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// 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_FILE_VALUE_SERIALIZER_H_
#define BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_
#include <string>
#include "base/base_export.h"
#include "base/basictypes.h"
#include "base/file_path.h"
#include "base/values.h"
class BASE_EXPORT JSONFileValueSerializer : public base::ValueSerializer {
public:
// json_file_patch is the path of a file that will be source of the
// deserialization or the destination of the serialization.
// When deserializing, the file should exist, but when serializing, the
// serializer will attempt to create the file at the specified location.
explicit JSONFileValueSerializer(const FilePath& json_file_path)
: json_file_path_(json_file_path),
allow_trailing_comma_(false) {}
virtual ~JSONFileValueSerializer() {}
// DO NOT USE except in unit tests to verify the file was written properly.
// We should never serialize directly to a file since this will block the
// thread. Instead, serialize to a string and write to the file you want on
// the file thread.
//
// Attempt to serialize the data structure represented by Value into
// JSON. If the return value is true, the result will have been written
// into the file whose name was passed into the constructor.
virtual bool Serialize(const Value& root) OVERRIDE;
// Equivalent to Serialize(root) except binary values are omitted from the
// output.
bool SerializeAndOmitBinaryValues(const Value& root);
// Attempt to deserialize the data structure encoded in the file passed
// in to the constructor into a structure of Value objects. If the return
// value is NULL, and if |error_code| is non-null, |error_code| will
// contain an integer error code (either JsonFileError or JsonParseError).
// If |error_message| is non-null, it will be filled in with a formatted
// error message including the location of the error if appropriate.
// The caller takes ownership of the returned value.
virtual Value* Deserialize(int* error_code,
std::string* error_message) OVERRIDE;
// This enum is designed to safely overlap with JSONReader::JsonParseError.
enum JsonFileError {
JSON_NO_ERROR = 0,
JSON_ACCESS_DENIED = 1000,
JSON_CANNOT_READ_FILE,
JSON_FILE_LOCKED,
JSON_NO_SUCH_FILE
};
// File-specific error messages that can be returned.
static const char* kAccessDenied;
static const char* kCannotReadFile;
static const char* kFileLocked;
static const char* kNoSuchFile;
// Convert an error code into an error message. |error_code| is assumed to
// be a JsonFileError.
static const char* GetErrorMessageForCode(int error_code);
void set_allow_trailing_comma(bool new_value) {
allow_trailing_comma_ = new_value;
}
private:
bool SerializeInternal(const Value& root, bool omit_binary_values);
FilePath json_file_path_;
bool allow_trailing_comma_;
// A wrapper for file_util::ReadFileToString which returns a non-zero
// JsonFileError if there were file errors.
int ReadFileToString(std::string* json_string);
DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueSerializer);
};
#endif // BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_