base_ruleset.h

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// Copyright (c) 2020, the GRAPHGEN contributors, as
// shown by the AUTHORS file. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
 
#ifndef GRAPHGEN_BASE_RULESET_H_
#define GRAPHGEN_BASE_RULESET_H_
 
#include <fstream>
#include <filesystem>
#include <string>
#include <utility>
 
#include "yaml-cpp/yaml.h"
 
#include "rule_set.h"
 
 
class BaseRuleSet {
    std::filesystem::path p_;
    bool force_generation_;
    bool disable_generation_;
    rule_set rs_;
 
    bool LoadRuleSet() {
 
        YAML::Node rs_node;
        try {
            rs_node = YAML::LoadFile(p_.string());
        }
        catch (...){
            return false;
        }
 
        rs_ = rule_set(rs_node);
        return true;
    }
 
    void SaveRuleSet() {
        std::ofstream os(p_.string());
        if (os) {
            YAML::Node n = rs_.Serialize();
            YAML::Emitter emitter(os);
            emitter.SetSeqFormat(YAML::EMITTER_MANIP::Flow);
            emitter << n;
        }
    }
 
public:
 
    BaseRuleSet(bool force_generation = false) : force_generation_{ force_generation }, disable_generation_{ false }
    {
        p_ = conf.rstable_path_;
    }
 
    BaseRuleSet(std::filesystem::path custom_path) : force_generation_{ false }, disable_generation_{ true }, p_{ custom_path } 
    {
    }
 
    rule_set GetRuleSet() {
        if (force_generation_ || !LoadRuleSet()) {
            if (disable_generation_) {
                auto msg = "Could not load rule set " + p_.string() + " from file (generation disabled).\n";
                std::cerr << msg;
                throw std::runtime_error((msg).c_str());
            }
 
            rs_ = GenerateRuleSet();
            SaveRuleSet();
        }
        return rs_;
    }
 
    virtual rule_set GenerateRuleSet() = 0;
 
};
 
#endif //GRAPHGEN_BASE_RULESET_H_