third_party/WebKit/Source/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
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#include "wtf/text/StringStatics.h"

#include "wtf/DynamicAnnotations.h"
#include "wtf/StaticConstructors.h"
#include "wtf/text/AtomicString.h"
#include "wtf/text/StringImpl.h"

namespace WTF {

StringImpl* StringImpl::empty() {
  DEFINE_STATIC_LOCAL(StringImpl, emptyString, (ConstructEmptyString));
  WTF_ANNOTATE_BENIGN_RACE(&emptyString,
                           "Benign race on the reference counter of a static "
                           "string created by StringImpl::empty");
  return &emptyString;
}

StringImpl* StringImpl::empty16Bit() {
  DEFINE_STATIC_LOCAL(StringImpl, emptyString, (ConstructEmptyString16Bit));
  WTF_ANNOTATE_BENIGN_RACE(&emptyString,
                           "Benign race on the reference counter of a static "
                           "string created by StringImpl::empty16Bit");
  return &emptyString;
}

WTF_EXPORT DEFINE_GLOBAL(AtomicString, nullAtom);
WTF_EXPORT DEFINE_GLOBAL(AtomicString, emptyAtom);
WTF_EXPORT DEFINE_GLOBAL(AtomicString, starAtom);
WTF_EXPORT DEFINE_GLOBAL(AtomicString, xmlAtom);
WTF_EXPORT DEFINE_GLOBAL(AtomicString, xmlnsAtom);
WTF_EXPORT DEFINE_GLOBAL(AtomicString, xlinkAtom);

// This is not an AtomicString because it is unlikely to be used as an
// event/element/attribute name, so it shouldn't pollute the AtomicString hash
// table.
WTF_EXPORT DEFINE_GLOBAL(String, xmlnsWithColon);

NEVER_INLINE unsigned StringImpl::hashSlowCase() const {
  if (is8Bit())
    setHash(StringHasher::computeHashAndMaskTop8Bits(characters8(), m_length));
  else
    setHash(StringHasher::computeHashAndMaskTop8Bits(characters16(), m_length));
  return existingHash();
}

void AtomicString::init() {
  ASSERT(isMainThread());

  new (NotNull, (void*)&nullAtom) AtomicString;
  new (NotNull, (void*)&emptyAtom) AtomicString("");
}

template <unsigned charactersCount>
PassRefPtr<StringImpl> addStaticASCIILiteral(
    const char (&characters)[charactersCount]) {
  unsigned length = charactersCount - 1;
  unsigned hash = StringHasher::computeHashAndMaskTop8Bits(
      reinterpret_cast<const LChar*>(characters), length);
  return adoptRef(StringImpl::createStatic(characters, length, hash));
}

void StringStatics::init() {
  ASSERT(isMainThread());

  // FIXME: These should be allocated at compile time.
  new (NotNull, (void*)&starAtom) AtomicString("*");
  new (NotNull, (void*)&xmlAtom) AtomicString(addStaticASCIILiteral("xml"));
  new (NotNull, (void*)&xmlnsAtom) AtomicString(addStaticASCIILiteral("xmlns"));
  new (NotNull, (void*)&xlinkAtom) AtomicString(addStaticASCIILiteral("xlink"));
  new (NotNull, (void*)&xmlnsWithColon) String("xmlns:");
}

}  // namespace WTF