cursor.hpp

// Copyright 2014 MongoDB Inc.
//
// 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.

#pragma once

#include <memory>

#include <bsoncxx/document/view.hpp>
#include <bsoncxx/stdx/optional.hpp>

#include <mongocxx/config/prelude.hpp>

namespace mongocxx {
MONGOCXX_INLINE_NAMESPACE_BEGIN

class collection;

class MONGOCXX_API cursor {
   public:
    enum class type { k_non_tailable, k_tailable, k_tailable_await };

    class MONGOCXX_API iterator;

    cursor(cursor&&) noexcept;

    cursor& operator=(cursor&&) noexcept;

    ~cursor();

    iterator begin();

    iterator end();

   private:
    friend class collection;
    friend class client;
    friend class database;
    friend class cursor::iterator;

    MONGOCXX_PRIVATE cursor(void* cursor_ptr,
                            bsoncxx::stdx::optional<type> cursor_type = bsoncxx::stdx::nullopt);

    class MONGOCXX_PRIVATE impl;
    std::unique_ptr<impl> _impl;
};

class MONGOCXX_API cursor::iterator
    : public std::iterator<std::input_iterator_tag, bsoncxx::document::view> {
   public:
    const bsoncxx::document::view& operator*() const;

    const bsoncxx::document::view* operator->() const;

    iterator& operator++();

    void operator++(int);

   private:
    friend class cursor;

    friend MONGOCXX_API bool MONGOCXX_CALL operator==(const iterator&, const iterator&);
    friend MONGOCXX_API bool MONGOCXX_CALL operator!=(const iterator&, const iterator&);

    MONGOCXX_PRIVATE bool is_exhausted() const;

    MONGOCXX_PRIVATE explicit iterator(cursor* cursor);

    // If this pointer is null, the iterator is considered "past-the-end".
    cursor* _cursor;
};

MONGOCXX_INLINE_NAMESPACE_END
}  // namespace mongocxx

#include <mongocxx/config/postlude.hpp>