Sibling invalidation sets

Source/core/css/invalidation/InvalidationSet.h

Index: Source/core/css/invalidation/InvalidationSet.h
diff --git a/Source/core/css/invalidation/DescendantInvalidationSet.h b/Source/core/css/invalidation/InvalidationSet.h
similarity index 74%
rename from Source/core/css/invalidation/DescendantInvalidationSet.h
rename to Source/core/css/invalidation/InvalidationSet.h
index 507d58fec0ccda9d635f4a0367c3707304469caf..7a0824eb6c3692bee52577f2749a786bb9f3b131 100644
--- a/Source/core/css/invalidation/DescendantInvalidationSet.h
+++ b/Source/core/css/invalidation/InvalidationSet.h
@@ -28,8 +28,8 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef DescendantInvalidationSet_h
-#define DescendantInvalidationSet_h
+#ifndef InvalidationSet_h
+#define InvalidationSet_h
 
 #include "core/CoreExport.h"
 #include "platform/heap/Handle.h"
@@ -47,25 +47,32 @@ class TracedValue;
 
 // Tracks data to determine which elements of a DOM subtree need to have style
 // recalculated.

[esprehn, 2015/09/10 08:54:53]

comment needs updating?

[Eric Willigers, 2015/09/15 05:39:17]

Done.

-class CORE_EXPORT DescendantInvalidationSet final : public RefCountedWillBeGarbageCollected<DescendantInvalidationSet> {
-    WTF_MAKE_NONCOPYABLE(DescendantInvalidationSet);
+class CORE_EXPORT InvalidationSet final : public RefCountedWillBeGarbageCollected<InvalidationSet> {

[rune, 2015/09/10 13:54:50]

Could we do the DescendantInvalidationSet -> InvalidationSet renaming in a
separate CL?

[Eric Willigers, 2015/09/14 07:20:24]

Done.

+    WTF_MAKE_NONCOPYABLE(InvalidationSet);
 public:
-    static PassRefPtrWillBeRawPtr<DescendantInvalidationSet> create()
+    static PassRefPtrWillBeRawPtr<InvalidationSet> create()
     {
-        return adoptRefWillBeNoop(new DescendantInvalidationSet);
+        return adoptRefWillBeNoop(new InvalidationSet);
     }
 
     static void cacheTracingFlag();
 
     bool invalidatesElement(Element&) const;
 
-    void combine(const DescendantInvalidationSet& other);
+    void combine(const InvalidationSet& other);
 
     void addClass(const AtomicString& className);
     void addId(const AtomicString& id);
     void addTagName(const AtomicString& tagName);
     void addAttribute(const AtomicString& attributeLocalName);
 
+    const InvalidationSet* descendants() const { return m_descendantInvalidationSet.get(); }
+
+    InvalidationSet& ensureInvalidationSet();

[Timothy Loh, 2015/09/10 06:09:40]

awkward name

[Eric Willigers, 2015/09/14 07:20:24]

Renamed to ensureDescendantInvalidationSet

+
+    void setAppliesDirectly() { m_appliesDirectly = true; }
+    bool appliesDirectly() const { return m_appliesDirectly; }
+
     void setWholeSubtreeInvalid();
     bool wholeSubtreeInvalid() const { return m_allDescendantsMightBeInvalid; }
 
@@ -78,6 +85,9 @@ public:
     void setCustomPseudoInvalid() { m_customPseudoInvalid = true; }
     bool customPseudoInvalid() const { return m_customPseudoInvalid; }
 
+    unsigned maxDirectAdjacentSelectors() const { return m_maxDirectAdjacentSelectors; }
+    void setMaxDirectAdjacentSelectors(unsigned value) { m_maxDirectAdjacentSelectors = std::max(value, m_maxDirectAdjacentSelectors); }
+
     bool isEmpty() const { return !m_classes && !m_ids && !m_tagNames && !m_attributes && !m_customPseudoInvalid; }
 
     DECLARE_TRACE();
@@ -89,7 +99,7 @@ public:
 #endif
 
 private:
-    DescendantInvalidationSet();
+    InvalidationSet();
 
     WillBeHeapHashSet<AtomicString>& ensureClassSet();
     WillBeHeapHashSet<AtomicString>& ensureIdSet();
@@ -102,6 +112,15 @@ private:
     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString>> m_tagNames;
     OwnPtrWillBeMember<WillBeHeapHashSet<AtomicString>> m_attributes;
 
+    // Only for sibling invalidation sets, indicates the maximum possible number of siblings affected.
+    unsigned m_maxDirectAdjacentSelectors;
+
+    // Only for sibling invalidation sets, indicates the descendants of siblings.
+    RefPtrWillBeMember<InvalidationSet> m_descendantInvalidationSet;
+
+    // Indicates the sibling/descendant itself is invalid.
+    unsigned m_appliesDirectly : 1;

[esprehn, 2015/09/10 08:54:53]

I'm not a fan of special cases like this where it can be yourself or your kids,
why do you need this?

[rune, 2015/09/10 13:54:50]

This is an optimization for the case where a feature occurs in non-leftmore
compounds only. For instance given the selector:

.a .b { }

We currently create an invalidation set for .a containing .b, but we currently
don't know if there was also a selector like ".a {}" which requires a
LocalStyleChange on the element which gets .a set. So currently, we always do a
LocalStyleChange for the element which gets an invalidation set scheduled.

I don't know if this optimization is more important for sibling invalidation
sets, but I would like to see that optimization as a separate CL.

+
     // If true, all descendants might be invalidated, so a full subtree recalc is required.
     unsigned m_allDescendantsMightBeInvalid : 1;
 
@@ -113,8 +132,12 @@ private:
 
     // If true, insertion point descendants must be invalidated.
     unsigned m_insertionPointCrossing : 1;
+
+    friend class RuleFeatureSetTest;
 };
 
+using InvalidationSetVector = WillBeHeapVector<RefPtrWillBeMember<InvalidationSet>, 8>;
+
 } // namespace blink
 
-#endif // DescendantInvalidationSet_h
+#endif // InvalidationSet_h