Add support for case-insensitive attribute value selectors

Source/core/css/CSSSelector.h

 /*
  * Copyright (C) 1999-2003 Lars Knoll (knoll@kde.org)
  *               1999 Waldo Bastian (bastian@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 219 matching lines @@
             BottomRightMarginBox,
             BottomRightCornerMarginBox,
             LeftTopMarginBox,
             LeftMiddleMarginBox,
             LeftBottomMarginBox,
             RightTopMarginBox,
             RightMiddleMarginBox,
             RightBottomMarginBox,
         };
 
+        enum AttributeFlags {
+            NoAttributeFlags,
+            CaseInsensitive,
+        };
+
         PseudoType pseudoType() const
         {
             if (m_pseudoType == PseudoNotParsed)
                 extractPseudoType();
             return static_cast<PseudoType>(m_pseudoType);
         }
 
         static PseudoType parsePseudoType(const AtomicString&);
         static PseudoId pseudoId(PseudoType);
 
         // Selectors are kept in an array by CSSSelectorList. The next component of the selector is
         // the next item in the array.
         const CSSSelector* tagHistory() const { return m_isLastInTagHistory ? 0 : const_cast<CSSSelector*>(this + 1); }
 
         const QualifiedName& tagQName() const;
         const AtomicString& value() const;
 
         // WARNING: Use of QualifiedName by attribute() is a lie.
         // attribute() will return a QualifiedName with prefix and namespaceURI
         // set to starAtom to mean "matches any namespace". Be very careful
         // how you use the returned QualifiedName.
         // http://www.w3.org/TR/css3-selectors/#attrnmsp
         const QualifiedName& attribute() const;
+        unsigned attributeFlags() const;

[eseidel, 2014/05/07 18:12:58]

Can't this return the enum?  Normally we store enums as unsigned (bitfields) but
cast them to/from their enum type in getters/setters to allow the rest of the
code to use the compiler's type-safety.

[fs, 2014/06/12 16:42:31]

Sure (done in [1]). It doesn't really add much in terms of type-safety though
(all uses as of now imply widening conversions). Having a flag-field with a
single flag might be a bit overkill though =)

         // Returns the argument of a parameterized selector. For example, nth-child(2) would have an argument of 2.
         const AtomicString& argument() const { return m_hasRareData ? m_data.m_rareData->m_argument : nullAtom; }
         const CSSSelectorList* selectorList() const { return m_hasRareData ? m_data.m_rareData->m_selectorList.get() : 0; }
 
 #ifndef NDEBUG
         void show() const;
         void show(int indent) const;
 #endif
 
         void setValue(const AtomicString&);
-        void setAttribute(const QualifiedName&);
+        void setAttribute(const QualifiedName&, unsigned flags);
         void setArgument(const AtomicString&);
         void setSelectorList(PassOwnPtr<CSSSelectorList>);
         void setMatchUserAgentOnly();
 
         bool parseNth() const;
         bool matchNth(int count) const;
 
         bool matchesPseudoElement() const;
         bool isUnknownPseudoElement() const;
         bool isCustomPseudoElement() const;
@@ skipping 46 matching lines @@
             static PassRefPtr<RareData> create(const AtomicString& value) { return adoptRef(new RareData(value)); }
             ~RareData();
 
             bool parseNth();
             bool matchNth(int count);
 
             AtomicString m_value;
             int m_a; // Used for :nth-*
             int m_b; // Used for :nth-*
             QualifiedName m_attribute; // used for attribute selector
+            unsigned m_attributeFlags; // used for attribute selector (with value)

[eseidel, 2014/05/29 00:25:01]

I think we have a ton of CSSSelector objects... I worry this could be bad for
memory?  Ojan would know.

[apavlov, 2014/06/11 12:26:19]

This is RareData. Consequently, it will be found in a small fraction of all
CSSSelectors...

[fs, 2014/06/12 16:42:31]

Yes, hopefully they are indeed "rare". Disregarding that though there's (at
least) two ways to pack this differently:

1) Move the field to the bitfield in CSSSelector (it's only 1 bit right now, and
there seems to be 10 bits left there).
2) Make a union of this and m_a/m_b.

Both of those will cause some "collateral damage" though
(renaming/initializer-lists/etc.)

Any preference there? ((2) sketched out in [1])

             AtomicString m_argument; // Used for :contains, :lang, :nth-*
             OwnPtr<CSSSelectorList> m_selectorList; // Used for :-webkit-any and :not
 
         private:
             RareData(const AtomicString& value);
         };
         void createRareData();
 
         union DataUnion {
             DataUnion() : m_value(0) { }
             StringImpl* m_value;
             QualifiedName::QualifiedNameImpl* m_tagQName;
             RareData* m_rareData;
         } m_data;
     };
 
 inline const QualifiedName& CSSSelector::attribute() const
 {
     ASSERT(isAttributeSelector());
     ASSERT(m_hasRareData);
     return m_data.m_rareData->m_attribute;
 }
 
+inline unsigned CSSSelector::attributeFlags() const
+{
+    ASSERT(isAttributeSelector());
+    ASSERT(m_hasRareData);
+    return m_data.m_rareData->m_attributeFlags;
+}
+
 inline bool CSSSelector::matchesPseudoElement() const
 {
     if (m_pseudoType == PseudoUnknown)
         extractPseudoType();
     return m_match == PseudoElement;
 }
 
 inline bool CSSSelector::isUnknownPseudoElement() const
 {
     return m_match == PseudoElement && m_pseudoType == PseudoUnknown;
@@ skipping 139 matching lines @@
     if (m_hasRareData)
         return m_data.m_rareData->m_value;
     // AtomicString is really just a StringImpl* so the cast below is safe.
     // FIXME: Perhaps call sites could be changed to accept StringImpl?
     return *reinterpret_cast<const AtomicString*>(&m_data.m_value);
 }
 
 } // namespace WebCore
 
 #endif // CSSSelector_h