servo: Merge #17318 - stylo: Fix pseudo element matching for XBL stylesheets (Bug 1371577) (from aethanyc:fix-pseudo-xbl-stylesheet); r=emilio

This change is reviewed in https://bugzilla.mozilla.org/show_bug.cgi?id=1371577#c9

Source-Repo: https://github.com/servo/servo
Source-Revision: 5dce166266d1f74e2ae88dbe52ca5ced75c2349b

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : c36859edd46fdd90296b4a89ba5dd9f8f9d9eb0c

servo/components/style/dom.rs

@@ -573,7 +573,8 @@ pub trait TElement : Eq + PartialEq + Debug + Hash + Sized + Copy + Clone +
 
     /// Gets declarations from XBL bindings from the element. Only gecko element could have this.
     fn get_declarations_from_xbl_bindings<V>(&self,
-                                             _: &mut V)
+                                             _pseudo_element: Option<&PseudoElement>,
+                                             _applicable_declarations: &mut V)
                                              -> bool
         where V: Push<ApplicableDeclarationBlock> + VecLike<ApplicableDeclarationBlock> {
         false

servo/components/style/gecko/wrapper.rs

@@ -382,17 +382,19 @@ impl<'lb> GeckoXBLBinding<'lb> {
     // Implements Gecko's nsXBLBinding::WalkRules().
     fn get_declarations_for<E, V>(&self,
                                   element: &E,
+                                  pseudo_element: Option<&PseudoElement>,
                                   applicable_declarations: &mut V)
         where E: TElement,
               V: Push<ApplicableDeclarationBlock> + VecLike<ApplicableDeclarationBlock> {
         if let Some(base_binding) = self.base_binding() {
-            base_binding.get_declarations_for(element, applicable_declarations);
+            base_binding.get_declarations_for(element, pseudo_element, applicable_declarations);
         }
 
         let raw_data = unsafe { bindings::Gecko_XBLBinding_GetRawServoStyleSet(self.0) };
         if let Some(raw_data) = raw_data {
             let data = PerDocumentStyleData::from_ffi(&*raw_data).borrow();
             data.stylist.push_applicable_declarations_as_xbl_only_stylist(element,
+                                                                          pseudo_element,
                                                                           applicable_declarations);
         }
     }
@@ -942,6 +944,7 @@ impl<'le> TElement for GeckoElement<'le> {
     // Implements Gecko's nsBindingManager::WalkRules(). Returns whether to cut off the
     // inheritance.
     fn get_declarations_from_xbl_bindings<V>(&self,
+                                             pseudo_element: Option<&PseudoElement>,
                                              applicable_declarations: &mut V)
                                              -> bool
         where V: Push<ApplicableDeclarationBlock> + VecLike<ApplicableDeclarationBlock> {
@@ -951,7 +954,9 @@ impl<'le> TElement for GeckoElement<'le> {
 
         while let Some(element) = current {
             if let Some(binding) = element.get_xbl_binding() {
-                binding.get_declarations_for(self, applicable_declarations);
+                binding.get_declarations_for(self,
+                                             pseudo_element,
+                                             applicable_declarations);
 
                 // If we're not looking at our original element, allow the binding to cut off
                 // style inheritance.

servo/components/style/stylist.rs

@@ -933,10 +933,38 @@ impl Stylist {
         self.quirks_mode = quirks_mode;
     }
 
+    /// Returns the correspond PerPseudoElementSelectorMap given PseudoElement.
+    fn get_map(&self,
+               pseudo_element: Option<&PseudoElement>) -> Option<&PerPseudoElementSelectorMap>
+    {
+        match pseudo_element {
+            Some(pseudo) => self.pseudos_map.get(pseudo),
+            None => Some(&self.element_map),
+        }
+    }
+
+    /// Returns the rule hash target given an element.
+    fn rule_hash_target<E>(&self, element: E) -> E
+        where E: TElement
+    {
+        let is_implemented_pseudo =
+            element.implemented_pseudo_element().is_some();
+
+        // NB: This causes use to rule has pseudo selectors based on the
+        // properties of the originating element (which is fine, given the
+        // find_first_from_right usage).
+        if is_implemented_pseudo {
+            element.closest_non_native_anonymous_ancestor().unwrap()
+        } else {
+            element
+        }
+    }
+
     /// Returns the applicable CSS declarations for the given element by
     /// treating us as an XBL stylesheet-only stylist.
     pub fn push_applicable_declarations_as_xbl_only_stylist<E, V>(&self,
                                                                   element: &E,
+                                                                  pseudo_element: Option<&PseudoElement>,
                                                                   applicable_declarations: &mut V)
         where E: TElement,
               V: Push<ApplicableDeclarationBlock> + VecLike<ApplicableDeclarationBlock>,
@@ -945,13 +973,21 @@ impl Stylist {
             MatchingContext::new(MatchingMode::Normal, None, self.quirks_mode);
         let mut dummy_flag_setter = |_: &E, _: ElementSelectorFlags| {};
 
-        self.element_map.author.get_all_matching_rules(element,
-                                                       element,
-                                                       applicable_declarations,
-                                                       &mut matching_context,
-                                                       self.quirks_mode,
-                                                       &mut dummy_flag_setter,
-                                                       CascadeLevel::XBL);
+        let map = match self.get_map(pseudo_element) {
+            Some(map) => map,
+            None => return,
+        };
+        let rule_hash_target = self.rule_hash_target(*element);
+
+        // nsXBLPrototypeResources::ComputeServoStyleSet() added XBL stylesheets under author
+        // (doc) level.
+        map.author.get_all_matching_rules(element,
+                                          &rule_hash_target,
+                                          applicable_declarations,
+                                          &mut matching_context,
+                                          self.quirks_mode,
+                                          &mut dummy_flag_setter,
+                                          CascadeLevel::XBL);
     }
 
     /// Returns the applicable CSS declarations for the given element.
@@ -983,22 +1019,11 @@ impl Stylist {
                       "Style attributes do not apply to pseudo-elements");
         debug_assert!(pseudo_element.map_or(true, |p| !p.is_precomputed()));
 
-        let map = match pseudo_element {
-            Some(pseudo) => self.pseudos_map.get(pseudo).unwrap(),
-            None => &self.element_map,
-        };
-
-        let is_implemented_pseudo =
-            element.implemented_pseudo_element().is_some();
-
-        // NB: This causes use to rule has pseudo selectors based on the
-        // properties of the originating element (which is fine, given the
-        // find_first_from_right usage).
-        let rule_hash_target = if is_implemented_pseudo {
-            element.closest_non_native_anonymous_ancestor().unwrap()
-        } else {
-            *element
+        let map = match self.get_map(pseudo_element) {
+            Some(map) => map,
+            None => return,
         };
+        let rule_hash_target = self.rule_hash_target(*element);
 
         debug!("Determining if style is shareable: pseudo: {}",
                pseudo_element.is_some());
@@ -1060,7 +1085,8 @@ impl Stylist {
 
         // Step 3b: XBL rules.
         let cut_off_inheritance =
-            rule_hash_target.get_declarations_from_xbl_bindings(applicable_declarations);
+            rule_hash_target.get_declarations_from_xbl_bindings(pseudo_element,
+                                                                applicable_declarations);
         debug!("XBL: {:?}", context.relations);
 
         if rule_hash_target.matches_user_and_author_rules() && !only_default_rules {