DatabaseGlue: add function GetDatabase()

Allow using the object outside of DatabaseGlue.cxx.

src/DatabaseGlue.cxx

@@ -18,6 +18,7 @@
  */
 
 #include "config.h"
+#include "DatabaseGlue.hxx"
 
 extern "C" {
 #include "database.h"
@@ -79,6 +80,14 @@ db_finish(void)
 		delete db;
 }
 
+const Database *
+GetDatabase()
+{
+	assert(db == NULL || db_is_open);
+
+	return db;
+}
+
 struct directory *
 db_get_root(void)
 {

src/DatabaseGlue.hxx

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2003-2011 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_DATABASE_GLUE_HXX
+#define MPD_DATABASE_GLUE_HXX
+
+#include "gcc.h"
+
+class Database;
+
+/**
+ * Returns the global #Database instance.  May return NULL if this MPD
+ * configuration has no database (no music_directory was configured).
+ */
+gcc_pure
+const Database *
+GetDatabase();
+
+#endif