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 <stddef.h> 9 10 #include <string> 11 12 #include "base/base_export.h" 13 #include "base/files/file_path.h" 14 #include "base/macros.h" 15 #include "base/values.h" 16 17 class BASE_EXPORT JSONFileValueSerializer : public base::ValueSerializer { 18 public: 19 // |json_file_path_| is the path of a file that will be destination of the 20 // serialization. The serializer will attempt to create the file at the 21 // specified location. 22 explicit JSONFileValueSerializer(const base::FilePath& json_file_path); 23 24 ~JSONFileValueSerializer() override; 25 26 // DO NOT USE except in unit tests to verify the file was written properly. 27 // We should never serialize directly to a file since this will block the 28 // thread. Instead, serialize to a string and write to the file you want on 29 // the file thread. 30 // 31 // Attempt to serialize the data structure represented by Value into 32 // JSON. If the return value is true, the result will have been written 33 // into the file whose name was passed into the constructor. 34 bool Serialize(const base::Value& root) override; 35 36 // Equivalent to Serialize(root) except binary values are omitted from the 37 // output. 38 bool SerializeAndOmitBinaryValues(const base::Value& root); 39 40 private: 41 bool SerializeInternal(const base::Value& root, bool omit_binary_values); 42 43 const base::FilePath json_file_path_; 44 45 DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueSerializer); 46 }; 47 48 class BASE_EXPORT JSONFileValueDeserializer : public base::ValueDeserializer { 49 public: 50 // |json_file_path_| is the path of a file that will be source of the 51 // deserialization. 52 explicit JSONFileValueDeserializer(const base::FilePath& json_file_path); 53 54 ~JSONFileValueDeserializer() override; 55 56 // Attempt to deserialize the data structure encoded in the file passed 57 // in to the constructor into a structure of Value objects. If the return 58 // value is NULL, and if |error_code| is non-null, |error_code| will 59 // contain an integer error code (either JsonFileError or JsonParseError). 60 // If |error_message| is non-null, it will be filled in with a formatted 61 // error message including the location of the error if appropriate. 62 // The caller takes ownership of the returned value. 63 std::unique_ptr<base::Value> Deserialize(int* error_code, 64 std::string* error_message) override; 65 66 // This enum is designed to safely overlap with JSONReader::JsonParseError. 67 enum JsonFileError { 68 JSON_NO_ERROR = 0, 69 JSON_ACCESS_DENIED = 1000, 70 JSON_CANNOT_READ_FILE, 71 JSON_FILE_LOCKED, 72 JSON_NO_SUCH_FILE 73 }; 74 75 // File-specific error messages that can be returned. 76 static const char kAccessDenied[]; 77 static const char kCannotReadFile[]; 78 static const char kFileLocked[]; 79 static const char kNoSuchFile[]; 80 81 // Convert an error code into an error message. |error_code| is assumed to 82 // be a JsonFileError. 83 static const char* GetErrorMessageForCode(int error_code); 84 85 void set_allow_trailing_comma(bool new_value) { 86 allow_trailing_comma_ = new_value; 87 } 88 89 // Returns the size (in bytes) of JSON string read from disk in the last 90 // successful |Deserialize()| call. 91 size_t get_last_read_size() const { return last_read_size_; } 92 93 private: 94 // A wrapper for ReadFileToString which returns a non-zero JsonFileError if 95 // there were file errors. 96 int ReadFileToString(std::string* json_string); 97 98 const base::FilePath json_file_path_; 99 bool allow_trailing_comma_; 100 size_t last_read_size_; 101 102 DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueDeserializer); 103 }; 104 105 #endif // BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_ 106 107
