CommandLine: new command line parser

This implementation behaves mostly identical to old parser.
Few observable differences:
- There are no option groups (single group is used for all options)
- Option --stdout is hidden (it has been obsolete for a long time)
- MPD executable name (mpd) is hardcoded for simplicity

src/util/OptionDef.hxx

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_UTIL_OPTIONDEF_HXX
+#define MPD_UTIL_OPTIONDEF_HXX
+
+/**
+ * Command line option definition.
+ */
+class OptionDef
+{
+	const char *long_option;
+	char short_option;
+	const char *desc;
+public:
+	constexpr OptionDef(const char *_long_option, const char *_desc)
+		: long_option(_long_option),
+		  short_option(0),
+		  desc(_desc) { }
+
+	constexpr OptionDef(const char *_long_option,
+			    char _short_option, const char *_desc)
+		: long_option(_long_option),
+		  short_option(_short_option),
+		  desc(_desc) { }
+
+	bool HasLongOption() const { return long_option != nullptr; }
+	bool HasShortOption() const { return short_option != 0; }
+	bool HasDescription() const { return desc != nullptr; }
+
+	const char *GetLongOption() const {
+		assert(HasLongOption());
+		return long_option;
+	}
+
+	char GetShortOption() const {
+		assert(HasShortOption());
+		return short_option;
+	}
+
+	const char *GetDescription() const {
+		assert(HasDescription());
+		return desc;
+	}
+};
+
+#endif