From 3f583916719eeef598d10a5d4e14ef14f008243b Mon Sep 17 00:00:00 2001
From: Rob Mensching <rob@firegiant.com>
Date: Tue, 11 May 2021 07:36:37 -0700
Subject: Merge Dtf

---
 src/samples/Dtf/DDiff/TextFileDiffEngine.cs | 83 +++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 src/samples/Dtf/DDiff/TextFileDiffEngine.cs

(limited to 'src/samples/Dtf/DDiff/TextFileDiffEngine.cs')

diff --git a/src/samples/Dtf/DDiff/TextFileDiffEngine.cs b/src/samples/Dtf/DDiff/TextFileDiffEngine.cs
new file mode 100644
index 00000000..22567023
--- /dev/null
+++ b/src/samples/Dtf/DDiff/TextFileDiffEngine.cs
@@ -0,0 +1,83 @@
+// 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.Diagnostics;
+
+namespace WixToolset.Dtf.Samples.DDiff
+{
+	public class TextFileDiffEngine : IDiffEngine
+	{
+		public TextFileDiffEngine()
+		{
+		}
+
+		private bool IsTextFile(string file)
+		{
+			// Guess whether this is a text file by reading the first few bytes and checking for non-ascii chars.
+
+			bool isText = true;
+			FileStream stream = new FileStream(file, FileMode.Open, FileAccess.Read, FileShare.Read);
+			byte[] buf = new byte[256];
+			int count = stream.Read(buf, 0, buf.Length);
+			for(int i = 0; i < count; i++)
+			{
+				if((buf[i] & 0x80) != 0)
+				{
+					isText = false;
+					break;
+				}
+			}
+			stream.Close();
+			return isText;
+		}
+
+		public float GetDiffQuality(string diffInput1, string diffInput2, string[] options, IDiffEngineFactory diffFactory)
+		{
+			if(diffInput1 != null && File.Exists(diffInput1) &&
+				diffInput2 != null && File.Exists(diffInput2) &&
+				(IsTextFile(diffInput1) && IsTextFile(diffInput2)))
+			{
+				return .70f;
+			}
+			else
+			{
+				return 0;
+			}
+		}
+
+		public bool GetDiff(string diffInput1, string diffInput2, string[] options, TextWriter diffOutput, string linePrefix, IDiffEngineFactory diffFactory)
+		{
+			try
+			{
+				bool difference = false;
+				ProcessStartInfo psi = new ProcessStartInfo("diff.exe");
+				psi.Arguments = String.Format("\"{0}\" \"{1}\"", diffInput1, diffInput2);
+				psi.WorkingDirectory = null;
+				psi.UseShellExecute = false;
+				psi.WindowStyle = ProcessWindowStyle.Hidden;
+				psi.RedirectStandardOutput = true;
+				Process proc = Process.Start(psi);
+
+				string line;
+				while((line = proc.StandardOutput.ReadLine()) != null)
+				{
+					diffOutput.WriteLine("{0}{1}", linePrefix, line);
+					difference = true;
+				}
+
+				proc.WaitForExit();
+				return difference;
+			}
+			catch(System.ComponentModel.Win32Exception)  // If diff.exe is not found, just compare the bytes
+			{
+				return new FileDiffEngine().GetDiff(diffInput1, diffInput2, options, diffOutput, linePrefix, diffFactory);
+			}
+		}
+
+		public IDiffEngine Clone()
+		{
+			return new TextFileDiffEngine();
+		}
+	}
+}
-- 
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