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Year: 2017

NSFileHandle permission errors

Published December 4, 2017

In a macOS programming project I have a command that allows the user to open a file containing some configuration options. This file is a property list, so the contents were being read using NSDictionary(contentsOf:); this method simply returns nil if an error occurs. I wanted to provide more details about the failure than simply “The file could not be read”, so I looked for a Foundation method that would throw an NSError. I settled on FileHandle(forReadingFrom:) and inserted the following code:

    do {
        _ = try FileHandle(forReadingFrom: url)
    }
    catch let error as NSError {
        let alert = NSAlert()
        alert.messageText = "An error occurred while reading the options file.".localized()
        alert.informativeText = error.localizedDescription
        alert.beginSheetModal(for: mainWindow) { (response) in
            if response == NSAlertSecondButtonReturn {
                OperationQueue.main.addOperation { self.resetOptions(nil) }
            }
        }
        return
    }

Then I set up a few test cases, including a file that was owned by another user (with no read permission). To my surprise, the error description implied that I was unable to write the file:

[application icon redacted]

…and while that’s also true, that’s certainly not the error I expected to get.

I looked at the error object in the debugger, and sure enough, the error code was 513 (NSFileWriteNoPermissionError) and not 257 (NSFileReadNoPermissionError). Weird.

Well, I know I’m trying to read the file, and I don’t want to confuse the user, so I changed the catch clause to handle this case:

    catch var error as NSError {
        if error.code == NSFileWriteNoPermissionError {
            error = NSError(domain: NSCocoaErrorDomain, code: NSFileReadNoPermissionError, userInfo: error.userInfo)
        }
        let alert = NSAlert()
        //...
        return
    }

…and that seemed to do nicely. But I can’t find any documentation on whether this is expected behavior or what I might be doing wrong.

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Annoying new telemarketing tactic

Published June 16, 2017

Twice within the last week I’ve been hit by the following tactic:

I receive a call on my cell phone from a nearby calling area (Baltimore, in my case).  The middle-aged voice on the other end asks for “Mason” (or “Terence”). When I politely reply that there’s no one here by that name, the person responds “Oh, perhaps you can help me”, and launches into a solicitation for some high-minded charitable donation.

Last week I simply told the gentleman that I couldn’t help him and hung up.  Today, interrupted from a particularly knotty work issue, I pointedly asked the woman if this was a new marketing tactic and could I expect similar calls in the future. She simply said “I’ll update our records” and hung up.

Will no one rid me of these troublesome callers?

(I’d installed Nomorobo on my iPhone—it’s apparently the best of the current bunch of call blockers—but obviously technology has its limits. Also, for some reason Nomorobo had managed to disable itself and I had to go back into Settings to re-enable it.)

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