Ichthyostega
994a4cf557
Gradually, the header buffhandle.hpp became the minimal include to use basic `BufferProvider` functionality, since `BuffHandle` provides proxy functionality to lock and access a data buffer. The whole compound connected to the `BufferProvider` has evolved into a cohesive yet central connection hub related to buffer memory; it should thus be extracted, moved down to »Vault« layer and used 4as a foundation for various high-level tasks. In preparation of this step, relevant marker typedefs are re-arranged; notably ''Stream Type'' now includes `buffhandle.hpp`
129 lines
3.9 KiB
C++
129 lines
3.9 KiB
C++
/*
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BUFFER-PROVIDER-SETUP.hpp - configuration of the actual BufferProvider implementation
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Copyright (C)
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2026, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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*/
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/** @file buffer-provider-setup.hpp
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** Helper template for installing a suitable BufferProvider setup.
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**
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** @see engine-facilities.cpp
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** @see buffer-provider.hpp
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*/
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#ifndef STEAM_ENGINE_BUFFR_PROVIDER_SETUP_H
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#define STEAM_ENGINE_BUFFR_PROVIDER_SETUP_H
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#include "lib/error.hpp"
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#include "lib/symbol.hpp"
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#include "lib/hash-value.h"
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#include "steam/engine/buffer-provider.hpp"
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#include "lib/nocopy.hpp"
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#include <utility>
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#include <memory>
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namespace steam {
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namespace engine {
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using lib::Literal;
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using std::unique_ptr;
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using std::make_unique;
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// using std::forward;
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using std::move;
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/**
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* Framework for configuring the actual BufferPovider backend implementation.
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*
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* @todo WIP-WIP-WIP as of 2/2026 -- reworking BufferProvider implementation ////////////////////////////TICKET #1410
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*/
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class BufferProviderSetup
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: public BufferProvider
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{
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public:
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/**
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* Build a new BufferProvider setup to manage a number of buffers.
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* The metadata of these buffers is organised hierarchically based on
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* chained hash values, using an `implementationID` as a seed.
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* The \a CONF configuration record controls the actual implementation
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* of lifecycle transitions and storage management.
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*/
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template<class CONF>
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BufferProviderSetup (CONF&& confRec)
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: BufferProvider{}
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{
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bufferStage_ = move (confRec.buildStage());
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bufferStore_ = move (confRec.buildStore());
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}
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/* ======== Extension points ======== */
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class Stage
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: public BufferStage
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{ };
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class Store
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: public BufferStore
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{ };
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protected:
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/**
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* Enable subclasses to layer a decorator on top of
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* an already instantiated implementation object
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* @tparam IMP concrete type of the implementation decorator; must be specified.
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* @tparam API the API to decorate; the decorator IMP must implement this API
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* @tparam ARGS (optionally) further constructor arguments for the decorator
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* @param rawImp the `uniqe_ptr` with an already instantiated implementation of API
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* @note the decorator subclass is assumed to incorporate an unique_ptr&&, holding
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* and managing the underlying implementation from that point on
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* @warning the new decorator implementation is responsible for the overall sane state,
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* starting from that point when it picks up the given unique_ptr. An exception
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* emanating after that point will not leak memory, but destroy the original
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* implementation and thus leave the whole BufferProvider in undefined state.
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*/
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template<class IMP, class API, typename...ARGS>
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void
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decorate (unique_ptr<API>& rawImp, ARGS&& ...furtherDecoratorArgs)
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{
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unique_ptr<API> underlying;
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try {
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REQUIRE (rawImp);
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std::swap (rawImp, underlying);
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ENSURE (not rawImp);
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rawImp = make_unique<IMP> (move(underlying), forward<ARGS> (furtherDecoratorArgs)...);
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ENSURE (rawImp);
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}
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catch (...)
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{
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REQUIRE (not rawImp);
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REQUIRE (underlying);
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std::swap (rawImp, underlying);
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}
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}
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};
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/* === Implementation === */
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/** */
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}} // namespace steam::engine
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#endif /*STEAM_ENGINE_BUFFR_PROVIDER_SETUP_H*/
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