Implement RootedVec<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 +264,136 @@ 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 ()>>
+}
+
+/// 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: &mut 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 *mut _ 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: *const HashSet<*const RootedVec<T>>) {
+            unsafe {
+                for collection in (*collections).iter() {
+                    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(tracer,
+                              &self.set[CollectionType::JSVals as uint] as *const _ as *const HashSet<*const RootedVec<JSVal>>);
+        trace_collection_type(tracer,
+                              &self.set[CollectionType::JSObjects as uint] as *const _ as *const HashSet<*const RootedVec<*mut JSObject>>);
+    }
+}
+
+
+/// 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> {
+        let ret = RootedVec::<T> { v: vec!() };
+        unsafe {
+            RootedCollectionSet::add::<T>(&*(return_address() as *const _));
+        }
+        ret
+    }
+
+}
+
+#[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/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};
@@ -380,12 +381,17 @@ impl ScriptTask {
 
     pub fn new_rt_and_cx() -> (js::rust::rt, Rc<Cx>) {
         LiveDOMReferences::initialize();
+
         let js_runtime = js::rust::rt();
         assert!({
             let ptr: *mut JSRuntime = (*js_runtime).ptr;
             !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