WebCore/platform/text/AtomicString.cpp - platform/external/webkit - Git at Google

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */

 #include "config.h"

 #ifdef SKIP_STATIC_CONSTRUCTORS_ON_GCC
 #define ATOMICSTRING_HIDE_GLOBALS 1
 #endif

 #include "AtomicString.h"

 #include "StaticConstructors.h"
 #include "StringHash.h"
 #include "ThreadGlobalData.h"
 #include <wtf/Threading.h>
 #include <wtf/HashSet.h>

 #if USE(JSC)
 #include <runtime/Identifier.h>
 using JSC::Identifier;
 using JSC::UString;
 #endif

 namespace WebCore {

 static inline HashSet<StringImpl*>& stringTable()
 {
     return threadGlobalData().atomicStringTable();
 }

 struct CStringTranslator {
     static unsigned hash(const char* c)
     {
         return StringImpl::computeHash(c);
     }

     static bool equal(StringImpl* r, const char* s)
     {
         int length = r->length();
         const UChar* d = r->characters();
         for (int i = 0; i != length; ++i) {
             unsigned char c = s[i];
             if (d[i] != c)
                 return false;
         }
         return s[length] == 0;
     }

     static void translate(StringImpl*& location, const char* const& c, unsigned hash)
     {
         location = StringImpl::create(c).releaseRef();
         location->setHash(hash);
         location->setInTable();
     }
 };

 bool operator==(const AtomicString& a, const char* b)
 {
     StringImpl* impl = a.impl();
     if ((!impl || !impl->characters()) && !b)
         return true;
     if ((!impl || !impl->characters()) || !b)
         return false;
     return CStringTranslator::equal(impl, b);
 }

 PassRefPtr<StringImpl> AtomicString::add(const char* c)
 {
     if (!c)
         return 0;
     if (!*c)
         return StringImpl::empty();
     pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<const char*, CStringTranslator>(c);
     if (!addResult.second)
         return *addResult.first;
     return adoptRef(*addResult.first);
 }

 struct UCharBuffer {
     const UChar* s;
     unsigned length;
 };

 static inline bool equal(StringImpl* string, const UChar* characters, unsigned length)
 {
     if (string->length() != length)
         return false;

     // FIXME: perhaps we should have a more abstract macro that indicates when
     // going 4 bytes at a time is unsafe
 #if CPU(ARM) || CPU(SH4)
     const UChar* stringCharacters = string->characters();
     for (unsigned i = 0; i != length; ++i) {
         if (*stringCharacters++ != *characters++)
             return false;
     }
     return true;
 #else
     /* Do it 4-bytes-at-a-time on architectures where it's safe */

     const uint32_t* stringCharacters = reinterpret_cast<const uint32_t*>(string->characters());
     const uint32_t* bufferCharacters = reinterpret_cast<const uint32_t*>(characters);

     unsigned halfLength = length >> 1;
     for (unsigned i = 0; i != halfLength; ++i) {
         if (*stringCharacters++ != *bufferCharacters++)
             return false;
     }

     if (length & 1 &&  *reinterpret_cast<const uint16_t*>(stringCharacters) != *reinterpret_cast<const uint16_t*>(bufferCharacters))
         return false;

     return true;
 #endif
 }

 struct UCharBufferTranslator {
     static unsigned hash(const UCharBuffer& buf)
     {
         return StringImpl::computeHash(buf.s, buf.length);
     }

     static bool equal(StringImpl* const& str, const UCharBuffer& buf)
     {
         return WebCore::equal(str, buf.s, buf.length);
     }

     static void translate(StringImpl*& location, const UCharBuffer& buf, unsigned hash)
     {
         location = StringImpl::create(buf.s, buf.length).releaseRef();
         location->setHash(hash);
         location->setInTable();
     }
 };

 struct HashAndCharacters {
     unsigned hash;
     const UChar* characters;
     unsigned length;
 };

 struct HashAndCharactersTranslator {
     static unsigned hash(const HashAndCharacters& buffer)
     {
         ASSERT(buffer.hash == StringImpl::computeHash(buffer.characters, buffer.length));
         return buffer.hash;
     }

     static bool equal(StringImpl* const& string, const HashAndCharacters& buffer)
     {
         return WebCore::equal(string, buffer.characters, buffer.length);
     }

     static void translate(StringImpl*& location, const HashAndCharacters& buffer, unsigned hash)
     {
         location = StringImpl::create(buffer.characters, buffer.length).releaseRef();
         location->setHash(hash);
         location->setInTable();
     }
 };

 PassRefPtr<StringImpl> AtomicString::add(const UChar* s, int length)
 {
     if (!s)
         return 0;

     if (length == 0)
         return StringImpl::empty();

     UCharBuffer buf = { s, length };
     pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<UCharBuffer, UCharBufferTranslator>(buf);

     // If the string is newly-translated, then we need to adopt it.
     // The boolean in the pair tells us if that is so.
     return addResult.second ? adoptRef(*addResult.first) : *addResult.first;
 }

 PassRefPtr<StringImpl> AtomicString::add(const UChar* s)
 {
     if (!s)
         return 0;

     int length = 0;
     while (s[length] != UChar(0))
         length++;

     if (length == 0)
         return StringImpl::empty();

     UCharBuffer buf = {s, length};
     pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<UCharBuffer, UCharBufferTranslator>(buf);

     // If the string is newly-translated, then we need to adopt it.
     // The boolean in the pair tells us if that is so.
     return addResult.second ? adoptRef(*addResult.first) : *addResult.first;
 }

 PassRefPtr<StringImpl> AtomicString::add(StringImpl* r)
 {
     if (!r || r->inTable())
         return r;

     if (r->length() == 0)
         return StringImpl::empty();

     StringImpl* result = *stringTable().add(r).first;
     if (result == r)
         r->setInTable();
     return result;
 }

 void AtomicString::remove(StringImpl* r)
 {
     stringTable().remove(r);
 }

 AtomicString AtomicString::lower() const
 {
     // Note: This is a hot function in the Dromaeo benchmark.
     StringImpl* impl = this->impl();
     RefPtr<StringImpl> newImpl = impl->lower();
     if (LIKELY(newImpl == impl))
         return *this;
     return AtomicString(newImpl);
 }

 #if USE(JSC)
 PassRefPtr<StringImpl> AtomicString::add(const JSC::Identifier& identifier)
 {
     if (identifier.isNull())
         return 0;

     UString::Rep* string = identifier.ustring().rep();
     unsigned length = string->size();
     if (!length)
         return StringImpl::empty();

     HashAndCharacters buffer = { string->existingHash(), string->data(), length };
     pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<HashAndCharacters, HashAndCharactersTranslator>(buffer);
     if (!addResult.second)
         return *addResult.first;
     return adoptRef(*addResult.first);
 }

 PassRefPtr<StringImpl> AtomicString::add(const JSC::UString& ustring)
 {
     if (ustring.isNull())
         return 0;

     UString::Rep* string = ustring.rep();
     unsigned length = string->size();
     if (!length)
         return StringImpl::empty();

     HashAndCharacters buffer = { string->hash(), string->data(), length };
     pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<HashAndCharacters, HashAndCharactersTranslator>(buffer);
     if (!addResult.second)
         return *addResult.first;
     return adoptRef(*addResult.first);
 }

 AtomicStringImpl* AtomicString::find(const JSC::Identifier& identifier)
 {
     if (identifier.isNull())
         return 0;

     UString::Rep* string = identifier.ustring().rep();
     unsigned length = string->size();
     if (!length)
         return static_cast<AtomicStringImpl*>(StringImpl::empty());

     HashAndCharacters buffer = { string->existingHash(), string->data(), length };
     HashSet<StringImpl*>::iterator iterator = stringTable().find<HashAndCharacters, HashAndCharactersTranslator>(buffer);
     if (iterator == stringTable().end())
         return 0;
     return static_cast<AtomicStringImpl*>(*iterator);
 }

 AtomicString::operator UString() const
 {
     return m_string;
 }
 #endif

 DEFINE_GLOBAL(AtomicString, nullAtom)
 DEFINE_GLOBAL(AtomicString, emptyAtom, "")
 DEFINE_GLOBAL(AtomicString, textAtom, "#text")
 DEFINE_GLOBAL(AtomicString, commentAtom, "#comment")
 DEFINE_GLOBAL(AtomicString, starAtom, "*")
 DEFINE_GLOBAL(AtomicString, xmlAtom, "xml")
 DEFINE_GLOBAL(AtomicString, xmlnsAtom, "xmlns")

 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());

         // Use placement new to initialize the globals.
         new ((void*)&nullAtom) AtomicString;
         new ((void*)&emptyAtom) AtomicString("");
         new ((void*)&textAtom) AtomicString("#text");
         new ((void*)&commentAtom) AtomicString("#comment");
         new ((void*)&starAtom) AtomicString("*");
         new ((void*)&xmlAtom) AtomicString("xml");
         new ((void*)&xmlnsAtom) AtomicString("xmlns");

         initialized = true;
     }
 }

 }
	/*
	* Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public License
	* along with this library; see the file COPYING.LIB. If not, write to
	* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*
	*/

	#include "config.h"

	#ifdef SKIP_STATIC_CONSTRUCTORS_ON_GCC
	#define ATOMICSTRING_HIDE_GLOBALS 1
	#endif

	#include "AtomicString.h"

	#include "StaticConstructors.h"
	#include "StringHash.h"
	#include "ThreadGlobalData.h"
	#include <wtf/Threading.h>
	#include <wtf/HashSet.h>

	#if USE(JSC)
	#include <runtime/Identifier.h>
	using JSC::Identifier;
	using JSC::UString;
	#endif

	namespace WebCore {

	static inline HashSet<StringImpl*>& stringTable()
	{
	return threadGlobalData().atomicStringTable();
	}

	struct CStringTranslator {
	static unsigned hash(const char* c)
	{
	return StringImpl::computeHash(c);
	}

	static bool equal(StringImpl* r, const char* s)
	{
	int length = r->length();
	const UChar* d = r->characters();
	for (int i = 0; i != length; ++i) {
	unsigned char c = s[i];
	if (d[i] != c)
	return false;
	}
	return s[length] == 0;
	}

	static void translate(StringImpl& location, const char const& c, unsigned hash)
	{
	location = StringImpl::create(c).releaseRef();
	location->setHash(hash);
	location->setInTable();
	}
	};

	bool operator==(const AtomicString& a, const char* b)
	{
	StringImpl* impl = a.impl();
	if ((!impl \|\| !impl->characters()) && !b)
	return true;
	if ((!impl \|\| !impl->characters()) \|\| !b)
	return false;
	return CStringTranslator::equal(impl, b);
	}

	PassRefPtr<StringImpl> AtomicString::add(const char* c)
	{
	if (!c)
	return 0;
	if (!*c)
	return StringImpl::empty();
	pair<HashSet<StringImpl>::iterator, bool> addResult = stringTable().add<const char, CStringTranslator>(c);
	if (!addResult.second)
	return *addResult.first;
	return adoptRef(*addResult.first);
	}

	struct UCharBuffer {
	const UChar* s;
	unsigned length;
	};

	static inline bool equal(StringImpl* string, const UChar* characters, unsigned length)
	{
	if (string->length() != length)
	return false;

	// FIXME: perhaps we should have a more abstract macro that indicates when
	// going 4 bytes at a time is unsafe
	#if CPU(ARM) \|\| CPU(SH4)
	const UChar* stringCharacters = string->characters();
	for (unsigned i = 0; i != length; ++i) {
	if (stringCharacters++ != characters++)
	return false;
	}
	return true;
	#else
	/* Do it 4-bytes-at-a-time on architectures where it's safe */

	const uint32_t* stringCharacters = reinterpret_cast<const uint32_t*>(string->characters());
	const uint32_t* bufferCharacters = reinterpret_cast<const uint32_t*>(characters);

	unsigned halfLength = length >> 1;
	for (unsigned i = 0; i != halfLength; ++i) {
	if (stringCharacters++ != bufferCharacters++)
	return false;
	}

	if (length & 1 && reinterpret_cast<const uint16_t>(stringCharacters) != reinterpret_cast<const uint16_t>(bufferCharacters))
	return false;

	return true;
	#endif
	}

	struct UCharBufferTranslator {
	static unsigned hash(const UCharBuffer& buf)
	{
	return StringImpl::computeHash(buf.s, buf.length);
	}

	static bool equal(StringImpl* const& str, const UCharBuffer& buf)
	{
	return WebCore::equal(str, buf.s, buf.length);
	}

	static void translate(StringImpl*& location, const UCharBuffer& buf, unsigned hash)
	{
	location = StringImpl::create(buf.s, buf.length).releaseRef();
	location->setHash(hash);
	location->setInTable();
	}
	};

	struct HashAndCharacters {
	unsigned hash;
	const UChar* characters;
	unsigned length;
	};

	struct HashAndCharactersTranslator {
	static unsigned hash(const HashAndCharacters& buffer)
	{
	ASSERT(buffer.hash == StringImpl::computeHash(buffer.characters, buffer.length));
	return buffer.hash;
	}

	static bool equal(StringImpl* const& string, const HashAndCharacters& buffer)
	{
	return WebCore::equal(string, buffer.characters, buffer.length);
	}

	static void translate(StringImpl*& location, const HashAndCharacters& buffer, unsigned hash)
	{
	location = StringImpl::create(buffer.characters, buffer.length).releaseRef();
	location->setHash(hash);
	location->setInTable();
	}
	};

	PassRefPtr<StringImpl> AtomicString::add(const UChar* s, int length)
	{
	if (!s)
	return 0;

	if (length == 0)
	return StringImpl::empty();

	UCharBuffer buf = { s, length };
	pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<UCharBuffer, UCharBufferTranslator>(buf);

	// If the string is newly-translated, then we need to adopt it.
	// The boolean in the pair tells us if that is so.
	return addResult.second ? adoptRef(addResult.first) : addResult.first;
	}

	PassRefPtr<StringImpl> AtomicString::add(const UChar* s)
	{
	if (!s)
	return 0;

	int length = 0;
	while (s[length] != UChar(0))
	length++;

	if (length == 0)
	return StringImpl::empty();

	UCharBuffer buf = {s, length};
	pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<UCharBuffer, UCharBufferTranslator>(buf);

	// If the string is newly-translated, then we need to adopt it.
	// The boolean in the pair tells us if that is so.
	return addResult.second ? adoptRef(addResult.first) : addResult.first;
	}

	PassRefPtr<StringImpl> AtomicString::add(StringImpl* r)
	{
	if (!r \|\| r->inTable())
	return r;

	if (r->length() == 0)
	return StringImpl::empty();

	StringImpl* result = *stringTable().add(r).first;
	if (result == r)
	r->setInTable();
	return result;
	}

	void AtomicString::remove(StringImpl* r)
	{
	stringTable().remove(r);
	}

	AtomicString AtomicString::lower() const
	{
	// Note: This is a hot function in the Dromaeo benchmark.
	StringImpl* impl = this->impl();
	RefPtr<StringImpl> newImpl = impl->lower();
	if (LIKELY(newImpl == impl))
	return *this;
	return AtomicString(newImpl);
	}

	#if USE(JSC)
	PassRefPtr<StringImpl> AtomicString::add(const JSC::Identifier& identifier)
	{
	if (identifier.isNull())
	return 0;

	UString::Rep* string = identifier.ustring().rep();
	unsigned length = string->size();
	if (!length)
	return StringImpl::empty();

	HashAndCharacters buffer = { string->existingHash(), string->data(), length };
	pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<HashAndCharacters, HashAndCharactersTranslator>(buffer);
	if (!addResult.second)
	return *addResult.first;
	return adoptRef(*addResult.first);
	}

	PassRefPtr<StringImpl> AtomicString::add(const JSC::UString& ustring)
	{
	if (ustring.isNull())
	return 0;

	UString::Rep* string = ustring.rep();
	unsigned length = string->size();
	if (!length)
	return StringImpl::empty();

	HashAndCharacters buffer = { string->hash(), string->data(), length };
	pair<HashSet<StringImpl*>::iterator, bool> addResult = stringTable().add<HashAndCharacters, HashAndCharactersTranslator>(buffer);
	if (!addResult.second)
	return *addResult.first;
	return adoptRef(*addResult.first);
	}

	AtomicStringImpl* AtomicString::find(const JSC::Identifier& identifier)
	{
	if (identifier.isNull())
	return 0;

	UString::Rep* string = identifier.ustring().rep();
	unsigned length = string->size();
	if (!length)
	return static_cast<AtomicStringImpl*>(StringImpl::empty());

	HashAndCharacters buffer = { string->existingHash(), string->data(), length };
	HashSet<StringImpl*>::iterator iterator = stringTable().find<HashAndCharacters, HashAndCharactersTranslator>(buffer);
	if (iterator == stringTable().end())
	return 0;
	return static_cast<AtomicStringImpl>(iterator);
	}

	AtomicString::operator UString() const
	{
	return m_string;
	}
	#endif

	DEFINE_GLOBAL(AtomicString, nullAtom)
	DEFINE_GLOBAL(AtomicString, emptyAtom, "")
	DEFINE_GLOBAL(AtomicString, textAtom, "#text")
	DEFINE_GLOBAL(AtomicString, commentAtom, "#comment")
	DEFINE_GLOBAL(AtomicString, starAtom, "*")
	DEFINE_GLOBAL(AtomicString, xmlAtom, "xml")
	DEFINE_GLOBAL(AtomicString, xmlnsAtom, "xmlns")

	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());

	// Use placement new to initialize the globals.
	new ((void*)&nullAtom) AtomicString;
	new ((void*)&emptyAtom) AtomicString("");
	new ((void*)&textAtom) AtomicString("#text");
	new ((void*)&commentAtom) AtomicString("#comment");
	new ((void)&starAtom) AtomicString("");
	new ((void*)&xmlAtom) AtomicString("xml");
	new ((void*)&xmlnsAtom) AtomicString("xmlns");

	initialized = true;
	}
	}

	}