Fix camera permission handling

Author: Emilio Pavia

ScienceJournal/CaptureSession/CameraAccessHandler.swift

@@ -19,23 +19,27 @@ import AVFoundation
 /// Handles checking and asking for camera access permission.
 classCameraAccessHandler{
 
+ /// Returns `true` if the user authorized access to the device camera.
+staticvarhasGrantedAccess:Bool{
+AVCaptureDevice.authorizationStatus(for:.video)==.authorized
+}
+
  /// Checks the permissions status of the camera, and requests access if needed.
  ///
  /// - Parameter requestCompletion: Called with the status of the permission (true if granted),
- /// when access had to be requested.
- /// - Returns: Whether or not permission has been granted.
-staticfunc checkForPermission(requestCompletion:((Bool)->Void)?=nil)->Bool{
+staticfunc checkForPermission(requestCompletion:((Bool)->Void)?=nil){
 letauthStatus=AVCaptureDevice.authorizationStatus(for:.video)
 switch authStatus {
-case.denied,.restricted:returnfalse
-case.authorized:returntrue
+case.denied,.restricted:requestCompletion?(false)
+case.authorized:requestCompletion?(true)
 case.notDetermined:
  // Prompt user for the permission to use the camera.
 AVCaptureDevice.requestAccess(for:.video){ granted in
-requestCompletion?(granted)
+DispatchQueue.main.async{
+requestCompletion?(granted)
+}
 }
-returnfalse
-@unknowndefault:returnfalse
+@unknowndefault:requestCompletion?(false)
 }
 }
 

ScienceJournal/CaptureSession/CaptureSessionInterruptionObserver.swift

@@ -46,30 +46,26 @@ class CaptureSessionInterruptionObserver {
  /// recording, during which the camera cannot be used.
 varisCameraUseAllowed:Bool{
 return !isCaptureSessionInterrupted && !isBrightnessSensorInUse &&
-CameraAccessHandler.checkForPermission()
+CameraAccessHandler.hasGrantedAccess
 }
 
-varcameraAvailability:CameraAvailability{
-
-if isBrightnessSensorInUse {
-return.blockedByBrightnessSensor
+ // MARK: - Public
+func checkCameraAvailability(handler:@escaping(CameraAvailability)->Void){
+guard !isBrightnessSensorInUse else{
+handler(.blockedByBrightnessSensor)
+return
 }
 
-if isCaptureSessionInterrupted {
-return.captureInterrupted
+guard !isCaptureSessionInterrupted else{
+handler(.captureInterrupted)
+return
 }
 
- // Note: this check will request perms if they are not determined,
- // so it's not a 1:1 match with permissions denied
-ifCameraAccessHandler.checkForPermission(){
-return.available
-}else{
-return.permissionsDenied
+CameraAccessHandler.checkForPermission{
+ $0 ?handler(.available):handler(.permissionsDenied)
 }
 }
 
- // MARK: - Public
-
  // MARK: - Private
 
  /// Use `shared`.

ScienceJournal/UI/ExperimentCoordinatorViewController.swift

@@ -1752,17 +1752,21 @@ class ExperimentCoordinatorViewController: MaterialHeaderViewController, DrawerP
 }
 
 func cameraButtonPressed(){
-switchCaptureSessionInterruptionObserver.shared.cameraAvailability {
-case.permissionsDenied:
-showCameraPermissionsDeniedAlert()
-case.blockedByBrightnessSensor:
-showSnackbar(withMessage:String.inputCameraBlockedByBrightnessSensor,
- category:nil,
- actionTitle:String.actionOk,
- actionHandler:nil
-)
-default: // Handles .available and .captureInterrupted
-present(cameraImageProvider.cameraViewController, animated:true)
+CaptureSessionInterruptionObserver.shared.checkCameraAvailability{[weak self]in
+guardlet self =selfelse{return}
+
+switch $0 {
+case.permissionsDenied:
+self.showCameraPermissionsDeniedAlert()
+case.blockedByBrightnessSensor:
+showSnackbar(withMessage:String.inputCameraBlockedByBrightnessSensor,
+ category:nil,
+ actionTitle:String.actionOk,
+ actionHandler:nil
+)
+default: // Handles .available and .captureInterrupted
+self.present(self.cameraImageProvider.cameraViewController, animated:true)
+}
 }
 }
 

ScienceJournal/UI/PhotoCapturer.swift

@@ -99,10 +99,14 @@ class PhotoCapturer: NSObject, AVCapturePhotoCaptureDelegate {
 
  /// The permissions state of the capturer.
 varisCameraPermissionGranted:Bool{
-letgranted=CameraAccessHandler.checkForPermission{(permission)in
+ifCameraAccessHandler.hasGrantedAccess {
+returntrue
+}
+
+CameraAccessHandler.checkForPermission{(permission)in
 self.delegate?.photoCapturerCameraPermissionsDidChange(accessGranted: permission)
 }
-returngranted
+returnfalse
 }
 
  /// Switches to a camera.

ScienceJournal/UI/TrialDetailViewController.swift

@@ -1763,17 +1763,21 @@ class TrialDetailViewController: MaterialHeaderViewController,
 }
 
 func cameraButtonPressed(){
-switchCaptureSessionInterruptionObserver.shared.cameraAvailability {
-case.permissionsDenied:
-showCameraPermissionsDeniedAlert()
-case.blockedByBrightnessSensor:
-showSnackbar(withMessage:String.inputCameraBlockedByBrightnessSensor,
- category:nil,
- actionTitle:String.actionOk,
- actionHandler:nil
-)
-default: // Handles .available and .captureInterrupted
-present(cameraImageProvider.cameraViewController, animated:true)
+CaptureSessionInterruptionObserver.shared.checkCameraAvailability{[weak self]in
+guardlet self =selfelse{return}
+
+switch $0 {
+case.permissionsDenied:
+self.showCameraPermissionsDeniedAlert()
+case.blockedByBrightnessSensor:
+showSnackbar(withMessage:String.inputCameraBlockedByBrightnessSensor,
+ category:nil,
+ actionTitle:String.actionOk,
+ actionHandler:nil
+)
+default: // Handles .available and .captureInterrupted
+self.present(self.cameraImageProvider.cameraViewController, animated:true)
+}
 }
 }