Auto merge of #18641 - servo:ROOT-ALL-THE-THINGS, r=SimonSapin

Improve DomRoot<T>

<!-- Reviewable:start -->
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/18641)
<!-- Reviewable:end -->
This commit is contained in:
bors-servo 2017-09-26 14:25:20 -05:00 committed by GitHub
commit 0160aaeeea
3 changed files with 11 additions and 8 deletions

View file

@ -22,7 +22,6 @@
//! its hash table during the next GC. During GC, the entries of the hash table are counted //! its hash table during the next GC. During GC, the entries of the hash table are counted
//! as JS roots. //! as JS roots.
use core::nonzero::NonZero;
use dom::bindings::conversions::ToJSValConvertible; use dom::bindings::conversions::ToJSValConvertible;
use dom::bindings::error::Error; use dom::bindings::error::Error;
use dom::bindings::reflector::{DomObject, Reflector}; use dom::bindings::reflector::{DomObject, Reflector};
@ -185,7 +184,7 @@ impl<T: DomObject> Trusted<T> {
self.owner_thread == (&*live_references) as *const _ as *const libc::c_void self.owner_thread == (&*live_references) as *const _ as *const libc::c_void
})); }));
unsafe { unsafe {
DomRoot::new(NonZero::new_unchecked(self.refcount.0 as *const T)) DomRoot::from_ref(&*(self.refcount.0 as *const T))
} }
} }
} }

View file

@ -558,10 +558,11 @@ pub unsafe fn trace_roots(tracer: *mut JSTracer) {
/// are additive, so this object's destruction will not invalidate other roots /// are additive, so this object's destruction will not invalidate other roots
/// for the same JS value. `Root`s cannot outlive the associated /// for the same JS value. `Root`s cannot outlive the associated
/// `RootCollection` object. /// `RootCollection` object.
#[allow(unrooted_must_root)]
#[allow_unrooted_interior] #[allow_unrooted_interior]
pub struct DomRoot<T: DomObject> { pub struct DomRoot<T: DomObject> {
/// Reference to rooted value that must not outlive this container /// Reference to rooted value that must not outlive this container
ptr: NonZero<*const T>, ptr: Dom<T>,
/// List that ensures correct dynamic root ordering /// List that ensures correct dynamic root ordering
root_list: *const RootCollection, root_list: *const RootCollection,
} }
@ -591,11 +592,12 @@ impl<T: DomObject> DomRoot<T> {
/// Create a new stack-bounded root for the provided JS-owned value. /// Create a new stack-bounded root for the provided JS-owned value.
/// It cannot outlive its associated `RootCollection`, and it gives /// It cannot outlive its associated `RootCollection`, and it gives
/// out references which cannot outlive this new `Root`. /// out references which cannot outlive this new `Root`.
pub fn new(unrooted: NonZero<*const T>) -> DomRoot<T> { #[allow(unrooted_must_root)]
unsafe fn new(unrooted: Dom<T>) -> DomRoot<T> {
debug_assert!(thread_state::get().is_script()); debug_assert!(thread_state::get().is_script());
STACK_ROOTS.with(|ref collection| { STACK_ROOTS.with(|ref collection| {
let RootCollectionPtr(collection) = collection.get().unwrap(); let RootCollectionPtr(collection) = collection.get().unwrap();
unsafe { (*collection).root(&*(*unrooted.get()).reflector()) } (*collection).root(unrooted.reflector());
DomRoot { DomRoot {
ptr: unrooted, ptr: unrooted,
root_list: collection, root_list: collection,
@ -605,7 +607,7 @@ impl<T: DomObject> DomRoot<T> {
/// Generate a new root from a reference /// Generate a new root from a reference
pub fn from_ref(unrooted: &T) -> DomRoot<T> { pub fn from_ref(unrooted: &T) -> DomRoot<T> {
DomRoot::new(unsafe { NonZero::new_unchecked(unrooted) }) unsafe { DomRoot::new(Dom::from_ref(unrooted)) }
} }
} }
@ -620,7 +622,7 @@ impl<T: DomObject> Deref for DomRoot<T> {
type Target = T; type Target = T;
fn deref(&self) -> &T { fn deref(&self) -> &T {
debug_assert!(thread_state::get().is_script()); debug_assert!(thread_state::get().is_script());
unsafe { &*self.ptr.get() } &self.ptr
} }
} }

View file

@ -86,7 +86,9 @@ impl<T: WeakReferenceable> WeakRef<T> {
/// DomRoot a weak reference. Returns `None` if the object was already collected. /// DomRoot a weak reference. Returns `None` if the object was already collected.
pub fn root(&self) -> Option<DomRoot<T>> { pub fn root(&self) -> Option<DomRoot<T>> {
unsafe { &*self.ptr.get() }.value.get().map(DomRoot::new) unsafe { &*self.ptr.get() }.value.get().map(|ptr| unsafe {
DomRoot::from_ref(&*ptr.get())
})
} }
/// Return whether the weakly-referenced object is still alive. /// Return whether the weakly-referenced object is still alive.