Automatically handle Audio interruptions (#113)

* Remove audio device when interruption begins

* Remove ReactLogger:alsoLogToJS

* Fix ReactLogger.logJS calls

* Fix `AVCaptureSessionInterruptionReasonKey` cast

ios/CameraView+AVAudioSession.swift

@@ -48,13 +48,14 @@ extension CameraView {
   /**
    Configures the CaptureSession and adds the audio device if it has not already been added yet.
    */
-  private final func addAudioInput() throws {
+  func addAudioInput() throws {
     if audioDeviceInput != nil {
       // we already added the audio device, don't add it again
       return
     }
     removeAudioInput()
 
+    ReactLogger.log(level: .info, message: "Adding audio input...")
     captureSession.beginConfiguration()
     guard let audioDevice = AVCaptureDevice.default(for: .audio) else {
       throw CameraError.device(.microphoneUnavailable)
@@ -71,11 +72,12 @@ extension CameraView {
   /**
    Configures the CaptureSession and removes the audio device if it has been added before.
    */
-  private final func removeAudioInput() {
+  func removeAudioInput() {
     guard let audioInput = audioDeviceInput else {
       return
     }
 
+    ReactLogger.log(level: .info, message: "Removing audio input...")
     captureSession.beginConfiguration()
     captureSession.removeInput(audioInput)
     audioDeviceInput = nil

ios/CameraView+AVCaptureSession.swift

@@ -17,7 +17,7 @@ extension CameraView {
    Configures the Capture Session.
    */
   final func configureCaptureSession() {
-    ReactLogger.logJS(level: .info, message: "Configuring Session...")
+    ReactLogger.log(level: .info, message: "Configuring Session...")
     isReady = false
 
     #if targetEnvironment(simulator)
@@ -113,14 +113,14 @@ extension CameraView {
 
     invokeOnInitialized()
     isReady = true
-    ReactLogger.logJS(level: .info, message: "Session successfully configured!")
+    ReactLogger.log(level: .info, message: "Session successfully configured!")
   }
 
   /**
    Configures the Video Device with the given FPS, HDR and ColorSpace.
    */
   final func configureDevice() {
-    ReactLogger.logJS(level: .info, message: "Configuring Device...")
+    ReactLogger.log(level: .info, message: "Configuring Device...")
     guard let device = videoDeviceInput?.device else {
       return invokeOnError(.session(.cameraNotReady))
     }
@@ -159,7 +159,7 @@ extension CameraView {
       }
 
       device.unlockForConfiguration()
-      ReactLogger.logJS(level: .info, message: "Device successfully configured!")
+      ReactLogger.log(level: .info, message: "Device successfully configured!")
     } catch let error as NSError {
       return invokeOnError(.device(.configureError), cause: error)
     }
@@ -169,7 +169,7 @@ extension CameraView {
    Configures the Video Device to find the best matching Format.
    */
   final func configureFormat() {
-    ReactLogger.logJS(level: .info, message: "Configuring Format...")
+    ReactLogger.log(level: .info, message: "Configuring Format...")
     guard let filter = self.format else {
       // Format Filter was null. Ignore it.
       return
@@ -193,7 +193,7 @@ extension CameraView {
       try device.lockForConfiguration()
       device.activeFormat = format
       device.unlockForConfiguration()
-      ReactLogger.logJS(level: .info, message: "Format successfully configured!")
+      ReactLogger.log(level: .info, message: "Format successfully configured!")
     } catch let error as NSError {
       return invokeOnError(.device(.configureError), cause: error)
     }
@@ -215,4 +215,40 @@ extension CameraView {
       }
     }
   }
+
+  @objc
+  func sessionInterruptionBegin(notification: Notification) {
+    ReactLogger.log(level: .error, message: "Capture Session Interruption begin Notification!")
+    guard let reasonNumber = notification.userInfo?[AVCaptureSessionInterruptionReasonKey] as? NSNumber else {
+      return
+    }
+    let reason = AVCaptureSession.InterruptionReason(rawValue: reasonNumber.intValue)
+
+    switch reason {
+    case .audioDeviceInUseByAnotherClient:
+      // remove audio input so iOS thinks nothing is wrong and won't pause the session.
+      removeAudioInput()
+    default:
+      // don't do anything, iOS will automatically pause session
+      break
+    }
+  }
+
+  @objc
+  func sessionInterruptionEnd(notification: Notification) {
+    ReactLogger.log(level: .error, message: "Capture Session Interruption end Notification!")
+    guard let reasonNumber = notification.userInfo?[AVCaptureSessionInterruptionReasonKey] as? NSNumber else {
+      return
+    }
+    let reason = AVCaptureSession.InterruptionReason(rawValue: reasonNumber.intValue)
+
+    switch reason {
+    case .audioDeviceInUseByAnotherClient:
+      // add audio again because we removed it when we received the interruption.
+      configureAudioSession()
+    default:
+      // don't do anything, iOS will automatically resume session
+      break
+    }
+  }
 }

ios/CameraView.swift

@@ -46,6 +46,14 @@ final class CameraView: UIView {
                                            selector: #selector(sessionRuntimeError),
                                            name: .AVCaptureSessionRuntimeError,
                                            object: captureSession)
+    NotificationCenter.default.addObserver(self,
+                                           selector: #selector(sessionInterruptionBegin),
+                                           name: .AVCaptureSessionWasInterrupted,
+                                           object: captureSession)
+    NotificationCenter.default.addObserver(self,
+                                           selector: #selector(sessionInterruptionEnd),
+                                           name: .AVCaptureSessionInterruptionEnded,
+                                           object: captureSession)
     NotificationCenter.default.addObserver(self,
                                            selector: #selector(audioSessionInterrupted),
                                            name: AVAudioSession.interruptionNotification,
@@ -56,6 +64,12 @@ final class CameraView: UIView {
     NotificationCenter.default.removeObserver(self,
                                               name: .AVCaptureSessionRuntimeError,
                                               object: captureSession)
+    NotificationCenter.default.removeObserver(self,
+                                              name: .AVCaptureSessionWasInterrupted,
+                                              object: captureSession)
+    NotificationCenter.default.removeObserver(self,
+                                              name: .AVCaptureSessionInterruptionEnded,
+                                              object: captureSession)
     NotificationCenter.default.removeObserver(self,
                                               name: AVAudioSession.interruptionNotification,
                                               object: AVAudioSession.sharedInstance)
@@ -234,7 +248,7 @@ final class CameraView: UIView {
 
   // pragma MARK: Event Invokers
   internal final func invokeOnError(_ error: CameraError, cause: NSError? = nil) {
-    ReactLogger.log(level: .error, message: "Invoking onError(): \(error.message)", alsoLogToJS: true)
+    ReactLogger.log(level: .error, message: "Invoking onError(): \(error.message)")
     guard let onError = self.onError else { return }
 
     var causeDictionary: [String: Any]?
@@ -254,7 +268,7 @@ final class CameraView: UIView {
   }
 
   internal final func invokeOnInitialized() {
-    ReactLogger.log(level: .info, message: "Camera initialized!", alsoLogToJS: true)
+    ReactLogger.log(level: .info, message: "Camera initialized!")
     guard let onInitialized = self.onInitialized else { return }
     onInitialized([String: Any]())
   }

ios/React/ReactLogger.swift

@@ -15,21 +15,9 @@ let context = "VisionCamera"
 enum ReactLogger {
   static func log(level: RCTLogLevel,
                   message: String,
-                  alsoLogToJS: Bool = false,
                   _ file: String = #file,
                   _ lineNumber: Int = #line,
                   _ function: String = #function) {
     RCTDefaultLogFunction(level, RCTLogSource.native, file, lineNumber as NSNumber, "\(context).\(function): \(message)")
-    if alsoLogToJS {
-      ReactLogger.logJS(level: level, message: message, file, lineNumber, function)
-    }
-  }
-
-  static func logJS(level: RCTLogLevel,
-                    message: String,
-                    _ file: String = #file,
-                    _ lineNumber: Int = #line,
-                    _ function: String = #function) {
-    RCTDefaultLogFunction(level, RCTLogSource.javaScript, file, lineNumber as NSNumber, "\(context).\(function): \(message)")
   }
 }