From 5a94458d9ee3ee8afd978477c755200df432a9b0 Mon Sep 17 00:00:00 2001
From: Alex Merry <dev@randomguy3.me.uk>
Date: Wed, 7 Aug 2013 00:43:49 +0100
Subject: 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.
---
 tikzit/src/common/NSString+Util.h | 27 ++++++++++++++++
 tikzit/src/common/NSString+Util.m | 66 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 tikzit/src/common/NSString+Util.h
 create mode 100644 tikzit/src/common/NSString+Util.m

(limited to 'tikzit/src/common')

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
diff --git a/tikzit/src/common/NSString+Util.m b/tikzit/src/common/NSString+Util.m
new file mode 100644
index 0000000..b18f397
--- /dev/null
+++ b/tikzit/src/common/NSString+Util.m
@@ -0,0 +1,66 @@
+/*
+ * 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>
+#import "NSString+Util.h"
+#import "NSError+Tikzit.h"
+
+@implementation NSString (Util)
++ (NSString*) stringWithContentsOfFile:(NSString*)path
+								 error:(NSError**)error
+{
+	return [[[self alloc] initWithContentsOfFile:path error:error] autorelease];
+}
+- (id) initWithContentsOfFile:(NSString*)path
+						error:(NSError**)error
+{
+	// Fun fact: on GNUstep, at least,
+	// [stringWithContentsOfFile:usedEncoding:error:] only
+	// sets error objects if the decoding fails, not if file
+	// access fails.
+	// Fun fact 2: on GNUstep, trying to read a directory using
+	// [stringWithContentsOfFile:] causes an out-of-memory error;
+	// hence we do these checks *before* trying to read the file.
+	NSFileManager *fm = [NSFileManager defaultManager];
+	BOOL isDir = NO;
+	NSString *msg = nil;
+	if (![fm fileExistsAtPath:path isDirectory:&isDir]) {
+		msg = [NSString stringWithFormat:@"\"%@\" does not exist", path];
+	} else if (isDir) {
+		msg = [NSString stringWithFormat:@"\"%@\" is a directory", path];
+	} else if (![fm isReadableFileAtPath:path]) {
+		msg = [NSString stringWithFormat:@"\"%@\" is not readable", path];
+	}
+	if (msg != nil) {
+		if (error) {
+			*error = [NSError errorWithMessage:msg
+										  code:TZ_ERR_IO];
+		}
+		return nil;
+	}
+	self = [self initWithContentsOfFile:path];
+	if (self == nil) {
+		if (error) {
+			*error = [NSError errorWithMessage:@"unknown error"
+										  code:TZ_ERR_IO];
+		}
+	}
+	return self;
+}
+@end
+
+// vi:ft=objc:noet:ts=4:sts=4:sw=4
-- 
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