A thread-safe Media Query Parser

Source/core/html/parser/HTMLParserIdioms.cpp

 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  *
  * 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
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 356 matching lines @@
 bool threadSafeMatch(const QualifiedName& a, const QualifiedName& b)
 {
     return threadSafeEqual(a.localName().impl(), b.localName().impl());
 }
 
 bool threadSafeMatch(const String& localName, const QualifiedName& qName)
 {
     return threadSafeEqual(localName.impl(), qName.localName().impl());
 }
 
-StringImpl* findStringIfStatic(const UChar* characters, unsigned length)
+template<typename CharType>
+inline StringImpl* findStringIfStatic(const CharType* characters, unsigned length)
 {
     // We don't need to try hashing if we know the string is too long.
     if (length > StringImpl::highestStaticStringLength())
         return 0;
     // computeHashAndMaskTop8Bits is the function StringImpl::hash() uses.
     unsigned hash = StringHasher::computeHashAndMaskTop8Bits(characters, length);
     const WTF::StaticStringsTable& table = StringImpl::allStaticStrings();
     ASSERT(!table.isEmpty());
 
     WTF::StaticStringsTable::const_iterator it = table.find(hash);
     if (it == table.end())
         return 0;
     // It's possible to have hash collisions between arbitrary strings and
     // known identifiers (e.g. "bvvfg" collides with "script").
     // However ASSERTs in StringImpl::createStatic guard against there ever being collisions
     // between static strings.
     if (!equal(it->value, characters, length))
         return 0;
     return it->value;
 }
 
+String attemptStaticStringCreation(const LChar* characters, size_t size)
+{
+    String string(findStringIfStatic(characters, size));
+    if (string.impl())
+        return string;
+    return String(characters, size);
 }
+
+String attemptStaticStringCreation(const UChar* characters, size_t size, CharacterWidth width)
+{
+    String string(findStringIfStatic(characters, size));
+    if (string.impl())
+        return string;
+    if (width == Likely8Bit)
+        string = StringImpl::create8BitIfPossible(characters, size);
+    else if (width == Force8Bit)
+        string = String::make8BitFrom16BitSource(characters, size);
+    else
+        string = String(characters, size);
+
+    return string;
+}
+
+}