Use format detector feature for TextViewer

2025-09-12 18:39:45 +00:00 · 2025-06-19 16:38:27 +08:00
parent a580926059
commit efc83b0669
10 changed files with 496 additions and 218 deletions
--- a/QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/EncodingDetector.cs
+++ b/QuickLook.Plugin/QuickLook.Plugin.TextViewer/Detectors/EncodingDetector.cs
@@ -0,0 +1,89 @@
+// 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.ComponentModel.Composition;
+using System.Linq;
+using System.Text;
+using UtfUnknown;
+
+namespace QuickLook.Plugin.TextViewer.Detectors;
+
+[Export]
+public class EncodingDetector
+{
+    public static Encoding DetectFromBytes(byte[] bytes)
+    {
+        var result = CharsetDetector.DetectFromBytes(bytes);
+        var encoding = result.DoubleDetectFromResult(bytes); // Fix issues
+
+        return encoding;
+    }
+}
+
+file static class DetectionExtensions
+{
+    public static Encoding DoubleDetectFromResult(this DetectionResult result, byte[] buffer)
+    {
+        // Determine the highest confidence encoding, or fallback to ANSI
+        var encoding = result.Detected?.Encoding ?? Encoding.Default;
+
+        // When mixing encodings, one of the encodings may gain higher confidence
+        // In this case, we should return to encodings UTF8 / UTF32 / ANSI
+        // https://github.com/QL-Win/QuickLook/issues/769
+        if (encoding != Encoding.UTF8 && encoding != Encoding.UTF32 && encoding != Encoding.Default)
+        {
+            if (result.Details.Any(detail => detail.Encoding == Encoding.UTF8))
+            {
+                encoding = Encoding.UTF8;
+            }
+            else if (result.Details.Any(detail => detail.Encoding == Encoding.UTF32))
+            {
+                encoding = Encoding.UTF32;
+            }
+            else if (result.Details.Any(detail => detail.Encoding == Encoding.Default))
+            {
+                encoding = Encoding.Default;
+            }
+        }
+
+        // When the text is too short and lacks a BOM
+        // In this case, we should fallback to an encoding if it is not recognized as UTF8 / UTF32 / ANSI
+        // https://github.com/QL-Win/QuickLook/issues/471
+        // https://github.com/QL-Win/QuickLook/issues/600
+        // https://github.com/QL-Win/QuickLook/issues/954
+        if (buffer.Length <= 50)
+        {
+            if (encoding != Encoding.UTF8 && encoding != Encoding.UTF32 && encoding != Encoding.Default)
+            {
+                if (!Encoding.UTF8.GetString(buffer).Contains("\uFFFD"))
+                {
+                    encoding = Encoding.UTF8;
+                }
+                else if (!Encoding.UTF32.GetString(buffer).Contains("\uFFFD"))
+                {
+                    encoding = Encoding.UTF32;
+                }
+                else if (!Encoding.Default.GetString(buffer).Contains("\uFFFD"))
+                {
+                    encoding = Encoding.Default;
+                }
+            }
+        }
+
+        return encoding;
+    }
+}