Fixes #80335
(cherry picked from commit 6d43225bfb08ec91f7476b76c7fec632c4a096ef)
This commit is contained in:
parent
cc6d66fa58
commit
2fefd9ad07
|
@ -90,8 +90,8 @@ impl<S: Borrow<str>> Join<&str> for [S] {
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
macro_rules! spezialize_for_lengths {
|
macro_rules! specialize_for_lengths {
|
||||||
($separator:expr, $target:expr, $iter:expr; $($num:expr),*) => {
|
($separator:expr, $target:expr, $iter:expr; $($num:expr),*) => {{
|
||||||
let mut target = $target;
|
let mut target = $target;
|
||||||
let iter = $iter;
|
let iter = $iter;
|
||||||
let sep_bytes = $separator;
|
let sep_bytes = $separator;
|
||||||
|
@ -102,7 +102,8 @@ macro_rules! spezialize_for_lengths {
|
||||||
$num => {
|
$num => {
|
||||||
for s in iter {
|
for s in iter {
|
||||||
copy_slice_and_advance!(target, sep_bytes);
|
copy_slice_and_advance!(target, sep_bytes);
|
||||||
copy_slice_and_advance!(target, s.borrow().as_ref());
|
let content_bytes = s.borrow().as_ref();
|
||||||
|
copy_slice_and_advance!(target, content_bytes);
|
||||||
}
|
}
|
||||||
},
|
},
|
||||||
)*
|
)*
|
||||||
|
@ -110,11 +111,13 @@ macro_rules! spezialize_for_lengths {
|
||||||
// arbitrary non-zero size fallback
|
// arbitrary non-zero size fallback
|
||||||
for s in iter {
|
for s in iter {
|
||||||
copy_slice_and_advance!(target, sep_bytes);
|
copy_slice_and_advance!(target, sep_bytes);
|
||||||
copy_slice_and_advance!(target, s.borrow().as_ref());
|
let content_bytes = s.borrow().as_ref();
|
||||||
|
copy_slice_and_advance!(target, content_bytes);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
};
|
target
|
||||||
|
}}
|
||||||
}
|
}
|
||||||
|
|
||||||
macro_rules! copy_slice_and_advance {
|
macro_rules! copy_slice_and_advance {
|
||||||
|
@ -153,7 +156,7 @@ where
|
||||||
// if the `len` calculation overflows, we'll panic
|
// if the `len` calculation overflows, we'll panic
|
||||||
// we would have run out of memory anyway and the rest of the function requires
|
// we would have run out of memory anyway and the rest of the function requires
|
||||||
// the entire Vec pre-allocated for safety
|
// the entire Vec pre-allocated for safety
|
||||||
let len = sep_len
|
let reserved_len = sep_len
|
||||||
.checked_mul(iter.len())
|
.checked_mul(iter.len())
|
||||||
.and_then(|n| {
|
.and_then(|n| {
|
||||||
slice.iter().map(|s| s.borrow().as_ref().len()).try_fold(n, usize::checked_add)
|
slice.iter().map(|s| s.borrow().as_ref().len()).try_fold(n, usize::checked_add)
|
||||||
|
@ -161,22 +164,25 @@ where
|
||||||
.expect("attempt to join into collection with len > usize::MAX");
|
.expect("attempt to join into collection with len > usize::MAX");
|
||||||
|
|
||||||
// crucial for safety
|
// crucial for safety
|
||||||
let mut result = Vec::with_capacity(len);
|
let mut result = Vec::with_capacity(reserved_len);
|
||||||
assert!(result.capacity() >= len);
|
debug_assert!(result.capacity() >= reserved_len);
|
||||||
|
|
||||||
result.extend_from_slice(first.borrow().as_ref());
|
result.extend_from_slice(first.borrow().as_ref());
|
||||||
|
|
||||||
unsafe {
|
unsafe {
|
||||||
{
|
let pos = result.len();
|
||||||
let pos = result.len();
|
let target = result.get_unchecked_mut(pos..reserved_len);
|
||||||
let target = result.get_unchecked_mut(pos..len);
|
|
||||||
|
|
||||||
// copy separator and slices over without bounds checks
|
// copy separator and slices over without bounds checks
|
||||||
// generate loops with hardcoded offsets for small separators
|
// generate loops with hardcoded offsets for small separators
|
||||||
// massive improvements possible (~ x2)
|
// massive improvements possible (~ x2)
|
||||||
spezialize_for_lengths!(sep, target, iter; 0, 1, 2, 3, 4);
|
let remain = specialize_for_lengths!(sep, target, iter; 0, 1, 2, 3, 4);
|
||||||
}
|
|
||||||
result.set_len(len);
|
// issue #80335: A weird borrow implementation can return different
|
||||||
|
// slices for the length calculation and the actual copy, so
|
||||||
|
// `remain.len()` might be non-zero.
|
||||||
|
let result_len = reserved_len - remain.len();
|
||||||
|
result.set_len(result_len);
|
||||||
}
|
}
|
||||||
result
|
result
|
||||||
}
|
}
|
||||||
|
|
|
@ -160,6 +160,36 @@ fn test_join_for_different_lengths_with_long_separator() {
|
||||||
test_join!("~~~~~a~~~~~bc", ["", "a", "bc"], "~~~~~");
|
test_join!("~~~~~a~~~~~bc", ["", "a", "bc"], "~~~~~");
|
||||||
}
|
}
|
||||||
|
|
||||||
|
#[test]
|
||||||
|
fn test_join_isue_80335() {
|
||||||
|
use core::{borrow::Borrow, cell::Cell};
|
||||||
|
|
||||||
|
struct WeirdBorrow {
|
||||||
|
state: Cell<bool>,
|
||||||
|
}
|
||||||
|
|
||||||
|
impl Default for WeirdBorrow {
|
||||||
|
fn default() -> Self {
|
||||||
|
WeirdBorrow { state: Cell::new(false) }
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
impl Borrow<str> for WeirdBorrow {
|
||||||
|
fn borrow(&self) -> &str {
|
||||||
|
let state = self.state.get();
|
||||||
|
if state {
|
||||||
|
"0"
|
||||||
|
} else {
|
||||||
|
self.state.set(true);
|
||||||
|
"123456"
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
let arr: [WeirdBorrow; 3] = Default::default();
|
||||||
|
test_join!("0-0-0", arr, "-");
|
||||||
|
}
|
||||||
|
|
||||||
#[test]
|
#[test]
|
||||||
#[cfg_attr(miri, ignore)] // Miri is too slow
|
#[cfg_attr(miri, ignore)] // Miri is too slow
|
||||||
fn test_unsafe_slice() {
|
fn test_unsafe_slice() {
|
||||||
|
|
Loading…
Reference in New Issue