Differential D12885 Diff 43483 source/blender/blenkernel/intern/asset_library_service.hh

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source/blender/blenkernel/intern/asset_library_service.hh

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				/*
				* This program 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.
				*
				* This program 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 this program; if not, write to the Free Software Foundation,
				* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
				*/

				/** \file
				* \ingroup bke
				*/

				#pragma once

				#ifndef __cplusplus
				# error This is a C++-only header file.
				#endif

				#include "BKE_asset_library.hh"

				#include "BLI_map.hh"

				#include <memory>

				namespace blender::bke {

				/**
				* Global singleton-ish that provides access to individual #AssetLibrary instances.
				*
				* Whenever a blend file is loaded, the existing instance of AssetLibraryService is destructed, and
				* a new one is created -- hence the "singleton-ish". This ensures only information about relevant
				* asset libraries is loaded.
				*
				* \note How Asset libraries are identified may change in the future.
				* For now they are assumed to be:
				* - on disk (identified by the absolute directory), or
				* - the "current file" library (which is in memory but could have catalogs
				* loaded from a file on disk).
				*/
				class AssetLibraryService {
				public:
				using AssetLibraryPtr = std::unique_ptr<AssetLibrary>;

				AssetLibraryService() = default;
				~AssetLibraryService() = default;

				/** Return the AssetLibraryService singleton, allocating it if necessary. */
				static AssetLibraryService *get();

				/** Destroy the AssetLibraryService singleton. It will be reallocated by #get() if necessary. */
				static void destroy();

				/**
				* Get the given asset library. Opens it (i.e. creates a new AssetLibrary instance) if necessary.
				*/
				AssetLibrary *get_asset_library_on_disk(StringRefNull top_level_directory);

				/** Get the "Current File" asset library. */
				AssetLibrary *get_asset_library_current_file();

				protected:
				static std::unique_ptr<AssetLibraryService> instance_;

				/* Mapping absolute path of the library's top-level directory to the AssetLibrary instance. */
				Map<std::string, AssetLibraryPtr> on_disk_libraries_;
				AssetLibraryPtr current_file_library_;

				/* Handlers for managing the life cycle of the AssetLibraryService instance. */
				bCallbackFuncStore on_load_callback_store_;
				static bool atexit_handler_registered_;

				/** Allocate a new instance of the service and assign it to `instance_`. */
				static void allocate_service_instance();

				/**
				* Ensure the AssetLibraryService instance is destroyed before a new blend file is loaded.
				* This makes memory management simple, and ensures a fresh start for every blend file. */
				void app_handler_register();
				void app_handler_unregister();
				};

				} // namespace blender::bke