Clean up nth-index calculation in SelectorChecker.

Source/core/css/SelectorChecker.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 165 matching lines @@
 static bool isFirstOfType(Element& element, const QualifiedName& type)
 {
     return !ElementTraversal::previousSibling(element, HasTagName(type));
 }
 
 static bool isLastOfType(Element& element, const QualifiedName& type)
 {
     return !ElementTraversal::nextSibling(element, HasTagName(type));
 }
 
-static int countElementsBefore(Element& element)
+static int nthChildIndex(Element& element)
 {
     if (NthIndexCache* nthIndexCache = element.document().nthIndexCache())
-        return nthIndexCache->nthChildIndex(element) - 1;
+        return nthIndexCache->nthChildIndex(element);
 
-    int count = 0;
+    int index = 1;
     for (const Element* sibling = ElementTraversal::previousSibling(element); sibling; sibling = ElementTraversal::previousSibling(*sibling))
-        count++;
+        index++;
 
-    return count;
+    return index;
 }
 
-static int countElementsOfTypeBefore(Element& element, const QualifiedName& type)
+static int nthOfTypeIndex(Element& element, const QualifiedName& type)
 {
     if (NthIndexCache* nthIndexCache = element.document().nthIndexCache())
-        return nthIndexCache->nthChildIndexOfType(element, type) - 1;
-    int count = 0;
+        return nthIndexCache->nthChildIndexOfType(element, type);
+    int index = 1;
     for (const Element* sibling = ElementTraversal::previousSibling(element, HasTagName(type)); sibling; sibling = ElementTraversal::previousSibling(*sibling, HasTagName(type)))
-        ++count;
-    return count;
+        ++index;
+    return index;
 }
 
-static int countElementsAfter(Element& element)
+static int nthLastChildIndex(Element& element)
 {
     if (NthIndexCache* nthIndexCache = element.document().nthIndexCache())
-        return nthIndexCache->nthLastChildIndex(element) - 1;
+        return nthIndexCache->nthLastChildIndex(element);
 
-    int count = 0;
+    int index = 1;
     for (const Element* sibling = ElementTraversal::nextSibling(element); sibling; sibling = ElementTraversal::nextSibling(*sibling))
-        ++count;
-    return count;
+        ++index;
+    return index;
 }
 
-static int countElementsOfTypeAfter(Element& element, const QualifiedName& type)
+static int nthLastOfTypeIndex(Element& element, const QualifiedName& type)
 {
     if (NthIndexCache* nthIndexCache = element.document().nthIndexCache())
-        return nthIndexCache->nthLastChildIndexOfType(element, type) - 1;
+        return nthIndexCache->nthLastChildIndexOfType(element, type);
 
-    int count = 0;
+    int index = 1;
     for (const Element* sibling = ElementTraversal::nextSibling(element, HasTagName(type)); sibling; sibling = ElementTraversal::nextSibling(*sibling, HasTagName(type)))
-        ++count;
-    return count;
+        ++index;
+    return index;
 }
 
 bool SelectorChecker::match(const SelectorCheckingContext& context, MatchResult* result) const
 {
     return matchSelector(context, result) == SelectorMatches;
 }
 
 // Recursive check of selectors and combinators
 // It can return 4 different values:
 // * SelectorMatches          - the selector matches the element e
@@ skipping 566 matching lines @@
                 return false;
             return isFirstOfType(element, element.tagQName()) && isLastOfType(element, element.tagQName());
         }
         break;
     case CSSSelector::PseudoNthChild:
         if (!selector.parseNth())
             break;
         if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
             if (m_mode == ResolvingStyle)
                 parent->setChildrenAffectedByForwardPositionalRules();
-            return selector.matchNth(1 + countElementsBefore(element));
+            return selector.matchNth(nthChildIndex(element));
         }
         break;
     case CSSSelector::PseudoNthOfType:
         if (!selector.parseNth())
             break;
         if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
             if (m_mode == ResolvingStyle)
                 parent->setChildrenAffectedByForwardPositionalRules();
-            return selector.matchNth(1 + countElementsOfTypeBefore(element, element.tagQName()));
+            return selector.matchNth(nthOfTypeIndex(element, element.tagQName()));
         }
         break;
     case CSSSelector::PseudoNthLastChild:
         if (!selector.parseNth())
             break;
         if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
             if (m_mode == ResolvingStyle)
                 parent->setChildrenAffectedByBackwardPositionalRules();
             if (!parent->isFinishedParsingChildren())
                 return false;
-            return selector.matchNth(1 + countElementsAfter(element));
+            return selector.matchNth(nthLastChildIndex(element));
         }
         break;
     case CSSSelector::PseudoNthLastOfType:
         if (!selector.parseNth())
             break;
         if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
             if (m_mode == ResolvingStyle)
                 parent->setChildrenAffectedByBackwardPositionalRules();
             if (!parent->isFinishedParsingChildren())
                 return false;
-            return selector.matchNth(1 + countElementsOfTypeAfter(element, element.tagQName()));
+            return selector.matchNth(nthLastOfTypeIndex(element, element.tagQName()));
         }
         break;
     case CSSSelector::PseudoTarget:
         return element == element.document().cssTarget();
     case CSSSelector::PseudoAny:
         {
             SelectorCheckingContext subContext(context);
             subContext.isSubSelector = true;
             ASSERT(selector.selectorList());
             for (subContext.selector = selector.selectorList()->first(); subContext.selector; subContext.selector = CSSSelectorList::next(*subContext.selector)) {
@@ skipping 344 matching lines @@
 }
 
 bool SelectorChecker::matchesFocusPseudoClass(const Element& element)
 {
     if (InspectorInstrumentation::forcePseudoState(const_cast<Element*>(&element), CSSSelector::PseudoFocus))
         return true;
     return element.focused() && isFrameFocused(element);
 }
 
 }