1 // Copyright (c) 2012 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 #ifndef BASE_JSON_JSON_WRITER_H_ 6 #define BASE_JSON_JSON_WRITER_H_ 7 8 #include <string> 9 10 #include "base/base_export.h" 11 #include "base/basictypes.h" 12 13 namespace base { 14 15 class Value; 16 17 class BASE_EXPORT JSONWriter { 18 public: 19 enum Options { 20 // Do not escape the string, preserving its UTF8 characters. It is useful 21 // if you can pass the resulting string to the JSON parser in binary form 22 // (as UTF8). 23 OPTIONS_DO_NOT_ESCAPE = 1 << 0, 24 25 // For values of binary type, the value (and key if within a dictionary) 26 // will be omitted from the output. 27 OPTIONS_OMIT_BINARY_VALUES = 1 << 1, 28 29 // This option instructs the writer to write doubles that have no fractional 30 // part as a normal integer (i.e., without using exponential notation 31 // or appending a '.0') as long as the value is within the range of a 32 // 64-bit int. 33 OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION = 1 << 2, 34 35 // Return a slightly nicer formatted json string (pads with whitespace to 36 // help with readability). 37 OPTIONS_PRETTY_PRINT = 1 << 3 38 }; 39 40 // Given a root node, generates a JSON string and puts it into |json|. 41 // TODO(tc): Should we generate json if it would be invalid json (e.g., 42 // |node| is not a DictionaryValue/ListValue or if there are inf/-inf float 43 // values)? 44 static void Write(const Value* const node, std::string* json); 45 46 // Same as above but with |options| which is a bunch of JSONWriter::Options 47 // bitwise ORed together. 48 static void WriteWithOptions(const Value* const node, int options, 49 std::string* json); 50 51 // A static, constant JSON string representing an empty array. Useful 52 // for empty JSON argument passing. 53 static const char* kEmptyArray; 54 55 private: 56 JSONWriter(bool escape, bool omit_binary_values, 57 bool omit_double_type_preservation, bool pretty_print, 58 std::string* json); 59 60 // Called recursively to build the JSON string. Whe completed, value is 61 // json_string_ will contain the JSON. 62 void BuildJSONString(const Value* const node, int depth); 63 64 // Appends a quoted, escaped, version of (UTF-8) str to json_string_. 65 void AppendQuotedString(const std::string& str); 66 67 // Adds space to json_string_ for the indent level. 68 void IndentLine(int depth); 69 70 bool escape_; 71 bool omit_binary_values_; 72 bool omit_double_type_preservation_; 73 bool pretty_print_; 74 75 // Where we write JSON data as we generate it. 76 std::string* json_string_; 77 78 DISALLOW_COPY_AND_ASSIGN(JSONWriter); 79 }; 80 81 } // namespace base 82 83 #endif // BASE_JSON_JSON_WRITER_H_ 84
