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      1 /*
      2  * Copyright (C) 2010 Google 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 are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 #include "core/platform/JSONValues.h"
     33 
     34 #include "wtf/DecimalNumber.h"
     35 #include "wtf/dtoa.h"
     36 #include "wtf/text/StringBuilder.h"
     37 
     38 namespace WebCore {
     39 
     40 namespace {
     41 
     42 const char* const nullString = "null";
     43 const char* const trueString = "true";
     44 const char* const falseString = "false";
     45 
     46 inline bool escapeChar(UChar c, StringBuilder* dst)
     47 {
     48     switch (c) {
     49     case '\b': dst->append("\\b", 2); break;
     50     case '\f': dst->append("\\f", 2); break;
     51     case '\n': dst->append("\\n", 2); break;
     52     case '\r': dst->append("\\r", 2); break;
     53     case '\t': dst->append("\\t", 2); break;
     54     case '\\': dst->append("\\\\", 2); break;
     55     case '"': dst->append("\\\"", 2); break;
     56     default:
     57         return false;
     58     }
     59     return true;
     60 }
     61 
     62 inline void doubleQuoteString(const String& str, StringBuilder* dst)
     63 {
     64     dst->append('"');
     65     for (unsigned i = 0; i < str.length(); ++i) {
     66         UChar c = str[i];
     67         if (!escapeChar(c, dst)) {
     68             if (c < 32 || c > 126 || c == '<' || c == '>') {
     69                 // 1. Escaping <, > to prevent script execution.
     70                 // 2. Technically, we could also pass through c > 126 as UTF8, but this
     71                 //    is also optional. It would also be a pain to implement here.
     72                 unsigned symbol = static_cast<unsigned>(c);
     73                 String symbolCode = String::format("\\u%04X", symbol);
     74                 dst->append(symbolCode);
     75             } else {
     76                 dst->append(c);
     77             }
     78         }
     79     }
     80     dst->append('"');
     81 }
     82 
     83 } // anonymous namespace
     84 
     85 bool JSONValue::asBoolean(bool*) const
     86 {
     87     return false;
     88 }
     89 
     90 bool JSONValue::asNumber(double*) const
     91 {
     92     return false;
     93 }
     94 
     95 bool JSONValue::asNumber(long*) const
     96 {
     97     return false;
     98 }
     99 
    100 bool JSONValue::asNumber(int*) const
    101 {
    102     return false;
    103 }
    104 
    105 bool JSONValue::asNumber(unsigned long*) const
    106 {
    107     return false;
    108 }
    109 
    110 bool JSONValue::asNumber(unsigned*) const
    111 {
    112     return false;
    113 }
    114 
    115 bool JSONValue::asString(String*) const
    116 {
    117     return false;
    118 }
    119 
    120 bool JSONValue::asValue(RefPtr<JSONValue>* output)
    121 {
    122     *output = this;
    123     return true;
    124 }
    125 
    126 bool JSONValue::asObject(RefPtr<JSONObject>*)
    127 {
    128     return false;
    129 }
    130 
    131 bool JSONValue::asArray(RefPtr<JSONArray>*)
    132 {
    133     return false;
    134 }
    135 
    136 PassRefPtr<JSONObject> JSONValue::asObject()
    137 {
    138     return 0;
    139 }
    140 
    141 PassRefPtr<JSONArray> JSONValue::asArray()
    142 {
    143     return 0;
    144 }
    145 
    146 String JSONValue::toJSONString() const
    147 {
    148     StringBuilder result;
    149     result.reserveCapacity(512);
    150     writeJSON(&result);
    151     return result.toString();
    152 }
    153 
    154 void JSONValue::writeJSON(StringBuilder* output) const
    155 {
    156     ASSERT(m_type == TypeNull);
    157     output->append(nullString, 4);
    158 }
    159 
    160 bool JSONBasicValue::asBoolean(bool* output) const
    161 {
    162     if (type() != TypeBoolean)
    163         return false;
    164     *output = m_boolValue;
    165     return true;
    166 }
    167 
    168 bool JSONBasicValue::asNumber(double* output) const
    169 {
    170     if (type() != TypeNumber)
    171         return false;
    172     *output = m_doubleValue;
    173     return true;
    174 }
    175 
    176 bool JSONBasicValue::asNumber(long* output) const
    177 {
    178     if (type() != TypeNumber)
    179         return false;
    180     *output = static_cast<long>(m_doubleValue);
    181     return true;
    182 }
    183 
    184 bool JSONBasicValue::asNumber(int* output) const
    185 {
    186     if (type() != TypeNumber)
    187         return false;
    188     *output = static_cast<int>(m_doubleValue);
    189     return true;
    190 }
    191 
    192 bool JSONBasicValue::asNumber(unsigned long* output) const
    193 {
    194     if (type() != TypeNumber)
    195         return false;
    196     *output = static_cast<unsigned long>(m_doubleValue);
    197     return true;
    198 }
    199 
    200 bool JSONBasicValue::asNumber(unsigned* output) const
    201 {
    202     if (type() != TypeNumber)
    203         return false;
    204     *output = static_cast<unsigned>(m_doubleValue);
    205     return true;
    206 }
    207 
    208 void JSONBasicValue::writeJSON(StringBuilder* output) const
    209 {
    210     ASSERT(type() == TypeBoolean || type() == TypeNumber);
    211     if (type() == TypeBoolean) {
    212         if (m_boolValue)
    213             output->append(trueString, 4);
    214         else
    215             output->append(falseString, 5);
    216     } else if (type() == TypeNumber) {
    217         NumberToLStringBuffer buffer;
    218         if (!std::isfinite(m_doubleValue)) {
    219             output->append(nullString, 4);
    220             return;
    221         }
    222         DecimalNumber decimal = m_doubleValue;
    223         unsigned length = 0;
    224         if (decimal.bufferLengthForStringDecimal() > WTF::NumberToStringBufferLength) {
    225             // Not enough room for decimal. Use exponential format.
    226             if (decimal.bufferLengthForStringExponential() > WTF::NumberToStringBufferLength) {
    227                 // Fallback for an abnormal case if it's too little even for exponential.
    228                 output->append("NaN", 3);
    229                 return;
    230             }
    231             length = decimal.toStringExponential(buffer, WTF::NumberToStringBufferLength);
    232         } else {
    233             length = decimal.toStringDecimal(buffer, WTF::NumberToStringBufferLength);
    234         }
    235         output->append(buffer, length);
    236     }
    237 }
    238 
    239 bool JSONString::asString(String* output) const
    240 {
    241     *output = m_stringValue;
    242     return true;
    243 }
    244 
    245 void JSONString::writeJSON(StringBuilder* output) const
    246 {
    247     ASSERT(type() == TypeString);
    248     doubleQuoteString(m_stringValue, output);
    249 }
    250 
    251 JSONObjectBase::~JSONObjectBase()
    252 {
    253 }
    254 
    255 bool JSONObjectBase::asObject(RefPtr<JSONObject>* output)
    256 {
    257     COMPILE_ASSERT(sizeof(JSONObject) == sizeof(JSONObjectBase), cannot_cast);
    258     *output = static_cast<JSONObject*>(this);
    259     return true;
    260 }
    261 
    262 PassRefPtr<JSONObject> JSONObjectBase::asObject()
    263 {
    264     return openAccessors();
    265 }
    266 
    267 JSONObject* JSONObjectBase::openAccessors()
    268 {
    269     COMPILE_ASSERT(sizeof(JSONObject) == sizeof(JSONObjectBase), cannot_cast);
    270     return static_cast<JSONObject*>(this);
    271 }
    272 
    273 bool JSONObjectBase::getBoolean(const String& name, bool* output) const
    274 {
    275     RefPtr<JSONValue> value = get(name);
    276     if (!value)
    277         return false;
    278     return value->asBoolean(output);
    279 }
    280 
    281 bool JSONObjectBase::getString(const String& name, String* output) const
    282 {
    283     RefPtr<JSONValue> value = get(name);
    284     if (!value)
    285         return false;
    286     return value->asString(output);
    287 }
    288 
    289 PassRefPtr<JSONObject> JSONObjectBase::getObject(const String& name) const
    290 {
    291     RefPtr<JSONValue> value = get(name);
    292     if (!value)
    293         return 0;
    294     return value->asObject();
    295 }
    296 
    297 PassRefPtr<JSONArray> JSONObjectBase::getArray(const String& name) const
    298 {
    299     RefPtr<JSONValue> value = get(name);
    300     if (!value)
    301         return 0;
    302     return value->asArray();
    303 }
    304 
    305 PassRefPtr<JSONValue> JSONObjectBase::get(const String& name) const
    306 {
    307     Dictionary::const_iterator it = m_data.find(name);
    308     if (it == m_data.end())
    309         return 0;
    310     return it->value;
    311 }
    312 
    313 void JSONObjectBase::remove(const String& name)
    314 {
    315     m_data.remove(name);
    316     for (size_t i = 0; i < m_order.size(); ++i) {
    317         if (m_order[i] == name) {
    318             m_order.remove(i);
    319             break;
    320         }
    321     }
    322 }
    323 
    324 void JSONObjectBase::writeJSON(StringBuilder* output) const
    325 {
    326     output->append('{');
    327     for (size_t i = 0; i < m_order.size(); ++i) {
    328         Dictionary::const_iterator it = m_data.find(m_order[i]);
    329         ASSERT(it != m_data.end());
    330         if (i)
    331             output->append(',');
    332         doubleQuoteString(it->key, output);
    333         output->append(':');
    334         it->value->writeJSON(output);
    335     }
    336     output->append('}');
    337 }
    338 
    339 JSONObjectBase::JSONObjectBase()
    340     : JSONValue(TypeObject)
    341     , m_data()
    342     , m_order()
    343 {
    344 }
    345 
    346 JSONArrayBase::~JSONArrayBase()
    347 {
    348 }
    349 
    350 bool JSONArrayBase::asArray(RefPtr<JSONArray>* output)
    351 {
    352     COMPILE_ASSERT(sizeof(JSONArrayBase) == sizeof(JSONArray), cannot_cast);
    353     *output = static_cast<JSONArray*>(this);
    354     return true;
    355 }
    356 
    357 PassRefPtr<JSONArray> JSONArrayBase::asArray()
    358 {
    359     COMPILE_ASSERT(sizeof(JSONArrayBase) == sizeof(JSONArray), cannot_cast);
    360     return static_cast<JSONArray*>(this);
    361 }
    362 
    363 void JSONArrayBase::writeJSON(StringBuilder* output) const
    364 {
    365     output->append('[');
    366     for (Vector<RefPtr<JSONValue> >::const_iterator it = m_data.begin(); it != m_data.end(); ++it) {
    367         if (it != m_data.begin())
    368             output->append(',');
    369         (*it)->writeJSON(output);
    370     }
    371     output->append(']');
    372 }
    373 
    374 JSONArrayBase::JSONArrayBase()
    375     : JSONValue(TypeArray)
    376     , m_data()
    377 {
    378 }
    379 
    380 PassRefPtr<JSONValue> JSONArrayBase::get(size_t index)
    381 {
    382     ASSERT_WITH_SECURITY_IMPLICATION(index < m_data.size());
    383     return m_data[index];
    384 }
    385 
    386 } // namespace WebCore
    387