mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

std: update select internals to not use mutable transmuting

Browse Source
This commit is contained in:
Sean McArthur 2015-04-13 14:49:39 -07:00
parent d131f33557
commit e136f93d0f
1 changed files with 19 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
src/libstd/sync/mpsc/select.rs
View File

@ -58,7 +58,7 @@
use core::prelude::*;
use core::cell::Cell;
use core::cell::{Cell, UnsafeCell};
use core::marker;
use core::mem;
use core::ptr;
@ -70,9 +70,13 @@
/// The "receiver set" of the select interface. This structure is used to manage
/// a set of receivers which are being selected over.
pub struct Select {
inner: UnsafeCell<SelectInner>,
next_id: Cell<usize>,
}
struct SelectInner {
head: *mut Handle<'static, ()>,
tail: *mut Handle<'static, ()>,
next_id: Cell<usize>,
}
impl !marker::Send for Select {}
@ -84,7 +88,7 @@ pub struct Handle<'rx, T:Send+'rx> {
/// The ID of this handle, used to compare against the return value of
/// `Select::wait()`
id: usize,
selector: &'rx Select,
selector: *mut SelectInner,
next: *mut Handle<'static, ()>,
prev: *mut Handle<'static, ()>,
added: bool,
@ -127,8 +131,10 @@ impl Select {
/// ```
pub fn new() -> Select {
Select {
head: ptr::null_mut(),
tail: ptr::null_mut(),
inner: UnsafeCell::new(SelectInner {
head: ptr::null_mut(),
tail: ptr::null_mut(),
}),
next_id: Cell::new(1),
}
}
@ -141,7 +147,7 @@ pub fn handle<'a, T: Send>(&'a self, rx: &'a Receiver<T>) -> Handle<'a, T> {
self.next_id.set(id + 1);
Handle {
id: id,
selector: self,
selector: self.inner.get(),
next: ptr::null_mut(),
prev: ptr::null_mut(),
added: false,
@ -250,7 +256,7 @@ fn wait2(&self, do_preflight_checks: bool) -> usize {
}
}
fn iter(&self) -> Packets { Packets { cur: self.head } }
fn iter(&self) -> Packets { Packets { cur: unsafe { &*self.inner.get() }.head } }
}
impl<'rx, T: Send> Handle<'rx, T> {
@ -271,7 +277,7 @@ pub fn recv(&mut self) -> Result<T, RecvError> { self.rx.recv() }
/// while it is added to the `Select` set.
pub unsafe fn add(&mut self) {
if self.added { return }
let selector: &mut Select = mem::transmute(&*self.selector);
let selector = &mut *self.selector;
let me: *mut Handle<'static, ()> = mem::transmute(&*self);
if selector.head.is_null() {
@ -292,7 +298,7 @@ pub unsafe fn add(&mut self) {
pub unsafe fn remove(&mut self) {
if !self.added { return }
let selector: &mut Select = mem::transmute(&*self.selector);
let selector = &mut *self.selector;
let me: *mut Handle<'static, ()> = mem::transmute(&*self);
if self.prev.is_null() {
@ -317,8 +323,10 @@ pub unsafe fn remove(&mut self) {
impl Drop for Select {
fn drop(&mut self) {
assert!(self.head.is_null());
assert!(self.tail.is_null());
unsafe {
assert!((&*self.inner.get()).head.is_null());
assert!((&*self.inner.get()).tail.is_null());
}
}
}