Use a stack guard and a macro for RootedVec instead of return_address.

8 files changed, 70 insertions, 64 deletions

diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index ef50ebeb71d..12510e25d7d 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -1166,23 +1166,22 @@ class CGArgumentConverter(CGThing):
                 template, variadicConversion, declType, "slot")]
 
             arg = "arg%d" % index
-
             if argument.type.isGeckoInterface():
-                vec = "RootedVec::new()"
+                init = "rooted_vec!(let mut %s)" % arg
                 innerConverter.append(CGGeneric("%s.push(JS::from_ref(&*slot));" % arg))
             else:
-                vec = "vec![]"
+                init = "let mut %s = vec![]" % arg
                 innerConverter.append(CGGeneric("%s.push(slot);" % arg))
             inner = CGIndenter(CGList(innerConverter, "\n"), 8).define()
 
             self.converter = CGGeneric("""\
-let mut %(arg)s = %(vec)s;
+%(init)s;
 if %(argc)s > %(index)s {
     %(arg)s.reserve(%(argc)s as usize - %(index)s);
     for variadicArg in %(index)s..%(argc)s {
 %(inner)s
     }
-}""" % {'arg': arg, 'argc': argc, 'index': index, 'inner': inner, 'vec': vec})
+}""" % {'arg': arg, 'argc': argc, 'index': index, 'inner': inner, 'init': init})
 
     def define(self):
         return self.converter.define()
@@ -5603,7 +5602,6 @@ class CGBindingRoot(CGThing):
             'dom::bindings::proxyhandler::{get_expando_object, get_property_descriptor}',
             'dom::bindings::num::Finite',
             'dom::bindings::str::{ByteString, DOMString, USVString}',
-            'dom::bindings::trace::RootedVec',
             'dom::bindings::weakref::{DOM_WEAK_SLOT, WeakBox, WeakReferenceable}',
             'dom::browsingcontext::BrowsingContext',
             'mem::heap_size_of_raw_self_and_children',
diff --git a/components/script/dom/bindings/trace.rs b/components/script/dom/bindings/trace.rs
index 8816da8b099..aa9fa1b075d 100644
--- a/components/script/dom/bindings/trace.rs
+++ b/components/script/dom/bindings/trace.rs
@@ -77,8 +77,6 @@ use std::boxed::FnBox;
 use std::cell::{Cell, UnsafeCell};
 use std::collections::{BTreeMap, HashMap, HashSet};
 use std::hash::{BuildHasher, Hash};
-use std::intrinsics::return_address;
-use std::iter::{FromIterator, IntoIterator};
 use std::mem;
 use std::ops::{Deref, DerefMut};
 use std::rc::Rc;
@@ -466,7 +464,7 @@ impl RootedTraceableSet {
 ///
 /// If you have a valid Reflectable, use Root.
 /// If you have GC things like *mut JSObject or JSVal, use rooted!.
-/// If you have an arbitrary number of Reflectables to root, use RootedVec<JS<T>>
+/// If you have an arbitrary number of Reflectables to root, use rooted_vec!.
 /// If you know what you're doing, use this.
 #[derive(JSTraceable)]
 pub struct RootedTraceable<'a, T: 'a + JSTraceable> {
@@ -493,73 +491,73 @@ impl<'a, T: JSTraceable> Drop for RootedTraceable<'a, T> {
     }
 }
 
-/// A vector of items that are rooted for the lifetime of this struct.
+/// A vector of items to be rooted with `RootedVec`.
+/// Guaranteed to be empty when not rooted.
+/// Usage: `rooted_vec!(let mut v);` or if you have an
+/// iterator of `Root`s, `rooted_vec!(let v <- iterator);`.
 #[allow(unrooted_must_root)]
-#[no_move]
 #[derive(JSTraceable)]
 #[allow_unrooted_interior]
-pub struct RootedVec<T: JSTraceable> {
+pub struct RootableVec<T: JSTraceable> {
     v: Vec<T>,
 }
 
+impl<T: JSTraceable> RootableVec<T> {
+    /// Create a vector of items of type T that can be rooted later.
+    pub fn new_unrooted() -> RootableVec<T> {
+        RootableVec {
+            v: vec![],
+        }
+   }
+}
+
+/// A vector of items that are rooted for the lifetime 'a.
+#[allow_unrooted_interior]
+pub struct RootedVec<'a, T: 'a + JSTraceable> {
+    root: &'a mut RootableVec<T>,
+}
 
-impl<T: JSTraceable> RootedVec<T> {
+impl<'a, T: JSTraceable + Reflectable> RootedVec<'a, JS<T>> {
     /// Create a vector of items of type T that is rooted for
     /// the lifetime of this struct
-    pub fn new() -> RootedVec<T> {
-        let addr = unsafe { return_address() as *const libc::c_void };
-
-        unsafe { RootedVec::new_with_destination_address(addr) }
-    }
-
-    /// Create a vector of items of type T. This constructor is specific
-    /// for RootTraceableSet.
-    pub unsafe fn new_with_destination_address(addr: *const libc::c_void) -> RootedVec<T> {
-        RootedTraceableSet::add::<RootedVec<T>>(&*(addr as *const _));
-        RootedVec::<T> {
-            v: vec![],
+    pub fn new<I: Iterator<Item = Root<T>>>(root: &'a mut RootableVec<JS<T>>, iter: I)
+                                            -> RootedVec<'a, JS<T>> {
+        unsafe {
+            RootedTraceableSet::add(root);
+        }
+        root.v.extend(iter.map(|item| JS::from_ref(&*item)));
+        RootedVec {
+            root: root,
         }
     }
 }
 
-impl<T: JSTraceable + Reflectable> RootedVec<JS<T>> {
+impl<'a, T: JSTraceable + Reflectable> RootedVec<'a, JS<T>> {
     /// Obtain a safe slice of references that can't outlive that RootedVec.
     pub fn r(&self) -> &[&T] {
-        unsafe { mem::transmute(&self.v[..]) }
+        unsafe { mem::transmute(&self[..]) }
     }
 }
 
-impl<T: JSTraceable> Drop for RootedVec<T> {
+impl<'a, T: JSTraceable> Drop for RootedVec<'a, T> {
     fn drop(&mut self) {
+        self.clear();
         unsafe {
-            RootedTraceableSet::remove(self);
+            RootedTraceableSet::remove(self.root);
         }
     }
 }
 
-impl<T: JSTraceable> Deref for RootedVec<T> {
+impl<'a, T: JSTraceable> Deref for RootedVec<'a, T> {
     type Target = Vec<T>;
     fn deref(&self) -> &Vec<T> {
-        &self.v
+        &self.root.v
     }
 }
 
-impl<T: JSTraceable> DerefMut for RootedVec<T> {
+impl<'a, T: JSTraceable> DerefMut for RootedVec<'a, T> {
     fn deref_mut(&mut self) -> &mut Vec<T> {
-        &mut self.v
-    }
-}
-
-impl<A: JSTraceable + Reflectable> FromIterator<Root<A>> for RootedVec<JS<A>> {
-    #[allow(moved_no_move)]
-    fn from_iter<T>(iterable: T) -> RootedVec<JS<A>>
-        where T: IntoIterator<Item = Root<A>>
-    {
-        let mut vec = unsafe {
-            RootedVec::new_with_destination_address(return_address() as *const libc::c_void)
-        };
-        vec.extend(iterable.into_iter().map(|item| JS::from_ref(&*item)));
-        vec
+        &mut self.root.v
     }
 }
 
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 23c50075068..7b3697e6a1b 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -28,7 +28,6 @@ use dom::bindings::num::Finite;
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
-use dom::bindings::trace::RootedVec;
 use dom::bindings::xmlname::XMLName::InvalidXMLName;
 use dom::bindings::xmlname::{validate_and_extract, namespace_from_domstring, xml_name_type};
 use dom::browsingcontext::BrowsingContext;
@@ -115,6 +114,7 @@ use std::cell::{Cell, Ref, RefMut};
 use std::collections::HashMap;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::default::Default;
+use std::iter::once;
 use std::mem;
 use std::ptr;
 use std::rc::Rc;
@@ -1009,18 +1009,15 @@ impl Document {
             }
         }
 
-        let mut touches = RootedVec::new();
+        rooted_vec!(let mut touches);
         touches.extend(self.active_touch_points.borrow().iter().cloned());
-
-        let mut changed_touches = RootedVec::new();
-        changed_touches.push(JS::from_ref(&*touch));
-
-        let mut target_touches = RootedVec::new();
+        rooted_vec!(let mut target_touches);
         target_touches.extend(self.active_touch_points
                                   .borrow()
                                   .iter()
                                   .filter(|t| t.Target() == target)
                                   .cloned());
+        rooted_vec!(let changed_touches <- once(touch));
 
         let event = TouchEvent::new(window,
                                     DOMString::from(event_name),
diff --git a/components/script/dom/eventdispatcher.rs b/components/script/dom/eventdispatcher.rs
index cef67d2d18c..7509df2ef13 100644
--- a/components/script/dom/eventdispatcher.rs
+++ b/components/script/dom/eventdispatcher.rs
@@ -9,7 +9,6 @@ use dom::bindings::global::GlobalRoot;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, Root, RootedReference};
 use dom::bindings::reflector::Reflectable;
-use dom::bindings::trace::RootedVec;
 use dom::document::Document;
 use dom::event::{Event, EventPhase};
 use dom::eventtarget::{CompiledEventListener, EventTarget, ListenerPhase};
@@ -128,12 +127,12 @@ pub fn dispatch_event(target: &EventTarget,
 
     // Step 3. The "invoke" algorithm is only used on `target` separately,
     // so we don't put it in the path.
-    let mut event_path: RootedVec<JS<EventTarget>> = RootedVec::new();
+    rooted_vec!(let mut event_path);
 
     // Step 4.
     if let Some(target_node) = target.downcast::<Node>() {
         for ancestor in target_node.ancestors() {
-            event_path.push(JS::from_ref(ancestor.upcast()));
+            event_path.push(JS::from_ref(ancestor.upcast::<EventTarget>()));
         }
         let top_most_ancestor_or_target =
             Root::from_ref(event_path.r().last().cloned().unwrap_or(target));
diff --git a/components/script/dom/macros.rs b/components/script/dom/macros.rs
index 3ad9713fb70..58af2b28ac6 100644
--- a/components/script/dom/macros.rs
+++ b/components/script/dom/macros.rs
@@ -503,3 +503,18 @@ macro_rules! document_and_element_event_handlers(
         event_handler!(paste, GetOnpaste, SetOnpaste);
     )
 );
+
+#[macro_export]
+macro_rules! rooted_vec {
+    (let mut $name:ident) => {
+        rooted_vec!(let mut $name <- ::std::iter::empty())
+    };
+    (let $name:ident <- $iter:expr) => {
+        let mut __root = $crate::dom::bindings::trace::RootableVec::new_unrooted();
+        let $name = $crate::dom::bindings::trace::RootedVec::new(&mut __root, $iter);
+    };
+    (let mut $name:ident <- $iter:expr) => {
+        let mut __root = $crate::dom::bindings::trace::RootableVec::new_unrooted();
+        let mut $name = $crate::dom::bindings::trace::RootedVec::new(&mut __root, $iter);
+    }
+}
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index ec370dff293..7c844cab02e 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -28,7 +28,6 @@ use dom::bindings::js::RootedReference;
 use dom::bindings::js::{JS, LayoutJS, MutNullableHeap};
 use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
-use dom::bindings::trace::RootedVec;
 use dom::bindings::xmlname::namespace_from_domstring;
 use dom::characterdata::{CharacterData, LayoutCharacterDataHelpers};
 use dom::document::{Document, DocumentSource, IsHTMLDocument};
@@ -1559,7 +1558,7 @@ impl Node {
                 parent.ranges.increase_above(parent, index, count);
             }
         }
-        let mut new_nodes = RootedVec::new();
+        rooted_vec!(let mut new_nodes);
         let new_nodes = if let NodeTypeId::DocumentFragment = node.type_id() {
             // Step 3.
             new_nodes.extend(node.children().map(|kid| JS::from_ref(&*kid)));
@@ -1603,9 +1602,9 @@ impl Node {
             Node::adopt(node, &*parent.owner_doc());
         }
         // Step 2.
-        let removed_nodes = parent.children().collect::<RootedVec<_>>();
+        rooted_vec!(let removed_nodes <- parent.children());
         // Step 3.
-        let mut added_nodes = RootedVec::new();
+        rooted_vec!(let mut added_nodes);
         let added_nodes = if let Some(node) = node.as_ref() {
             if let NodeTypeId::DocumentFragment = node.type_id() {
                 added_nodes.extend(node.children().map(|child| JS::from_ref(&*child)));
@@ -2149,7 +2148,7 @@ impl NodeMethods for Node {
         };
 
         // Step 12.
-        let mut nodes = RootedVec::new();
+        rooted_vec!(let mut nodes);
         let nodes = if node.type_id() == NodeTypeId::DocumentFragment {
             nodes.extend(node.children().map(|node| JS::from_ref(&*node)));
             nodes.r()
diff --git a/components/script/dom/range.rs b/components/script/dom/range.rs
index bde5515238b..b8cb72c4dc4 100644
--- a/components/script/dom/range.rs
+++ b/components/script/dom/range.rs
@@ -17,7 +17,7 @@ use dom::bindings::inheritance::{CharacterDataTypeId, NodeTypeId};
 use dom::bindings::js::{JS, MutHeap, Root, RootedReference};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
-use dom::bindings::trace::{JSTraceable, RootedVec};
+use dom::bindings::trace::JSTraceable;
 use dom::bindings::weakref::{WeakRef, WeakRefVec};
 use dom::characterdata::CharacterData;
 use dom::document::Document;
@@ -762,7 +762,7 @@ impl RangeMethods for Range {
         }
 
         // Step 4.
-        let mut contained_children: RootedVec<JS<Node>> = RootedVec::new();
+        rooted_vec!(let mut contained_children);
         let ancestor = self.CommonAncestorContainer();
 
         let mut iter = start_node.following_nodes(ancestor.r());
diff --git a/components/script/lib.rs b/components/script/lib.rs
index ebc5b4a1686..4f66095e1ff 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -6,7 +6,7 @@
 #![feature(borrow_state)]
 #![feature(box_syntax)]
 #![feature(const_fn)]
-#![feature(core_intrinsics)]
+#![cfg_attr(debug_assertions, feature(core_intrinsics))]
 #![feature(custom_attribute)]
 #![feature(custom_derive)]
 #![feature(fnbox)]