Issue #1592 - Part 8: Test the assigned slot for type/class/ID/attribute instead of the slottable when matching ::slotted()

3 files changed, 43 insertions, 15 deletions

diff --git a/dom/xbl/nsBindingManager.cpp b/dom/xbl/nsBindingManager.cpp
index c6dc58ec89..b50c86c002 100644
--- a/dom/xbl/nsBindingManager.cpp
+++ b/dom/xbl/nsBindingManager.cpp
@@ -713,9 +713,11 @@ nsBindingManager::WalkRules(nsIStyleRuleProcessor::EnumFunc aFunc,
       nsXBLBinding* binding = stack.ElementAt(index);
       stack.RemoveElementAt(index);
 
+      aData->mTreeMatchContext.mForAssignedSlot = true;
       aData->mTreeMatchContext.mIsTopmostScope = (index == 0);
       binding->WalkRules(aFunc, aData);
     }
+    aData->mTreeMatchContext.mForAssignedSlot = false;
 
     aData->mTreeMatchContext.mRestrictToSlottedPseudo = false;
   }
diff --git a/layout/style/nsCSSRuleProcessor.cpp b/layout/style/nsCSSRuleProcessor.cpp
index a13b35214d..ff8b8ec032 100644
--- a/layout/style/nsCSSRuleProcessor.cpp
+++ b/layout/style/nsCSSRuleProcessor.cpp
@@ -48,6 +48,7 @@
 #include "nsCSSRules.h"
 #include "nsStyleSet.h"
 #include "mozilla/dom/Element.h"
+#include "mozilla/dom/HTMLSlotElement.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "nsNthIndexCache.h"
 #include "mozilla/ArrayUtils.h"
@@ -684,6 +685,7 @@ void RuleHash::EnumerateAllRules(Element* aElement, ElementDependentRuleProcesso
       filter->AssertHasAllAncestors(aElement);
     }
 #endif
+    bool isForAssignedSlot = aData->mTreeMatchContext.mForAssignedSlot;
     // Merge the lists while there are still multiple lists to merge.
     while (valueCount > 1) {
       int32_t valueIndex = 0;
@@ -696,6 +698,7 @@ void RuleHash::EnumerateAllRules(Element* aElement, ElementDependentRuleProcesso
         }
       }
       const RuleValue *cur = mEnumList[valueIndex].mCurValue;
+      aData->mTreeMatchContext.mForAssignedSlot = isForAssignedSlot;
       ContentEnumFunc(*cur, cur->mSelector, aData, aNodeContext, filter);
       cur++;
       if (cur == mEnumList[valueIndex].mEnd) {
@@ -709,6 +712,7 @@ void RuleHash::EnumerateAllRules(Element* aElement, ElementDependentRuleProcesso
     for (const RuleValue *value = mEnumList[0].mCurValue,
                          *end = mEnumList[0].mEnd;
          value != end; ++value) {
+      aData->mTreeMatchContext.mForAssignedSlot = isForAssignedSlot;
       ContentEnumFunc(*value, value->mSelector, aData, aNodeContext, filter);
     }
   }
@@ -1706,24 +1710,29 @@ static bool SelectorMatches(Element* aElement,
     return false;
   }
 
+  Element* targetElement = aElement;
+  if (aTreeMatchContext.mForAssignedSlot) {
+    targetElement = aElement->GetAssignedSlot()->AsElement();
+  }
+
   // namespace/tag match
   // optimization : bail out early if we can
   if ((kNameSpaceID_Unknown != aSelector->mNameSpace &&
-       aElement->GetNameSpaceID() != aSelector->mNameSpace))
+       targetElement->GetNameSpaceID() != aSelector->mNameSpace))
     return false;
 
   if (aSelector->mLowercaseTag) {
     nsIAtom* selectorTag =
-      (aTreeMatchContext.mIsHTMLDocument && aElement->IsHTMLElement()) ?
+      (aTreeMatchContext.mIsHTMLDocument && targetElement->IsHTMLElement()) ?
         aSelector->mLowercaseTag : aSelector->mCasedTag;
-    if (selectorTag != aElement->NodeInfo()->NameAtom()) {
+    if (selectorTag != targetElement->NodeInfo()->NameAtom()) {
       return false;
     }
   }
 
   nsAtomList* IDList = aSelector->mIDList;
   if (IDList) {
-    nsIAtom* id = aElement->GetID();
+    nsIAtom* id = targetElement->GetID();
     if (id) {
       // case sensitivity: bug 93371
       const bool isCaseSensitive =
@@ -1758,7 +1767,7 @@ static bool SelectorMatches(Element* aElement,
   nsAtomList* classList = aSelector->mClassList;
   if (classList) {
     // test for class match
-    const nsAttrValue *elementClasses = aElement->GetClasses();
+    const nsAttrValue *elementClasses = targetElement->GetClasses();
     if (!elementClasses) {
       // Element has no classes but we have a class selector
       return false;
@@ -1948,6 +1957,10 @@ static bool SelectorMatches(Element* aElement,
 
       case CSSPseudoClassType::slotted:
         {
+          if (aTreeMatchContext.mForAssignedSlot) {
+            aTreeMatchContext.mForAssignedSlot = false;
+          }
+
           // Slottables cannot be matched from the outer tree.
           if (isOutsideShadowTree) {
             return false;
@@ -2349,7 +2362,7 @@ static bool SelectorMatches(Element* aElement,
   bool result = true;
   if (aSelector->mAttrList) {
     // test for attribute match
-    if (!aElement->HasAttrs()) {
+    if (!targetElement->HasAttrs()) {
       // if no attributes on the content, no match
       return false;
     } else {
@@ -2359,7 +2372,7 @@ static bool SelectorMatches(Element* aElement,
 
       do {
         bool isHTML =
-          (aTreeMatchContext.mIsHTMLDocument && aElement->IsHTMLElement());
+          (aTreeMatchContext.mIsHTMLDocument && targetElement->IsHTMLElement());
         matchAttribute = isHTML ? attr->mLowercaseAttr : attr->mCasedAttr;
         if (attr->mNameSpace == kNameSpaceID_Unknown) {
           // Attr selector with a wildcard namespace.  We have to examine all
@@ -2371,7 +2384,7 @@ static bool SelectorMatches(Element* aElement,
           // actually has attributes in), short-circuiting if we ever match.
           result = false;
           const nsAttrName* attrName;
-          for (uint32_t i = 0; (attrName = aElement->GetAttrNameAt(i)); ++i) {
+          for (uint32_t i = 0; (attrName = targetElement->GetAttrNameAt(i)); ++i) {
             if (attrName->LocalName() != matchAttribute) {
               continue;
             }
@@ -2382,7 +2395,7 @@ static bool SelectorMatches(Element* aElement,
 #ifdef DEBUG
               bool hasAttr =
 #endif
-                aElement->GetAttr(attrName->NamespaceID(),
+                targetElement->GetAttr(attrName->NamespaceID(),
                                   attrName->LocalName(), value);
               NS_ASSERTION(hasAttr, "GetAttrNameAt lied");
               result = AttrMatchesValue(attr, value, isHTML);
@@ -2400,12 +2413,12 @@ static bool SelectorMatches(Element* aElement,
         }
         else if (attr->mFunction == NS_ATTR_FUNC_EQUALS) {
           result =
-            aElement->
+            targetElement->
               AttrValueIs(attr->mNameSpace, matchAttribute, attr->mValue,
                           attr->IsValueCaseSensitive(isHTML) ? eCaseMatters
                                                              : eIgnoreCase);
         }
-        else if (!aElement->HasAttr(attr->mNameSpace, matchAttribute)) {
+        else if (!targetElement->HasAttr(attr->mNameSpace, matchAttribute)) {
           result = false;
         }
         else if (attr->mFunction != NS_ATTR_FUNC_SET) {
@@ -2413,7 +2426,7 @@ static bool SelectorMatches(Element* aElement,
 #ifdef DEBUG
           bool hasAttr =
 #endif
-              aElement->GetAttr(attr->mNameSpace, matchAttribute, value);
+              targetElement->GetAttr(attr->mNameSpace, matchAttribute, value);
           NS_ASSERTION(hasAttr, "HasAttr lied");
           result = AttrMatchesValue(attr, value, isHTML);
         }
@@ -2428,7 +2441,7 @@ static bool SelectorMatches(Element* aElement,
     for (nsCSSSelector *negation = aSelector->mNegations;
          result && negation; negation = negation->mNegations) {
       bool dependence = false;
-      result = !SelectorMatches(aElement, negation, aNodeMatchContext,
+      result = !SelectorMatches(targetElement, negation, aNodeMatchContext,
                                 aTreeMatchContext,
                                 SelectorMatchesFlags::IS_PSEUDO_CLASS_ARGUMENT,
                                 &dependence);
@@ -2822,7 +2835,9 @@ void ContentEnumFunc(const RuleValue& value, nsCSSSelector* aSelector,
   if (nodeContext.mIsRelevantLink) {
     data->mTreeMatchContext.SetHaveRelevantLink();
   }
-  if (ancestorFilter &&
+  // XXX: Ignore the ancestor filter if we're testing the assigned slot.
+  bool useAncestorFilter = !(data->mTreeMatchContext.mForAssignedSlot);
+  if (useAncestorFilter && ancestorFilter &&
       !ancestorFilter->MightHaveMatchingAncestor<RuleValue::eMaxAncestorHashes>(
           value.mAncestorSelectorHashes)) {
     // We won't match; nothing else to do here
@@ -2894,7 +2909,13 @@ nsCSSRuleProcessor::RulesMatching(ElementRuleProcessorData *aData)
     NodeMatchContext nodeContext(EventStates(),
                                  nsCSSRuleProcessor::IsLink(aData->mElement),
 				 aData->mElementIsFeatureless);
-    cascade->mRuleHash.EnumerateAllRules(aData->mElement, aData, nodeContext);
+    // Test against the assigned slot rather than the slottable if we're
+    // matching the ::slotted() pseudo.
+    Element* targetElement = aData->mElement;
+    if (aData->mTreeMatchContext.mForAssignedSlot) {
+      targetElement = aData->mElement->GetAssignedSlot()->AsElement();
+    }
+    cascade->mRuleHash.EnumerateAllRules(targetElement, aData, nodeContext);
   }
 }
 
diff --git a/layout/style/nsRuleProcessorData.h b/layout/style/nsRuleProcessorData.h
index 07c885994f..94ec400cfc 100644
--- a/layout/style/nsRuleProcessorData.h
+++ b/layout/style/nsRuleProcessorData.h
@@ -409,6 +409,10 @@ struct MOZ_STACK_CLASS TreeMatchContext {
   // Whether we're currently in the topmost scope for shadow DOM.
   bool mIsTopmostScope;
 
+  // Whether we're testing for the assigned slot instead of the slottable
+  // when matching type/class/ID/attribute.
+  bool mForAssignedSlot;
+
   enum MatchVisited {
     eNeverMatchVisited,
     eMatchVisitedDefault
@@ -444,6 +448,7 @@ struct MOZ_STACK_CLASS TreeMatchContext {
     , mForScopedStyle(false)
     , mCurrentStyleScope(nullptr)
     , mIsTopmostScope(false)
+    , mForAssignedSlot(false)
   {
     if (aMatchVisited != eNeverMatchVisited) {
       nsILoadContext* loadContext = mDocument->GetLoadContext();