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std: minor simplification to sync::deque.

This commit is contained in:
Huon Wilson 2014-05-24 01:07:05 +10:00
parent 9e244d7084
commit 9a8379deb2
1 changed files with 5 additions and 5 deletions
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10
src/libstd/sync/deque.rs
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@ -54,7 +54,7 @@ use clone::Clone;
use iter::{range, Iterator};
use kinds::Send;
use kinds::marker;
use mem::{forget, min_align_of, size_of, transmute};
use mem::{forget, min_align_of, size_of, transmute, overwrite};
use ops::Drop;
use option::{Option, Some, None};
use owned::Box;
@ -371,20 +371,20 @@ impl<T: Send> Buffer<T> {
// Apparently LLVM cannot optimize (foo % (1 << bar)) into this implicitly
fn mask(&self) -> int { (1 << self.log_size) - 1 }
unsafe fn elem(&self, i: int) -> *T { self.storage.offset(i & self.mask()) }
// This does not protect against loading duplicate values of the same cell,
// nor does this clear out the contents contained within. Hence, this is a
// very unsafe method which the caller needs to treat specially in case a
// race is lost.
unsafe fn get(&self, i: int) -> T {
ptr::read(self.storage.offset(i & self.mask()))
ptr::read(self.elem(i))
}
// Unsafe because this unsafely overwrites possibly uninitialized or
// initialized data.
unsafe fn put(&self, i: int, t: T) {
let ptr = self.storage.offset(i & self.mask());
ptr::copy_nonoverlapping_memory(ptr as *mut T, &t as *T, 1);
forget(t);
overwrite(self.elem(i) as *mut T, t);
}
// Again, unsafe because this has incredibly dubious ownership violations.