sql_result.h

/*
 * Copyright (c) 2008-2021, Hazelcast, Inc. All Rights Reserved.
 *
 * 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 <iterator>
#include <chrono>
 
#include <boost/thread/future.hpp>
 
#include "hazelcast/util/export.h"
#include "hazelcast/client/connection/Connection.h"
#include "hazelcast/client/sql/sql_page.h"
#include "hazelcast/client/sql/sql_row_metadata.h"
 
namespace hazelcast {
namespace client {
namespace sql {
class sql_service;
 
// This class is NOT thread-safe. Do NOT use simultaneously from multiple
// threads.
class HAZELCAST_API sql_result : public std::enable_shared_from_this<sql_result>
{
public:

    class HAZELCAST_API page_iterator
    {
    public:
        page_iterator(std::shared_ptr<sql_result> result,
                      std::shared_ptr<sql_page> first_page);
 
        page_iterator(const page_iterator&) = delete;
        page_iterator(page_iterator&&) = default;
        page_iterator& operator=(const page_iterator&) = delete;
        page_iterator& operator=(page_iterator&&) = default;

        boost::future<std::shared_ptr<sql_page>> next();

        bool has_next() const;
 
    private:
 
        std::shared_ptr<std::atomic<bool>> in_progress_;
        std::shared_ptr<std::atomic<bool>> last_;
        std::shared_ptr<sql_row_metadata> row_metadata_;
        serialization::pimpl::SerializationService* serialization_;
        std::shared_ptr<sql_result> result_;
        std::shared_ptr<sql_page> first_page_;
    };

    class HAZELCAST_API page_iterator_sync
    {
    public:
        using difference_type = void;
        using value_type = std::shared_ptr<sql_page>;
        using pointer = std::shared_ptr<sql_page>;
        using reference = std::shared_ptr<sql_page>&;
        using iterator_category = std::input_iterator_tag;

        void set_timeout(std::chrono::milliseconds);

        std::chrono::milliseconds timeout() const;
 
        friend HAZELCAST_API bool operator==(const page_iterator_sync&,
                                             const page_iterator_sync&);
        friend HAZELCAST_API bool operator!=(const page_iterator_sync&,
                                             const page_iterator_sync&);
 

        std::shared_ptr<sql_page> operator*() const;

        std::shared_ptr<sql_page> operator->() const;

        page_iterator_sync operator++(int) = delete;

        page_iterator_sync& operator++();
 
    private:
 
        friend class sql_result;
        page_iterator_sync(page_iterator&&, std::chrono::milliseconds timeout);
        page_iterator_sync() = default;
 
        struct non_copyables
        {
            explicit non_copyables(page_iterator&&);
 
            boost::future<std::shared_ptr<sql_page>> preloaded_page_;
            page_iterator iter_;
        };
 
        std::shared_ptr<non_copyables> block_;
        std::shared_ptr<sql_page> current_;
        std::chrono::milliseconds timeout_;
    };

    class HAZELCAST_API row_iterator_sync
    {
    public:
        using difference_type = void;
        using value_type = sql_page::sql_row;
        using pointer = sql_page::sql_row*;
        using reference = const sql_page::sql_row&;
        using iterator_category = std::input_iterator_tag;

        void set_timeout(std::chrono::milliseconds);

        std::chrono::milliseconds timeout() const;
 
        friend HAZELCAST_API bool operator==(const row_iterator_sync&,
                                             const row_iterator_sync&);
        friend HAZELCAST_API bool operator!=(const row_iterator_sync&,
                                             const row_iterator_sync&);

        const sql_page::sql_row& operator*() const;
 

        const sql_page::sql_row* operator->() const;

        row_iterator_sync operator++(int) = delete;

        row_iterator_sync& operator++();
 
    private:
 
        friend class sql_result;
        row_iterator_sync(page_iterator_sync&&);
        row_iterator_sync() = default;
 
        mutable page_iterator_sync iterator_;
        std::size_t row_idx_;
    };

    virtual ~sql_result();

    bool row_set() const;

    const sql_row_metadata& row_metadata() const;

    int64_t update_count() const;

    boost::future<void> close();

    page_iterator iterator();
 
    page_iterator_sync pbegin(
      std::chrono::milliseconds timeout = std::chrono::milliseconds{ -1 });
    page_iterator_sync pend();
    row_iterator_sync begin(
      std::chrono::milliseconds timeout = std::chrono::milliseconds{ -1 });
    row_iterator_sync end();
 
private:
    friend class sql_service;
 
    spi::ClientContext* client_context_;
    sql_service* service_;
    std::shared_ptr<connection::Connection> connection_;
    impl::query_id query_id_;
    int64_t update_count_;
    std::shared_ptr<sql_row_metadata> row_metadata_;
    std::shared_ptr<sql_page> first_page_;
 
    bool iterator_requested_;

    std::atomic<bool> closed_;
    std::mutex mtx_;
 
    int32_t cursor_buffer_size_;

    sql_result(
      spi::ClientContext* client_context,
      sql_service* service,
      std::shared_ptr<connection::Connection> connection,
      impl::query_id id,
      int64_t update_count,
      std::shared_ptr<sql_row_metadata> row_metadata,
      std::shared_ptr<sql_page> first_page,
      int32_t cursor_buffer_size);
 
private:
    boost::future<std::shared_ptr<sql_page>> fetch_page();
 
    template<typename T>
    boost::optional<T> to_object(serialization::pimpl::data data)
    {
        return client_context_->get_serialization_service().to_object<T>(data);
    }
    void check_closed() const;
};
 
} // namespace sql
} // namespace client
} // namespace hazelcast