style: Implement selector matching for :nth-child(An+B of selector list) and :nth-last-child(An+B of selector list)

Since we have been using a single hash map to cache all :nth-child
indices (with no selector list), each different selector will need its
own cache.

As a side note, this patch does not address invalidation.

Differential Revision: https://phabricator.services.mozilla.com/D166266

components/style/dom_apis.rs

@@ -14,7 +14,7 @@ use crate::values::AtomIdent;
 use selectors::attr::CaseSensitivity;
 use selectors::matching::{self, MatchingContext, MatchingMode, NeedsSelectorFlags};
 use selectors::parser::{Combinator, Component, LocalName, SelectorImpl};
-use selectors::{Element, NthIndexCache, SelectorList};
+use selectors::{Element, SelectorList};
 use smallvec::SmallVec;
 
 /// <https://dom.spec.whatwg.org/#dom-element-matches>
@@ -26,10 +26,12 @@ pub fn element_matches<E>(
 where
     E: Element,
 {
+    let mut nth_index_cache = Default::default();
+
     let mut context = MatchingContext::new(
         MatchingMode::Normal,
         None,
-        None,
+        &mut nth_index_cache,
         quirks_mode,
         NeedsSelectorFlags::No,
     );
@@ -47,12 +49,12 @@ pub fn element_closest<E>(
 where
     E: Element,
 {
-    let mut nth_index_cache = NthIndexCache::default();
+    let mut nth_index_cache = Default::default();
 
     let mut context = MatchingContext::new(
         MatchingMode::Normal,
         None,
-        Some(&mut nth_index_cache),
+        &mut nth_index_cache,
         quirks_mode,
         NeedsSelectorFlags::No,
     );
@@ -621,13 +623,13 @@ pub fn query_selector<E, Q>(
 {
     use crate::invalidation::element::invalidator::TreeStyleInvalidator;
 
+    let mut nth_index_cache = Default::default();
     let quirks_mode = root.owner_doc().quirks_mode();
 
-    let mut nth_index_cache = NthIndexCache::default();
     let mut matching_context = MatchingContext::new(
         MatchingMode::Normal,
         None,
-        Some(&mut nth_index_cache),
+        &mut nth_index_cache,
         quirks_mode,
         NeedsSelectorFlags::No,
     );

components/style/invalidation/element/document_state.rs

@@ -13,6 +13,7 @@ use crate::stylist::CascadeData;
 use selectors::matching::{
     MatchingContext, MatchingMode, NeedsSelectorFlags, QuirksMode, VisitedHandlingMode,
 };
+use selectors::NthIndexCache;
 use style_traits::dom::DocumentState;
 
 /// A struct holding the members necessary to invalidate document state
@@ -43,11 +44,16 @@ pub struct DocumentStateInvalidationProcessor<'a, E: TElement, I> {
 impl<'a, E: TElement, I> DocumentStateInvalidationProcessor<'a, E, I> {
     /// Creates a new DocumentStateInvalidationProcessor.
     #[inline]
-    pub fn new(rules: I, document_states_changed: DocumentState, quirks_mode: QuirksMode) -> Self {
+    pub fn new(
+        rules: I,
+        document_states_changed: DocumentState,
+        nth_index_cache: &'a mut NthIndexCache,
+        quirks_mode: QuirksMode,
+    ) -> Self {
         let mut matching_context = MatchingContext::<'a, E::Impl>::new_for_visited(
             MatchingMode::Normal,
             None,
-            None,
+            nth_index_cache,
             VisitedHandlingMode::AllLinksVisitedAndUnvisited,
             quirks_mode,
             NeedsSelectorFlags::No,

components/style/invalidation/element/state_and_attributes.rs

@@ -65,7 +65,7 @@ impl<'a, 'b: 'a, E: TElement + 'b> StateAndAttrInvalidationProcessor<'a, 'b, E>
         let matching_context = MatchingContext::new_for_visited(
             MatchingMode::Normal,
             None,
-            Some(nth_index_cache),
+            nth_index_cache,
             VisitedHandlingMode::AllLinksVisitedAndUnvisited,
             shared_context.quirks_mode(),
             NeedsSelectorFlags::No,

components/style/style_resolver.rs

@@ -462,7 +462,7 @@ where
         let mut matching_context = MatchingContext::new_for_visited(
             MatchingMode::Normal,
             Some(bloom_filter),
-            Some(nth_index_cache),
+            nth_index_cache,
             visited_handling,
             self.context.shared.quirks_mode(),
             NeedsSelectorFlags::Yes,
@@ -538,7 +538,7 @@ where
         let mut matching_context = MatchingContext::<'_, E::Impl>::new_for_visited(
             MatchingMode::ForStatelessPseudoElement,
             Some(bloom_filter),
-            Some(nth_index_cache),
+            nth_index_cache,
             visited_handling,
             self.context.shared.quirks_mode(),
             NeedsSelectorFlags::Yes,

components/style/stylist.rs

@@ -1125,6 +1125,7 @@ impl Stylist {
     {
         debug_assert!(pseudo.is_lazy());
 
+        let mut nth_index_cache = Default::default();
         // No need to bother setting the selector flags when we're computing
         // default styles.
         let needs_selector_flags = if rule_inclusion == RuleInclusion::DefaultOnly {
@@ -1137,7 +1138,7 @@ impl Stylist {
         let mut matching_context = MatchingContext::<'_, E::Impl>::new(
             MatchingMode::ForStatelessPseudoElement,
             None,
-            None,
+            &mut nth_index_cache,
             self.quirks_mode,
             needs_selector_flags,
         );
@@ -1166,10 +1167,12 @@ impl Stylist {
         let mut visited_rules = None;
         if parent_style.visited_style().is_some() {
             let mut declarations = ApplicableDeclarationList::new();
+            let mut nth_index_cache = Default::default();
+
             let mut matching_context = MatchingContext::<'_, E::Impl>::new_for_visited(
                 MatchingMode::ForStatelessPseudoElement,
                 None,
-                None,
+                &mut nth_index_cache,
                 VisitedHandlingMode::RelevantLinkVisited,
                 self.quirks_mode,
                 needs_selector_flags,
@@ -1417,7 +1420,7 @@ impl Stylist {
         let mut matching_context = MatchingContext::new(
             MatchingMode::Normal,
             bloom,
-            Some(nth_index_cache),
+            nth_index_cache,
             self.quirks_mode,
             needs_selector_flags,
         );