1// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "base/json/string_escape.h"
6
7#include <string>
8
9#include "base/string_util.h"
10
11namespace base {
12
13namespace {
14
15// Try to escape |c| as a "SingleEscapeCharacter" (\n, etc).  If successful,
16// returns true and appends the escape sequence to |dst|.  This isn't required
17// by the spec, but it's more readable by humans than the \uXXXX alternatives.
18template<typename CHAR>
19static bool JsonSingleEscapeChar(const CHAR c, std::string* dst) {
20  // WARNING: if you add a new case here, you need to update the reader as well.
21  // Note: \v is in the reader, but not here since the JSON spec doesn't
22  // allow it.
23  switch (c) {
24    case '\b':
25      dst->append("\\b");
26      break;
27    case '\f':
28      dst->append("\\f");
29      break;
30    case '\n':
31      dst->append("\\n");
32      break;
33    case '\r':
34      dst->append("\\r");
35      break;
36    case '\t':
37      dst->append("\\t");
38      break;
39    case '\\':
40      dst->append("\\\\");
41      break;
42    case '"':
43      dst->append("\\\"");
44      break;
45    default:
46      return false;
47  }
48  return true;
49}
50
51template <class STR>
52void JsonDoubleQuoteT(const STR& str,
53                      bool put_in_quotes,
54                      std::string* dst) {
55  if (put_in_quotes)
56    dst->push_back('"');
57
58  for (typename STR::const_iterator it = str.begin(); it != str.end(); ++it) {
59    typename ToUnsigned<typename STR::value_type>::Unsigned c = *it;
60    if (!JsonSingleEscapeChar(c, dst)) {
61      if (c < 32 || c > 126 || c == '<' || c == '>') {
62        // 1. Escaping <, > to prevent script execution.
63        // 2. Technically, we could also pass through c > 126 as UTF8, but this
64        //    is also optional.  It would also be a pain to implement here.
65        unsigned int as_uint = static_cast<unsigned int>(c);
66        StringAppendF(dst, "\\u%04X", as_uint);
67      } else {
68        unsigned char ascii = static_cast<unsigned char>(*it);
69        dst->push_back(ascii);
70      }
71    }
72  }
73
74  if (put_in_quotes)
75    dst->push_back('"');
76}
77
78}  // namespace
79
80void JsonDoubleQuote(const std::string& str,
81                     bool put_in_quotes,
82                     std::string* dst) {
83  JsonDoubleQuoteT(str, put_in_quotes, dst);
84}
85
86std::string GetDoubleQuotedJson(const std::string& str) {
87  std::string dst;
88  JsonDoubleQuote(str, true, &dst);
89  return dst;
90}
91
92void JsonDoubleQuote(const string16& str,
93                     bool put_in_quotes,
94                     std::string* dst) {
95  JsonDoubleQuoteT(str, put_in_quotes, dst);
96}
97
98std::string GetDoubleQuotedJson(const string16& str) {
99  std::string dst;
100  JsonDoubleQuote(str, true, &dst);
101  return dst;
102}
103
104}  // namespace base
105