DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (b66b287a2650)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175
// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/json_writer.h"

#include "base/logging.h"
#include "base/string_util.h"
#include "base/values.h"
#include "base/string_escape.h"

const char kPrettyPrintLineEnding[] = "\r\n";

/* static */
void JSONWriter::Write(const Value* const node, bool pretty_print,
                       std::string* json) {
  json->clear();
  // Is there a better way to estimate the size of the output?
  json->reserve(1024);
  JSONWriter writer(pretty_print, json);
  writer.BuildJSONString(node, 0);
  if (pretty_print)
    json->append(kPrettyPrintLineEnding);
}

JSONWriter::JSONWriter(bool pretty_print, std::string* json)
    : json_string_(json),
      pretty_print_(pretty_print) {
  DCHECK(json);
}

void JSONWriter::BuildJSONString(const Value* const node, int depth) {
  switch(node->GetType()) {
    case Value::TYPE_NULL:
      json_string_->append("null");
      break;

    case Value::TYPE_BOOLEAN:
      {
        bool value;
        bool result = node->GetAsBoolean(&value);
        DCHECK(result);
        json_string_->append(value ? "true" : "false");
        break;
      }

    case Value::TYPE_INTEGER:
      {
        int value;
        bool result = node->GetAsInteger(&value);
        DCHECK(result);
        StringAppendF(json_string_, "%d", value);
        break;
      }

    case Value::TYPE_REAL:
      {
        double value;
        bool result = node->GetAsReal(&value);
        DCHECK(result);
        std::string real = DoubleToString(value);
        // Ensure that the number has a .0 if there's no decimal or 'e'.  This
        // makes sure that when we read the JSON back, it's interpreted as a
        // real rather than an int.
        if (real.find('.') == std::string::npos &&
            real.find('e') == std::string::npos &&
            real.find('E') == std::string::npos) {
          real.append(".0");
        }
        // The JSON spec requires that non-integer values in the range (-1,1)
        // have a zero before the decimal point - ".52" is not valid, "0.52" is.
        if (real[0] == '.') {
          real.insert(0, "0");
        } else if (real.length() > 1 && real[0] == '-' && real[1] == '.') {
          // "-.1" bad "-0.1" good
          real.insert(1, "0");
        }
        json_string_->append(real);
        break;
      }

    case Value::TYPE_STRING:
      {
        std::wstring value;
        bool result = node->GetAsString(&value);
        DCHECK(result);
        AppendQuotedString(value);
        break;
      }

    case Value::TYPE_LIST:
      {
        json_string_->append("[");
        if (pretty_print_)
          json_string_->append(" ");

        const ListValue* list = static_cast<const ListValue*>(node);
        for (size_t i = 0; i < list->GetSize(); ++i) {
          if (i != 0) {
            json_string_->append(",");
            if (pretty_print_)
              json_string_->append(" ");
          }

          Value* value = NULL;
          bool result = list->Get(i, &value);
          DCHECK(result);
          BuildJSONString(value, depth);
        }

        if (pretty_print_)
          json_string_->append(" ");
        json_string_->append("]");
        break;
      }

    case Value::TYPE_DICTIONARY:
      {
        json_string_->append("{");
        if (pretty_print_)
          json_string_->append(kPrettyPrintLineEnding);

        const DictionaryValue* dict =
          static_cast<const DictionaryValue*>(node);
        for (DictionaryValue::key_iterator key_itr = dict->begin_keys();
             key_itr != dict->end_keys();
             ++key_itr) {

          if (key_itr != dict->begin_keys()) {
            json_string_->append(",");
            if (pretty_print_)
              json_string_->append(kPrettyPrintLineEnding);
          }

          Value* value = NULL;
          bool result = dict->Get(*key_itr, &value);
          DCHECK(result);

          if (pretty_print_)
            IndentLine(depth + 1);
          AppendQuotedString(*key_itr);
          if (pretty_print_) {
            json_string_->append(": ");
          } else {
            json_string_->append(":");
          }
          BuildJSONString(value, depth + 1);
        }

        if (pretty_print_) {
          json_string_->append(kPrettyPrintLineEnding);
          IndentLine(depth);
          json_string_->append("}");
        } else {
          json_string_->append("}");
        }
        break;
      }

    default:
      // TODO(jhughes): handle TYPE_BINARY
      NOTREACHED() << "unknown json type";
  }
}

void JSONWriter::AppendQuotedString(const std::wstring& str) {
  string_escape::JavascriptDoubleQuote(WideToUTF16Hack(str), true,
                                       json_string_);
}

void JSONWriter::IndentLine(int depth) {
  // It may be faster to keep an indent string so we don't have to keep
  // reallocating.
  json_string_->append(std::string(depth * 3, ' '));
}