fix: Fix torch not working on iOS (#2031)

* fix: Fix `torch` not working on iOS

* Format

* fix: Use `withSessionLock` and `withDeviceLock`

* Update CameraSession.swift

* Update RecordingSession.swift

package/ios/Core/CameraConfiguration.swift

@@ -70,6 +70,7 @@ class CameraConfiguration {
     let orientationChanged: Bool
     let formatChanged: Bool
     let sidePropsChanged: Bool
+    let torchChanged: Bool
     let zoomChanged: Bool
 
     let audioSessionChanged: Bool
@@ -100,7 +101,9 @@ class CameraConfiguration {
       // format (depends on cameraId)
       formatChanged = inputChanged || left?.format != right.format
       // side-props (depends on format)
-      sidePropsChanged = formatChanged || left?.fps != right.fps || left?.enableLowLightBoost != right.enableLowLightBoost || left?.torch != right.torch
+      sidePropsChanged = formatChanged || left?.fps != right.fps || left?.enableLowLightBoost != right.enableLowLightBoost
+      // torch (depends on isActive)
+      torchChanged = left?.isActive != right.isActive || left?.torch != right.torch
       // zoom (depends on format)
       zoomChanged = formatChanged || left?.zoom != right.zoom
 

package/ios/Core/CameraSession+Configuration.swift

@@ -175,16 +175,13 @@ extension CameraSession {
   /**
    Configures the active format (`format`)
    */
-  func configureFormat(configuration: CameraConfiguration) throws {
+  func configureFormat(configuration: CameraConfiguration, device: AVCaptureDevice) throws {
     guard let targetFormat = configuration.format else {
       // No format was set, just use the default.
       return
     }
 
     ReactLogger.log(level: .info, message: "Configuring Format (\(targetFormat))...")
-    guard let device = videoDeviceInput?.device else {
-      throw CameraError.session(.cameraNotReady)
-    }
 
     let currentFormat = CameraDeviceFormat(fromFormat: device.activeFormat)
     if currentFormat == targetFormat {
@@ -207,13 +204,9 @@ extension CameraSession {
   // pragma MARK: Side-Props
 
   /**
-   Configures format-dependant "side-props" (`fps`, `lowLightBoost`, `torch`)
+   Configures format-dependant "side-props" (`fps`, `lowLightBoost`)
    */
-  func configureSideProps(configuration: CameraConfiguration) throws {
+  func configureSideProps(configuration: CameraConfiguration, device: AVCaptureDevice) throws {
-    guard let device = videoDeviceInput?.device else {
-      throw CameraError.session(.cameraNotReady)
-    }
-
     // Configure FPS
     if let fps = configuration.fps {
       let supportsGivenFps = device.activeFormat.videoSupportedFrameRateRanges.contains { range in
@@ -238,13 +231,20 @@ extension CameraSession {
       }
       device.automaticallyEnablesLowLightBoostWhenAvailable = configuration.enableLowLightBoost
     }
+  }
 
+  /**
+   Configures the torch.
+   The CaptureSession has to be running for the Torch to work.
+   */
+  func configureTorch(configuration: CameraConfiguration, device: AVCaptureDevice) throws {
     // Configure Torch
     let torchMode = configuration.torch.toTorchMode()
     if device.torchMode != torchMode {
       guard device.hasTorch else {
         throw CameraError.device(.flashUnavailable)
       }
+
       device.torchMode = torchMode
       if torchMode == .on {
         try device.setTorchModeOn(level: 1.0)
@@ -257,10 +257,7 @@ extension CameraSession {
   /**
    Configures zoom (`zoom`)
    */
-  func configureZoom(configuration: CameraConfiguration) throws {
+  func configureZoom(configuration: CameraConfiguration, device: AVCaptureDevice) {
-    guard let device = videoDeviceInput?.device else {
-      throw CameraError.session(.cameraNotReady)
-    }
     guard let zoom = configuration.zoom else {
       return
     }

package/ios/Core/CameraSession.swift

@@ -114,10 +114,7 @@ class CameraSession: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate, AVC
       do {
         // If needed, configure the AVCaptureSession (inputs, outputs)
         if difference.isSessionConfigurationDirty {
-          // Lock Capture Session for configuration
+          try self.withSessionLock {
-          ReactLogger.log(level: .info, message: "Beginning CameraSession configuration...")
-          self.captureSession.beginConfiguration()
-
             // 1. Update input device
             if difference.inputChanged {
               try self.configureDevice(configuration: config)
@@ -130,40 +127,37 @@ class CameraSession: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate, AVC
             if difference.orientationChanged {
               self.configureOrientation(configuration: config)
             }
-
+          }
-          // Unlock Capture Session again and submit configuration to Hardware
-          self.captureSession.commitConfiguration()
-          ReactLogger.log(level: .info, message: "Committed CameraSession configuration!")
         }
 
         // If needed, configure the AVCaptureDevice (format, zoom, low-light-boost, ..)
         if difference.isDeviceConfigurationDirty {
-          guard let device = self.videoDeviceInput?.device else {
+          try self.withDeviceLock { device in
-            throw CameraError.session(.cameraNotReady)
-          }
-          ReactLogger.log(level: .info, message: "Beginning CaptureDevice configuration...")
-          try device.lockForConfiguration()
-
             // 4. Configure format
             if difference.formatChanged {
-            try self.configureFormat(configuration: config)
+              try self.configureFormat(configuration: config, device: device)
             }
             // 5. Configure side-props (fps, lowLightBoost)
             if difference.sidePropsChanged {
-            try self.configureSideProps(configuration: config)
+              try self.configureSideProps(configuration: config, device: device)
             }
             // 6. Configure zoom
             if difference.zoomChanged {
-            try self.configureZoom(configuration: config)
+              self.configureZoom(configuration: config, device: device)
+            }
+          }
         }
 
-          device.unlockForConfiguration()
+        // 7. Start or stop the session if needed
-          ReactLogger.log(level: .info, message: "Committed CaptureDevice configuration!")
-        }
-
-        // 6. Start or stop the session if needed
         self.checkIsActive(configuration: config)
 
+        // 8. Enable or disable the Torch if needed (requires session to be running)
+        if difference.torchChanged {
+          try self.withDeviceLock { device in
+            try self.configureTorch(configuration: config, device: device)
+          }
+        }
+
         // Update successful, set the new configuration!
         self.configuration = config
       } catch {
@@ -191,6 +185,41 @@ class CameraSession: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate, AVC
     }
   }
 
+  /**
+   Runs the given [lambda] under an AVCaptureSession configuration lock (`beginConfiguration()`)
+   */
+  private func withSessionLock(_ lambda: () throws -> Void) throws {
+    // Lock Capture Session for configuration
+    ReactLogger.log(level: .info, message: "Beginning CameraSession configuration...")
+    captureSession.beginConfiguration()
+    defer {
+      // Unlock Capture Session again and submit configuration to Hardware
+      self.captureSession.commitConfiguration()
+      ReactLogger.log(level: .info, message: "Committed CameraSession configuration!")
+    }
+
+    // Call lambda
+    try lambda()
+  }
+
+  /**
+   Runs the given [lambda] under an AVCaptureDevice configuration lock (`lockForConfiguration()`)
+   */
+  private func withDeviceLock(_ lambda: (_ device: AVCaptureDevice) throws -> Void) throws {
+    guard let device = videoDeviceInput?.device else {
+      throw CameraError.session(.cameraNotReady)
+    }
+    ReactLogger.log(level: .info, message: "Beginning CaptureDevice configuration...")
+    try device.lockForConfiguration()
+    defer {
+      device.unlockForConfiguration()
+      ReactLogger.log(level: .info, message: "Committed CaptureDevice configuration!")
+    }
+
+    // Call lambda with Device
+    try lambda(device)
+  }
+
   /**
    Starts or stops the CaptureSession if needed (`isActive`)
    */

package/ios/Core/RecordingSession.swift

@@ -36,10 +36,16 @@ class RecordingSession {
   private var hasWrittenFirstVideoFrame = false
   private var isFinishing = false
 
+  /**
+   Gets the file URL of the recorded video.
+   */
   var url: URL {
     return assetWriter.outputURL
   }
 
+  /**
+   Get the duration (in seconds) of the recorded video.
+   */
   var duration: Double {
     guard let latestTimestamp = latestTimestamp,
           let initialTimestamp = initialTimestamp else {