perf: Fix double configuration flicker on fast device change (#2537)

* fix: Fix double configuration on device change

Fixes a situation that happened on every device change (or initial mount) where the device was configured after the session, separately, instead of just all at once causing an additonal delay/flicker of the prevjew.

* Try?

* Format

* Update CameraSession.swift

* Use `defer`

* Throw `.device`

package/ios/Core/CameraSession.swift

@@ -117,7 +117,8 @@ class CameraSession: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate, AVC
       do {
         // If needed, configure the AVCaptureSession (inputs, outputs)
         if difference.isSessionConfigurationDirty {
-          try self.withSessionLock {
+          self.captureSession.beginConfiguration()
+
           // 1. Update input device
           if difference.inputChanged {
             try self.configureDevice(configuration: config)
@@ -135,11 +136,18 @@ class CameraSession: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate, AVC
             self.configureOrientation(configuration: config)
           }
         }
+
+        guard let device = self.videoDeviceInput?.device else {
+          throw CameraError.device(.noDevice)
         }
 
         // If needed, configure the AVCaptureDevice (format, zoom, low-light-boost, ..)
         if difference.isDeviceConfigurationDirty {
-          try self.withDeviceLock { device in
+          try device.lockForConfiguration()
+          defer {
+            device.unlockForConfiguration()
+          }
+
           // 4. Configure format
           if difference.formatChanged {
             try self.configureFormat(configuration: config, device: device)
@@ -162,6 +170,11 @@ class CameraSession: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate, AVC
             self.configureExposure(configuration: config, device: device)
           }
         }
+
+        if difference.isSessionConfigurationDirty {
+          // We commit the session config updates AFTER the device config,
+          // that way we can also batch those changes into one update instead of doing two updates.
+          self.captureSession.commitConfiguration()
         }
 
         // 9. Start or stop the session if needed
@@ -169,9 +182,11 @@ class CameraSession: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate, AVC
 
         // 10. 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)
+          try device.lockForConfiguration()
+          defer {
+            device.unlockForConfiguration()
           }
+          try self.configureTorch(configuration: config, device: device)
         }
 
         // Notify about Camera initialization
@@ -206,41 +221,6 @@ 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`)
    */