lib/vfs: seperate implemention and API headers

Issue #1891

repos/os/src/lib/vfs/rtc_file_system.h

@@ -0,0 +1,99 @@
+/*
+ * \brief  Rtc file system
+ * \author Josef Soentgen
+ * \date   2014-08-20
+ */
+
+/*
+ * Copyright (C) 2014 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__VFS__RTC_FILE_SYSTEM_H_
+#define _INCLUDE__VFS__RTC_FILE_SYSTEM_H_
+
+/* Genode includes */
+#include <rtc_session/connection.h>
+#include <vfs/file_system.h>
+
+
+namespace Vfs { class Rtc_file_system; }
+
+
+class Vfs::Rtc_file_system : public Single_file_system
+{
+	private:
+
+		Rtc::Connection _rtc;
+
+	public:
+
+		Rtc_file_system(Xml_node config)
+		:
+			Single_file_system(NODE_TYPE_CHAR_DEVICE, name(), config)
+		{ }
+
+		static char const *name() { return "rtc"; }
+
+
+		/*********************************
+		 ** Directory-service interface **
+		 *********************************/
+
+		Stat_result stat(char const *path, Stat &out) override
+		{
+			Stat_result result = Single_file_system::stat(path, out);
+			out.mode |= 0444;
+
+			return result;
+		}
+
+
+		/********************************
+		 ** File I/O service interface **
+		 ********************************/
+
+		Write_result write(Vfs_handle *, char const *, file_size,
+		                   file_size &) override
+		{
+			return WRITE_ERR_IO;
+		}
+
+		/**
+		 * Read the current time from the Rtc session
+		 *
+		 * On each read the current time is queried and afterwards formated
+		 * as '%Y-%m-%d %H:%M\n'.
+		 */
+		Read_result read(Vfs_handle *vfs_handle, char *dst, file_size count,
+		                 file_size &out_count) override
+		{
+			enum { TIMESTAMP_LEN = 17 };
+
+			file_size seek = vfs_handle->seek();
+
+			if (seek >= TIMESTAMP_LEN) {
+				out_count = 0;
+				return READ_OK;
+			}
+
+			Rtc::Timestamp ts = _rtc.current_time();
+
+			char buf[TIMESTAMP_LEN+1];
+			char *b = buf;
+			unsigned n = Genode::snprintf(buf, sizeof(buf), "%04u-%02u-%02u %02u:%02u\n",
+			                              ts.year, ts.month, ts.day, ts.hour, ts.minute);
+			n -= seek;
+			b += seek;
+
+			file_size len = count > n ? n : count;
+			Genode::memcpy(dst, b, len);
+			out_count = len;
+
+			return READ_OK;
+		}
+};
+
+#endif /* _INCLUDE__VFS__RTC_FILE_SYSTEM_H_ */