Pull decls from Gecko for link preshints

Based on a link's active state and the visited handling mode, pull in link,
vlink, and alink preshint declaration blocks from Gecko as needed.

MozReview-Commit-ID: A6udMYbzQnK

components/script/layout_wrapper.rs

@@ -51,7 +51,7 @@ use script_layout_interface::{OpaqueStyleAndLayoutData, StyleData};
 use script_layout_interface::wrapper_traits::{DangerousThreadSafeLayoutNode, GetLayoutData, LayoutNode};
 use script_layout_interface::wrapper_traits::{PseudoElementType, ThreadSafeLayoutElement, ThreadSafeLayoutNode};
 use selectors::attr::{AttrSelectorOperation, NamespaceConstraint};
-use selectors::matching::{ElementSelectorFlags, MatchingContext, RelevantLinkStatus};
+use selectors::matching::{ElementSelectorFlags, MatchingContext, RelevantLinkStatus, VisitedHandlingMode};
 use servo_atoms::Atom;
 use servo_url::ServoUrl;
 use std::fmt;
@@ -364,7 +364,9 @@ impl<'le> fmt::Debug for ServoLayoutElement<'le> {
 }
 
 impl<'le> PresentationalHintsSynthesizer for ServoLayoutElement<'le> {
-    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, hints: &mut V)
+    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self,
+                                                                _visited_handling: VisitedHandlingMode,
+                                                                hints: &mut V)
         where V: Push<ApplicableDeclarationBlock>
     {
         unsafe {
@@ -1228,6 +1230,8 @@ impl<'le> ::selectors::Element for ServoThreadSafeLayoutElement<'le> {
 }
 
 impl<'le> PresentationalHintsSynthesizer for ServoThreadSafeLayoutElement<'le> {
-    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, _hints: &mut V)
+    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self,
+                                                                _visited_handling: VisitedHandlingMode,
+                                                                _hints: &mut V)
         where V: Push<ApplicableDeclarationBlock> {}
 }

components/style/dom.rs

@@ -18,7 +18,7 @@ use properties::{ComputedValues, PropertyDeclarationBlock};
 #[cfg(feature = "gecko")] use properties::animated_properties::TransitionProperty;
 use rule_tree::CascadeLevel;
 use selector_parser::{ElementExt, PreExistingComputedValues, PseudoElement};
-use selectors::matching::ElementSelectorFlags;
+use selectors::matching::{ElementSelectorFlags, VisitedHandlingMode};
 use shared_lock::Locked;
 use sink::Push;
 use std::fmt;
@@ -270,7 +270,9 @@ pub unsafe fn raw_note_descendants<E, B>(element: E) -> bool
 pub trait PresentationalHintsSynthesizer {
     /// Generate the proper applicable declarations due to presentational hints,
     /// and insert them into `hints`.
-    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, hints: &mut V)
+    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self,
+                                                                visited_handling: VisitedHandlingMode,
+                                                                hints: &mut V)
         where V: Push<ApplicableDeclarationBlock>;
 }
 

components/style/gecko/wrapper.rs

@@ -35,12 +35,15 @@ use gecko_bindings::bindings::Gecko_ClassOrClassList;
 use gecko_bindings::bindings::Gecko_ElementHasAnimations;
 use gecko_bindings::bindings::Gecko_ElementHasCSSAnimations;
 use gecko_bindings::bindings::Gecko_ElementHasCSSTransitions;
+use gecko_bindings::bindings::Gecko_GetActiveLinkAttrDeclarationBlock;
 use gecko_bindings::bindings::Gecko_GetAnimationRule;
 use gecko_bindings::bindings::Gecko_GetExtraContentStyleDeclarations;
 use gecko_bindings::bindings::Gecko_GetHTMLPresentationAttrDeclarationBlock;
 use gecko_bindings::bindings::Gecko_GetSMILOverrideDeclarationBlock;
 use gecko_bindings::bindings::Gecko_GetStyleAttrDeclarationBlock;
 use gecko_bindings::bindings::Gecko_GetStyleContext;
+use gecko_bindings::bindings::Gecko_GetUnvisitedLinkAttrDeclarationBlock;
+use gecko_bindings::bindings::Gecko_GetVisitedLinkAttrDeclarationBlock;
 use gecko_bindings::bindings::Gecko_IsSignificantChild;
 use gecko_bindings::bindings::Gecko_MatchStringArgPseudo;
 use gecko_bindings::bindings::Gecko_UnsetDirtyStyleAttr;
@@ -66,7 +69,8 @@ use rule_tree::CascadeLevel as ServoCascadeLevel;
 use selector_parser::ElementExt;
 use selectors::Element;
 use selectors::attr::{AttrSelectorOperation, AttrSelectorOperator, CaseSensitivity, NamespaceConstraint};
-use selectors::matching::{ElementSelectorFlags, MatchingContext, MatchingMode, RelevantLinkStatus};
+use selectors::matching::{ElementSelectorFlags, MatchingContext, MatchingMode};
+use selectors::matching::{RelevantLinkStatus, VisitedHandlingMode};
 use shared_lock::Locked;
 use sink::Push;
 use std::cell::RefCell;
@@ -1036,7 +1040,9 @@ impl<'le> Hash for GeckoElement<'le> {
 }
 
 impl<'le> PresentationalHintsSynthesizer for GeckoElement<'le> {
-    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, hints: &mut V)
+    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self,
+                                                                visited_handling: VisitedHandlingMode,
+                                                                hints: &mut V)
         where V: Push<ApplicableDeclarationBlock>,
     {
         use properties::longhands::_x_lang::SpecifiedValue as SpecifiedLang;
@@ -1098,6 +1104,37 @@ impl<'le> PresentationalHintsSynthesizer for GeckoElement<'le> {
             );
         }
 
+        // Support for link, vlink, and alink presentation hints on <body>
+        if self.is_link() {
+            // Unvisited vs. visited styles are computed up-front based on the
+            // visited mode (not the element's actual state).
+            let declarations = match visited_handling {
+                VisitedHandlingMode::AllLinksUnvisited => unsafe {
+                    Gecko_GetUnvisitedLinkAttrDeclarationBlock(self.0)
+                },
+                VisitedHandlingMode::RelevantLinkVisited => unsafe {
+                    Gecko_GetVisitedLinkAttrDeclarationBlock(self.0)
+                },
+            };
+            let declarations = declarations.and_then(|s| s.as_arc_opt());
+            if let Some(decl) = declarations {
+                hints.push(
+                    ApplicableDeclarationBlock::from_declarations(Clone::clone(decl), ServoCascadeLevel::PresHints)
+                );
+            }
+
+            let active = self.get_state().intersects(NonTSPseudoClass::Active.state_flag());
+            if active {
+                let declarations = unsafe { Gecko_GetActiveLinkAttrDeclarationBlock(self.0) };
+                let declarations = declarations.and_then(|s| s.as_arc_opt());
+                if let Some(decl) = declarations {
+                    hints.push(
+                        ApplicableDeclarationBlock::from_declarations(Clone::clone(decl), ServoCascadeLevel::PresHints)
+                    );
+                }
+            }
+        }
+
         // xml:lang has precedence over lang, which can be
         // set by Gecko_GetHTMLPresentationAttrDeclarationBlock
         //

components/style/sharing/mod.rs

@@ -14,7 +14,7 @@ use dom::{TElement, SendElement};
 use matching::{ChildCascadeRequirement, MatchMethods};
 use properties::ComputedValues;
 use selectors::bloom::BloomFilter;
-use selectors::matching::{ElementSelectorFlags, StyleRelations};
+use selectors::matching::{ElementSelectorFlags, VisitedHandlingMode, StyleRelations};
 use smallvec::SmallVec;
 use std::mem;
 use std::ops::Deref;
@@ -66,7 +66,10 @@ impl ValidationData {
     {
         if self.pres_hints.is_none() {
             let mut pres_hints = SmallVec::new();
-            element.synthesize_presentational_hints_for_legacy_attributes(&mut pres_hints);
+            element.synthesize_presentational_hints_for_legacy_attributes(
+                VisitedHandlingMode::AllLinksUnvisited,
+                &mut pres_hints
+            );
             self.pres_hints = Some(pres_hints);
         }
         &*self.pres_hints.as_ref().unwrap()

components/style/stylist.rs

@@ -959,7 +959,10 @@ impl Stylist {
         if pseudo_element.is_none() && !only_default_rules {
             // Step 2: Presentational hints.
             let length_before_preshints = applicable_declarations.len();
-            element.synthesize_presentational_hints_for_legacy_attributes(applicable_declarations);
+            element.synthesize_presentational_hints_for_legacy_attributes(
+                context.visited_handling,
+                applicable_declarations
+            );
             if applicable_declarations.len() != length_before_preshints {
                 if cfg!(debug_assertions) {
                     for declaration in &applicable_declarations[length_before_preshints..] {