Materials: Model Manager External Interface (#20825)

* Materials: Model Manager External Interface

Implement the ModelManagerExternal class for the external Materials
interface.

This is part of the ongoing merges of code to support external material
interfaces. In this PR the ModelManagerExternal class is implemented,
along with changes to supporting classes required for this class.

* Apply reviewer feedback

src/Mod/Material/App/ModelManagerExternal.h

@@ -0,0 +1,86 @@
+/***************************************************************************
+ *   Copyright (c) 2024 David Carter <dcarter@david.carter.ca>             *
+ *                                                                         *
+ *   This file is part of FreeCAD.                                         *
+ *                                                                         *
+ *   FreeCAD is free software: you can redistribute it and/or modify it    *
+ *   under the terms of the GNU Lesser General Public License as           *
+ *   published by the Free Software Foundation, either version 2.1 of the  *
+ *   License, or (at your option) any later version.                       *
+ *                                                                         *
+ *   FreeCAD 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      *
+ *   Lesser General Public License for more details.                       *
+ *                                                                         *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with FreeCAD. If not, see                               *
+ *   <https://www.gnu.org/licenses/>.                                      *
+ *                                                                         *
+ **************************************************************************/
+
+#ifndef MATERIAL_MODELMANAGEREXTERNAL_H
+#define MATERIAL_MODELMANAGEREXTERNAL_H
+
+#include <memory>
+#include <lru/lru.hpp>
+
+#include <Mod/Material/MaterialGlobal.h>
+
+#include <QMutex>
+
+#include "Exceptions.h"
+#include "FolderTree.h"
+#include "Model.h"
+#include "ModelLibrary.h"
+
+namespace Materials
+{
+
+class MaterialsExport ModelManagerExternal: public Base::BaseClass
+{
+    TYPESYSTEM_HEADER_WITH_OVERRIDE();
+
+public:
+    ModelManagerExternal();
+    ~ModelManagerExternal() override = default;
+
+    static void cleanup();
+    void refresh();
+
+    static const int DEFAULT_CACHE_SIZE = 100;
+
+    // Library management
+    std::shared_ptr<std::list<std::shared_ptr<ModelLibrary>>> getLibraries();
+    std::shared_ptr<ModelLibrary> getLibrary(const QString& name) const;
+    void createLibrary(const QString& libraryName,
+                       const QString& icon,
+                       bool readOnly = true);
+    std::shared_ptr<std::vector<std::tuple<QString, QString, QString>>>
+    libraryModels(const QString& libraryName);
+
+    // Model management
+    std::shared_ptr<Model> getModel(const QString& uuid);
+    std::shared_ptr<std::map<QString, std::shared_ptr<Model>>> getModels();
+    void
+    addModel(const QString& libraryName, const QString& path, const std::shared_ptr<Model>& model);
+    void
+    migrateModel(const QString& libraryName, const QString& path, const std::shared_ptr<Model>& model);
+
+    // Cache functions
+    void resetCache();
+    double modelHitRate();
+
+private:
+    static void initCache();
+
+    static QMutex _mutex;
+
+    // Older platforms (Ubuntu 20.04) can't use QString as the index
+    // due to a lack of a move constructor
+    static LRU::Cache<std::string, std::shared_ptr<Model>> _cache;
+};
+
+}  // namespace Materials
+
+#endif  // MATERIAL_MODELMANAGEREXTERNAL_H