rrset_collection_base.h

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// Copyright (C) 2012-2022 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef RRSET_COLLECTION_BASE_H
#define RRSET_COLLECTION_BASE_H 1

#include <dns/rrset.h>
#include <dns/name.h>

#include <boost/shared_ptr.hpp>

#include <iterator>

namespace isc {
namespace dns {

class RRsetCollectionError : public Exception {
public:
    RRsetCollectionError(const char* file, size_t line, const char* what) :
        Exception(file, line, what)
    {}
};

class RRsetCollectionBase {
public:
    virtual isc::dns::ConstRRsetPtr find
        (const isc::dns::Name& name, const isc::dns::RRClass& rrclass,
         const isc::dns::RRType& rrtype)
        const = 0;

    virtual ~RRsetCollectionBase() {}

protected:
    class Iter; // forward declaration

    typedef boost::shared_ptr<Iter> IterPtr;

    class Iter {
    public:
        virtual ~Iter() {};

        virtual const isc::dns::AbstractRRset& getValue() = 0;

        virtual IterPtr getNext() = 0;

        virtual bool equals(Iter& other) = 0;
    };

    virtual IterPtr getBeginning() = 0;

    virtual IterPtr getEnd() = 0;

public:
    class Iterator {
    public:
        // Aliases used to enable iterator behavior on this class
        using iterator_category = std::forward_iterator_tag;
        using value_type = isc::dns::AbstractRRset const;
        using difference_type = std::ptrdiff_t;
        using pointer = isc::dns::AbstractRRset const*;
        using reference = isc::dns::AbstractRRset const&;

        explicit Iterator(IterPtr iter) :
            iter_(iter)
        {}

        reference operator*() {
            return (iter_->getValue());
        }

        Iterator& operator++() {
            iter_ = iter_->getNext();
            return (*this);
        }

        Iterator operator++(int) {
            Iterator tmp(iter_);
            ++*this;
            return (tmp);
        }

        bool operator==(const Iterator& other) const {
            return (iter_->equals(*other.iter_));
        }

        bool operator!=(const Iterator& other) const {
            return (!iter_->equals(*other.iter_));
        }

    private:
        IterPtr iter_;
    };

    Iterator begin() {
      return Iterator(getBeginning());
    }

    Iterator end() {
      return Iterator(getEnd());
    }
};

typedef boost::shared_ptr<RRsetCollectionBase> RRsetCollectionPtr;

} // end of namespace dns
} // end of namespace isc

#endif  // RRSET_COLLECTION_BASE_H