Detecting application crash in XCode/swift

Question

For an OS X app with persistent state, is there anyway to programatically detect whether the last time the application was open, it crashed, or closed unexpectedly? (So I can perform some actions to ensure the application is in a consistent state)

Answer 1

You can use NSSetUncaughtExceptionHandler as described here.

    NSSetUncaughtExceptionHandler { exception in
        print("Exception: \(exception.name) 
                          \(exception.reason!)
                          \(exception.description)")
        print(exception.callStackSymbols)
    }

The code I am using is...

NSSetUncaughtExceptionHandler {
    exception in
    ExceptionManager.handle(exception)
}

And the ExceptionManager class includes...

class ExceptionManager {

    class func handle(exception: NSException) {
        var exceptions = [ExceptionItem]()
        if let items = NSUserDefaults.standardUserDefaults().arrayForKey("UncaughtExceptions") as? [NSData] {
            for item in items {
                if let exception = NSKeyedUnarchiver.unarchiveObjectWithData(item) as? ExceptionItem {
                    exceptions.append(exception)
                }
            }
        }

        let newItem = ExceptionItem(NSDate(), exception)
        exceptions.insert(newItem, atIndex: 0)
        if exceptions.count > 5 { // Only keep the last 5 exceptions
            exceptions = Array(exceptions[0..<5])
        }

        var items = [NSData]()
        for e in exceptions {
            let item = NSKeyedArchiver.archivedDataWithRootObject(e) as NSData
            items.append(item)
        }
        NSUserDefaults.standardUserDefaults().setObject(items, forKey: "UncaughtExceptions")
    }