pool.hpp

// Copyright 2015 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 <functional>
#include <memory>

#include <bsoncxx/stdx/optional.hpp>
#include <mongocxx/options/pool.hpp>
#include <mongocxx/stdx.hpp>
#include <mongocxx/uri.hpp>

#include <mongocxx/config/prelude.hpp>

namespace mongocxx {
MONGOCXX_INLINE_NAMESPACE_BEGIN

class client;

class MONGOCXX_API pool {
   public:
    explicit pool(const uri& mongodb_uri = mongocxx::uri(),
                  const options::pool& options = options::pool());

    ~pool();

    class MONGOCXX_API entry {
       public:
        client* operator->() const& noexcept;
        client* operator->() && = delete;

        client& operator*() const& noexcept;
        client& operator*() && = delete;

        entry& operator=(std::nullptr_t) noexcept;

        explicit operator bool() const noexcept;

       private:
        friend class pool;

        using unique_client = std::unique_ptr<client, std::function<void MONGOCXX_CALL(client*)>>;

        MONGOCXX_PRIVATE explicit entry(unique_client);

        unique_client _client;
    };

    entry acquire();

    stdx::optional<entry> try_acquire();

   private:
    MONGOCXX_PRIVATE void _release(client* client);

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

MONGOCXX_INLINE_NAMESPACE_END
}  // namespace mongocxx

#include <mongocxx/config/postlude.hpp>