API/OpaqueJSString.cpp

   1 /*
   2  * Copyright (C) 2008 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 #include "OpaqueJSString.h"
  28
  29 #include "CallFrame.h"
  30 #include "Identifier.h"
  31 #include "IdentifierInlines.h"
  32 #include "JSGlobalObject.h"
  33 #include <wtf/text/StringView.h>
  34
  35 using namespace JSC;
  36
  37 RefPtr<OpaqueJSString> OpaqueJSString::create(const String& string)
  38 {
  39     if (string.isNull())
  40         return nullptr;
  41
  42     return adoptRef(new OpaqueJSString(string));
  43 }
  44
  45 OpaqueJSString::~OpaqueJSString()
  46 {
  47     // m_characters is put in a local here to avoid an extra atomic load.
  48     UChar* characters = m_characters;
  49     if (!characters)
  50         return;
  51
  52     if (!m_string.is8Bit() && m_string.characters16() == characters)
  53         return;
  54
  55     fastFree(characters);
  56 }
  57
  58 String OpaqueJSString::string() const
  59 {
  60     // Return a copy of the wrapped string, because the caller may make it an Identifier.
  61     return m_string.isolatedCopy();
  62 }
  63
  64 Identifier OpaqueJSString::identifier(VM* vm) const
  65 {
  66     if (m_string.isNull())
  67         return Identifier();
  68
  69     if (m_string.isEmpty())
  70         return Identifier(Identifier::EmptyIdentifier);
  71
  72     if (m_string.is8Bit())
  73         return Identifier::fromString(vm, m_string.characters8(), m_string.length());
  74
  75     return Identifier::fromString(vm, m_string.characters16(), m_string.length());
  76 }
  77
  78 const UChar* OpaqueJSString::characters()
  79 {
  80     // m_characters is put in a local here to avoid an extra atomic load.
  81     UChar* characters = m_characters;
  82     if (characters)
  83         return characters;
  84
  85     if (m_string.isNull())
  86         return nullptr;
  87
  88     unsigned length = m_string.length();
  89     UChar* newCharacters = static_cast<UChar*>(fastMalloc(length * sizeof(UChar)));
  90     StringView(m_string).getCharactersWithUpconvert(newCharacters);
  91
  92     if (!m_characters.compare_exchange_strong(characters, newCharacters)) {
  93         fastFree(newCharacters);
  94         return characters;
  95     }
  96
  97     return newCharacters;
  98 }
  99
 100 bool OpaqueJSString::equal(const OpaqueJSString* a, const OpaqueJSString* b)
 101 {
 102     if (a == b)
 103         return true;
 104
 105     if (!a || !b)
 106         return false;
 107
 108     return a->m_string == b->m_string;
 109 }