Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/PredefinedPropertyFunctions.cs

@@ -27,6 +27,7 @@
 //
 
 using System;
+using System.IO;
 using Mono.XBuild.Utilities;
 
 namespace Microsoft.Build.BuildEngine
@@ -121,7 +122,20 @@ namespace Microsoft.Build.BuildEngine
 
 		public static string GetDirectoryNameOfFileAbove (string path, string file)
 		{
-			throw new NotImplementedException ("GetDirectoryNameOfFileAbove");
+			string filePath;
+			path = Path.GetFullPath (path);
+
+			while (true) {
+				filePath = Path.Combine (path, file);
+
+				if (File.Exists (filePath))
+					return path;
+
+				path = Path.GetDirectoryName (path);
+
+				if (path == null)  // we traversed up until root without a match, return empty string
+					return "";
+			}
 		}
 
 		public static object GetRegistryValue (string key, string value)
@@ -136,7 +150,18 @@ namespace Microsoft.Build.BuildEngine
 
 		public static string MakeRelative (string basePath, string path)
 		{
-			throw new NotImplementedException ("MakeRelative");
+			if (String.IsNullOrEmpty (basePath))
+				return path;
+
+			// ensure trailing slash for basePath
+			if (basePath [basePath.Length - 1] != '\\' && basePath [basePath.Length - 1] != '/')
+				basePath += '/';
+
+			var uriBasePath = new Uri (basePath, UriKind.Absolute);
+			var uriPath = new Uri (path);
+
+			var uriRelative = uriBasePath.MakeRelativeUri (uriPath);
+			return Uri.UnescapeDataString (uriRelative.ToString ()).Replace ('/', '\\'); // msbuild uses backslash paths everywhere
 		}
 
 		public static string ValueOrDefault (string value, string defaultValue)
@@ -144,4 +169,4 @@ namespace Microsoft.Build.BuildEngine
 			return string.IsNullOrEmpty (value) ? defaultValue : value;
 		}
 	}
-}
+}