Use ordinal to ensure no mistakes on linux

Don't call through the get full directory path
Reduce three variables down to two to help the scanners
Move the desination path out of the loop since it doesn't change

Author: marcpopMSFT

src/Tasks/sdk-tasks/ExtractArchiveToDirectory.cs

@@ -84,15 +84,15 @@ public override bool Execute()
                         if (isZipArchive)
                         {
                             using var zip = new ZipArchive(File.OpenRead(SourceArchive));
+                            string fullDestDirPath = GetFullDirectoryPathWithSeperator(DestinationDirectory);
+
                             foreach (var entry in zip.Entries)
                             {
                                 if (ShouldExtractItem(entry.FullName))
                                 {
-                                    string destinationPath = Path.Combine(DestinationDirectory, entry.FullName);
-                                    string destinationFileName = GetFullDirectoryPathWithSeperator(destinationPath);
-                                    string fullDestDirPath = GetFullDirectoryPathWithSeperator(DestinationDirectory);
+                                    string destinationPath = Path.GetFullPath(Path.Combine(DestinationDirectory, entry.FullName));
 
-                                    CheckDestinationPath(destinationFileName, fullDestDirPath);
+                                    CheckDestinationPath(destinationPath, fullDestDirPath);
 
                                     if (!Directory.Exists(Path.Combine(DestinationDirectory, Path.GetDirectoryName(entry.FullName))))
                                     {
@@ -116,6 +116,7 @@ public override bool Execute()
                             using var decompressedStream = new MemoryStream();
                             decompressor.CopyTo(decompressedStream);
                             decompressedStream.Seek(0, SeekOrigin.Begin);
+                            string fullDestDirPath = GetFullDirectoryPathWithSeperator(DestinationDirectory);
 
                             // Extract Tar content
                             using TarReader tr = new TarReader(decompressedStream);
@@ -127,11 +128,9 @@ public override bool Execute()
                                     entryName = entryName.StartsWith("./") ? entryName[2..] : entryName;
                                     if (ShouldExtractItem(entryName))
                                     {
-                                        string destinationPath = Path.Combine(DestinationDirectory, entryName);
-                                        string destinationFileName = GetFullDirectoryPathWithSeperator(destinationPath);
-                                        string fullDestDirPath = GetFullDirectoryPathWithSeperator(DestinationDirectory);
+                                        string destinationPath = Path.GetFullPath(Path.Combine(DestinationDirectory, entryName));
 
-                                        CheckDestinationPath(destinationFileName, fullDestDirPath);
+                                        CheckDestinationPath(destinationPath, fullDestDirPath);
 
                                         Log.LogMessage(entryName);
 
@@ -186,7 +185,7 @@ private string GetFullDirectoryPathWithSeperator(string directory)
         {
             string fullDirectoryPath = Path.GetFullPath(directory);
 
-            if (!fullDirectoryPath.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.OrdinalIgnoreCase))
+            if (!fullDirectoryPath.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal))
             {
                 fullDirectoryPath = string.Concat(fullDirectoryPath, Path.DirectorySeparatorChar);
             }
@@ -196,7 +195,7 @@ private string GetFullDirectoryPathWithSeperator(string directory)
 
         private void CheckDestinationPath(string destinationFileName, string fullDestDirPath)
         {
-            if (!destinationFileName.StartsWith(fullDestDirPath, StringComparison.OrdinalIgnoreCase))
+            if (!destinationFileName.StartsWith(fullDestDirPath, StringComparison.Ordinal))
             {
                 throw new System.InvalidOperationException("Entry is outside the target dir: " + destinationFileName);
             }