pcsx2/common/DynamicLibrary.h

// SPDX-FileCopyrightText: 2002-2023 PCSX2 Dev Team
// SPDX-License-Identifier: LGPL-3.0+

#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.
		DynamicLibrary();

		/// Automatically loads the specified library. Call IsOpen() to check validity before use.
		DynamicLibrary(const char* filename);

		/// Move constructor, transfers ownership.
		DynamicLibrary(DynamicLibrary&& move);

		/// Closes the library.
		~DynamicLibrary();

		/// Returns the specified library name with the platform-specific suffix added.
		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
		static std::string GetVersionedFilename(const char* libname, int major = -1, int minor = -1);

		/// Returns true if a module is loaded, otherwise false.
		bool IsOpen() const { return m_handle != nullptr; }

		/// Loads (or replaces) the handle with the specified library file name.
		/// Returns true if the library was loaded and can be used.
		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		/// Unloads the library, any function pointers from this library are no longer valid.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.
		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>
		bool GetSymbol(const char* name, T* ptr) const
		{
			*ptr = reinterpret_cast<T>(GetSymbolAddress(name));
			return *ptr != nullptr;
		}

		/// Move assignment, transfer ownership.
		DynamicLibrary& operator=(DynamicLibrary&& move);

	private:
		DynamicLibrary(const DynamicLibrary&) = delete;
		DynamicLibrary& operator=(const DynamicLibrary&) = delete;

		/// Platform-dependent data type representing a dynamic library handle.
		void* m_handle = nullptr;
	};

} // namespace Common