A thread-safe Media Query Parser

Source/core/css/MediaQuery.cpp

 /*
  * CSS Media Query
  *
  * Copyright (C) 2005, 2006 Kimmo Kinnunen <kimmo.t.kinnunen@nokia.com>.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 11 matching lines @@
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/css/MediaQuery.h"
 
+#include "MediaTypeNames.h"
 #include "core/css/MediaQueryExp.h"
+#include "core/html/parser/HTMLParserIdioms.h"
 #include "wtf/NonCopyingSort.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace WebCore {
 
 // http://dev.w3.org/csswg/cssom/#serialize-a-media-query
 String MediaQuery::serialize() const
 {
     StringBuilder result;
     switch (m_restrictor) {
     case MediaQuery::Only:
         result.append("only ");
         break;
     case MediaQuery::Not:
         result.append("not ");
         break;
     case MediaQuery::None:
         break;
     }
 
     if (m_expressions->isEmpty()) {
         result.append(m_mediaType);
         return result.toString();
     }
 
-    if (m_mediaType != "all" || m_restrictor != None) {
+    if (m_mediaType != MediaTypeNames::all || m_restrictor != None) {
         result.append(m_mediaType);
         result.append(" and ");
     }
 
     result.append(m_expressions->at(0)->serialize());
     for (size_t i = 1; i < m_expressions->size(); ++i) {
         result.append(" and ");
         result.append(m_expressions->at(i)->serialize());
     }
     return result.toString();
 }
 
 static bool expressionCompare(const OwnPtr<MediaQueryExp>& a, const OwnPtr<MediaQueryExp>& b)
 {
     return codePointCompare(a->serialize(), b->serialize()) < 0;
 }
 
-MediaQuery::MediaQuery(Restrictor r, const AtomicString& mediaType, PassOwnPtr<ExpressionVector> expressions)
+MediaQuery::MediaQuery(Restrictor r, const String& mediaType, PassOwnPtr<ExpressionVector> expressions)
     : m_restrictor(r)
-    , m_mediaType(mediaType.lower())
+    , m_mediaType(attemptStaticStringCreation(mediaType.lower()))
     , m_expressions(expressions)
 {
     if (!m_expressions) {
         m_expressions = adoptPtr(new ExpressionVector);
         return;
     }
 
     nonCopyingSort(m_expressions->begin(), m_expressions->end(), expressionCompare);
 
     // Remove all duplicated expressions.
     MediaQueryExp* key = 0;
     for (int i = m_expressions->size() - 1; i >= 0; --i) {
         MediaQueryExp* exp = m_expressions->at(i).get();
 
         if (key && *exp == *key)
             m_expressions->remove(i);
         else
             key = exp;
     }
 }
 
 MediaQuery::MediaQuery(const MediaQuery& o)
     : m_restrictor(o.m_restrictor)
-    , m_mediaType(o.m_mediaType)
+    , m_mediaType(o.m_mediaType.impl())
     , m_expressions(adoptPtr(new ExpressionVector(o.m_expressions->size())))
     , m_serializationCache(o.m_serializationCache)
 {
     for (unsigned i = 0; i < m_expressions->size(); ++i)
         (*m_expressions)[i] = o.m_expressions->at(i)->copy();
 }
 
 MediaQuery::~MediaQuery()
 {
 }
 
 // http://dev.w3.org/csswg/cssom/#compare-media-queries
 bool MediaQuery::operator==(const MediaQuery& other) const
 {
     return cssText() == other.cssText();
 }
 
 // http://dev.w3.org/csswg/cssom/#serialize-a-list-of-media-queries
 String MediaQuery::cssText() const
 {
     if (m_serializationCache.isNull())
         const_cast<MediaQuery*>(this)->m_serializationCache = serialize();
 
     return m_serializationCache;
 }
 
 }