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1 // Copyright (c) 2011 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 // This file defines utility functions for escaping strings suitable for JSON.
6 
7 #ifndef BASE_JSON_STRING_ESCAPE_H_
8 #define BASE_JSON_STRING_ESCAPE_H_
9 
10 #include <string>
11 #include <string_view>
12 
13 namespace base {
14 
15 // Appends to |dest| an escaped version of |str|. Valid UTF-8 code units and
16 // characters will pass through from the input to the output. Invalid code
17 // units and characters will be replaced with the U+FFFD replacement character.
18 // This function returns true if no replacement was necessary and false if
19 // there was a lossy replacement. On return, |dest| will contain a valid UTF-8
20 // JSON string.
21 //
22 // Non-printing control characters will be escaped as \uXXXX sequences for
23 // readability.
24 //
25 // If |put_in_quotes| is true, then a leading and trailing double-quote mark
26 // will be appended to |dest| as well.
27 void EscapeJSONString(std::string_view str,
28                       bool put_in_quotes,
29                       std::string* dest);
30 
31 // Performs a similar function to the UTF-8 std::string_view version above,
32 // converting UTF-16 code units to UTF-8 code units and escaping non-printing
33 // control characters. On return, |dest| will contain a valid UTF-8 JSON string.
34 void EscapeJSONString(std::u16string_view str,
35                       bool put_in_quotes,
36                       std::string* dest);
37 
38 // Given an arbitrary byte string |str|, this will escape all non-ASCII bytes
39 // as \uXXXX escape sequences. This function is *NOT* meant to be used with
40 // Unicode strings and does not validate |str| as one.
41 //
42 // CAVEAT CALLER: The output of this function may not be valid JSON, since
43 // JSON requires escape sequences to be valid UTF-16 code units. This output
44 // will be mangled if passed to to the base::JSONReader, since the reader will
45 // interpret it as UTF-16 and convert it to UTF-8.
46 //
47 // The output of this function takes the *appearance* of JSON but is not in
48 // fact valid according to RFC 4627.
49 std::string EscapeBytesAsInvalidJSONString(std::string_view str,
50                                            bool put_in_quotes);
51 
52 }  // namespace base
53 
54 #endif  // BASE_JSON_STRING_ESCAPE_H_
55