runtime/JSStringBuilder.h

   1 /*
   2  * Copyright (C) 2009 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 JSStringBuilder_h
  27 #define JSStringBuilder_h
  28
  29 #include "ExceptionHelpers.h"
  30 #include "JSString.h"
  31 #include <wtf/Vector.h>
  32
  33 namespace JSC {
  34
  35 // FIXME: Should move the last few callers over from this to WTF::StringBuilder.
  36 class JSStringBuilder {
  37 public:
  38     JSStringBuilder()
  39         : m_okay(true)
  40         , m_is8Bit(true)
  41     {
  42     }
  43
  44     void append(LChar character)
  45     {
  46         if (m_is8Bit) {
  47             m_okay &= buffer8.tryAppend(&character, 1);
  48             return;
  49         }
  50         UChar upconvertedCharacter = character;
  51         m_okay &= buffer16.tryAppend(&upconvertedCharacter, 1);
  52     }
  53
  54     void append(UChar character)
  55     {
  56         if (m_is8Bit) {
  57             if (character < 0x100) {
  58                 LChar narrowedCharacter = character;
  59                 m_okay &= buffer8.tryAppend(&narrowedCharacter, 1);
  60                 return;
  61             }
  62             upConvert();
  63         }
  64         m_okay &= buffer16.tryAppend(&character, 1);
  65     }
  66
  67     void append(const char* str)
  68     {
  69         append(reinterpret_cast<const LChar*>(str), strlen(str));
  70     }
  71
  72     JSValue build(ExecState* exec)
  73     {
  74         if (!m_okay)
  75             return throwOutOfMemoryError(exec);
  76         if (m_is8Bit) {
  77             buffer8.shrinkToFit();
  78             if (!buffer8.data())
  79                 return throwOutOfMemoryError(exec);
  80             return jsString(exec, String::adopt(buffer8));
  81         }
  82         buffer16.shrinkToFit();
  83         if (!buffer16.data())
  84             return throwOutOfMemoryError(exec);
  85         return jsString(exec, String::adopt(buffer16));
  86     }
  87
  88 private:
  89     void append(const LChar* characters, size_t length)
  90     {
  91         if (m_is8Bit) {
  92             m_okay &= buffer8.tryAppend(characters, length);
  93             return;
  94         }
  95         // FIXME: There must be a more efficient way of doing this.
  96         m_okay &= buffer16.tryReserveCapacity(buffer16.size() + length);
  97         for (size_t i = 0; i < length; i++) {
  98             UChar upconvertedCharacter = characters[i];
  99             m_okay &= buffer16.tryAppend(&upconvertedCharacter, 1);
 100         }
 101     }
 102
 103     void upConvert()
 104     {
 105         ASSERT(m_is8Bit);
 106         size_t len = buffer8.size();
 107
 108         for (size_t i = 0; i < len; i++)
 109             buffer16.append(buffer8[i]);
 110
 111         buffer8.clear();
 112         m_is8Bit = false;
 113     }
 114
 115     Vector<LChar, 64, UnsafeVectorOverflow> buffer8;
 116     Vector<UChar, 64, UnsafeVectorOverflow> buffer16;
 117     bool m_okay;
 118     bool m_is8Bit;
 119 };
 120
 121 template<typename StringType>
 122 inline JSValue jsMakeNontrivialString(ExecState* exec, StringType&& string)
 123 {
 124     return jsNontrivialString(exec, std::forward<StringType>(string));
 125 }
 126
 127 template<typename StringType, typename... StringTypes>
 128 inline JSValue jsMakeNontrivialString(ExecState* exec, const StringType& string, const StringTypes&... strings)
 129 {
 130     RefPtr<StringImpl> result = WTF::tryMakeString(string, strings...);
 131     if (!result)
 132         return throwOutOfMemoryError(exec);
 133     return jsNontrivialString(exec, result.release());
 134 }
 135
 136 }
 137
 138 #endif