* create mu-error.h, update some functions to use GError for errors

src/mu-error.h

@@ -0,0 +1,39 @@
+/*
+** Copyright (C) 2010 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+**
+** 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 3, 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 __MU_ERROR_H__
+#define __MU_ERROR_H__
+
+enum _MuError {
+	/* general xapian related error */
+	MU_ERROR_XAPIAN,
+	/* xapian dir is not accessible */
+	MU_ERROR_XAPIAN_DIR,
+	/* database version is not uptodate (ie. not compatible with
+	 * the version that mu expects) */
+	MU_ERROR_XAPIAN_NOT_UPTODATE,
+	/* (parsnng) error in the query */ 
+	MU_ERROR_QUERY,
+	/* some other, internal error */
+	MU_ERROR_INTERNAL
+};
+typedef enum _MuError MuError;
+
+#endif /*__MU_ERROR_H__*/