]
);

let v: &mut [i32] = &mut [1, 2, 3];
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(v).to_vec(),
vec![1, 2, 3]
);

assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(vec![1, 2, 3]).to_vec(),
vec![1, 2, 3]
);
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(
vec![1, 2, 3].into_iter().collect::<VecDeque<_>>()
)
.to_vec(),
vec![1, 2, 3]
);
assert_eq!(
ConstGenericRingBuffer::<i32, 3>::from(
vec![1, 2, 3].into_iter().collect::<LinkedList<_>>()
)
.to_vec(),
vec![1, 2, 3]
);
assert_eq!(
ConstGenericRingBuffer::<_, 3>::from("abc".to_string()).to_vec(),
vec!['a', 'b', 'c']
);
assert_eq!(
ConstGenericRingBuffer::<_, 3>::from("abc").to_vec(),
vec!['a', 'b', 'c']
);
assert_eq!(
ConstGenericRingBuffer::<_, 3>::from(GrowableAllocRingBuffer::from(vec![1, 2, 3]))
.to_vec(),
vec![1, 2, 3]
);
assert_eq!(
ConstGenericRingBuffer::<_, 3>::from("abc".to_string()).to_vec(),
vec!['a', 'b', 'c']
);
assert_eq!(
ConstGenericRingBuffer::<_, 3>::from("abc").to_vec(),
vec!['a', 'b', 'c']
);
assert_eq!(
ConstGenericRingBuffer::<_, 3>::from(GrowableAllocRingBuffer::from(vec![1, 2, 3]))
.to_vec(),
vec![1, 2, 3]
);
assert_eq!(
ConstGenericRingBuffer::<_, 3>::from(AllocRingBuffer::from(vec![1, 2, 3])).to_vec(),
vec![1, 2, 3]
);
}
vec![1, 2, 3]
);
assert_eq!(
ConstGenericRingBuffer::<_, 3>::from(AllocRingBuffer::from(vec![1, 2, 3])).to_vec(),
vec![1, 2, 3]
);
}
}

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