Modify the base::JSONReader interface to take a set of options rather than a boolean flag.

base/json/json_reader.h

 // Copyright (c) 2012 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.
 //
 // A JSON parser.  Converts strings of JSON into a Value object (see
 // base/values.h).
 // http://www.ietf.org/rfc/rfc4627.txt?number=4627
 //
 // Known limitations/deviations from the RFC:
 // - Only knows how to parse ints within the range of a signed 32 bit int and
@@ skipping 32 matching lines @@
 #define FRIEND_TEST_ALL_PREFIXES(test_case_name, test_name) \
   FRIEND_TEST(test_case_name, test_name); \
   FRIEND_TEST(test_case_name, DISABLED_##test_name); \
   FRIEND_TEST(test_case_name, FLAKY_##test_name); \
   FRIEND_TEST(test_case_name, FAILS_##test_name)
 
 namespace base {
 
 class Value;
 
+enum JSONParserOptions {
+  JSON_PARSE_RFC = 0,

[Mark Mentovai, 2012/04/10 21:51:02]

…the idea being 0 is strict, and every other weird feature you might want to
support will be represented as a bit?

[Robert Sesek, 2012/04/10 22:06:15]

Correct. Other weird features may include single-quoted strings.

+  JSON_ALLOW_TRAILING_COMMAS = 1 << 1,

[Mark Mentovai, 2012/04/10 21:51:02]

Because if so, this should be 1 << 0.

[Robert Sesek, 2012/04/10 22:06:15]

Oops. Forgot to cherry-pick that fix from the rewrite branch.

+};
+
 class BASE_EXPORT JSONReader {
  public:
   // A struct to hold a JS token.
   class Token {
    public:
     enum Type {
      OBJECT_BEGIN,           // {
      OBJECT_END,             // }
      ARRAY_BEGIN,            // [
      ARRAY_END,              // ]
@@ skipping 49 matching lines @@
   static const char* kTrailingComma;
   static const char* kTooMuchNesting;
   static const char* kUnexpectedDataAfterRoot;
   static const char* kUnsupportedEncoding;
   static const char* kUnquotedDictionaryKey;
 
   JSONReader();
 
   // Reads and parses |json|, returning a Value. The caller owns the returned
   // instance. If |json| is not a properly formed JSON string, returns NULL.
-  // If |allow_trailing_comma| is true, we will ignore trailing commas in
-  // objects and arrays even though this goes against the RFC.
-  static Value* Read(const std::string& json, bool allow_trailing_comma);
+  static Value* Read(const std::string& json);
+
+  // Reads and parses |json|, returning a Value owned by the caller. The
+  // parser respects the given |options|. If the input is not properly formed,
+  // returns NULL.
+  static Value* Read(const std::string& json, JSONParserOptions options);

[Mark Mentovai, 2012/04/10 21:51:02]

More importantly, if so, you can’t use JSONParserOptions as a named type in this
way. If you had another bit, let’s call it JSON_MULTIFACH = 1 << 2, then the
combination (JSON_ALLOW_TRAILING_COMMAS | JSON_MULTIFACH) would be some value
that isn’t a member of the JSONParserOptions enum at all. “or”-ing these values
together to stick back into a JSONParserOptions (such as when passing to this
function) wouldn’t compile at all, for good reason.

[Robert Sesek, 2012/04/10 22:06:15]

I want C++11 typesafe enums.

 
   // Reads and parses |json| like Read(). |error_code_out| and |error_msg_out|
   // are optional. If specified and NULL is returned, they will be populated
   // an error code and a formatted error message (including error location if
   // appropriate). Otherwise, they will be unmodified.
   static Value* ReadAndReturnError(const std::string& json,
-                                   bool allow_trailing_comma,
+                                   JSONParserOptions options,
                                    int* error_code_out,
                                    std::string* error_msg_out);
 
   // Converts a JSON parse error code into a human readable message.
   // Returns an empty string if error_code is JSON_NO_ERROR.
   static std::string ErrorCodeToString(JsonParseError error_code);
 
   // Returns the error code if the last call to JsonToValue() failed.
   // Returns JSON_NO_ERROR otherwise.
   JsonParseError error_code() const { return error_code_; }
@@ skipping 92 matching lines @@
   JsonParseError error_code_;
   int error_line_;
   int error_col_;
 
   DISALLOW_COPY_AND_ASSIGN(JSONReader);
 };
 
 }  // namespace base
 
 #endif  // BASE_JSON_JSON_READER_H_