Prepare Dockerfile format detector

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/DockerfileDetector.cs

@@ -0,0 +1,35 @@
+// Copyright © 2017-2025 QL-Win Contributors
+//
+// This file is part of QuickLook program.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System;
+using System.IO;
+
+namespace QuickLook.Plugin.TextViewer.Detectors;
+
+public sealed class DockerfileDetector : IFormatDetector
+{
+    public string Name => "Dockerfile";
+
+    public string Extension => ".df";
+
+    public bool Detect(string path, string text)
+    {
+        if (string.IsNullOrWhiteSpace(text)) return false;
+
+        return "Dockerfile".Equals(Path.GetFileName(path), StringComparison.OrdinalIgnoreCase);
+    }
+}

QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/FormatDetector.cs

@@ -29,6 +29,7 @@ public class FormatDetector
         new JSONDetector(),
         new MakefileDetector(),
         //new CMakeListsDetector(),
+        //new DockerfileDetector(),
     ];
 
     public static IFormatDetector Detect(string path, string text)