Clean up shared memory

include/dynamic_library.hpp

@@ -0,0 +1,73 @@
+// SPDX-FileCopyrightText: 2019 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <string>
+
+namespace Common {
+	/**
+	 * Provides a platform-independent interface for loading a dynamic library and retrieving symbols.
+	 * The interface maintains an internal reference count to allow one handle to be shared between
+	 * multiple users.
+	 */
+	class DynamicLibrary final {
+	  public:
+		/// Default constructor, does not load a library.
+		explicit DynamicLibrary();
+
+		/// Automatically loads the specified library. Call IsOpen() to check validity before use.
+		explicit DynamicLibrary(const char* filename);
+
+		/// Initializes the dynamic library with an already opened handle.
+		explicit DynamicLibrary(void* handle_);
+
+		/// Moves the library.
+		DynamicLibrary(DynamicLibrary&&) noexcept;
+		DynamicLibrary& operator=(DynamicLibrary&&) noexcept;
+
+		/// Delete copies, we can't copy a dynamic library.
+		DynamicLibrary(const DynamicLibrary&) = delete;
+		DynamicLibrary& operator=(const DynamicLibrary&) = delete;
+
+		/// Closes the library.
+		~DynamicLibrary();
+
+		/// Returns the specified library name with the platform-specific suffix added.
+		[[nodiscard]] static std::string getUnprefixedFilename(const char* filename);
+
+		/// Returns the specified library name in platform-specific format.
+		/// Major/minor versions will not be included if set to -1.
+		/// If libname already contains the "lib" prefix, it will not be added again.
+		/// Windows: LIBNAME-MAJOR-MINOR.dll
+		/// Linux: libLIBNAME.so.MAJOR.MINOR
+		/// Mac: libLIBNAME.MAJOR.MINOR.dylib
+		[[nodiscard]] static std::string getVersionedFilename(const char* libname, int major = -1, int minor = -1);
+
+		/// Returns true if a module is loaded, otherwise false.
+		[[nodiscard]] bool isOpen() const { return handle != nullptr; }
+
+		/// Loads (or replaces) the handle with the specified library file name.
+		/// Returns true if the library was loaded and can be used.
+		[[nodiscard]] bool open(const char* filename);
+
+		/// Unloads the library, any function pointers from this library are no longer valid.
+		void close();
+
+		/// Returns the address of the specified symbol (function or variable) as an untyped pointer.
+		/// If the specified symbol does not exist in this library, nullptr is returned.
+		[[nodiscard]] void* getSymbolAddress(const char* name) const;
+
+		/// Obtains the address of the specified symbol, automatically casting to the correct type.
+		/// Returns true if the symbol was found and assigned, otherwise false.
+		template <typename T>
+		[[nodiscard]] bool getSymbol(const char* name, T* ptr) const {
+			*ptr = reinterpret_cast<T>(getSymbolAddress(name));
+			return *ptr != nullptr;
+		}
+
+	  private:
+		/// Platform-dependent data type representing a dynamic library handle.
+		void* handle = nullptr;
+	};
+}  // namespace Common