Add option for not adding '.0' to the end of doubles that have no fractional

base/json/json_writer.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
 #ifndef BASE_JSON_JSON_WRITER_H_
 #define BASE_JSON_JSON_WRITER_H_
 #pragma once
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 
 namespace base {
 
 class Value;
 
 class BASE_EXPORT JSONWriter {
  public:
   enum Options {
     // Do not escape the string, preserving its UTF8 characters. It is useful
     // if you can pass the resulting string to the JSON parser in binary form
     // (as UTF8).
     OPTIONS_DO_NOT_ESCAPE = 1 << 0,
 
     // For values of binary type, the value (and key if within a dictionary)
     // will be omitted from the output.
-    OPTIONS_OMIT_BINARY_VALUES = 1 << 1
+    OPTIONS_OMIT_BINARY_VALUES = 1 << 1,
+
+    // An external consumer of your JSON may expect a 64-bit integer value.
+    // However, the |Value| classes only support 32-bit ints. One feasible
+    // way to mitigate this is to use a double to represent the integer.
+    // However, this class writes all doubles in such a way that causes many
+    // JSON readers to parse the number as a double instead of a 64-bit int.
+    // This may break the external consumer of the JSON if it expects a
+    // 64-bit int.

[tony, 2012/03/06 21:50:13]

I would remove the text from line 30-36.  It's sufficient to just describe the
behavior.

[kkania, 2012/03/06 22:41:57]

Done.

+    // This option instructs the writer to write doubles that have no fractional
+    // part as a normal integer (i.e., without using exponential notation
+    // or appending a '.0') as long as the value is within the range of a
+    // 64-bit int.
+    OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION = 1 << 2
   };
 
   // Given a root node, generates a JSON string and puts it into |json|.
   // If |pretty_print| is true, return a slightly nicer formated json string
   // (pads with whitespace to help readability).  If |pretty_print| is false,
   // we try to generate as compact a string as possible.
   // TODO(tc): Should we generate json if it would be invalid json (e.g.,
   // |node| is not a DictionaryValue/ListValue or if there are inf/-inf float
   // values)?
   static void Write(const Value* const node, bool pretty_print,
                     std::string* json);
 
   // Same as above but with |options| which is a bunch of JSONWriter::Options
   // bitwise ORed together.
   static void WriteWithOptions(const Value* const node, bool pretty_print,
                                int options, std::string* json);
 
   // A static, constant JSON string representing an empty array.  Useful
   // for empty JSON argument passing.
   static const char* kEmptyArray;
 
  private:
   JSONWriter(bool pretty_print, std::string* json);
 
   // Called recursively to build the JSON string.  Whe completed, value is
   // json_string_ will contain the JSON.
   void BuildJSONString(const Value* const node, int depth, bool escape,
-                       bool ignore_binary_values);
+                       bool ignore_binary_values,
+                       bool omit_double_type_preservation);
 
   // Appends a quoted, escaped, version of (UTF-8) str to json_string_.
   void AppendQuotedString(const std::string& str);
 
   // Adds space to json_string_ for the indent level.
   void IndentLine(int depth);
 
   // Where we write JSON data as we generate it.
   std::string* json_string_;
 
   bool pretty_print_;
 
   DISALLOW_COPY_AND_ASSIGN(JSONWriter);
 };
 
 }  // namespace base
 
 #endif  // BASE_JSON_JSON_WRITER_H_