stable_interprocess_map.hpp

Go to the documentation of this file.

/*
Copyright (c) 2025 acrion innovations GmbH
Authors: Stefan Zipproth, s.zipproth@acrion.ch
 
This file is part of Cbeam, see https://github.com/acrion/cbeam and https://cbeam.org
 
Cbeam is offered under a commercial and under the AGPL license.
For commercial licensing, contact us at https://acrion.ch/sales. For AGPL licensing, see below.
 
AGPL licensing:
 
Cbeam is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
 
Cbeam is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
 
You should have received a copy of the GNU Affero General Public License
along with Cbeam. If not, see <https://www.gnu.org/licenses/>.
*/
 
#pragma once
 
#include <cbeam/container/stable_interprocess_container.hpp> // for cbeam::container::stable_interprocess_container
#include <cbeam/error/out_of_range.hpp>                      // for cbeam::error:out_of_range
#include <cbeam/error/runtime_error.hpp>                     // for cbeam::error:runtime_error
#include <cbeam/serialization/map.hpp>                       // IWYU pragma: keep (required for serialization of the template type of stable_interprocess_container, which is a std::map)
 
#include <cstddef> // for std::size_t
 
#include <functional>       // for std::function
#include <initializer_list> // for std::initializer_list
#include <map>              // for std::allocator, std::map
#include <string>           // for std::string
#include <utility>          // for std::pair
 
namespace cbeam::container
{
    template <typename Key, typename Value>
    class stable_interprocess_map : public stable_interprocess_container<std::map<Key, Value>>
    {
    public:
        stable_interprocess_map(const std::string& unique_identifier, std::size_t size)
            : stable_interprocess_container<std::map<Key, Value>>(unique_identifier, size)
        {
        }

        stable_interprocess_map& operator=(const std::initializer_list<std::pair<const Key, Value>>& list)
        {
            std::map<Key, Value> local_instance;
 
            for (const auto& item : list)
            {
                local_instance[item.first] = item.second;
            }
 
            auto lock = this->get_lock_guard();
            this->serialize(local_instance);
            return *this;
        }

        Value at(const Key& key) const
        {
            std::map<Key, Value> local_instance;
            {
                auto lock = this->get_lock_guard();
 
                local_instance = this->deserialize();
            }
 
            try
            {
                return local_instance.at(key);
            }
            catch (const std::out_of_range& ex)
            {
                throw cbeam::error::out_of_range(ex.what());
            }
        }

        Value at_or_default(const Key& key, const Value& default_value) const
        {
            std::map<Key, Value> local_instance;
            {
                auto lock = this->get_lock_guard();
 
                local_instance = this->deserialize();
            }
 
            return local_instance.count(key) == 1 ? local_instance.at(key) : default_value;
        }

        void insert(const Key& key, const Value& value)
        {
            auto lock = this->get_lock_guard();
 
            auto local_instance = this->deserialize();
            local_instance[key] = value;
            this->serialize(local_instance);
        }

        void erase(const Key& key)
        {
            auto lock = this->get_lock_guard();
 
            auto local_instance = this->deserialize();
            local_instance.erase(key);
            this->serialize(local_instance);
        }

        std::size_t count(const Key& key) const
        {
            auto lock = this->get_lock_guard();
 
            return this->deserialize().count(key);
        }

        void update_or_insert(const Key& key, std::function<void(Value&)> updater, const Value& default_value)
        {
            auto lock           = this->get_lock_guard();
            auto local_instance = this->deserialize();
 
            if (local_instance.find(key) != local_instance.end())
            {
                updater(local_instance[key]);
            }
            else
            {
                local_instance[key] = default_value;
            }
 
            this->serialize(local_instance);
        }

        const Value update(const Key& key, std::function<void(Value&)> updater, const std::string& error_string = {"cbeam::stable_interprocess_map::update: key not found"})
        {
            auto lock           = this->get_lock_guard();
            auto local_instance = this->deserialize();
 
            if (local_instance.find(key) == local_instance.end())
            {
                throw cbeam::error::runtime_error(error_string);
            }
 
            updater(local_instance[key]);
            this->serialize(local_instance);
            return local_instance.at(key);
        }
    };
}