style: layout: Allow a lazy pseudo-element implementation in Servo.

3 files changed, 12 insertions, 17 deletions

diff --git a/components/style/dom.rs b/components/style/dom.rs
index fed1597c627..badd4f31065 100644
--- a/components/style/dom.rs
+++ b/components/style/dom.rs
@@ -195,7 +195,12 @@ pub trait TDocument : Sized + Copy + Clone {
     fn drain_modified_elements(&self) -> Vec<(Self::ConcreteElement, ElementSnapshot)>;
 }
 
-pub trait TElement : Sized + Copy + Clone + ElementExt {
+pub trait PresentationalHintsSynthetizer {
+    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, hints: &mut V)
+        where V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
+}
+
+pub trait TElement : Sized + Copy + Clone + ElementExt + PresentationalHintsSynthetizer {
     type ConcreteNode: TNode<ConcreteElement = Self, ConcreteDocument = Self::ConcreteDocument>;
     type ConcreteDocument: TDocument<ConcreteNode = Self::ConcreteNode, ConcreteElement = Self>;
 
@@ -205,9 +210,6 @@ pub trait TElement : Sized + Copy + Clone + ElementExt {
 
     fn get_state(&self) -> ElementState;
 
-    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, &mut V)
-        where V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
-
     fn get_attr<'a>(&'a self, namespace: &Namespace, attr: &Atom) -> Option<&'a str>;
     fn get_attrs<'a>(&'a self, attr: &Atom) -> Vec<&'a str>;
 
diff --git a/components/style/selector_impl.rs b/components/style/selector_impl.rs
index e0c1b2c3f98..b424affb101 100644
--- a/components/style/selector_impl.rs
+++ b/components/style/selector_impl.rs
@@ -104,19 +104,11 @@ pub enum PseudoElement {
 impl PseudoElement {
     #[inline]
     pub fn cascade_type(&self) -> PseudoElementCascadeType {
-        // TODO: Make PseudoElementCascadeType::Lazy work for Servo.
-        //
-        // This can't be done right now since it would require
-        // ServoThreadSafeLayoutElement to implement ::selectors::Element,
-        // and it might not be thread-safe.
-        //
-        // After that, we'd probably want ::selection and
-        // ::-servo-details-summary to be lazy.
         match *self {
             PseudoElement::Before |
             PseudoElement::After |
-            PseudoElement::Selection |
-            PseudoElement::DetailsSummary => PseudoElementCascadeType::Eager,
+            PseudoElement::Selection => PseudoElementCascadeType::Eager,
+            PseudoElement::DetailsSummary => PseudoElementCascadeType::Lazy,
             PseudoElement::DetailsContent => PseudoElementCascadeType::Precomputed,
         }
     }
diff --git a/components/style/selector_matching.rs b/components/style/selector_matching.rs
index e59955f3a0e..4faf9aa0eb4 100644
--- a/components/style/selector_matching.rs
+++ b/components/style/selector_matching.rs
@@ -5,7 +5,7 @@
 // For lazy_static
 #![allow(unsafe_code)]
 
-use dom::TElement;
+use dom::PresentationalHintsSynthetizer;
 use element_state::*;
 use error_reporting::{ParseErrorReporter, StdoutErrorReporter};
 use media_queries::{Device, MediaType};
@@ -281,7 +281,8 @@ impl<Impl: SelectorImplExt> Stylist<Impl> {
                                                   pseudo: &Impl::PseudoElement,
                                                   parent: &Arc<Impl::ComputedValues>)
                                                   -> Option<Arc<Impl::ComputedValues>>
-                                                  where E: Element<Impl=Impl> + TElement {
+                                                  where E: Element<Impl=Impl> +
+                                                        PresentationalHintsSynthetizer {
         debug_assert!(Impl::pseudo_element_cascade_type(pseudo).is_lazy());
         if self.pseudos_map.get(pseudo).is_none() {
             return None;
@@ -358,7 +359,7 @@ impl<Impl: SelectorImplExt> Stylist<Impl> {
                                         pseudo_element: Option<&Impl::PseudoElement>,
                                         applicable_declarations: &mut V)
                                         -> bool
-                                        where E: Element<Impl=Impl> + TElement,
+                                        where E: Element<Impl=Impl> + PresentationalHintsSynthetizer,
                                               V: VecLike<DeclarationBlock> {
         assert!(!self.is_device_dirty);
         assert!(style_attribute.is_none() || pseudo_element.is_none(),