1/* 2 * Copyright (C) 2010 Apple Inc. All Rights Reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#include "config.h" 27 28#ifdef SKIP_STATIC_CONSTRUCTORS_ON_GCC 29#define ATOMICSTRING_HIDE_GLOBALS 1 30#endif 31 32#include "AtomicString.h" 33#include "MainThread.h" 34#include "NeverDestroyed.h" 35#include "StaticConstructors.h" 36#include "StringImpl.h" 37 38#if USE(WEB_THREAD) 39#include <pthread.h> 40#endif 41 42namespace WTF { 43 44StringImpl* StringImpl::empty() 45{ 46 static NeverDestroyed<StringImpl> emptyString(ConstructEmptyString); 47 return &emptyString.get(); 48} 49 50// Set the hash early, so that all empty unique StringImpls have a hash, 51// and don't use the normal hashing algorithm - the unique nature of these 52// keys means that we don't need them to match any other string (in fact, 53// that's exactly the oposite of what we want!), and the normal hash would 54// lead to lots of conflicts. 55unsigned StringImpl::hashAndFlagsForEmptyUnique() 56{ 57 static unsigned s_nextHashAndFlagsForEmptyUnique = BufferInternal | s_hashFlag8BitBuffer | s_hashFlagIsAtomic; 58 s_nextHashAndFlagsForEmptyUnique += 1 << s_flagCount; 59 s_nextHashAndFlagsForEmptyUnique |= 1 << 31; 60 return s_nextHashAndFlagsForEmptyUnique; 61} 62 63WTF_EXPORTDATA DEFINE_GLOBAL(AtomicString, nullAtom) 64WTF_EXPORTDATA DEFINE_GLOBAL(AtomicString, emptyAtom) 65WTF_EXPORTDATA DEFINE_GLOBAL(AtomicString, textAtom) 66WTF_EXPORTDATA DEFINE_GLOBAL(AtomicString, commentAtom) 67WTF_EXPORTDATA DEFINE_GLOBAL(AtomicString, starAtom) 68WTF_EXPORTDATA DEFINE_GLOBAL(AtomicString, xmlAtom) 69WTF_EXPORTDATA DEFINE_GLOBAL(AtomicString, xmlnsAtom) 70WTF_EXPORTDATA DEFINE_GLOBAL(AtomicString, xlinkAtom) 71 72NEVER_INLINE unsigned StringImpl::hashSlowCase() const 73{ 74 if (is8Bit()) 75 setHash(StringHasher::computeHashAndMaskTop8Bits(m_data8, m_length)); 76 else 77 setHash(StringHasher::computeHashAndMaskTop8Bits(m_data16, m_length)); 78 return existingHash(); 79} 80 81void AtomicString::init() 82{ 83 static bool initialized; 84 if (!initialized) { 85 // Initialization is not thread safe, so this function must be called from the main thread first. 86 ASSERT(isUIThread()); 87 88 // Use placement new to initialize the globals. 89 new (NotNull, (void*)&nullAtom) AtomicString; 90 new (NotNull, (void*)&emptyAtom) AtomicString(""); 91 new (NotNull, (void*)&textAtom) AtomicString("#text", AtomicString::ConstructFromLiteral); 92 new (NotNull, (void*)&commentAtom) AtomicString("#comment", AtomicString::ConstructFromLiteral); 93 new (NotNull, (void*)&starAtom) AtomicString("*", AtomicString::ConstructFromLiteral); 94 new (NotNull, (void*)&xmlAtom) AtomicString("xml", AtomicString::ConstructFromLiteral); 95 new (NotNull, (void*)&xmlnsAtom) AtomicString("xmlns", AtomicString::ConstructFromLiteral); 96 new (NotNull, (void*)&xlinkAtom) AtomicString("xlink", AtomicString::ConstructFromLiteral); 97 98 initialized = true; 99 } 100} 101 102} 103