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_FILE_VALUE_SERIALIZER_H_ 6 #define BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_ 7 8 #include <string> 9 10 #include "base/base_export.h" 11 #include "base/basictypes.h" 12 #include "base/files/file_path.h" 13 #include "base/values.h" 14 15 class BASE_EXPORT JSONFileValueSerializer : public base::ValueSerializer { 16 public: 17 // json_file_patch is the path of a file that will be source of the 18 // deserialization or the destination of the serialization. 19 // When deserializing, the file should exist, but when serializing, the 20 // serializer will attempt to create the file at the specified location. JSONFileValueSerializer(const base::FilePath & json_file_path)21 explicit JSONFileValueSerializer(const base::FilePath& json_file_path) 22 : json_file_path_(json_file_path), 23 allow_trailing_comma_(false) {} 24 ~JSONFileValueSerializer()25 virtual ~JSONFileValueSerializer() {} 26 27 // DO NOT USE except in unit tests to verify the file was written properly. 28 // We should never serialize directly to a file since this will block the 29 // thread. Instead, serialize to a string and write to the file you want on 30 // the file thread. 31 // 32 // Attempt to serialize the data structure represented by Value into 33 // JSON. If the return value is true, the result will have been written 34 // into the file whose name was passed into the constructor. 35 virtual bool Serialize(const base::Value& root) OVERRIDE; 36 37 // Equivalent to Serialize(root) except binary values are omitted from the 38 // output. 39 bool SerializeAndOmitBinaryValues(const base::Value& root); 40 41 // Attempt to deserialize the data structure encoded in the file passed 42 // in to the constructor into a structure of Value objects. If the return 43 // value is NULL, and if |error_code| is non-null, |error_code| will 44 // contain an integer error code (either JsonFileError or JsonParseError). 45 // If |error_message| is non-null, it will be filled in with a formatted 46 // error message including the location of the error if appropriate. 47 // The caller takes ownership of the returned value. 48 virtual base::Value* Deserialize(int* error_code, 49 std::string* error_message) OVERRIDE; 50 51 // This enum is designed to safely overlap with JSONReader::JsonParseError. 52 enum JsonFileError { 53 JSON_NO_ERROR = 0, 54 JSON_ACCESS_DENIED = 1000, 55 JSON_CANNOT_READ_FILE, 56 JSON_FILE_LOCKED, 57 JSON_NO_SUCH_FILE 58 }; 59 60 // File-specific error messages that can be returned. 61 static const char* kAccessDenied; 62 static const char* kCannotReadFile; 63 static const char* kFileLocked; 64 static const char* kNoSuchFile; 65 66 // Convert an error code into an error message. |error_code| is assumed to 67 // be a JsonFileError. 68 static const char* GetErrorMessageForCode(int error_code); 69 set_allow_trailing_comma(bool new_value)70 void set_allow_trailing_comma(bool new_value) { 71 allow_trailing_comma_ = new_value; 72 } 73 74 private: 75 bool SerializeInternal(const base::Value& root, bool omit_binary_values); 76 77 base::FilePath json_file_path_; 78 bool allow_trailing_comma_; 79 80 // A wrapper for ReadFileToString which returns a non-zero JsonFileError if 81 // there were file errors. 82 int ReadFileToString(std::string* json_string); 83 84 DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueSerializer); 85 }; 86 87 #endif // BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_ 88 89