Use guard statements to reduce nesting

pass/Controllers/PGPKeyArmorImportTableViewController.swift

@@ -51,11 +51,10 @@ class PGPKeyArmorImportTableViewController: AutoCellHeightUITableViewController,
         let selectedCell = tableView.cellForRow(at: indexPath)
         if selectedCell == scanPublicKeyCell {
             scanned.reset(keytype: ScannedPGPKey.KeyType.publicKey)
-            performSegue(withIdentifier: "showPGPScannerSegue", sender: self)
         } else if selectedCell == scanPrivateKeyCell {
             scanned.reset(keytype: ScannedPGPKey.KeyType.privateKey)
-            performSegue(withIdentifier: "showPGPScannerSegue", sender: self)
         }
+        performSegue(withIdentifier: "showPGPScannerSegue", sender: self)
         tableView.deselectRow(at: indexPath, animated: true)
     }
 
@@ -78,14 +77,15 @@ class PGPKeyArmorImportTableViewController: AutoCellHeightUITableViewController,
     }
 
     override func prepare(for segue: UIStoryboardSegue, sender _: Any?) {
-        if segue.identifier == "showPGPScannerSegue" {
+        guard segue.identifier == "showPGPScannerSegue" else {
-            if let navController = segue.destination as? UINavigationController {
+            return
-                if let viewController = navController.topViewController as? QRScannerController {
+        }
-                    viewController.delegate = self
+        if let navController = segue.destination as? UINavigationController {
-                }
+            if let viewController = navController.topViewController as? QRScannerController {
-            } else if let viewController = segue.destination as? QRScannerController {
                 viewController.delegate = self
             }
+        } else if let viewController = segue.destination as? QRScannerController {
+            viewController.delegate = self
         }
     }
 }

pass/Controllers/PasswordEditorTableViewController.swift

@@ -419,9 +419,8 @@ extension PasswordEditorTableViewController: QRScannerControllerDelegate {
     func checkScannedOutput(line: String) -> (accept: Bool, message: String) {
         if let url = URL(string: line), Token(url: url) != nil {
             return (accept: true, message: "ValidTokenUrl".localize())
-        } else {
-            return (accept: false, message: "InvalidTokenUrl".localize())
         }
+        return (accept: false, message: "InvalidTokenUrl".localize())
     }
 
     func handleScannedOutput(line: String) {

pass/Controllers/QRScannerController.swift

@@ -86,61 +86,63 @@ class QRScannerController: UIViewController, AVCaptureMetadataOutputObjectsDeleg
         }
     }
 
-    override func didReceiveMemoryWarning() {
-        super.didReceiveMemoryWarning()
-        // Dispose of any resources that can be recreated.
-    }
-
     // MARK: - AVCaptureMetadataOutputObjectsDelegate Methods
 
     func metadataOutput(_: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from _: AVCaptureConnection) {
-        if let metadataObj = metadataObjects.first as? AVMetadataMachineReadableCodeObject,
+        guard let metadataObj = metadataObjects.first as? AVMetadataMachineReadableCodeObject else {
-            supportedCodeTypes.contains(metadataObj.type),
+            return setNotDetected()
-            let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj) {
+        }
-            // draw a bounds on the found QR code
+        guard supportedCodeTypes.contains(metadataObj.type) else {
-            qrCodeFrameView?.frame = barCodeObject.bounds
+            return setNotDetected()
+        }
+        guard let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj) else {
+            return setNotDetected()
+        }
 
-            // check whether it is a valid result
+        // draw a bounds on the found QR code
-            if let scanned = metadataObj.stringValue {
+        qrCodeFrameView?.frame = barCodeObject.bounds
-                if let (accept, message) = delegate?.checkScannedOutput(line: scanned) {
+
-                    scannerOutput.text = message
+        // check whether it is a valid result
-                    if accept == true {
+        guard let scanned = metadataObj.stringValue else {
-                        captureSession?.stopRunning()
+            scannerOutput.text = "NoStringValue".localize()
-                        delegate?.handleScannedOutput(line: scanned)
+            return
-                        DispatchQueue.main.async {
+        }
-                            SVProgressHUD.showSuccess(withStatus: "Done".localize())
+        guard let (accept, message) = delegate?.checkScannedOutput(line: scanned) else {
-                            SVProgressHUD.dismiss(withDelay: 1)
+            // no delegate, show the scanned result
-                            self.navigationController?.popViewController(animated: true)
+            scannerOutput.text = scanned
-                        }
+            return
-                    }
+        }
-                } else {
+        scannerOutput.text = message
-                    // no delegate, show the scanned result
+        guard accept else {
-                    scannerOutput.text = scanned
+            return
-                }
+        }
-            } else {
+        captureSession?.stopRunning()
-                scannerOutput.text = "NoStringValue".localize()
+        delegate?.handleScannedOutput(line: scanned)
-            }
+        DispatchQueue.main.async {
-        } else {
+            SVProgressHUD.showSuccess(withStatus: "Done".localize())
-            qrCodeFrameView?.frame = CGRect.zero
+            SVProgressHUD.dismiss(withDelay: 1)
-            scannerOutput.text = "NoQrCodeDetected.".localize()
+            self.navigationController?.popViewController(animated: true)
         }
     }
 
-    func presentCameraSettings() {
+    private func setNotDetected() {
+        qrCodeFrameView?.frame = CGRect.zero
+        scannerOutput.text = "NoQrCodeDetected.".localize()
+    }
+
+    private func presentCameraSettings() {
         let alertController = UIAlertController(
             title: "Error".localize(),
             message: "CameraAccessDenied.".localize() | "WarningToggleCameraPermissionsResetsApp.".localize(),
             preferredStyle: .alert
         )
         alertController.addAction(UIAlertAction(title: "Cancel".localize(), style: .default))
-        alertController.addAction(
+        alertController.addAction(UIAlertAction(title: "Settings".localize(), style: .cancel) { _ in
-            UIAlertAction(title: "Settings".localize(), style: .cancel) { _ in
+            if let url = URL(string: UIApplication.openSettingsURLString) {
-                if let url = URL(string: UIApplication.openSettingsURLString) {
+                UIApplication.shared.open(url)
-                    UIApplication.shared.open(url, options: [:]) { _ in }
-                }
             }
+        }
         )
-
         present(alertController, animated: true)
     }
 }

pass/Controllers/SSHKeyArmorImportTableViewController.swift

@@ -95,14 +95,15 @@ class SSHKeyArmorImportTableViewController: AutoCellHeightUITableViewController,
     }
 
     override func prepare(for segue: UIStoryboardSegue, sender _: Any?) {
-        if segue.identifier == "showSSHScannerSegue" {
+        guard segue.identifier == "showSSHScannerSegue" else {
-            if let navController = segue.destination as? UINavigationController {
+            return
-                if let viewController = navController.topViewController as? QRScannerController {
+        }
-                    viewController.delegate = self
+        if let navController = segue.destination as? UINavigationController {
-                }
+            if let viewController = navController.topViewController as? QRScannerController {
-            } else if let viewController = segue.destination as? QRScannerController {
                 viewController.delegate = self
             }
+        } else if let viewController = segue.destination as? QRScannerController {
+            viewController.delegate = self
         }
     }