Fix wrong error when disk is full

#531

NAPS2.Lib/Pdf/SavePdfOperation.cs

@@ -114,7 +114,7 @@ public bool Start(string fileName, Placeholders placeholders, ICollection<Proces
             }
             catch (IOException ex)
             {
-                if (File.Exists(subFileName))
+                if (File.Exists(subFileName) && !FileSystemHelper.IsDiskFullException(ex))
                 {
                     InvokeError(MiscResources.FileInUse, ex);
                 }

NAPS2.Sdk/Util/FileSystemHelper.cs

@@ -2,6 +2,9 @@
 
 internal static class FileSystemHelper
 {
+    private const int HR_ERROR_HANDLE_DISK_FULL = unchecked((int) 0x80070027);
+    private const int HR_ERROR_DISK_FULL = unchecked((int) 0x80070070);
+
     /// <summary>
     /// Creates the parent directory for the provided path if needed.
     /// </summary>
@@ -15,6 +18,10 @@ public static void EnsureParentDirExists(string filePath)
         }
     }
 
+    // TODO: Can we detect this on Linux/Mac?
+    public static bool IsDiskFullException(IOException exception) =>
+        exception.HResult is HR_ERROR_DISK_FULL or HR_ERROR_HANDLE_DISK_FULL;
+
     public static bool IsFileInUse(string filePath, out Exception? exception)
     {
         if (File.Exists(filePath))
@@ -34,7 +41,7 @@ public static bool IsFileInUse(string filePath, out Exception? exception)
         exception = null;
         return false;
     }
-    
+
     // https://learn.microsoft.com/en-us/dotnet/standard/io/how-to-copy-directories
     public static void CopyDirectory(string sourceDir, string destinationDir, bool recursive)
     {