Restart UWP as user when started from Task Manager (#6530)

Author: gave92

Files.Launcher/Program.cs

@@ -256,7 +256,21 @@ private static bool HandleCommandLineArgs()
             {
                 localSettings.Values.Remove("Arguments");
 
-                if (arguments == "TerminateUwp")
+                if (arguments == "StartUwp")
+                {
+                    var folder = localSettings.Values.Get("Folder", "");
+                    localSettings.Values.Remove("Folder");
+
+                    using Process process = new Process();
+                    process.StartInfo.UseShellExecute = true;
+                    process.StartInfo.FileName = "files.exe";
+                    process.StartInfo.Arguments = folder;
+                    process.Start();
+
+                    TerminateProcess((int)localSettings.Values["pid"]);
+                    return true;
+                }
+                else if (arguments == "TerminateUwp")
                 {
                     TerminateProcess((int)localSettings.Values["pid"]);
                     return true;

Files/App.xaml.cs

@@ -342,6 +342,11 @@ protected override async void OnActivated(IActivatedEventArgs args)
                     {
                         var parsedArgs = eventArgs.Uri.Query.TrimStart('?').Split('=');
                         var unescapedValue = Uri.UnescapeDataString(parsedArgs[1]);
+                        var folder = (StorageFolder)await FilesystemTasks.Wrap(() => StorageFolder.GetFolderFromPathAsync(unescapedValue).AsTask());
+                        if (folder != null && !string.IsNullOrEmpty(folder.Path))
+                        {
+                            unescapedValue = folder.Path; // Convert short name to long name (#6190)
+                        }
                         switch (parsedArgs[0])
                         {
                             case "tab":

Files/Program.cs

@@ -3,6 +3,7 @@
 using Files.Helpers;
 using System;
 using System.Linq;
+using System.Security.Principal;
 using System.Threading.Tasks;
 using Windows.ApplicationModel;
 using Windows.ApplicationModel.Activation;
@@ -15,10 +16,24 @@ internal class Program
     {
         const string PrelaunchInstanceKey = "PrelaunchInstance";
 
+        private static bool IsAdministrator()
+        {
+            using var identity = WindowsIdentity.GetCurrent();
+            var principal = new WindowsPrincipal(identity);
+            return principal.IsInRole(WindowsBuiltInRole.Administrator);
+        }
+
         private static async Task Main()
         {
             var proc = System.Diagnostics.Process.GetCurrentProcess();
 
+            if (IsAdministrator())
+            {
+                // UWP can't start as admin, restart as normal user from FTP
+                await SpawnUnelevatedUwpAppInstance(proc.Id);
+                return;
+            }
+
             if (!ApplicationData.Current.LocalSettings.Values.Get("AlwaysOpenANewInstance", false))
             {
                 IActivatedEventArgs activatedArgs = AppInstance.GetActivatedEventArgs();
@@ -128,6 +143,26 @@ public static async Task OpenShellCommandInExplorerAsync(string shellCommand, in
             await FullTrustProcessLauncher.LaunchFullTrustProcessForCurrentAppAsync();
         }
 
+        public static async Task SpawnUnelevatedUwpAppInstance(int pid)
+        {
+            IActivatedEventArgs activatedArgs = AppInstance.GetActivatedEventArgs();
+            if (activatedArgs is CommandLineActivatedEventArgs cmdLineArgs)
+            {
+                var parsedCommands = CommandLineParser.ParseUntrustedCommands(cmdLineArgs.Operation.Arguments);
+                switch (parsedCommands.FirstOrDefault()?.Type)
+                {
+                    case ParsedCommandType.ExplorerShellCommand:
+                    case ParsedCommandType.OpenDirectory:
+                    case ParsedCommandType.OpenPath:
+                        ApplicationData.Current.LocalSettings.Values["Folder"] = parsedCommands[0].Payload;
+                        break;
+                }
+            }
+            ApplicationData.Current.LocalSettings.Values["Arguments"] = "StartUwp";
+            ApplicationData.Current.LocalSettings.Values["pid"] = pid;
+            await FullTrustProcessLauncher.LaunchFullTrustProcessForCurrentAppAsync();
+        }
+
         public static async Task TerminateUwpAppInstance(int pid)
         {
             ApplicationData.Current.LocalSettings.Values["Arguments"] = "TerminateUwp";