GDExtension: Implement `GDExtensionLoader` concept

- Implements the concept of GDExtension loaders that can be used to customize how GDExtensions are loaded and initialized.
- Moves the parsing of `.gdextension` config files to the new `GDExtensionLibraryLoader`.
- `GDExtensionManager` is now meant to be the main way to load/unload extensions and can optionally take a `GDExtensionLoader`.
- `EditorFileSystem` avoids unloading extensions if the file still exists, this should prevent unloading extensions that are outside the user project.

1 files changed, 84 insertions, 0 deletions

diff --git a/core/extension/gdextension_library_loader.h b/core/extension/gdextension_library_loader.h
new file mode 100644
index 0000000000..f4372a75d4
--- /dev/null
+++ b/core/extension/gdextension_library_loader.h
@@ -0,0 +1,84 @@
+/**************************************************************************/
+/*  gdextension_library_loader.h                                          */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#ifndef GDEXTENSION_LIBRARY_LOADER_H
+#define GDEXTENSION_LIBRARY_LOADER_H
+
+#include <functional>
+
+#include "core/extension/gdextension_loader.h"
+#include "core/io/config_file.h"
+#include "core/os/shared_object.h"
+
+class GDExtensionLibraryLoader : public GDExtensionLoader {
+	friend class GDExtensionManager;
+	friend class GDExtension;
+
+private:
+	String resource_path;
+
+	void *library = nullptr; // pointer if valid.
+	String library_path;
+	String entry_symbol;
+
+	bool is_static_library = false;
+
+#ifdef TOOLS_ENABLED
+	bool is_reloadable = false;
+#endif
+
+	Vector<SharedObject> library_dependencies;
+
+	HashMap<String, String> class_icon_paths;
+
+#ifdef TOOLS_ENABLED
+	uint64_t resource_last_modified_time = 0;
+	uint64_t library_last_modified_time = 0;
+
+	void update_last_modified_time(uint64_t p_resource_last_modified_time, uint64_t p_library_last_modified_time) {
+		resource_last_modified_time = p_resource_last_modified_time;
+		library_last_modified_time = p_library_last_modified_time;
+	}
+#endif
+
+public:
+	static String find_extension_library(const String &p_path, Ref<ConfigFile> p_config, std::function<bool(String)> p_has_feature, PackedStringArray *r_tags = nullptr);
+	static Vector<SharedObject> find_extension_dependencies(const String &p_path, Ref<ConfigFile> p_config, std::function<bool(String)> p_has_feature);
+
+	virtual Error open_library(const String &p_path) override;
+	virtual Error initialize(GDExtensionInterfaceGetProcAddress p_get_proc_address, const Ref<GDExtension> &p_extension, GDExtensionInitialization *r_initialization) override;
+	virtual void close_library() override;
+	virtual bool is_library_open() const override;
+	virtual bool has_library_changed() const override;
+
+	Error parse_gdextension_file(const String &p_path);
+};
+
+#endif // GDEXTENSION_LIBRARY_LOADER_H