Implement a replacement for Vec<Root<T>>

components/script/dom/bindings/trace.rs

@@ -54,11 +54,13 @@ use msg::constellation_msg::ConstellationChan;
 use util::smallvec::{SmallVec1, SmallVec};
 use util::str::{LengthOrPercentageOrAuto};
 use std::cell::{Cell, RefCell};
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use std::collections::hash_state::HashState;
 use std::ffi::CString;
 use std::hash::{Hash, Hasher};
+use std::intrinsics::return_address;
 use std::old_io::timer::Timer;
+use std::ops::{Deref, DerefMut};
 use std::rc::Rc;
 use std::sync::mpsc::{Receiver, Sender};
 use string_cache::{Atom, Namespace};
@@ -262,3 +264,134 @@ impl JSTraceable for Box<LayoutRPC+'static> {
         // Do nothing
     }
 }
+
+/// Holds a set of vectors that need to be rooted
+pub struct RootedCollectionSet {
+    set: Vec<HashSet<*const RootedVec<()>>>
+}
+
+/// TLV Holds a set of vectors that need to be rooted
+thread_local!(pub static ROOTED_COLLECTIONS: Rc<RefCell<RootedCollectionSet>> =
+              Rc::new(RefCell::new(RootedCollectionSet::new())));
+
+enum CollectionType {
+    DOMObjects,
+    JSVals,
+    JSObjects,
+}
+
+
+impl RootedCollectionSet {
+    fn new() -> RootedCollectionSet {
+        RootedCollectionSet {
+            set: vec!(HashSet::new(), HashSet::new(), HashSet::new())
+        }
+    }
+
+    fn remove<T: VecRootableType>(collection: &RootedVec<T>) {
+        ROOTED_COLLECTIONS.with(|ref collections| {
+            let type_ = VecRootableType::tag(None::<T>);
+            let mut collections = collections.borrow_mut();
+            assert!(collections.set[type_ as uint].remove(&(collection as *const _ as *const _)));
+        });
+    }
+
+    fn add<T: VecRootableType>(collection: &RootedVec<T>) {
+        ROOTED_COLLECTIONS.with(|ref collections| {
+            let type_ = VecRootableType::tag(None::<T>);
+            let mut collections = collections.borrow_mut();
+            collections.set[type_ as uint].insert(collection as *const _ as *const _);
+        })
+    }
+
+    unsafe fn trace(&self, tracer: *mut JSTracer) {
+        fn trace_collection_type<T: JSTraceable>(tracer: *mut JSTracer,
+                                                 collections: &HashSet<*const RootedVec<()>>) {
+            for collection in collections.iter() {
+                let collection = &(*collection as *const RootedVec<T>);
+                unsafe {
+                    let _ = (**collection).trace(tracer);
+                }
+            }
+        }
+
+        let dom_collections = &self.set[CollectionType::DOMObjects as uint] as *const _ as *const HashSet<*const RootedVec<*const Reflector>>;
+        for dom_collection in (*dom_collections).iter() {
+            for reflector in (**dom_collection).iter() {
+                trace_reflector(tracer, "", &**reflector);
+            }
+        }
+
+        trace_collection_type::<JSVal>(tracer, &self.set[CollectionType::JSVals as uint]);
+        trace_collection_type::<*mut JSObject>(tracer, &self.set[CollectionType::JSObjects as uint]);
+    }
+}
+
+
+/// Trait implemented by all types that can be used with RootedVec
+trait VecRootableType {
+    /// Return the type tag used to determine how to trace RootedVec
+    fn tag(_a: Option<Self>) -> CollectionType;
+}
+
+impl<T: Reflectable> VecRootableType for JS<T> {
+    fn tag(_a: Option<JS<T>>) -> CollectionType { CollectionType::DOMObjects }
+}
+
+impl VecRootableType for JSVal {
+    fn tag(_a: Option<JSVal>) -> CollectionType { CollectionType::JSVals }
+}
+
+impl VecRootableType for *mut JSObject {
+    fn tag(_a: Option<*mut JSObject>) -> CollectionType { CollectionType::JSObjects }
+}
+
+/// A vector of items that are rooted for the lifetime
+/// of this struct
+#[allow(unrooted_must_root)]
+#[jstraceable]
+pub struct RootedVec<T> {
+    v: Vec<T>
+}
+
+
+impl<T: VecRootableType> RootedVec<T> {
+    /// Create a vector of items of type T that is rooted for
+    /// the lifetime of this struct
+    pub fn new() -> RootedVec<T> {
+        unsafe {
+            RootedCollectionSet::add::<T>(&*(return_address() as *const _));
+        }
+        RootedVec::<T> { v: vec!() }
+    }
+
+}
+
+#[unsafe_destructor]
+impl<T: VecRootableType> Drop for RootedVec<T> {
+    fn drop(&mut self) {
+        RootedCollectionSet::remove(self);
+    }
+}
+
+impl<T> Deref for RootedVec<T> {
+    type Target = Vec<T>;
+    fn deref(&self) -> &Vec<T> {
+        &self.v
+    }
+}
+
+impl<T> DerefMut for RootedVec<T> {
+    fn deref_mut(&mut self) -> &mut Vec<T> {
+        &mut self.v
+    }
+}
+
+
+/// SM Callback that traces the rooted collections
+pub unsafe extern fn trace_collections(tracer: *mut JSTracer, _data: *mut libc::c_void) {
+    ROOTED_COLLECTIONS.with(|ref collections| {
+        let collections = collections.borrow();
+        collections.trace(tracer);
+    });
+}

components/script/dom/domrectlist.rs

@@ -6,6 +6,7 @@ use dom::bindings::codegen::Bindings::DOMRectListBinding;
 use dom::bindings::codegen::Bindings::DOMRectListBinding::DOMRectListMethods;
 use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, JSRef, Temporary};
+use dom::bindings::trace::RootedVec;
 use dom::bindings::utils::{Reflector, reflect_dom_object};
 use dom::domrect::DOMRect;
 use dom::window::Window;
@@ -19,17 +20,16 @@ pub struct DOMRectList {
 
 impl DOMRectList {
     fn new_inherited(window: JSRef<Window>,
-                         rects: Vec<JSRef<DOMRect>>) -> DOMRectList {
-        let rects = rects.iter().map(|rect| JS::from_rooted(*rect)).collect();
+                     rects: &RootedVec<JS<DOMRect>>) -> DOMRectList {
         DOMRectList {
             reflector_: Reflector::new(),
-            rects: rects,
+            rects: (**rects).clone(),
             window: JS::from_rooted(window),
         }
     }
 
     pub fn new(window: JSRef<Window>,
-               rects: Vec<JSRef<DOMRect>>) -> Temporary<DOMRectList> {
+               rects: &RootedVec<JS<DOMRect>>) -> Temporary<DOMRectList> {
         reflect_dom_object(box DOMRectList::new_inherited(window, rects),
                            GlobalRef::Window(window), DOMRectListBinding::Wrap)
     }

components/script/dom/element.rs

@@ -25,7 +25,8 @@ use dom::bindings::codegen::InheritTypes::HTMLAnchorElementCast;
 use dom::bindings::error::{ErrorResult, Fallible};
 use dom::bindings::error::Error::{NamespaceError, InvalidCharacter, Syntax};
 use dom::bindings::js::{MutNullableJS, JS, JSRef, LayoutJS, Temporary, TemporaryPushable};
-use dom::bindings::js::{OptionalRootable, Root};
+use dom::bindings::js::OptionalRootable;
+use dom::bindings::trace::RootedVec;
 use dom::bindings::utils::xml_name_type;
 use dom::bindings::utils::XMLName::{QName, Name, InvalidXMLName};
 use dom::create::create_element;
@@ -1061,17 +1062,18 @@ impl<'a> ElementMethods for JSRef<'a, Element> {
     fn GetClientRects(self) -> Temporary<DOMRectList> {
         let win = window_from_node(self).root();
         let node: JSRef<Node> = NodeCast::from_ref(self);
-        let rects = node.get_content_boxes();
-        let rects: Vec<Root<DOMRect>> = rects.iter().map(|r| {
-            DOMRect::new(
-                win.r(),
-                r.origin.y,
-                r.origin.y + r.size.height,
-                r.origin.x,
-                r.origin.x + r.size.width).root()
-        }).collect();
-
-        DOMRectList::new(win.r(), rects.iter().map(|rect| rect.r()).collect())
+        let raw_rects = node.get_content_boxes();
+        let mut rects = RootedVec::new();
+        for rect in raw_rects.iter() {
+            let rect = DOMRect::new(win.r(),
+                                    rect.origin.y,
+                                    rect.origin.y + rect.size.height,
+                                    rect.origin.x,
+                                    rect.origin.x + rect.size.width);
+            rects.push(JS::from_rooted(rect));
+        }
+
+        DOMRectList::new(win.r(), &rects)
     }
 
     // http://dev.w3.org/csswg/cssom-view/#dom-element-getboundingclientrect

components/script/dom/eventdispatcher.rs

@@ -4,8 +4,9 @@
 
 use dom::bindings::callback::ExceptionHandling::Report;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
-use dom::bindings::codegen::InheritTypes::{EventTargetCast, NodeCast, NodeDerived};
-use dom::bindings::js::{JS, JSRef, OptionalRootable, Root};
+use dom::bindings::codegen::InheritTypes::{EventTargetCast, NodeCast};
+use dom::bindings::js::{JS, JSRef, OptionalRootable};
+use dom::bindings::trace::RootedVec;
 use dom::eventtarget::{EventTarget, ListenerPhase};
 use dom::event::{Event, EventPhase};
 use dom::node::{Node, NodeHelpers};
@@ -27,22 +28,21 @@ pub fn dispatch_event<'a, 'b>(target: JSRef<'a, EventTarget>,
     let type_ = event.Type();
 
     //TODO: no chain if not participating in a tree
-    let mut chain: Vec<Root<EventTarget>> = if target.is_node() {
-        let target_node: JSRef<Node> = NodeCast::to_ref(target).unwrap();
-        target_node.ancestors().map(|ancestor| {
+    let mut chain: RootedVec<JS<EventTarget>> = RootedVec::new();
+    if let Some(target_node) = NodeCast::to_ref(target) {
+        for ancestor in target_node.ancestors() {
             let ancestor_target: JSRef<EventTarget> = EventTargetCast::from_ref(ancestor);
-            JS::from_rooted(ancestor_target).root()
-        }).collect()
-    } else {
-        vec!()
-    };
+            chain.push(JS::from_rooted(ancestor_target))
+        }
+    }
 
     event.set_phase(EventPhase::Capturing);
 
     //FIXME: The "callback this value" should be currentTarget
 
     /* capturing */
     for cur_target in chain.as_slice().iter().rev() {
+        let cur_target = cur_target.root();
         let stopped = match cur_target.r().get_listeners_for(type_.as_slice(), ListenerPhase::Capturing) {
             Some(listeners) => {
                 event.set_current_target(cur_target.r());
@@ -88,6 +88,7 @@ pub fn dispatch_event<'a, 'b>(target: JSRef<'a, EventTarget>,
         event.set_phase(EventPhase::Bubbling);
 
         for cur_target in chain.iter() {
+            let cur_target = cur_target.root();
             let stopped = match cur_target.r().get_listeners_for(type_.as_slice(), ListenerPhase::Bubbling) {
                 Some(listeners) => {
                     event.set_current_target(cur_target.r());

components/script/script_task.rs

@@ -16,7 +16,7 @@ use dom::bindings::js::{JS, JSRef, Temporary, OptionalRootable, RootedReference}
 use dom::bindings::js::{RootCollection, RootCollectionPtr};
 use dom::bindings::refcounted::{LiveDOMReferences, Trusted, TrustedReference};
 use dom::bindings::structuredclone::StructuredCloneData;
-use dom::bindings::trace::JSTraceable;
+use dom::bindings::trace::{JSTraceable, trace_collections};
 use dom::bindings::utils::{wrap_for_same_compartment, pre_wrap};
 use dom::document::{Document, IsHTMLDocument, DocumentHelpers, DocumentProgressHandler, DocumentProgressTask, DocumentSource};
 use dom::element::{Element, AttributeHandlers};
@@ -63,7 +63,7 @@ use geom::point::Point2D;
 use hyper::header::{LastModified, Headers};
 use js::jsapi::{JS_SetWrapObjectCallbacks, JS_SetGCZeal, JS_DEFAULT_ZEAL_FREQ, JS_GC};
 use js::jsapi::{JSContext, JSRuntime, JSObject};
-use js::jsapi::{JS_SetGCParameter, JSGC_MAX_BYTES};
+use js::jsapi::{JS_SetExtraGCRootsTracer, JS_SetGCParameter, JSGC_MAX_BYTES};
 use js::jsapi::{JS_SetGCCallback, JSGCStatus, JSGC_BEGIN, JSGC_END};
 use js::rust::{Cx, RtUtils};
 use js;
@@ -75,6 +75,7 @@ use std::borrow::ToOwned;
 use std::cell::Cell;
 use std::mem::replace;
 use std::num::ToPrimitive;
+use std::ptr;
 use std::rc::Rc;
 use std::result::Result;
 use std::sync::mpsc::{channel, Sender, Receiver, Select};
@@ -386,6 +387,10 @@ impl ScriptTask {
             !ptr.is_null()
         });
 
+
+        unsafe {
+            JS_SetExtraGCRootsTracer((*js_runtime).ptr, Some(trace_collections), ptr::null_mut());
+        }
         // Unconstrain the runtime's threshold on nominal heap size, to avoid
         // triggering GC too often if operating continuously near an arbitrary
         // finite threshold. This leaves the maximum-JS_malloc-bytes threshold