Copyright 2023 Travis J. West, https://traviswest.ca, Input Devices and Music Interaction Laboratory (IDMIL), Centre for Interdisciplinary Research in Music Media and Technology (CIRMMT), McGill University, Montréal, Canada, and Univ. Lille, Inria, CNRS, Centrale Lille, UMR 9189 CRIStAL, F-59000 Lille, France

SPDX-License-Identifier: MIT

It's common that some configurable parameters of a DMI system should be persistent in the long term, e.g. across boot cycles of the processor. We term these parameters session data. A component that manages storing and reloading session data is termed a session manager. Currently, a JSON session manager is provided. Other formats and storage mechanisms are easy to imagine, and may be provided in future work.

This document describes the implementation of fundamental functionality shared by all session managers.

Representation

Session data is represented by endpoints marked with the tag session_data. Using the endpoint helpers library, an endpoint can be marked as session data by passing the tag_session_data class as part of the endpoint's variadic template type parameter pack (if using one of the built in endpoint templates), or by inheriting from tag_session_data (if defining a custom endpoint by assembling the helper base classes), or by defining an unscoped enumeration with a member called session_data. The presence of the session data endpoint can be queried at compile time using the concept tagged_session_data provided by the endpoint concepts library.

For Each Session Datum

All session managers require a means to iterate over all session data endpoint. This is accomplished using the for_each_endpoint function provided by the component concepts library.

// @#'sygbp-session_data.hpp'
#pragma once
/*
Copyright 2023 Travis J. West, https://traviswest.ca, Input Devices and Music Interaction Laboratory
(IDMIL), Centre for Interdisciplinary Research in Music Media and Technology
(CIRMMT), McGill University, Montréal, Canada, and Univ. Lille, Inria, CNRS,
Centrale Lille, UMR 9189 CRIStAL, F-59000 Lille, France
 
SPDX-License-Identifier: MIT
*/
 
#include "sygac-components.hpp"
#include "sygac-endpoints.hpp"
 
namespace sygaldry { namespace sygbp {
 
template<typename C>
constexpr void for_each_session_datum(C& components, auto fn)
{
    for_each_endpoint(components, [&]<typename T>(T& endpoint)
    {
        if constexpr (tagged_session_data<T>) fn(endpoint);
    });
}
 
} }
// @/

# @#'CMakeLists.txt'
set(lib sygbp-session_data)
add_library(${lib} INTERFACE)
target_include_directories(${lib} INTERFACE .)
# @/

Table of Contents

Representation

For Each Session Datum