Auto merge of #16900 - emilio:pseudos, r=bholley

Bug 1364850: Move PseudoElement to be just another combinator in selectors. r=bholley

On top of https://github.com/servo/servo/pull/16890.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16900)
<!-- Reviewable:end -->

3 files changed, 38 insertions, 8 deletions

diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 011b87aabf1..6b844dd83a2 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -86,7 +86,7 @@ use net_traits::request::CorsSettings;
 use ref_filter_map::ref_filter_map;
 use script_layout_interface::message::ReflowQueryType;
 use script_thread::Runnable;
-use selectors::matching::{ElementSelectorFlags, MatchingContext, matches_selector_list};
+use selectors::matching::{ElementSelectorFlags, MatchingContext, MatchingMode, matches_selector_list};
 use selectors::matching::{HAS_EDGE_CHILD_SELECTOR, HAS_SLOW_SELECTOR, HAS_SLOW_SELECTOR_LATER_SIBLINGS};
 use selectors::parser::{AttrSelector, NamespaceConstraint};
 use servo_atoms::Atom;
@@ -104,7 +104,7 @@ use style::properties::{Importance, PropertyDeclaration, PropertyDeclarationBloc
 use style::properties::longhands::{self, background_image, border_spacing, font_family, font_size, overflow_x};
 use style::restyle_hints::RESTYLE_SELF;
 use style::rule_tree::CascadeLevel;
-use style::selector_parser::{NonTSPseudoClass, RestyleDamage, SelectorImpl, SelectorParser};
+use style::selector_parser::{NonTSPseudoClass, PseudoElement, RestyleDamage, SelectorImpl, SelectorParser};
 use style::shared_lock::{SharedRwLock, Locked};
 use style::sink::Push;
 use style::stylearc::Arc;
@@ -2058,7 +2058,8 @@ impl ElementMethods for Element {
         match SelectorParser::parse_author_origin_no_namespace(&selectors) {
             Err(()) => Err(Error::Syntax),
             Ok(selectors) => {
-                Ok(matches_selector_list(&selectors.0, &Root::from_ref(self), None))
+                let mut ctx = MatchingContext::new(MatchingMode::Normal, None);
+                Ok(matches_selector_list(&selectors.0, &Root::from_ref(self), &mut ctx))
             }
         }
     }
@@ -2076,8 +2077,8 @@ impl ElementMethods for Element {
                 let root = self.upcast::<Node>();
                 for element in root.inclusive_ancestors() {
                     if let Some(element) = Root::downcast::<Element>(element) {
-                        if matches_selector_list(&selectors.0, &element, None)
-                        {
+                        let mut ctx = MatchingContext::new(MatchingMode::Normal, None);
+                        if matches_selector_list(&selectors.0, &element, &mut ctx) {
                             return Ok(Some(element));
                         }
                     }
@@ -2386,6 +2387,15 @@ impl<'a> ::selectors::Element for Root<Element> {
         self.upcast::<Node>().GetParentElement()
     }
 
+    fn match_pseudo_element(&self,
+                            _pseudo: &PseudoElement,
+                            _context: &mut MatchingContext)
+                            -> bool
+    {
+        false
+    }
+
+
     fn first_child_element(&self) -> Option<Root<Element>> {
         self.node.child_elements().next()
     }
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index 8c8831801ef..1ad28974f3d 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -70,7 +70,7 @@ use script_layout_interface::{LayoutElementType, LayoutNodeType, TrustedNodeAddr
 use script_layout_interface::message::Msg;
 use script_traits::DocumentActivity;
 use script_traits::UntrustedNodeAddress;
-use selectors::matching::matches_selector_list;
+use selectors::matching::{matches_selector_list, MatchingContext, MatchingMode};
 use selectors::parser::SelectorList;
 use servo_url::ServoUrl;
 use std::borrow::ToOwned;
@@ -346,11 +346,14 @@ impl<'a> Iterator for QuerySelectorIterator {
 
     fn next(&mut self) -> Option<Root<Node>> {
         let selectors = &self.selectors.0;
+
         // TODO(cgaebel): Is it worth it to build a bloom filter here
         // (instead of passing `None`)? Probably.
+        let mut ctx = MatchingContext::new(MatchingMode::Normal, None);
+
         self.iterator.by_ref().filter_map(|node| {
             if let Some(element) = Root::downcast(node) {
-                if matches_selector_list(selectors, &element, None) {
+                if matches_selector_list(selectors, &element, &mut ctx) {
                     return Some(Root::upcast(element));
                 }
             }
@@ -717,8 +720,9 @@ impl Node {
             Err(()) => Err(Error::Syntax),
             // Step 3.
             Ok(selectors) => {
+                let mut ctx = MatchingContext::new(MatchingMode::Normal, None);
                 Ok(self.traverse_preorder().filter_map(Root::downcast).find(|element| {
-                    matches_selector_list(&selectors.0, element, None)
+                    matches_selector_list(&selectors.0, element, &mut ctx)
                 }))
             }
         }
diff --git a/components/script/layout_wrapper.rs b/components/script/layout_wrapper.rs
index 7802d446114..4cf1789beef 100644
--- a/components/script/layout_wrapper.rs
+++ b/components/script/layout_wrapper.rs
@@ -652,6 +652,14 @@ impl<'le> ::selectors::Element for ServoLayoutElement<'le> {
         self.element.namespace()
     }
 
+    fn match_pseudo_element(&self,
+                            _pseudo: &PseudoElement,
+                            _context: &mut MatchingContext)
+                            -> bool
+    {
+        false
+    }
+
     fn match_non_ts_pseudo_class<F>(&self,
                                     pseudo_class: &NonTSPseudoClass,
                                     _: &mut MatchingContext,
@@ -1150,6 +1158,14 @@ impl<'le> ::selectors::Element for ServoThreadSafeLayoutElement<'le> {
         self.element.get_namespace()
     }
 
+    fn match_pseudo_element(&self,
+                            _pseudo: &PseudoElement,
+                            _context: &mut MatchingContext)
+                            -> bool
+    {
+        false
+    }
+
     fn match_non_ts_pseudo_class<F>(&self,
                                     _: &NonTSPseudoClass,
                                     _: &mut MatchingContext,