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Remove unnecessary check in VecDeque::grow

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All callers already check that the buffer is full before calling
`grow()`. This is where it makes the most sense, since `grow()` is
`inline(never)` and we don't want to pay for a function call just for
that check.
It could also be argued that it would be correct to call `grow()` even
if the buffer wasn't full yet.
This change breaks no code since `grow()` is not `pub`.
This commit is contained in:
Cédric Barreteau 2021-11-28 17:59:17 -05:00
parent 6db0a0e9a4
commit 29f5c98a17
1 changed files with 11 additions and 9 deletions
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20
library/alloc/src/collections/vec_deque/mod.rs
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@ -2179,19 +2179,21 @@ impl<T, A: Allocator> VecDeque<T, A> {
} }
} }
// Double the buffer size. This method is inline(never), so we expect it to only
// be called in cold paths.
// This may panic or abort // This may panic or abort
#[inline(never)] #[inline(never)]
fn grow(&mut self) { fn grow(&mut self) {
if self.is_full() { // Extend or possibly remove this assertion when valid use-cases for growing the
let old_cap = self.cap(); // buffer without it being full emerge
// Double the buffer size. debug_assert!(self.is_full());
self.buf.reserve_exact(old_cap, old_cap); let old_cap = self.cap();
assert!(self.cap() == old_cap * 2); self.buf.reserve_exact(old_cap, old_cap);
unsafe { assert!(self.cap() == old_cap * 2);
self.handle_capacity_increase(old_cap); unsafe {
} self.handle_capacity_increase(old_cap);
debug_assert!(!self.is_full());
} }
debug_assert!(!self.is_full());
} }
/// Modifies the `VecDeque` in-place so that `len()` is equal to `new_len`, /// Modifies the `VecDeque` in-place so that `len()` is equal to `new_len`,