Update environment variables changed (#12689)

src/modules/launcher/PowerLauncher/Helper/EnvironmentHelper.cs

@@ -0,0 +1,98 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Security.Principal;
+using Microsoft.Win32.SafeHandles;
+using Wox.Plugin.Logger;
+
+namespace PowerLauncher.Helper
+{
+    public static class EnvironmentHelper
+    {
+        private const string EnvironmentChangeType = "Environment";
+        private const string Username = "USERNAME";
+        private const string ProcessorArchitecture = "PROCESSOR_ARCHITECTURE";
+        private const string Path = "PATH";
+
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "CA1801:Review unused parameters", Justification = "Params are required for delegate signature requirements.")]
+        public static IntPtr ProcessWindowMessages(IntPtr hwnd, int msg, IntPtr wparam, IntPtr lparam, ref bool handled)
+        {
+            switch ((WM)msg)
+            {
+                case WM.SETTINGCHANGE:
+                    string changeType = Marshal.PtrToStringUni(lparam);
+                    if (changeType == EnvironmentChangeType)
+                    {
+                        Log.Info("Reload environment", typeof(EnvironmentHelper));
+                        UpdateEnvironment();
+                        handled = true;
+                    }
+
+                    break;
+            }
+
+            return IntPtr.Zero;
+        }
+
+        private static void UpdateEnvironment()
+        {
+            // Username and process architecture are set by the machine vars, this
+            // may lead to incorrect values so save off the current values to restore.
+            string originalUsername = Environment.GetEnvironmentVariable(Username, EnvironmentVariableTarget.Process);
+            string originalArch = Environment.GetEnvironmentVariable(ProcessorArchitecture, EnvironmentVariableTarget.Process);
+
+            var environment = new Dictionary<string, string>();
+            MergeTargetEnvironmentVariables(environment, EnvironmentVariableTarget.Process);
+            MergeTargetEnvironmentVariables(environment, EnvironmentVariableTarget.Machine);
+
+            if (!IsRunningAsSystem())
+            {
+                MergeTargetEnvironmentVariables(environment, EnvironmentVariableTarget.User);
+
+                // Special handling for PATH - merge Machine & User instead of override
+                var pathTargets = new[] { EnvironmentVariableTarget.Machine, EnvironmentVariableTarget.User };
+                var paths = pathTargets
+                    .Select(t => Environment.GetEnvironmentVariable(Path, t))
+                    .Where(e => e != null)
+                    .SelectMany(e => e.Split(';', StringSplitOptions.RemoveEmptyEntries))
+                    .Distinct();
+
+                environment[Path] = string.Join(';', paths);
+            }
+
+            environment[Username] = originalUsername;
+            environment[ProcessorArchitecture] = originalArch;
+
+            foreach (KeyValuePair<string, string> kv in environment)
+            {
+                Environment.SetEnvironmentVariable(kv.Key, kv.Value, EnvironmentVariableTarget.Process);
+            }
+        }
+
+        private static void MergeTargetEnvironmentVariables(
+            Dictionary<string, string> environment, EnvironmentVariableTarget target)
+        {
+            IDictionary variables = Environment.GetEnvironmentVariables(target);
+            foreach (DictionaryEntry entry in variables)
+            {
+                environment[(string)entry.Key] = (string)entry.Value;
+            }
+        }
+
+        private static bool IsRunningAsSystem()
+        {
+            using (var identity = WindowsIdentity.GetCurrent())
+            {
+                return identity.IsSystem;
+            }
+        }
+    }
+}