feat.PLONDS在线安装器继续优化

LanDesktopPLONDS.installer/Services/InstallerElevation.cs

@@ -0,0 +1,52 @@
+using System.Security.Principal;
+
+namespace LanDesktopPLONDS.Installer.Services;
+
+internal static class InstallerElevation
+{
+    public static bool IsRunningElevated()
+    {
+        if (!OperatingSystem.IsWindows())
+        {
+            return true;
+        }
+
+        using var identity = WindowsIdentity.GetCurrent();
+        var principal = new WindowsPrincipal(identity);
+        return principal.IsInRole(WindowsBuiltInRole.Administrator);
+    }
+
+    public static bool RequiresElevation(string installPath)
+    {
+        if (!OperatingSystem.IsWindows())
+        {
+            return false;
+        }
+
+        var fullPath = Path.GetFullPath(installPath);
+        return IsUnderSpecialFolder(fullPath, Environment.SpecialFolder.ProgramFiles)
+               || IsUnderSpecialFolder(fullPath, Environment.SpecialFolder.ProgramFilesX86)
+               || IsUnderWindowsDirectory(fullPath);
+    }
+
+    public static void EnsureCanInstall(string installPath)
+    {
+        if (RequiresElevation(installPath) && !IsRunningElevated())
+        {
+            throw new UnauthorizedAccessException(
+                "The selected installation path requires administrator permission. Restart the installer as administrator or choose a user-writable folder.");
+        }
+    }
+
+    private static bool IsUnderSpecialFolder(string fullPath, Environment.SpecialFolder folder)
+    {
+        var root = Environment.GetFolderPath(folder);
+        return !string.IsNullOrWhiteSpace(root) && InstallerPathGuard.IsSameOrChildPath(root, fullPath);
+    }
+
+    private static bool IsUnderWindowsDirectory(string fullPath)
+    {
+        var windows = Environment.GetFolderPath(Environment.SpecialFolder.Windows);
+        return !string.IsNullOrWhiteSpace(windows) && InstallerPathGuard.IsSameOrChildPath(windows, fullPath);
+    }
+}