Differential D3801 Diff 16930 source/ps/ParamNodeLayer.h

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source/ps/ParamNodeLayer.h

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				/* Copyright (C) 2021 Wildfire Games.
				* This file is part of 0 A.D.
				*
				* 0 A.D. is free software: you can redistribute it and/or modify
				* it under the terms of the GNU General Public License as published by
				* the Free Software Foundation, either version 2 of the License, or
				* (at your option) any later version.
				*
				* 0 A.D. 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 General Public License for more details.
				*
				* You should have received a copy of the GNU General Public License
				* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
				*/

				#ifndef INCLUDED_PARAMNODELAYER
				#define INCLUDED_PARAMNODELAYER

				#include <memory>

				class CParamNode;

				/**
				* A layer to apply on a ParamNode.
				* A ParamNode is made by applying several layers to the same node.
				* This class is intended as a file-format agnostic wrapper:
				* you pass a VfsPath and it does its thing and can be applied on a CParamNode.
				*/
				class ParamNodeLayer
				{
				public:
				ParamNodeLayer();
				~ParamNodeLayer();
				bool ApplyOnNode(CParamNode& node);

				// Generic layer loader - automatically determines the correct format.
				bool Load(const VfsPath& path);

				// Specific loaders below for optimisation.
				// XML loaders support validating individual layers (on top of the ParamNode validation).
				bool LoadXML(const VfsPath& path, const std::string& validator = "");
				bool LoadXML(const std::string& xml, const std::string& validator = "");

				std::string GetParent() const;
				void SetParent(const std::string& parent);
				private:
				// The whole point of this class is to modify CParamNode,
				// and as such it is a friend of CParamNode to make things convenient.
				// However, friendship is neither transitive nor inherited, so the 'apply'
				// function cannot be virtual and/or in the implementation classes.
				// The workaround is to define them here, but that leaks implementation details in the header.
				// To avoid that, we'll just specialize this template function: it's a friend,
				// and it can be defined entirely in the .cpp file.
				template<typename ...T>
				bool ApplyOnNode(CParamNode& node, T&&... args);

				std::string m_Parent;

				// PImpled data, to hide implementation details & make it easier to implement different file types.
				// (shared pointer to make copying cheaper - it seems fair to assume the raw data won't be changed).
				class Impl;
				std::shared_ptr<Impl> m_Data;
				};


				#endif // INCLUDED_PARAMLAYERNODE