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// Copyright 2012 The Chromium Authors
// 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 <stddef.h>
#include <memory>
#include <string>
#include "base/base_export.h"
#include "base/files/file_path.h"
#include "base/json/json_reader.h"
#include "base/values.h"
class BASE_EXPORT JSONFileValueSerializer : public base::ValueSerializer {
public:
JSONFileValueSerializer() = delete;
// |json_file_path_| is the path of a file that will be destination of the
// serialization. The serializer will attempt to create the file at the
// specified location.
explicit JSONFileValueSerializer(const base::FilePath& json_file_path);
JSONFileValueSerializer(const JSONFileValueSerializer&) = delete;
JSONFileValueSerializer& operator=(const JSONFileValueSerializer&) = delete;
~JSONFileValueSerializer() override;
// 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 thread pool.
//
// 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.
bool Serialize(base::ValueView root) override;
// Equivalent to Serialize(root) except binary values are omitted from the
// output.
bool SerializeAndOmitBinaryValues(base::ValueView root);
private:
bool SerializeInternal(base::ValueView root, bool omit_binary_values);
const base::FilePath json_file_path_;
};
class BASE_EXPORT JSONFileValueDeserializer : public base::ValueDeserializer {
public:
JSONFileValueDeserializer() = delete;
// |json_file_path_| is the path of a file that will be source of the
// deserialization. |options| is a bitmask of JSONParserOptions.
explicit JSONFileValueDeserializer(
const base::FilePath& json_file_path,
int options = base::JSON_PARSE_CHROMIUM_EXTENSIONS);
JSONFileValueDeserializer(const JSONFileValueDeserializer&) = delete;
JSONFileValueDeserializer& operator=(const JSONFileValueDeserializer&) =
delete;
~JSONFileValueDeserializer() override;
// Attempts to deserialize the data structure encoded in the file passed to
// the constructor into a structure of Value objects. If the return value is
// null, then
// (1) |error_code| will be filled with an integer error code (either a
// JsonFileError or base::ValueDeserializer::kErrorCodeInvalidFormat) if a
// non-null |error_code| was given.
// (2) |error_message| will be filled with a formatted error message,
// including the location of the error (if appropriate), if a non-null
// |error_message| was given.
// The caller takes ownership of the returned value.
std::unique_ptr<base::Value> Deserialize(int* error_code,
std::string* error_message) override;
// This enum is designed to safely overlap with JSONParser::JsonParseError.
//
// These values are persisted to logs. Entries should not be renumbered and
// numeric values should never be reused.
enum JsonFileError {
JSON_NO_ERROR = 0,
JSON_ACCESS_DENIED = kErrorCodeFirstMetadataError,
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);
// Returns the size (in bytes) of JSON string read from disk in the last
// successful |Deserialize()| call.
size_t get_last_read_size() const { return last_read_size_; }
private:
// A wrapper for ReadFileToString which returns a non-zero JsonFileError if
// there were file errors.
int ReadFileToString(std::string* json_string);
const base::FilePath json_file_path_;
const int options_;
size_t last_read_size_ = 0u;
};
#endif // BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_
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