#413 Fix handling of relative paths

Relative paths are now correctly resolved. Files not inside of the base directory are just copied to the output root directory, without any sub directory structure.

Confuser.Core/ConfuserEngine.cs

@@ -379,10 +379,17 @@ static void OptimizeMethods(ConfuserContext context) {
 
 		static void EndModule(ConfuserContext context) {
 			string output = context.Modules[context.CurrentModuleIndex].Location;
-			if (output != null) {
+			if (!(output is null)) {
 				if (!Path.IsPathRooted(output))
-					output = Path.Combine(Environment.CurrentDirectory, output);
-				output = Utils.GetRelativePath(output, context.BaseDirectory);
+					output = Path.Combine(context.BaseDirectory, output);
+				string relativeOutput = Utils.GetRelativePath(output, context.BaseDirectory);
+				if (relativeOutput is null) {
+					context.Logger.WarnFormat("Input file is not inside the base directory. Relative path can't be created. Placing file into output root." +
+						Environment.NewLine + "Responsible file is: {0}", output);
+					output = Path.GetFileName(output);
+				} else {
+					output = relativeOutput;
+				}
 			}
 			else {
 				output = context.CurrentModule.Name;

Confuser.Core/Utils.cs

@@ -71,19 +71,33 @@ public static void AddListEntry<TKey, TValue>(this IDictionary<TKey, List<TValue
 		/// <summary>
 		///     Obtains the relative path from the specified base path.
 		/// </summary>
-		/// <param name="filespec">The file path.</param>
-		/// <param name="folder">The base path.</param>
+		/// <param name="fileSpec">The file path.</param>
+		/// <param name="baseDirectory">The base path.</param>
 		/// <returns>The path of <paramref name="filespec" /> relative to <paramref name="folder" />.</returns>
-		public static string GetRelativePath(string filespec, string folder) {
-			//http://stackoverflow.com/a/703292/462805
+		public static string GetRelativePath(string fileSpec, string baseDirectory) {
+			if (fileSpec is null) throw new ArgumentNullException(nameof(fileSpec));
+			if (baseDirectory is null) throw new ArgumentNullException(nameof(fileSpec));
 
-			var pathUri = new Uri(filespec);
-			// Folders must end in a slash
-			if (!folder.EndsWith(Path.DirectorySeparatorChar.ToString())) {
-				folder += Path.DirectorySeparatorChar;
+			return GetRelativePath(new FileInfo(fileSpec), new DirectoryInfo(baseDirectory));
+		}
+
+		public static string GetRelativePath(FileInfo fileSpec, DirectoryInfo baseDirectory) {
+			if (fileSpec is null) throw new ArgumentNullException(nameof(fileSpec));
+			if (baseDirectory is null) throw new ArgumentNullException(nameof(fileSpec));
+
+			if (baseDirectory.FullName.EndsWith(Path.DirectorySeparatorChar.ToString())) {
+				baseDirectory = new DirectoryInfo(baseDirectory.FullName.TrimEnd(Path.DirectorySeparatorChar));
 			}
-			var folderUri = new Uri(folder);
-			return Uri.UnescapeDataString(folderUri.MakeRelativeUri(pathUri).ToString().Replace('/', Path.DirectorySeparatorChar));
+
+			var relativePath = fileSpec.Name;
+			var currentDirectory = fileSpec.Directory;
+			while (!(currentDirectory is null) && !string.Equals(currentDirectory.FullName, baseDirectory.FullName, StringComparison.OrdinalIgnoreCase)) {
+				relativePath = currentDirectory.Name + Path.DirectorySeparatorChar + relativePath;
+				currentDirectory = currentDirectory.Parent;
+			}
+
+			if (currentDirectory is null) return null; //file is not inside the base directory
+			return relativePath;
 		}
 
 		/// <summary>

ConfuserEx/ViewModel/UI/ProjectTabVM.cs

@@ -117,7 +117,7 @@ void AddModule(string file) {
 			}
 			var module = new ProjectModuleVM(App.Project, new ProjectModule());
 			try {
-				module.Path = Confuser.Core.Utils.GetRelativePath(file, App.Project.BaseDirectory);
+				module.Path = Confuser.Core.Utils.GetRelativePath(file, App.Project.BaseDirectory) ?? file;
 			}
 			catch {
 				module.Path = file;

Tests/Confuser.Core.Test/UtilsTest.cs

@@ -0,0 +1,27 @@
+using System.Collections.Generic;
+using Xunit;
+
+namespace Confuser.Core.Test {
+	public class UtilsTest {
+		[Theory]
+		[MemberData(nameof(BuildRelativePathTestData))]
+		[Trait("Issue", "https://github.com/mkaring/ConfuserEx/issues/413")]
+		public void BuildRelativePath(string baseDirectory, string fileReference, string expectedRelativePath) => 
+			Assert.Equal(expectedRelativePath, Utils.GetRelativePath(fileReference, baseDirectory), ignoreCase: true);
+
+		public static IEnumerable<object[]> BuildRelativePathTestData() {
+			yield return new object[] { "C:\\Test", "C:\\Test\\Asm.dll", "Asm.dll" };
+			yield return new object[] { "C:\\Test\\", "C:\\Test\\Asm.dll", "Asm.dll" };
+			yield return new object[] { "C:\\Test", "C:\\Test\\Test2\\Asm.dll", "Test2\\Asm.dll" };
+			yield return new object[] { "C:\\Test\\", "C:\\Test\\Test2\\Asm.dll", "Test2\\Asm.dll" };
+			yield return new object[] { "C:\\Test", "C:\\Test\\Test2\\Test3\\Asm.dll", "Test2\\Test3\\Asm.dll" };
+			yield return new object[] { "C:\\Test\\", "C:\\Test\\Test2\\Test3\\Asm.dll", "Test2\\Test3\\Asm.dll" };
+			yield return new object[] { "C:\\Test", "C:\\Test2\\Asm.dll", null };
+			yield return new object[] { "C:\\Test\\", "C:\\Test2\\Asm.dll", null };
+
+			// Only for case insensitive file systems (windows)
+			yield return new object[] { "C:\\Test", "c:\\test\\test2\\test3\\asm.dll", "Test2\\Test3\\Asm.dll" };
+			yield return new object[] { "C:\\Test", "C:\\TEST\\TEST2\\TEST3\\ASM.DLL", "Test2\\Test3\\Asm.dll" };
+		}
+	}
+}