libcruft-util/json/constraint/base.hpp

/*
 * 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.
 *
 * Copyright 2018 Danny Robson <danny@nerdcruft.net>
 */

#pragma once

#include "except.hpp"

#include <string>
#include <vector>
#include <iosfwd>


namespace util::json::schema::constraint {
    struct failure {
        constraint::base const &rule;
        ::json::tree::node const &target;
    };


    class base {
    public:
        using output_container = std::vector<failure>;
        using output_iterator = std::back_insert_iterator<output_container>;

        base () = default;
        base (base &&) = default;
        base& operator= (base &&) = default;
        base (base const&) = delete;
        base& operator= (base const&) = delete;
        virtual ~base () = default;

        virtual output_iterator validate (output_iterator res, ::json::tree::node &) const noexcept = 0;
        virtual std::ostream& describe (std::ostream&) const = 0;

        static std::unique_ptr<base> instantiate (std::string const &name, ::json::tree::node const&);
    };


    inline std::ostream&
    operator<< (std::ostream &os, base const &obj)
    {
        return obj.describe (os);
    }
}