platform_system_core/init/parser.h
Tom Cherry bbcbc2ffb3 init: replace Result<Success> with Result<void>
Now that Result<T> is actually expected<T, ...>, and the expected
proposal states expected<void, ...> as the way to indicate an expected
object that returns either successfully with no object or an error,
let's move init's Result<Success> to the preferred Result<void>.

Bug: 132145659
Test: boot, init unit tests
Change-Id: Ib2f98396d8e6e274f95a496fcdfd8341f77585ee
2019-06-10 12:39:18 -07:00

96 lines
3.4 KiB
C++

/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _INIT_PARSER_H_
#define _INIT_PARSER_H_
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "result.h"
// SectionParser is an interface that can parse a given 'section' in init.
//
// You can implement up to 4 functions below, with ParseSection being mandatory. The first two
// functions return Result<void> indicating if they have an error. It will be reported along
// with the filename and line number of where the error occurred.
//
// 1) ParseSection
// This function is called when a section is first encountered.
//
// 2) ParseLineSection
// This function is called on each subsequent line until the next section is encountered.
//
// 3) EndSection
// This function is called either when a new section is found or at the end of the file.
// It indicates that parsing of the current section is complete and any relevant objects should
// be committed.
//
// 4) EndFile
// This function is called at the end of the file.
// It indicates that the parsing has completed and any relevant objects should be committed.
namespace android {
namespace init {
class SectionParser {
public:
virtual ~SectionParser() {}
virtual Result<void> ParseSection(std::vector<std::string>&& args, const std::string& filename,
int line) = 0;
virtual Result<void> ParseLineSection(std::vector<std::string>&&, int) { return {}; };
virtual Result<void> EndSection() { return {}; };
virtual void EndFile(){};
};
class Parser {
public:
// LineCallback is the type for callbacks that can parse a line starting with a given prefix.
//
// They take the form of bool Callback(std::vector<std::string>&& args, std::string* err)
//
// Similar to ParseSection() and ParseLineSection(), this function returns bool with false
// indicating a failure and has an std::string* err parameter into which an error string can
// be written.
using LineCallback = std::function<Result<void>(std::vector<std::string>&&)>;
Parser();
bool ParseConfig(const std::string& path);
bool ParseConfigFile(const std::string& path);
void AddSectionParser(const std::string& name, std::unique_ptr<SectionParser> parser);
void AddSingleLineParser(const std::string& prefix, LineCallback callback);
// Host init verifier check file permissions.
bool ParseConfigFileInsecure(const std::string& path);
size_t parse_error_count() const { return parse_error_count_; }
private:
void ParseData(const std::string& filename, std::string* data);
bool ParseConfigDir(const std::string& path);
std::map<std::string, std::unique_ptr<SectionParser>> section_parsers_;
std::vector<std::pair<std::string, LineCallback>> line_callbacks_;
size_t parse_error_count_ = 0;
};
} // namespace init
} // namespace android
#endif