Merge pull request #842 from navaronbracke/fix_torch_on_start

fix: Fix torch state sync issues

@@ -376,7 +376,7 @@ class MobileScanner(
      */
     fun toggleTorch(enableTorch: Boolean) {
         if (camera == null) {
-            throw TorchWhenStopped()
+            return
         }
 
         if (camera?.cameraInfo?.hasFlashUnit() == true) {

@@ -4,6 +4,5 @@ class NoCamera : Exception()
 class AlreadyStarted : Exception()
 class AlreadyStopped : Exception()
 class CameraError : Exception()
-class TorchWhenStopped : Exception()
 class ZoomWhenStopped : Exception()
 class ZoomNotInRange : Exception()
\ No newline at end of file

@@ -237,12 +237,8 @@ class MobileScannerHandler(
     }
 
     private fun toggleTorch(call: MethodCall, result: MethodChannel.Result) {
-        try {
-            mobileScanner!!.toggleTorch(call.arguments == 1)
-            result.success(null)
-        } catch (e: TorchWhenStopped) {
-            result.error("MobileScanner", "Called toggleTorch() while stopped!", null)
-        }
+        mobileScanner!!.toggleTorch(call.arguments == 1)
+        result.success(null)
     }
 
     private fun setScale(call: MethodCall, result: MethodChannel.Result) {

@@ -133,7 +133,7 @@ public class MobileScanner: NSObject, AVCaptureVideoDataOutputSampleBufferDelega
     }
 
     /// Start scanning for barcodes
-    func start(barcodeScannerOptions: BarcodeScannerOptions?, returnImage: Bool, cameraPosition: AVCaptureDevice.Position, torch: AVCaptureDevice.TorchMode, detectionSpeed: DetectionSpeed, completion: @escaping (MobileScannerStartParameters) -> ()) throws {
+    func start(barcodeScannerOptions: BarcodeScannerOptions?, returnImage: Bool, cameraPosition: AVCaptureDevice.Position, torch: Bool, detectionSpeed: DetectionSpeed, completion: @escaping (MobileScannerStartParameters) -> ()) throws {
         self.detectionSpeed = detectionSpeed
         if (device != nil) {
             throw MobileScannerError.alreadyStarted
@@ -213,18 +213,23 @@ public class MobileScanner: NSObject, AVCaptureVideoDataOutputSampleBufferDelega
 
         backgroundQueue.async {
             self.captureSession.startRunning()
-            // Enable the torch if parameter is set and torch is available
-            // torch should be set after 'startRunning' is called
-            do {
-                try self.toggleTorch(torch)
-            } catch {
-                print("Failed to set initial torch state.")
+            
+            // Turn on the flashlight if requested,
+            // but after the capture session started.
+            if (torch) {
+                do {
+                    try self.toggleTorch(.on)
+                } catch {
+                    // If the torch does not turn on,
+                    // continue with the capture session anyway.
+                }
             }
 
             do {
                 try self.resetScale()
             } catch {
-                print("Failed to reset zoom scale")
+                // If the zoom scale could not be reset,
+                // continue with the capture session anyway.
             }
             
             if let device = self.device {
@@ -270,19 +275,16 @@ public class MobileScanner: NSObject, AVCaptureVideoDataOutputSampleBufferDelega
         device = nil
     }
 
-    /// Toggle the flashlight between on and off
+    /// Toggle the flashlight between on and off.
     func toggleTorch(_ torch: AVCaptureDevice.TorchMode) throws {
-        if (device == nil) {
-            throw MobileScannerError.torchWhenStopped
+        if (device == nil || !device.hasTorch || !device.isTorchAvailable) {
+            return
         }
-        if (device.hasTorch && device.isTorchAvailable) {
-            do {
-                try device.lockForConfiguration()
-                device.torchMode = torch
-                device.unlockForConfiguration()
-            } catch {
-                throw MobileScannerError.torchError(error)
-            }
+
+        if (device.torchMode != torch) {
+            try device.lockForConfiguration()
+            device.torchMode = torch
+            device.unlockForConfiguration()
         }
     }
 

@@ -10,9 +10,7 @@ enum MobileScannerError: Error {
     case noCamera
     case alreadyStarted
     case alreadyStopped
-    case torchError(_ error: Error)
     case cameraError(_ error: Error)
-    case torchWhenStopped
     case zoomWhenStopped
     case zoomError(_ error: Error)
     case analyzerError(_ error: Error)

@@ -120,7 +120,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
         let detectionSpeed: DetectionSpeed = DetectionSpeed(rawValue: speed)!
 
         do {
-            try mobileScanner.start(barcodeScannerOptions: barcodeOptions, returnImage: returnImage, cameraPosition: position, torch: torch ? .on : .off, detectionSpeed: detectionSpeed) { parameters in
+            try mobileScanner.start(barcodeScannerOptions: barcodeOptions, returnImage: returnImage, cameraPosition: position, torch: torch, detectionSpeed: detectionSpeed) { parameters in
                 DispatchQueue.main.async {
                     result([
                         "textureId": parameters.textureId,
@@ -136,17 +136,13 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
             result(FlutterError(code: "MobileScanner",
                                 message: "No camera found or failed to open camera!",
                                 details: nil))
-        } catch MobileScannerError.torchError(let error) {
-            result(FlutterError(code: "MobileScanner",
-                                message: "Error occured when setting torch!",
-                                details: error))
         } catch MobileScannerError.cameraError(let error) {
             result(FlutterError(code: "MobileScanner",
                                 message: "Error occured when setting up camera!",
                                 details: error))
         } catch {
             result(FlutterError(code: "MobileScanner",
-                                message: "Unknown error occured..",
+                                message: "Unknown error occured.",
                                 details: nil))
         }
     }
@@ -165,9 +161,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin {
             try mobileScanner.toggleTorch(call.arguments as? Int == 1 ? .on : .off)
             result(nil)
         } catch {
-            result(FlutterError(code: "MobileScanner",
-                                message: "Called toggleTorch() while stopped!",
-                                details: nil))
+            result(FlutterError(code: "MobileScanner", message: error.localizedDescription, details: nil))
         }
     }
     

@@ -149,9 +149,10 @@ class MobileScannerWebPlugin {
       });
 
       final hasTorch = await barCodeReader.hasTorch();
+      final bool? enableTorch = arguments['torch'] as bool?;
 
-      if (hasTorch && arguments.containsKey('torch')) {
-        await barCodeReader.toggleTorch(enabled: arguments['torch'] as bool);
+      if (hasTorch && enableTorch != null) {
+        await barCodeReader.toggleTorch(enabled: enableTorch);
       }
 
       return {

@@ -282,9 +282,6 @@ class MobileScannerController {
 
     final hasTorch = startResult['torchable'] as bool? ?? false;
     hasTorchState.value = hasTorch;
-    if (hasTorch && torchEnabled) {
-      torchState.value = TorchState.on;
-    }
 
     final Size size;
 
@@ -314,11 +311,11 @@ class MobileScannerController {
 
   /// Stops the camera, but does not dispose this controller.
   Future<void> stop() async {
-    try {
-      await _methodChannel.invokeMethod('stop');
-    } catch (e) {
-      debugPrint('$e');
-    }
+    await _methodChannel.invokeMethod('stop');
+
+    // After the camera stopped, set the torch state to off,
+    // as the torch state callback is never called when the camera is stopped.
+    torchState.value = TorchState.off;
   }
 
   /// Switches the torch on or off.
@@ -333,14 +330,16 @@ class MobileScannerController {
       throw const MobileScannerException(
         errorCode: MobileScannerErrorCode.controllerUninitialized,
       );
-    } else if (!hasTorch) {
+    }
+
+    if (!hasTorch) {
       return;
     }
 
-    torchState.value =
+    final TorchState newState =
         torchState.value == TorchState.off ? TorchState.on : TorchState.off;
 
-    await _methodChannel.invokeMethod('torch', torchState.value.rawValue);
+    await _methodChannel.invokeMethod('torch', newState.rawValue);
   }
 
   /// Changes the state of the camera (front or back).

@@ -274,15 +274,13 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
             return
         }
         
-        // Enable the torch if parameter is set and torch is available
-        if (device.hasTorch) {
+        // Turn on the torch if requested.
+        if (torch) {
             do {
-                try device.lockForConfiguration()
-                device.torchMode = torch ? .on : .off
-                device.unlockForConfiguration()
+                try self.toggleTorchInternal(.on)
             } catch {
-                result(FlutterError(code: error.localizedDescription, message: nil, details: nil))
-                return
+                // If the torch could not be turned on,
+                // continue the capture session.
             }
         }
         
@@ -294,7 +292,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
             let input = try AVCaptureDeviceInput(device: device)
             captureSession.addInput(input)
         } catch {
-            result(FlutterError(code: error.localizedDescription, message: nil, details: nil))
+            result(FlutterError(code: "MobileScanner", message: error.localizedDescription, details: nil))
             return
         }
         captureSession.sessionPreset = AVCaptureSession.Preset.photo
@@ -319,19 +317,34 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
         let answer: [String : Any?] = ["textureId": textureId, "size": size, "torchable": device.hasTorch]
         result(answer)
     }
-    
-    func toggleTorch(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
-        if (device == nil) {
-            result(nil)
+
+    // TODO: this method should be removed when iOS and MacOS share their implementation.
+    private func toggleTorchInternal(_ torch: AVCaptureDevice.TorchMode) throws {
+        if (device == nil || !device.hasTorch) {
             return
         }
-        do {
+        
+        if #available(macOS 15.0, *) {
+            if(!device.isTorchAvailable) {
+                return
+            }
+        }
+
+        if (device.torchMode != torch) {
             try device.lockForConfiguration()
-            device.torchMode = call.arguments as! Int == 1 ? .on : .off
+            device.torchMode = torch
             device.unlockForConfiguration()
+        }
+    }
+    
+    func toggleTorch(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
+        let requestedTorchMode: AVCaptureDevice.TorchMode = call.arguments as! Int == 1 ? .on : .off
+
+        do {
+            try self.toggleTorchInternal(requestedTorchMode)
             result(nil)
         } catch {
-            result(FlutterError(code: error.localizedDescription, message: nil, details: nil))
+            result(FlutterError(code: "MobileScanner", message: error.localizedDescription, details: nil))
         }
     }