1 files changed, 68 insertions, 0 deletions

diff --git a/src/samples/Dtf/DDiff/IDiffEngine.cs b/src/samples/Dtf/DDiff/IDiffEngine.cs
new file mode 100644
index 00000000..9895d6ff
--- /dev/null
+++ b/src/samples/Dtf/DDiff/IDiffEngine.cs
@@ -0,0 +1,68 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+using System;
+using System.IO;
+using System.Collections;
+
+namespace WixToolset.Dtf.Samples.DDiff
+{
+        public interface IDiffEngine
+        {
+                float GetDiffQuality(string diffInput1, string diffInput2, string[] options, IDiffEngineFactory diffFactory);
+
+                bool GetDiff(string diffInput1, string diffInput2, string[] options, TextWriter diffOutput, string linePrefix, IDiffEngineFactory diffFactory);
+
+                IDiffEngine Clone();
+        }
+
+        public interface IDiffEngineFactory
+        {
+                IDiffEngine GetDiffEngine(string diffInput1, string diffInput2, string[] options);
+        }
+
+        public class BestQualityDiffEngineFactory : IDiffEngineFactory
+        {
+                public virtual IDiffEngine GetDiffEngine(string diffInput1, string diffInput2, string[] options)
+                {
+                        float bestDiffQuality = 0;
+                        IDiffEngine bestDiffEngine = null;
+
+                        foreach(IDiffEngine diffEngine in diffEngines)
+                        {
+                                float diffQuality = diffEngine.GetDiffQuality(diffInput1, diffInput2, options, this);
+                                if(diffQuality > bestDiffQuality)
+                                {
+                                        bestDiffQuality = diffQuality;
+                                        bestDiffEngine = diffEngine;
+                                }
+                        }
+                        return (bestDiffEngine != null ? bestDiffEngine.Clone() : null);
+                }
+
+                public BestQualityDiffEngineFactory() : this(null) { }
+                public BestQualityDiffEngineFactory(IDiffEngine[] diffEngines)
+                {
+                        this.diffEngines = (diffEngines != null ? new ArrayList(diffEngines) : new ArrayList());
+                }
+
+                protected IList diffEngines;
+
+                public virtual void Add(IDiffEngine diffEngine)
+                {
+                        diffEngines.Add(diffEngine);
+                }
+
+                public virtual void Remove(IDiffEngine diffEngine)
+                {
+                        diffEngines.Remove(diffEngine);
+                }
+
+                public IList DiffEngines
+                {
+                        get
+                        {
+                                return ArrayList.ReadOnly(diffEngines);
+                        }
+                }
+        }
+}