Use parking_lot::RwLock instead of DOMRefCell for PropertyDeclaration…

…Block

components/script/Cargo.toml

@@ -51,6 +51,7 @@ net_traits = {path = "../net_traits"}
 num-traits = "0.1.32"
 offscreen_gl_context = "0.4"
 open = "1.1.1"
+parking_lot = "0.3"
 phf = "0.7.16"
 phf_macros = "0.7.16"
 plugins = {path = "../plugins"}

components/script/dom/cssstyledeclaration.rs

@@ -3,7 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use cssparser::ToCss;
-use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::CSSStyleDeclarationBinding::{self, CSSStyleDeclarationMethods};
 use dom::bindings::error::{Error, ErrorResult, Fallible};
 use dom::bindings::global::GlobalRef;
@@ -14,6 +13,7 @@ use dom::bindings::str::DOMString;
 use dom::element::Element;
 use dom::node::{Node, NodeDamage, window_from_node};
 use dom::window::Window;
+use parking_lot::RwLock;
 use std::ascii::AsciiExt;
 use std::sync::Arc;
 use string_cache::Atom;
@@ -92,7 +92,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
     fn Length(&self) -> u32 {
         let elem = self.owner.upcast::<Element>();
         let len = match *elem.style_attribute().borrow() {
-            Some(ref declarations) => declarations.borrow().declarations.len(),
+            Some(ref declarations) => declarations.read().declarations.len(),
             None => 0,
         };
         len as u32
@@ -120,7 +120,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
         if let Some(shorthand) = Shorthand::from_name(&property) {
             let style_attribute = owner.style_attribute().borrow();
             let style_attribute = if let Some(ref style_attribute) = *style_attribute {
-                style_attribute.borrow()
+                style_attribute.read()
             } else {
                 // shorthand.longhands() is never empty, so with no style attribute
                 // step 2.2.2 would do this:
@@ -331,7 +331,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
         let elem = self.owner.upcast::<Element>();
         let style_attribute = elem.style_attribute().borrow();
         style_attribute.as_ref().and_then(|declarations| {
-            declarations.borrow().declarations.get(index).map(|entry| {
+            declarations.read().declarations.get(index).map(|entry| {
                 let (ref declaration, importance) = *entry;
                 let mut css = declaration.to_css_string();
                 if importance.important() {
@@ -348,7 +348,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
         let style_attribute = elem.style_attribute().borrow();
 
         if let Some(declarations) = style_attribute.as_ref() {
-            DOMString::from(declarations.borrow().to_css_string())
+            DOMString::from(declarations.read().to_css_string())
         } else {
             DOMString::new()
         }
@@ -370,7 +370,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
         *element.style_attribute().borrow_mut() = if decl_block.declarations.is_empty() {
             None // Step 2
         } else {
-            Some(Arc::new(DOMRefCell::new(decl_block)))
+            Some(Arc::new(RwLock::new(decl_block)))
         };
         element.sync_property_with_attrs_style();
         let node = element.upcast::<Node>();

components/script/dom/element.rs

@@ -70,6 +70,7 @@ use html5ever::serialize::SerializeOpts;
 use html5ever::serialize::TraversalScope;
 use html5ever::serialize::TraversalScope::{ChildrenOnly, IncludeNode};
 use html5ever::tree_builder::{LimitedQuirks, NoQuirks, Quirks};
+use parking_lot::RwLock;
 use selectors::matching::{ElementFlags, MatchingReason, matches};
 use selectors::matching::{HAS_EDGE_CHILD_SELECTOR, HAS_SLOW_SELECTOR, HAS_SLOW_SELECTOR_LATER_SIBLINGS};
 use selectors::parser::{AttrSelector, NamespaceConstraint, parse_author_origin_selector_list_from_str};
@@ -110,7 +111,7 @@ pub struct Element {
     attrs: DOMRefCell<Vec<JS<Attr>>>,
     id_attribute: DOMRefCell<Option<Atom>>,
     #[ignore_heap_size_of = "Arc"]
-    style_attribute: DOMRefCell<Option<Arc<DOMRefCell<PropertyDeclarationBlock>>>>,
+    style_attribute: DOMRefCell<Option<Arc<RwLock<PropertyDeclarationBlock>>>>,
     attr_list: MutNullableHeap<JS<NamedNodeMap>>,
     class_list: MutNullableHeap<JS<DOMTokenList>>,
     state: Cell<ElementState>,
@@ -298,7 +299,7 @@ pub trait LayoutElementHelpers {
     #[allow(unsafe_code)]
     unsafe fn html_element_in_html_document_for_layout(&self) -> bool;
     fn id_attribute(&self) -> *const Option<Atom>;
-    fn style_attribute(&self) -> *const Option<Arc<DOMRefCell<PropertyDeclarationBlock>>>;
+    fn style_attribute(&self) -> *const Option<Arc<RwLock<PropertyDeclarationBlock>>>;
     fn local_name(&self) -> &Atom;
     fn namespace(&self) -> &Namespace;
     fn get_checked_state_for_layout(&self) -> bool;
@@ -330,7 +331,7 @@ impl LayoutElementHelpers for LayoutJS<Element> {
         #[inline]
         fn from_declaration(rule: PropertyDeclaration) -> ApplicableDeclarationBlock {
             ApplicableDeclarationBlock::from_declarations(
-                Arc::new(DOMRefCell::new(PropertyDeclarationBlock {
+                Arc::new(RwLock::new(PropertyDeclarationBlock {
                     declarations: vec![(rule, Importance::Normal)],
                     important_count: 0,
                 })),
@@ -619,7 +620,7 @@ impl LayoutElementHelpers for LayoutJS<Element> {
     }
 
     #[allow(unsafe_code)]
-    fn style_attribute(&self) -> *const Option<Arc<DOMRefCell<PropertyDeclarationBlock>>> {
+    fn style_attribute(&self) -> *const Option<Arc<RwLock<PropertyDeclarationBlock>>> {
         unsafe {
             (*self.unsafe_get()).style_attribute.borrow_for_layout()
         }
@@ -708,7 +709,7 @@ impl Element {
         self.attrs.borrow()
     }
 
-    pub fn style_attribute(&self) -> &DOMRefCell<Option<Arc<DOMRefCell<PropertyDeclarationBlock>>>> {
+    pub fn style_attribute(&self) -> &DOMRefCell<Option<Arc<RwLock<PropertyDeclarationBlock>>>> {
         &self.style_attribute
     }
 
@@ -738,7 +739,7 @@ impl Element {
     // therefore, it should not trigger subsequent mutation events
     pub fn sync_property_with_attrs_style(&self) {
         let style_str = if let &Some(ref declarations) = &*self.style_attribute().borrow() {
-            declarations.borrow().to_css_string()
+            declarations.read().to_css_string()
         } else {
             String::new()
         };
@@ -770,15 +771,15 @@ impl Element {
             let mut inline_declarations = element.style_attribute.borrow_mut();
             if let &mut Some(ref mut declarations) = &mut *inline_declarations {
                 let mut importance = None;
-                let index = declarations.borrow().declarations.iter().position(|&(ref decl, i)| {
+                let index = declarations.read().declarations.iter().position(|&(ref decl, i)| {
                     let matching = decl.matches(property);
                     if matching {
                         importance = Some(i)
                     }
                     matching
                 });
                 if let Some(index) = index {
-                    let mut declarations = Arc::make_mut(declarations).borrow_mut();
+                    let mut declarations = declarations.write();
                     declarations.declarations.remove(index);
                     if importance.unwrap().important() {
                         declarations.important_count -= 1;
@@ -799,9 +800,7 @@ impl Element {
             let mut inline_declarations = element.style_attribute().borrow_mut();
             if let &mut Some(ref mut declaration_block) = &mut *inline_declarations {
                 {
-                    // Usually, the reference count will be 1 here. But transitions could make it greater
-                    // than that.
-                    let mut declaration_block = Arc::make_mut(declaration_block).borrow_mut();
+                    let mut declaration_block = declaration_block.write();
                     let declaration_block = &mut *declaration_block;
                     let existing_declarations = &mut declaration_block.declarations;
 
@@ -836,7 +835,7 @@ impl Element {
                 0
             };
 
-            *inline_declarations = Some(Arc::new(DOMRefCell::new(PropertyDeclarationBlock {
+            *inline_declarations = Some(Arc::new(RwLock::new(PropertyDeclarationBlock {
                 declarations: declarations.into_iter().map(|d| (d, importance)).collect(),
                 important_count: important_count,
             })));
@@ -852,9 +851,7 @@ impl Element {
         {
             let mut inline_declarations = self.style_attribute().borrow_mut();
             if let &mut Some(ref mut block) = &mut *inline_declarations {
-                // Usually, the reference counts of `from` and `to` will be 1 here. But transitions
-                // could make them greater than that.
-                let mut block = Arc::make_mut(block).borrow_mut();
+                let mut block = block.write();
                 let block = &mut *block;
                 let declarations = &mut block.declarations;
                 for &mut (ref declaration, ref mut importance) in declarations {
@@ -881,7 +878,7 @@ impl Element {
     where F: FnOnce(Option<&(PropertyDeclaration, Importance)>) -> R {
         let style_attr = self.style_attribute.borrow();
         if let Some(ref block) = *style_attr {
-            let block = block.borrow();
+            let block = block.read();
             f(block.get(property))
         } else {
             f(None)
@@ -2131,7 +2128,7 @@ impl VirtualMethods for Element {
                 *self.style_attribute.borrow_mut() =
                     mutation.new_value(attr).map(|value| {
                         let win = window_from_node(self);
-                        Arc::new(DOMRefCell::new(parse_style_attribute(
+                        Arc::new(RwLock::new(parse_style_attribute(
                             &value,
                             &doc.base_url(),
                             win.css_error_reporter(),

components/script/layout_wrapper.rs

@@ -30,7 +30,6 @@
 
 #![allow(unsafe_code)]
 
-use dom::bindings::cell::DOMRefCell;
 use dom::bindings::inheritance::{CharacterDataTypeId, ElementTypeId};
 use dom::bindings::inheritance::{HTMLElementTypeId, NodeTypeId};
 use dom::bindings::js::LayoutJS;
@@ -42,6 +41,7 @@ use dom::node::{LayoutNodeHelpers, Node};
 use dom::text::Text;
 use gfx_traits::ByteIndex;
 use msg::constellation_msg::PipelineId;
+use parking_lot::RwLock;
 use range::Range;
 use script_layout_interface::{HTMLCanvasData, LayoutNodeType, TrustedNodeAddress};
 use script_layout_interface::{OpaqueStyleAndLayoutData, PartialPersistentLayoutData};
@@ -462,7 +462,7 @@ impl<'le> TElement for ServoLayoutElement<'le> {
         ServoLayoutNode::from_layout_js(self.element.upcast())
     }
 
-    fn style_attribute(&self) -> Option<&Arc<DOMRefCell<PropertyDeclarationBlock>>> {
+    fn style_attribute(&self) -> Option<&Arc<RwLock<PropertyDeclarationBlock>>> {
         unsafe {
             (*self.element.style_attribute()).as_ref()
         }

components/script/lib.rs

@@ -64,6 +64,7 @@ extern crate net_traits;
 extern crate num_traits;
 extern crate offscreen_gl_context;
 extern crate open;
+extern crate parking_lot;
 extern crate phf;
 #[macro_use]
 extern crate profile_traits;

components/style/Cargo.toml

@@ -17,7 +17,7 @@ servo = ["serde/unstable", "serde", "serde_macros", "heapsize_plugin",
          "style_traits/servo", "app_units/plugins",
          "cssparser/heap_size", "cssparser/serde-serialization",
          "selectors/unstable", "string_cache",
-         "url/heap_size", "plugins"]
+         "url/heap_size", "plugins", "parking_lot/nightly"]
 testing = []
 
 [dependencies]

components/style/animation.rs

@@ -383,7 +383,7 @@ fn compute_style_for_animation_step(context: &SharedStyleContext,
         // TODO: avoiding this spurious clone might involve having to create
         // an Arc in the below (more common case).
         KeyframesStepValue::ComputedValues => style_from_cascade.clone(),
-        KeyframesStepValue::Declarations(ref declarations) => {
+        KeyframesStepValue::Declarations { block: ref declarations } => {
             let declaration_block = ApplicableDeclarationBlock {
                 mixed_declarations: declarations.clone(),
                 importance: Importance::Normal,

components/style/dom.rs

@@ -8,8 +8,8 @@
 
 use atomic_refcell::{AtomicRef, AtomicRefMut};
 use data::PersistentStyleData;
-use domrefcell::DOMRefCell;
 use element_state::ElementState;
+use parking_lot::RwLock;
 use properties::{ComputedValues, PropertyDeclarationBlock};
 use restyle_hints::{RESTYLE_DESCENDANTS, RESTYLE_LATER_SIBLINGS, RESTYLE_SELF, RestyleHint};
 use selector_impl::{ElementExt, PseudoElement};
@@ -203,7 +203,7 @@ pub trait TElement : PartialEq + Debug + Sized + Copy + Clone + ElementExt + Pre
 
     fn as_node(&self) -> Self::ConcreteNode;
 
-    fn style_attribute(&self) -> Option<&Arc<DOMRefCell<PropertyDeclarationBlock>>>;
+    fn style_attribute(&self) -> Option<&Arc<RwLock<PropertyDeclarationBlock>>>;
 
     fn get_state(&self) -> ElementState;
 

components/style/gecko/wrapper.rs

@@ -32,6 +32,7 @@ use gecko_bindings::structs::{nsChangeHint, nsIAtom, nsIContent, nsStyleContext}
 use gecko_bindings::structs::OpaqueStyleData;
 use gecko_bindings::sugar::ownership::{FFIArcHelpers, HasArcFFI, HasFFI};
 use libc::uintptr_t;
+use parking_lot::RwLock;
 use parser::ParserContextExtraData;
 use properties::{ComputedValues, parse_style_attribute};
 use properties::PropertyDeclarationBlock;
@@ -46,7 +47,6 @@ use std::ptr;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, AtomicPtr};
 use string_cache::{Atom, Namespace, WeakAtom, WeakNamespace};
-use style::domrefcell::DOMRefCell;
 use url::Url;
 
 pub struct NonOpaqueStyleData(AtomicRefCell<PersistentStyleData>);
@@ -59,7 +59,7 @@ impl NonOpaqueStyleData {
 
 
 pub struct GeckoDeclarationBlock {
-    pub declarations: Option<Arc<PropertyDeclarationBlock>>,
+    pub declarations: Option<Arc<RwLock<PropertyDeclarationBlock>>>,
     // XXX The following two fields are made atomic to work around the
     // ownership system so that they can be changed inside a shared
     // instance. It wouldn't provide safety as Rust usually promises,
@@ -469,7 +469,7 @@ impl<'le> TElement for GeckoElement<'le> {
         unsafe { GeckoNode(&*(self.0 as *const _ as *const RawGeckoNode)) }
     }
 
-    fn style_attribute(&self) -> Option<&Arc<DOMRefCell<PropertyDeclarationBlock>>> {
+    fn style_attribute(&self) -> Option<&Arc<RwLock<PropertyDeclarationBlock>>> {
         let declarations = unsafe { Gecko_GetServoDeclarationBlock(self.0) };
         if declarations.is_null() {
             None