From 94a3d1981e416ed42a2e5fcbe88718d549a470c2 Mon Sep 17 00:00:00 2001
From: Henrik Stickann <4376396-Mithradir@users.noreply.gitlab.com>
Date: Fri, 2 Dec 2022 16:41:56 +0100
Subject: [PATCH] Add handle wrapper class

---
 include/sta/rtos/handle.hpp | 74 +++++++++++++++++++++++++++++++++++++
 include/sta/rtos/handle.tpp | 46 +++++++++++++++++++++++
 2 files changed, 120 insertions(+)
 create mode 100644 include/sta/rtos/handle.hpp
 create mode 100644 include/sta/rtos/handle.tpp

diff --git a/include/sta/rtos/handle.hpp b/include/sta/rtos/handle.hpp
new file mode 100644
index 0000000..2b92e8e
--- /dev/null
+++ b/include/sta/rtos/handle.hpp
@@ -0,0 +1,74 @@
+#ifndef STA_RTOS_HANDLE_HPP
+#define STA_RTOS_HANDLE_HPP
+
+#include <type_traits>
+
+
+namespace sta
+{
+	/**
+	 * @brief Helper for managing access to RTOS handles.
+	 *
+	 * @tparam T    CMSIS RTOS2 handle type
+	 *
+	 * @ingroup STA_RTOS_API
+	 */
+	template <typename T>
+	class RtosHandle
+	{
+	public:
+		using handle_type = T;  /**< Handle type */
+
+		// TODO Support integer type with sizeof(T) == sizeof(void *)
+		static_assert(std::is_same<handle_type, void *>::value, "Only compatible with void * handle types");
+
+		/**
+		 * @brief Helper type for deferred handle evaluation.
+		 */
+		struct Deferred
+		{
+			handle_type * pointer;
+
+			/**
+			 * @brief Construct from handle address.
+			 *
+			 * @param handlePointer Handle variable address
+			 */
+			Deferred(handle_type * handlePointer);
+		};
+
+	public:
+		/**
+		 * @brief Construct handle from value.
+		 *
+		 * @param handle    Handle value
+		 */
+		RtosHandle(handle_type handle);
+		/**
+		 * @brief Construct handle with deferred evaluation.
+		 *
+		 * @param handle    Handle variable address
+		 */
+		RtosHandle(Deferred handle);
+
+		/**
+		 * @brief Access handle value.
+		 *
+		 * If the deferred ctor was used the handle value is
+		 * evaluated on the first call to this method.
+		 *
+		 * @return Handle value
+		 */
+		handle_type get();
+
+	private:
+		handle_type handle_;    /**< Handle value or variable address */
+		bool deferred_;         /**< Is handle evaluation deferred */
+	};
+} // namespace sta
+
+
+#include <sta/rtos/handle.tpp>
+
+
+#endif // STA_RTOS_HANDLE_HPP
diff --git a/include/sta/rtos/handle.tpp b/include/sta/rtos/handle.tpp
new file mode 100644
index 0000000..6c6927c
--- /dev/null
+++ b/include/sta/rtos/handle.tpp
@@ -0,0 +1,46 @@
+#ifndef STA_RTOS_HANDLE_TPP
+#define STA_RTOS_HANDLE_TPP
+
+#ifndef STA_RTOS_HANDLE_HPP
+#  error "Internal header. Use <sta/rtos/handle.hpp> instead."
+#endif // !STA_RTOS_HANDLE_HPP
+
+#include <sta/assert.hpp>
+
+
+namespace sta
+{
+	template <typename T>
+	RtosHandle<T>::Deferred::Deferred(handle_type * handlePointer)
+		: pointer{handlePointer}
+	{}
+
+
+	template <typename T>
+	RtosHandle<T>::RtosHandle(handle_type handle)
+		: handle_{handle}, deferred_{false}
+	{}
+
+	template <typename T>
+	RtosHandle<T>::RtosHandle(Deferred handle)
+		: handle_{handle.pointer}, deferred_{true}
+	{
+		STA_ASSERT(handle.pointer != nullptr);
+	}
+
+	template <typename T>
+	typename RtosHandle<T>::handle_type RtosHandle<T>::get()
+	{
+		if (deferred_)
+		{
+			// Dereference void ** in handle
+			handle_ = *reinterpret_cast<handle_type *>(handle_);
+			deferred_ = false;
+		}
+
+		return handle_;
+	}
+} // namespace sta
+
+
+#endif // STA_RTOS_HANDLE_TPP