Restore SEBPatch

SafeExamBrowser.UserInterface.Shared/Utilities/IconLoader.cs

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+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+using System.Drawing;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Windows;
+using System.Windows.Interop;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+
+namespace SafeExamBrowser.UserInterface.Shared.Utilities
+{
+	public static class IconLoader
+	{
+		private const int MAX_PATH_CHARS = 260;
+		private const uint SHGFI_ICON = 0x100;
+		private const uint SHGFI_LARGEICON = 0x0;
+		private const uint SHGFI_SMALLICON = 0x1;
+
+		public static ImageSource LoadIconFor(DirectoryInfo directory)
+		{
+			var fileInfo = new SHFILEINFO();
+			var result = SHGetFileInfo(directory.FullName, 0, ref fileInfo, (uint) Marshal.SizeOf(fileInfo), SHGFI_ICON | SHGFI_SMALLICON);
+			var imageSource = Imaging.CreateBitmapSourceFromHIcon(fileInfo.hIcon, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
+
+			DestroyIcon(fileInfo.hIcon);
+
+			return imageSource;
+		}
+
+		public static ImageSource LoadIconFor(FileInfo file)
+		{
+			try
+			{
+				using (var icon = Icon.ExtractAssociatedIcon(file.FullName))
+				{
+					return Imaging.CreateBitmapSourceFromHIcon(icon.Handle, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
+				}
+			}
+			catch
+			{
+				// Icon.ExtractAssociatedIcon(...) has proven to be error-prone, especially for network paths. Thus we try to use the native API
+				// in those cases, see also https://stackoverflow.com/questions/1842226/how-to-get-the-associated-icon-from-a-network-share-file.
+				var builder = new StringBuilder(MAX_PATH_CHARS);
+
+				builder.Append(file.FullName);
+
+				var handle = ExtractAssociatedIcon(IntPtr.Zero, builder, out _);
+
+				using (var icon = Icon.FromHandle(handle))
+				{
+					return Imaging.CreateBitmapSourceFromHIcon(icon.Handle, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
+				}
+			}
+		}
+
+		[DllImport("user32.dll")]
+		private static extern int DestroyIcon(IntPtr hIcon);
+
+		[DllImport("shell32.dll", CharSet = CharSet.Unicode)]
+		static extern IntPtr ExtractAssociatedIcon(IntPtr hInst, StringBuilder lpIconPath, out ushort lpiIcon);
+
+		[DllImport("shell32.dll", CharSet = CharSet.Unicode)]
+		private static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbSizeFileInfo, uint uFlags);
+
+		[StructLayout(LayoutKind.Sequential)]
+		private struct SHFILEINFO
+		{
+			public IntPtr hIcon;
+			public IntPtr iIcon;
+			public uint dwAttributes;
+			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
+			public string szDisplayName;
+			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
+			public string szTypeName;
+		};
+	}
+}