Issue #1593 - Part 1: Import William Chen's patches w/o selector implementation, fixed up.

layout/style/nsCSSRuleProcessor.cpp

@@ -48,6 +48,7 @@
 #include "nsCSSRules.h"
 #include "nsStyleSet.h"
 #include "mozilla/dom/Element.h"
+#include "mozilla/dom/ShadowRoot.h"
 #include "nsNthIndexCache.h"
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/EventStates.h"
@@ -1342,9 +1343,17 @@ struct NodeMatchContext {
   // mForStyling is false, we have to assume we don't know.)
   const bool mIsRelevantLink;
 
-  NodeMatchContext(EventStates aStateMask, bool aIsRelevantLink)
+  // If the node should be considered featureless (as specified in
+  // selectors 4), then mIsFeature should be set to true to prevent
+  // matching unless the selector is a special pseudo class or pseudo
+  // element that matches featureless elements.
+  const bool mIsFeatureless;
+
+  NodeMatchContext(EventStates aStateMask, bool aIsRelevantLink,
+                   bool aIsFeatureless = false)
     : mStateMask(aStateMask)
     , mIsRelevantLink(aIsRelevantLink)
+    , mIsFeatureless(aIsFeatureless)
   {
   }
 };
@@ -1631,6 +1640,11 @@ StateSelectorMatches(Element* aElement,
   return true;
 }
 
+static bool AnySelectorInArgListMatches(Element* aElement,
+                                     nsPseudoClassList* aList,
+                                     NodeMatchContext& aNodeMatchContext,
+                                     TreeMatchContext& aTreeMatchContext);
+
 static bool
 StateSelectorMatches(Element* aElement,
                      nsCSSSelector* aSelector,
@@ -1652,6 +1666,17 @@ StateSelectorMatches(Element* aElement,
   return true;
 }
 
+// Returns whether aSelector can match featureless elements.
+static bool CanMatchFeaturelessElement(nsCSSSelector* aSelector)
+{
+  if (aSelector->HasFeatureSelectors()) {
+    return false;
+  }
+
+  return false;
+}
+
+
 // |aDependence| has two functions:
 //  * when non-null, it indicates that we're processing a negation,
 //    which is done only when SelectorMatches calls itself recursively
@@ -1672,6 +1697,11 @@ static bool SelectorMatches(Element* aElement,
              "is false since we don't know how to set it correctly in "
              "Has(Attribute|State)DependentStyle");
 
+  if (aNodeMatchContext.mIsFeatureless &&
+      !CanMatchFeaturelessElement(aSelector)) {
+    return false;
+  }
+
   // namespace/tag match
   // optimization : bail out early if we can
   if ((kNameSpaceID_Unknown != aSelector->mNameSpace &&
@@ -1870,18 +1900,9 @@ static bool SelectorMatches(Element* aElement,
 
       case CSSPseudoClassType::any:
         {
-          nsCSSSelectorList *l;
-          for (l = pseudoClass->u.mSelectors; l; l = l->mNext) {
-            nsCSSSelector *s = l->mSelectors;
-            MOZ_ASSERT(!s->mNext && !s->IsPseudoElement(),
-                       "parser failed");
-            if (SelectorMatches(
-                  aElement, s, aNodeMatchContext, aTreeMatchContext,
-                  SelectorMatchesFlags::IS_PSEUDO_CLASS_ARGUMENT)) {
-              break;
-            }
-          }
-          if (!l) {
+          if (!AnySelectorInArgListMatches(aElement, pseudoClass,
+                                           aNodeMatchContext,
+                                           aTreeMatchContext)) {
             return false;
           }
         }
@@ -2263,6 +2284,26 @@ static bool SelectorMatches(Element* aElement,
   return result;
 }
 
+static bool AnySelectorInArgListMatches(Element* aElement,
+                                     nsPseudoClassList* aList,
+                                     NodeMatchContext& aNodeMatchContext,
+                                     TreeMatchContext& aTreeMatchContext)
+{
+  nsCSSSelectorList *l;
+  for (l = aList->u.mSelectors; l; l = l->mNext) {
+    nsCSSSelector *s = l->mSelectors;
+    MOZ_ASSERT(!s->mNext && !s->IsPseudoElement(),
+           "parser failed");
+    if (SelectorMatches(
+          aElement, s, aNodeMatchContext, aTreeMatchContext,
+          SelectorMatchesFlags::IS_PSEUDO_CLASS_ARGUMENT)) {
+      break;
+    }
+  }
+
+  return !!l;
+}
+
 #undef STATE_CHECK
 
 #ifdef DEBUG
@@ -2352,7 +2393,9 @@ SelectorMatchesTree(Element* aPrevElement,
   MOZ_ASSERT(!aSelector || !aSelector->IsPseudoElement());
   nsCSSSelector* selector = aSelector;
   Element* prevElement = aPrevElement;
+  bool crossedShadowRootBoundary = false;
   while (selector) { // check compound selectors
+    bool contentIsFeatureless = false;
     NS_ASSERTION(!selector->mNext ||
                  selector->mNext->mOperator != char16_t(0),
                  "compound selector without combinator");
@@ -2383,6 +2426,20 @@ SelectorMatchesTree(Element* aPrevElement,
     // to test against is the parent
     else {
       nsIContent *content = prevElement->GetParent();
+
+      // In the shadow tree, the shadow host behaves as if it
+      // is a featureless parent of top-level elements of the shadow
+      // tree. Only cross shadow root boundary when the selector is the
+      // left most selector because ancestors of the host are not in
+      // the selector match list.
+      ShadowRoot* shadowRoot = content ?
+        ShadowRoot::FromNode(content) : nullptr;
+      if (shadowRoot && !selector->mNext && !crossedShadowRootBoundary) {
+      content = shadowRoot->GetHost();
+      crossedShadowRootBoundary = true;
+      contentIsFeatureless = true;
+      }
+
       // GetParent could return a document fragment; we only want
       // element parents.
       if (content && content->IsElement()) {
@@ -2434,7 +2491,8 @@ SelectorMatchesTree(Element* aPrevElement,
     }
     const bool isRelevantLink = (aFlags & eLookForRelevantLink) &&
                                 nsCSSRuleProcessor::IsLink(element);
-    NodeMatchContext nodeContext(EventStates(), isRelevantLink);
+
+    NodeMatchContext nodeContext(EventStates(), isRelevantLink, contentIsFeatureless);
     if (isRelevantLink) {
       // If we find an ancestor of the matched node that is a link
       // during the matching process, then it's the relevant link (see
@@ -2504,6 +2562,20 @@ void ContentEnumFunc(const RuleValue& value, nsCSSSelector* aSelector,
     // We won't match; nothing else to do here
     return;
   }
+  // If mOnlyMatchHostPseudo is set, then we only want to match against
+  // selectors that contain a :host-context pseudo class.
+  if (data->mTreeMatchContext.mOnlyMatchHostPseudo) {
+    nsCSSSelector* selector = aSelector;
+    while (selector && selector->mNext != nullptr) {
+      selector = selector->mNext;
+    }
+
+    bool seenHostPseudo = false;
+
+    if (!seenHostPseudo) {
+      return;
+    }
+  }
   if (!data->mTreeMatchContext.SetStyleScopeForSelectorMatching(data->mElement,
                                                                 data->mScope)) {
     // The selector is for a rule in a scoped style sheet, and the subject
@@ -2563,7 +2635,8 @@ nsCSSRuleProcessor::RulesMatching(ElementRuleProcessorData *aData)
 
   if (cascade) {
     NodeMatchContext nodeContext(EventStates(),
-                                 nsCSSRuleProcessor::IsLink(aData->mElement));
+                                 nsCSSRuleProcessor::IsLink(aData->mElement),
+				 aData->mElementIsFeatureless);
     cascade->mRuleHash.EnumerateAllRules(aData->mElement, aData, nodeContext);
   }
 }
@@ -2847,6 +2920,24 @@ AttributeEnumFunc(nsCSSSelector* aSelector,
   nsRestyleHint possibleChange =
     RestyleHintForSelectorWithAttributeChange(aData->change,
                                               aSelector, aRightmostSelector);
+  // If mOnlyMatchHostPseudo is set, then we only want to match against
+  // selectors that contain a :host-context pseudo class.
+  if (data->mTreeMatchContext.mOnlyMatchHostPseudo) {
+    nsCSSSelector* selector = aSelector;
+    while (selector && selector->mNext != nullptr) {
+      selector = selector->mNext;
+    }
+
+    bool seenHostPseudo = false;
+    break;
+      }
+    }
+
+    if (!seenHostPseudo) {
+      return;
+    }
+  }
+
 
   // If, ignoring eRestyle_SomeDescendants, enumData->change already includes
   // all the bits of possibleChange, don't bother calling SelectorMatches, since
@@ -3318,7 +3409,7 @@ AddSelector(RuleCascadeData* aCascade,
       }
     }
 
-    // Recur through any :-moz-any selectors
+    // Recur through any :-moz-any or :host-context selectors
     for (nsPseudoClassList* pseudoClass = negation->mPseudoClassList;
          pseudoClass; pseudoClass = pseudoClass->mNext) {
       if (pseudoClass->mType == CSSPseudoClassType::any) {
@@ -3970,6 +4061,7 @@ TreeMatchContext::InitAncestors(Element *aElement)
     for (uint32_t i = ancestors.Length(); i-- != 0; ) {
       mAncestorFilter.PushAncestor(ancestors[i]);
       PushStyleScope(ancestors[i]);
+      PushShadowHost(ancestors[i]);
     }
   }
 }