API/OpaqueJSString.h

   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 #ifndef OpaqueJSString_h
  27 #define OpaqueJSString_h
  28
  29 #include <atomic>
  30 #include <wtf/ThreadSafeRefCounted.h>
  31 #include <wtf/text/WTFString.h>
  32
  33 namespace JSC {
  34     class Identifier;
  35     class VM;
  36 }
  37
  38 struct OpaqueJSString : public ThreadSafeRefCounted<OpaqueJSString> {
  39     static PassRefPtr<OpaqueJSString> create()
  40     {
  41         return adoptRef(new OpaqueJSString);
  42     }
  43
  44     static PassRefPtr<OpaqueJSString> create(const LChar* characters, unsigned length)
  45     {
  46         return adoptRef(new OpaqueJSString(characters, length));
  47     }
  48
  49     static PassRefPtr<OpaqueJSString> create(const UChar* characters, unsigned length)
  50     {
  51         return adoptRef(new OpaqueJSString(characters, length));
  52     }
  53
  54     JS_EXPORT_PRIVATE static PassRefPtr<OpaqueJSString> create(const String&);
  55
  56     JS_EXPORT_PRIVATE ~OpaqueJSString();
  57
  58     bool is8Bit() { return this ? m_string.is8Bit() : false; }
  59     const LChar* characters8() { return this ? m_string.characters8() : nullptr; }
  60     const UChar* characters16() { return this ? m_string.characters16() : nullptr; }
  61     unsigned length() { return this ? m_string.length() : 0; }
  62
  63     const UChar* characters();
  64
  65     JS_EXPORT_PRIVATE String string() const;
  66     JSC::Identifier identifier(JSC::VM*) const;
  67
  68     static bool equal(const OpaqueJSString*, const OpaqueJSString*);
  69
  70 private:
  71     friend class WTF::ThreadSafeRefCounted<OpaqueJSString>;
  72
  73     OpaqueJSString()
  74         : m_characters(nullptr)
  75     {
  76     }
  77
  78     OpaqueJSString(const String& string)
  79         : m_string(string.isolatedCopy())
  80         , m_characters(m_string.impl() && m_string.is8Bit() ? nullptr : const_cast<UChar*>(m_string.characters16()))
  81     {
  82     }
  83
  84     OpaqueJSString(const LChar* characters, unsigned length)
  85         : m_string(characters, length)
  86         , m_characters(nullptr)
  87     {
  88     }
  89
  90     OpaqueJSString(const UChar* characters, unsigned length)
  91         : m_string(characters, length)
  92         , m_characters(m_string.impl() && m_string.is8Bit() ? nullptr : const_cast<UChar*>(m_string.characters16()))
  93     {
  94     }
  95
  96     String m_string;
  97
  98     // This will be initialized on demand when characters() is called if the string needs up-conversion.
  99     std::atomic<UChar*> m_characters;
 100 };
 101
 102 #endif