1 files changed, 65 insertions, 0 deletions
diff --git a/Models/PipelineStep.cs b/Models/PipelineStep.cs
new file mode 100644
index 0000000..e8a4bf1
--- /dev/null
+++ b/Models/PipelineStep.cs
@@ -0,0 +1,65 @@
+using Avalar.Services;
+using Avalonia.Media.Imaging;
+using ReactiveUI;
+using System;
+using System.ComponentModel;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Avalar.Models
+{
+    public class PipelineStep<T> : IPipelineStep where T : INotifyPropertyChanged, IProcessor
+    {
+        public PipelineStep(T processor)
+        {
+            m_Processor = processor ?? throw new ArgumentNullException(nameof(processor));
+            m_Processor.PropertyChanged += OnPropertyChanged;
+        }
+
+        private void OnPropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Result)));
+        }
+
+        public void InvalidateResult()
+        {
+            Result = null;
+        }
+
+        private T m_Processor;
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        private IBitmap Result { get; set; }
+
+        public Task<IBitmap> Run(IBitmap bitmap, CancellationToken token)
+        {
+            if (Result != null)
+            {
+                return Task.FromResult(Result);
+            }
+            else
+            {
+                return Task.Run(() =>
+                {
+                    Result = m_Processor.Process(bitmap, token);
+                    token.ThrowIfCancellationRequested();
+                    return Result;
+                });
+            }
+        }
+    }
+
+    public static class PipelineStep
+    {
+        public static PipelineStep<T> Create<T>(T processor) where T : INotifyPropertyChanged, IProcessor
+        {
+            return new PipelineStep<T>(processor);
+        }
+
+        public static PipelineStep<T> AsPipelineStep<T>(this T processor) where T : INotifyPropertyChanged, IProcessor
+        {
+            return Create(processor);
+        }
+    }
+}