From 140472600c9a68301c7c0154636bd68929f9960f Mon Sep 17 00:00:00 2001
From: Huo Yaoyuan <huoyaoyuan@hotmail.com>
Date: Tue, 28 Feb 2023 17:26:57 +0800
Subject: [PATCH] Use RegDeleteTree in RegistryKey.DeleteSubKeyTree

---
 .../Windows/Advapi32/Interop.RegDeleteTree.cs | 20 +++++++
 .../src/Microsoft.Win32.Registry.csproj       |  2 +
 .../src/Microsoft/Win32/RegistryKey.cs        | 57 ++-----------------
 3 files changed, 27 insertions(+), 52 deletions(-)
 create mode 100644 src/libraries/Common/src/Interop/Windows/Advapi32/Interop.RegDeleteTree.cs

diff --git a/src/libraries/Common/src/Interop/Windows/Advapi32/Interop.RegDeleteTree.cs b/src/libraries/Common/src/Interop/Windows/Advapi32/Interop.RegDeleteTree.cs
new file mode 100644
index 00000000000000..52289627bc243d
--- /dev/null
+++ b/src/libraries/Common/src/Interop/Windows/Advapi32/Interop.RegDeleteTree.cs
@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#if REGISTRY_ASSEMBLY
+using Microsoft.Win32.SafeHandles;
+#else
+using Internal.Win32.SafeHandles;
+#endif
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class Advapi32
+    {
+        [LibraryImport(Libraries.Advapi32, EntryPoint = "RegDeleteTreeW", StringMarshalling = StringMarshalling.Utf16)]
+        internal static partial int RegDeleteTree(
+            SafeRegistryHandle hKey,
+            string lpSubKey);
+    }
+}
diff --git a/src/libraries/Microsoft.Win32.Registry/src/Microsoft.Win32.Registry.csproj b/src/libraries/Microsoft.Win32.Registry/src/Microsoft.Win32.Registry.csproj
index 5920905308d2fc..438a4d0caf5926 100644
--- a/src/libraries/Microsoft.Win32.Registry/src/Microsoft.Win32.Registry.csproj
+++ b/src/libraries/Microsoft.Win32.Registry/src/Microsoft.Win32.Registry.csproj
@@ -27,6 +27,8 @@
              Link="Common\Interop\Windows\Interop.RegCreateKeyEx.cs" />
     <Compile Include="$(CommonPath)Interop\Windows\Advapi32\Interop.RegDeleteKeyEx.cs"
              Link="Common\Interop\Windows\Interop.RegDeleteKeyEx.cs" />
+    <Compile Include="$(CommonPath)Interop\Windows\Advapi32\Interop.RegDeleteTree.cs"
+             Link="Common\Interop\Windows\Interop.RegDeleteTree.cs" />
     <Compile Include="$(CommonPath)Interop\Windows\Advapi32\Interop.RegDeleteValue.cs"
              Link="Common\Interop\Windows\Interop.RegDeleteValue.cs" />
     <Compile Include="$(CommonPath)Interop\Windows\Advapi32\Interop.RegEnumKeyEx.cs"
diff --git a/src/libraries/Microsoft.Win32.Registry/src/Microsoft/Win32/RegistryKey.cs b/src/libraries/Microsoft.Win32.Registry/src/Microsoft/Win32/RegistryKey.cs
index 7203d322646cab..70d2788a56695d 100644
--- a/src/libraries/Microsoft.Win32.Registry/src/Microsoft/Win32/RegistryKey.cs
+++ b/src/libraries/Microsoft.Win32.Registry/src/Microsoft/Win32/RegistryKey.cs
@@ -334,63 +334,16 @@ public void DeleteSubKeyTree(string subkey, bool throwOnMissingSubKey)
 
             subkey = FixupName(subkey); // Fixup multiple slashes to a single slash
 
-            RegistryKey? key = InternalOpenSubKeyWithoutSecurityChecks(subkey, true);
-            if (key != null)
-            {
-                using (key)
-                {
-                    if (key.SubKeyCount > 0)
-                    {
-                        string[] keys = key.GetSubKeyNames();
-
-                        for (int i = 0; i < keys.Length; i++)
-                        {
-                            key.DeleteSubKeyTreeInternal(keys[i]);
-                        }
-                    }
-                }
+            int ret = Interop.Advapi32.RegDeleteTree(_hkey, subkey);
 
-                DeleteSubKeyTreeCore(subkey);
-            }
-            else if (throwOnMissingSubKey)
-            {
-                throw new ArgumentException(SR.Arg_RegSubKeyAbsent);
-            }
-        }
-
-        /// <summary>
-        /// An internal version which does no security checks or argument checking.  Skipping the
-        /// security checks should give us a slight perf gain on large trees.
-        /// </summary>
-        private void DeleteSubKeyTreeInternal(string subkey)
-        {
-            RegistryKey? key = InternalOpenSubKeyWithoutSecurityChecks(subkey, true);
-            if (key != null)
+            if (ret == Interop.Errors.ERROR_FILE_NOT_FOUND)
             {
-                using (key)
+                if (throwOnMissingSubKey)
                 {
-                    if (key.SubKeyCount > 0)
-                    {
-                        string[] keys = key.GetSubKeyNames();
-                        for (int i = 0; i < keys.Length; i++)
-                        {
-                            key.DeleteSubKeyTreeInternal(keys[i]);
-                        }
-                    }
+                    throw new ArgumentException(SR.Arg_RegSubKeyAbsent);
                 }
-
-                DeleteSubKeyTreeCore(subkey);
-            }
-            else
-            {
-                throw new ArgumentException(SR.Arg_RegSubKeyAbsent);
             }
-        }
-
-        private void DeleteSubKeyTreeCore(string subkey)
-        {
-            int ret = Interop.Advapi32.RegDeleteKeyEx(_hkey, subkey, (int)_regView, 0);
-            if (ret != 0)
+            else if (ret != 0)
             {
                 Win32Error(ret, null);
             }