Add variant of stringWithContentsOfFile that produces an error

It turns out that the [NSString stringWithContentsOfFile:] family of
methods do not have a way of reporting why a file could not be read;
[NSString stringWithContentsOfFile:usedEncoding:error:] will only set
the error object if there was a problem with decoding.

So, we cook our own variant that tries to figure out why opening the
file failed.

User-visible effect: in the GTK+ port, if you try to open a file from
the "open recent" menu that no longer exists, you will get a more
helpful error message.

1 files changed, 27 insertions, 0 deletions

diff --git a/tikzit/src/common/NSString+Util.h b/tikzit/src/common/NSString+Util.h
new file mode 100644
index 0000000..548edb3
--- /dev/null
+++ b/tikzit/src/common/NSString+Util.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2013  Alex Merry <alex.merry@kdemail.net>
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#import <Foundation/Foundation.h>
+
+@interface NSString (Util)
+	+ (NSString*) stringWithContentsOfFile:(NSString*)path
+									 error:(NSError**)error;
+	- (id) initWithContentsOfFile:(NSString*)path
+							error:(NSError**)error;
+@end
+
+// vi:ft=objc:noet:ts=4:sts=4:sw=4