Make HTMLNames threadsafe

Source/WTF/wtf/text/StringStatics.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
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * 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 "StringStatics.h"
 
 #ifdef SKIP_STATIC_CONSTRUCTORS_ON_GCC
 #define ATOMICSTRING_HIDE_GLOBALS 1
 #endif
 
 #include "AtomicString.h"
 #include "DynamicAnnotations.h"
 #include "MainThread.h"
 #include "StaticConstructors.h"
 #include "StringImpl.h"
@@ skipping 29 matching lines @@
     if (is8Bit())
         setHash(StringHasher::computeHashAndMaskTop8Bits(m_data8, m_length));
     else
         setHash(StringHasher::computeHashAndMaskTop8Bits(m_data16, m_length));
     return existingHash();
 }
 
 void AtomicString::init()
 {
     static bool initialized;
-    if (!initialized) {
-        // Initialization is not thread safe, so this function must be called from the main thread first.
-        ASSERT(isMainThread());
+    if (initialized)
+        return;
+    initialized = true;
 
-        // Use placement new to initialize the globals.
-        new (NotNull, (void*)&nullAtom) AtomicString;
-        new (NotNull, (void*)&emptyAtom) AtomicString("");
-        new (NotNull, (void*)&textAtom) AtomicString("#text", AtomicString::ConstructFromLiteral);
-        new (NotNull, (void*)&commentAtom) AtomicString("#comment", AtomicString::ConstructFromLiteral);
-        new (NotNull, (void*)&starAtom) AtomicString("*", AtomicString::ConstructFromLiteral);
-        new (NotNull, (void*)&xmlAtom) AtomicString("xml", AtomicString::ConstructFromLiteral);
-        new (NotNull, (void*)&xmlnsAtom) AtomicString("xmlns", AtomicString::ConstructFromLiteral);
-        new (NotNull, (void*)&xlinkAtom) AtomicString("xlink", AtomicString::ConstructFromLiteral);
+    ASSERT(isMainThread());
 
-        initialized = true;
-    }
+    new (NotNull, (void*)&nullAtom) AtomicString;
+    new (NotNull, (void*)&emptyAtom) AtomicString("");

[eseidel, 2013/04/10 20:53:50]

I assume this is going to correctly end up with "emptyString()" as the
underlying StringImpl?

[abarth-chromium, 2013/04/10 21:00:51]

Yes.  This part isn't changing.  I'm just switching the if-statement to be an
early return.

+}
+
+void StringStatics::init()
+{
+    static bool initialized;
+    if (initialized)
+        return;
+    initialized = true;
+
+    ASSERT(isMainThread());
+
+    // FIXME: These should be allocated at compile time.
+    new (NotNull, (void*)&textAtom) AtomicString("#text", AtomicString::ConstructFromLiteral);
+    new (NotNull, (void*)&commentAtom) AtomicString("#comment", AtomicString::ConstructFromLiteral);
+    new (NotNull, (void*)&starAtom) AtomicString("*", AtomicString::ConstructFromLiteral);
+    new (NotNull, (void*)&xmlAtom) AtomicString("xml", AtomicString::ConstructFromLiteral);
+    new (NotNull, (void*)&xmlnsAtom) AtomicString("xmlns", AtomicString::ConstructFromLiteral);
+    new (NotNull, (void*)&xlinkAtom) AtomicString("xlink", AtomicString::ConstructFromLiteral);
 }
 
 }