Add project files.

source/HotReload/src/ModuleHandle.hpp

@@ -0,0 +1,58 @@
+#pragma once
+
+#include <string>
+
+namespace hot_reload::detail
+{
+
+	/// RAII wrapper around dlopen()/LoadLibrary(). Move-only, closes
+	/// the underlying module on destruction (or on being replaced by a
+	/// move-assignment).
+	class ModuleHandle
+	{
+	public:
+		ModuleHandle() = default;
+		~ModuleHandle();
+
+		ModuleHandle(const ModuleHandle&) = delete;
+		ModuleHandle& operator=(const ModuleHandle&) = delete;
+		ModuleHandle(ModuleHandle&& other) noexcept;
+		ModuleHandle& operator=(ModuleHandle&& other) noexcept;
+
+		/// Loads path. On failure the returned handle's isValid() is
+		/// false and loadedBase() is null.
+		static ModuleHandle load(const std::string& path);
+
+		bool isValid() const
+		{
+			return m_native != nullptr;
+		}
+
+		/// The address to pass as SymbolTable's loadedBase: on Windows
+		/// this is simply the HMODULE; on POSIX it is the runtime load
+		/// bias (struct link_map::l_addr) that turns an ELF symbol's
+		/// file-relative st_value into a real address.
+		void* loadedBase() const
+		{
+			return m_loadedBase;
+		}
+
+		/// Only meaningful when isValid() is false: the underlying
+		/// platform's own description of why loading failed --
+		/// dlerror() on POSIX, the formatted message for
+		/// GetLastError() on Windows. Captured immediately inside
+		/// load()'s failing branch, before any other dl*/Win32 call
+		/// that could otherwise overwrite it first. Empty if load()
+		/// was never attempted, or if the platform gave no message.
+		const std::string& errorMessage() const
+		{
+			return m_errorMessage;
+		}
+
+	private:
+		void* m_native = nullptr;
+		void* m_loadedBase = nullptr;
+		std::string m_errorMessage;
+	};
+
+}