Imported Genode release 11.11

base-linux/include/base/local_interface.h

@@ -0,0 +1,89 @@
+/*
+ * \brief  Support for process-local pseudo capabilities
+ * \author Norman Feske
+ * \date   2011-11-21
+ *
+ * Pseudo capabilities have a zero 'tid' and a non-zero 'local_name'. The local
+ * name is a pointer to the local object implementing the interface. Pseudo
+ * capabilties are valid only as arguments for local services that are prepared
+ * for it. I.e., the locally implemented RM service accepts pseudo dataspace
+ * capabilities that refer to managed dataspaces. Or the Linux-specific
+ * 'Rm_session_client' takes a pseudo capability to target RM-session
+ * invokations to the local implementation.
+ *
+ * Please note that this header file is not part of the official Genode API.
+ * It exists on no other platform than Linux and is meant for Genode-internal
+ * use only.
+ */
+
+/*
+ * Copyright (C) 2011 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#ifndef _INCLUDE__BASE__LOCAL_INTERFACE_H_
+#define _INCLUDE__BASE__LOCAL_INTERFACE_H_
+
+#include <base/capability.h>
+#include <base/printf.h>
+
+namespace Genode {
+
+	/**
+	 * Common base class of local interface implementations
+	 */
+	struct Local_interface
+	{
+		virtual ~Local_interface() { }
+
+		/**
+		 * Exception type
+		 */
+		class Non_local_capability { };
+
+		/**
+		 * Convert pseudo capability to pointer to locally implemented session
+		 *
+		 * \param IF   interface type
+		 * \param cap  pseudo capability
+		 *
+		 * \throw Non_local_capability  if the argument does not refer to a
+		 *                              locally implemented interface
+		 */
+		template <typename IF>
+		static IF *deref(Capability<IF> cap)
+		{
+			/* check if this is a pseudo capability */
+			if (cap.tid() != 0 || !cap.local_name())
+				throw Non_local_capability();
+
+			/*
+			 * For a pseudo capability, the 'local_name' points to the local
+			 * session object of the correct type.
+			 */
+			IF *interface = dynamic_cast<IF *>((Local_interface *)cap.local_name());
+			if (!interface)
+				throw Non_local_capability();
+
+			return interface;
+		}
+
+		/**
+		 * Construct pseudo capability to process-local interface implementation
+		 *
+		 * \param IF         interface type
+		 * \param interface  pointer to local interface implementation
+		 * \return           pseudo capability
+		 *
+		 */
+		template <typename IF>
+		static Capability<IF> capability(IF *interface)
+		{
+			return reinterpret_cap_cast<IF>(Native_capability(0, (long)interface));
+		};
+	};
+}
+
+#endif /* _INCLUDE__BASE__LOCAL_INTERFACE_H_ */