Remove ScanController.ScanError event

This always happens in concert with the ScanEnd event so merging them is a simplification.

NAPS2.Lib/Scan/ScanPerformer.cs

@@ -65,18 +65,16 @@ internal class ScanPerformer : IScanPerformer
             _scanBridgeFactory);
         var op = new ScanOperation(options);
 
-        Exception? error = null;
         controller.PageStart += (sender, args) => op.NextPage(args.PageNumber);
         controller.ScanEnd += (sender, args) =>
         {
             // Close the progress window before showing the error dialog
             op.Completed();
-            if (error != null)
+            if (args.Error != null)
             {
-                HandleError(error);
+                HandleError(args.Error);
             }
         };
-        controller.ScanError += (sender, args) => error = args.Exception;
         controller.PropagateErrors = false;
         TranslateProgress(controller, op);
 

NAPS2.Sdk/Remoting/Server/ScanJob.cs

@@ -20,23 +20,21 @@ internal class ScanJob : IEsclScanJob
     private readonly TaskCompletionSource<bool> _completedTcs = new();
     private readonly List<ProcessedImage> _pdfImages = [];
     private Action<StatusTransition>? _callback;
-    private bool _hasError;
 
     public ScanJob(ScanningContext scanningContext, ScanController controller, ScanDevice device,
         EsclScanSettings settings)
     {
         _scanningContext = scanningContext;
         _controller = controller;
-        _controller.ScanEnd += (_, _) =>
+        _controller.ScanEnd += (_, args) =>
         {
             _callback?.Invoke(StatusTransition.DeviceIdle);
-            if (_hasError)
+            if (args.HasError)
             {
                 _callback?.Invoke(StatusTransition.AbortJob);
             }
-            _completedTcs.TrySetResult(!_hasError);
+            _completedTcs.TrySetResult(!args.HasError);
         };
-        _controller.ScanError += (_, _) => { _hasError = true; };
         var options = new ScanOptions
         {
             Device = device,

NAPS2.Sdk/Scan/ScanController.cs

@@ -130,9 +130,9 @@ public class ScanController
         options = _scanOptionsValidator.ValidateAll(options, _scanningContext, true);
         int pageNumber = 0;
 
+        Exception? scanError = null;
         void ScanStartCallback() => ScanStart?.Invoke(this, EventArgs.Empty);
-        void ScanEndCallback() => ScanEnd?.Invoke(this, EventArgs.Empty);
-        void ScanErrorCallback(Exception ex) => ScanError?.Invoke(this, new ScanErrorEventArgs(ex));
+        void ScanEndCallback() => ScanEnd?.Invoke(this, new ScanEndEventArgs(scanError));
         void PageStartCallback() => PageStart?.Invoke(this, new PageStartEventArgs(++pageNumber));
 
         void PageProgressCallback(double progress) =>
@@ -156,7 +156,7 @@ public class ScanController
             }
             catch (Exception ex)
             {
-                ScanErrorCallback(ex);
+                scanError = ex;
                 if (PropagateErrors)
                 {
                     throw;
@@ -181,15 +181,10 @@ public class ScanController
     public event EventHandler? ScanStart;
 
     /// <summary>
-    /// Occurs when a Scan operation has completed.
+    /// Occurs when a Scan operation has completed. If the scan ends due to an error, the Error property will be set on
+    /// the event args. For more detailed diagnostics, set ScanningContext.Logger.
     /// </summary>
-    public event EventHandler? ScanEnd;
-
-    /// <summary>
-    /// Occurs when a fatal error happens during a Scan operation. For more detailed diagnostics, set
-    /// ScanningContext.Logger.
-    /// </summary>
-    public event EventHandler<ScanErrorEventArgs>? ScanError;
+    public event EventHandler<ScanEndEventArgs>? ScanEnd;
 
     /// <summary>
     /// Occurs when scanning starts for a page. This can be called multiple times during a single Scan operation if it

NAPS2.Sdk/Scan/ScanEndEventArgs.cs

@@ -0,0 +1,16 @@
+namespace NAPS2.Scan;
+
+public class ScanEndEventArgs : EventArgs
+{
+    public ScanEndEventArgs(Exception? error = null)
+    {
+        Error = error;
+    }
+
+    /// <summary>
+    /// Gets the exception that ended the scan, if any.
+    /// </summary>
+    public Exception? Error { get; }
+
+    public bool HasError => Error != null;
+}

NAPS2.Sdk/Scan/ScanErrorEventArgs.cs

@@ -1,14 +0,0 @@
-namespace NAPS2.Scan;
-
-public class ScanErrorEventArgs : EventArgs
-{
-    public ScanErrorEventArgs(Exception exception)
-    {
-        Exception = exception;
-    }
-
-    /// <summary>
-    /// Gets the exception that occurred.
-    /// </summary>
-    public Exception Exception { get; }
-}