Use Xcode comment syntax, introduce objective-c modern syntax and some other code rearrange

Classes/NSFileManager+DirectoryLocations.m

@@ -31,120 +31,93 @@ NSString * const DirectoryLocationDomain = @"DirectoryLocationDomain";
 
 @implementation NSFileManager (DirectoryLocations)
 
-//
-// findOrCreateDirectory:inDomain:appendPathComponent:error:
-//
-// Method to tie together the steps of:
-//	1) Locate a standard directory by search path and domain mask
-//  2) Select the first path in the results
-//	3) Append a subdirectory to that path
-//	4) Create the directory and intermediate directories if needed
-//	5) Handle errors by emitting a proper NSError object
-//
-// Parameters:
-//    searchPathDirectory - the search path passed to NSSearchPathForDirectoriesInDomains
-//    domainMask - the domain mask passed to NSSearchPathForDirectoriesInDomains
-//    appendComponent - the subdirectory appended
-//    errorOut - any error from file operations
-//
-// returns the path to the directory (if path found and exists), nil otherwise
-//
+
+/*!  Method to tie together the steps of:
+	1) Locate a standard directory by search path and domain mask
+    2) Select the first path in the results
+ 	3) Append a subdirectory to that path
+	4) Create the directory and intermediate directories if needed
+	5) Handle errors by emitting a proper NSError object
+
+* \pararm searchPathDirectory - the search path passed to NSSearchPathForDirectoriesInDomains
+* \pararm domainMask - the domain mask passed to NSSearchPathForDirectoriesInDomains
+* \pararm appendComponent - the subdirectory appended
+* \pararm errorOut - any error from file operations
+
+* \returns returns the path to the directory (if path found and exists), nil otherwise
+*/
 - (NSString *)findOrCreateDirectory:(NSSearchPathDirectory)searchPathDirectory
 	inDomain:(NSSearchPathDomainMask)domainMask
 	appendPathComponent:(NSString *)appendComponent
 	error:(NSError **)errorOut
 {
+    // Declare an NSError first, so we don't need to check errorOut again and again
+    NSError *error;
+    
+    if (errorOut) {
+        error = *errorOut;
+    }
+    else {
+        error = nil;
+    }
+
 	//
 	// Search for the path
 	//
-	NSArray* paths = NSSearchPathForDirectoriesInDomains(
-		searchPathDirectory,
-		domainMask,
-		YES);
+	NSArray* paths = NSSearchPathForDirectoriesInDomains(searchPathDirectory,domainMask,YES);
+    
 	if ([paths count] == 0)
 	{
-		if (errorOut)
-		{
-			NSDictionary *userInfo =
-				[NSDictionary dictionaryWithObjectsAndKeys:
-					NSLocalizedStringFromTable(
-						@"No path found for directory in domain.",
-						@"Errors",
-					nil),
-					NSLocalizedDescriptionKey,
-					[NSNumber numberWithInteger:searchPathDirectory],
-					@"NSSearchPathDirectory",
-					[NSNumber numberWithInteger:domainMask],
-					@"NSSearchPathDomainMask",
-				nil];
-			*errorOut =
-				[NSError 
-					errorWithDomain:DirectoryLocationDomain
-					code:DirectoryLocationErrorNoPathFound
-					userInfo:userInfo];
-		}
+        NSDictionary *userInfo = @{NSLocalizedDescriptionKey: NSLocalizedStringFromTable(@"No path found for directory in domain.",@"Errors",nil),
+                                    @"NSSearchPathDirectory":@(searchPathDirectory),
+                                    @"NSSearchPathDomainMask":@(domainMask)};
+				
+        error = [NSError errorWithDomain:DirectoryLocationDomain
+                                        code:DirectoryLocationErrorNoPathFound
+                                    userInfo:userInfo];
 		return nil;
 	}
 	
 	//
 	// Normally only need the first path returned
 	//
-	NSString *resolvedPath = [paths objectAtIndex:0];
+	NSString *resolvedPath = paths[0];
 
 	//
 	// Append the extra path component
 	//
 	if (appendComponent)
 	{
-		resolvedPath = [resolvedPath
-			stringByAppendingPathComponent:appendComponent];
+		resolvedPath = [resolvedPath stringByAppendingPathComponent:appendComponent];
 	}
 	
 	//
 	// Create the path if it doesn't exist
 	//
-	NSError *error = nil;
-	BOOL success = [self
-		createDirectoryAtPath:resolvedPath
-		withIntermediateDirectories:YES
-		attributes:nil
-		error:&error];
-	if (!success) 
-	{
-		if (errorOut)
-		{
-			*errorOut = error;
-		}
-		return nil;
-	}
     
-	//
-	// If we've made it this far, we have a success
-	//
-	if (errorOut)
-	{
-		*errorOut = nil;
-	}
-	return resolvedPath;
+    
+	if ([self createDirectoryAtPath:resolvedPath withIntermediateDirectories:YES
+                          attributes:nil error:&error])
+        return resolvedPath;
+    else
+        return nil;
 }
 
-//
-// applicationSupportDirectory
-//
-// Returns the path to the applicationSupportDirectory (creating it if it doesn't
-// exist).
-//
+
+/*! applicationSupportDirectory
+
+* \returns The path to the applicationSupportDirectory (creating it if it doesn't exist).
+*/
 - (NSString *)applicationSupportDirectory
 {
-	NSString *executableName =
-		[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleExecutable"];
-	NSError *error;
-	NSString *result =
-		[self
-			findOrCreateDirectory:NSApplicationSupportDirectory
-			inDomain:NSUserDomainMask
-			appendPathComponent:executableName
-			error:&error];
+	NSString *executableName = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleExecutable"];
+    
+	NSError *error = nil;
+    
+	NSString *result = [self findOrCreateDirectory:NSApplicationSupportDirectory
+                                          inDomain:NSUserDomainMask
+                               appendPathComponent:executableName
+                                             error:&error];
 	if (!result)
 	{
 		NSLog(@"Unable to find or create application support directory:\n%@", error);