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Remove Deref and DerefMut implementations from WeakFlowRef.

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By definition of a weak pointer, these implementations cannot be safe.
This commit is contained in:
Ms2ger 2015-06-27 18:09:14 +02:00
parent 8892f8175d
commit b37d9cc173
2 changed files with 13 additions and 22 deletions
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33
components/layout/flow_ref.rs
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@ -10,7 +10,7 @@
#![allow(unsafe_code)]
use flow::Flow;
use flow::{Flow, BaseFlow};
use flow;
use std::mem;
@ -133,11 +133,19 @@ impl Clone for FlowRef {
}
}
fn base<'a>(r: &WeakFlowRef) -> &'a BaseFlow {
let data = r.object.data;
debug_assert!(!data.is_null());
unsafe {
mem::transmute::<*mut (), &'a BaseFlow>(data)
}
}
impl WeakFlowRef {
/// Upgrades a WeakFlowRef to a FlowRef.
pub fn upgrade(&self) -> Option<FlowRef> {
unsafe {
let object = flow::base(&**self);
let object = base(self);
// We use a CAS loop to increment the strong count instead of a
// fetch_add because once the count hits 0 is must never be above
// 0.
@ -153,27 +161,10 @@ impl WeakFlowRef {
}
}
impl<'a> Deref for WeakFlowRef {
type Target = Flow + 'a;
fn deref(&self) -> &(Flow + 'a) {
unsafe {
mem::transmute_copy::<raw::TraitObject, &(Flow + 'a)>(&self.object)
}
}
}
impl DerefMut for WeakFlowRef {
fn deref_mut<'a>(&mut self) -> &mut (Flow + 'a) {
unsafe {
mem::transmute_copy::<raw::TraitObject, &mut (Flow + 'a)>(&self.object)
}
}
}
impl Clone for WeakFlowRef {
fn clone(&self) -> WeakFlowRef {
unsafe {
flow::base(&**self).weak_ref_count().fetch_add(1, Ordering::Relaxed);
base(self).weak_ref_count().fetch_add(1, Ordering::Relaxed);
}
WeakFlowRef { object: self. object }
}
@ -187,7 +178,7 @@ impl Drop for WeakFlowRef {
return
}
if flow::base(&**self).weak_ref_count().fetch_sub(1, Ordering::Release) == 1 {
if base(self).weak_ref_count().fetch_sub(1, Ordering::Release) == 1 {
atomic::fence(Ordering::Acquire);
// This dance deallocates the Box<Flow> without running its