From 85075cd419df9488e13f5ebc8aaaf1d65c72ed66 Mon Sep 17 00:00:00 2001
From: Simon Rozman <simon@rozman.si>
Date: Mon, 29 Jun 2020 15:15:36 +0200
Subject: [PATCH] Introduce reg_key::delete_subkey() method

Signed-off-by: Simon Rozman <simon@rozman.si>
---
 include/WinStd/Win.h | 11 +++++++++++
 src/Win.cpp          | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/include/WinStd/Win.h b/include/WinStd/Win.h
index 90b8c19e..397a0ed9 100644
--- a/include/WinStd/Win.h
+++ b/include/WinStd/Win.h
@@ -1069,6 +1069,17 @@ namespace winstd
             }
         }
 
+        ///
+        /// Deletes the specified registry subkey.
+        ///
+        /// \param[in] szSubkey  Name of the subkey to delete
+        ///
+        /// \return
+        /// - true when creation succeeds;
+        /// - false when creation fails. For extended error information, call `GetLastError()`.
+        ///
+        bool delete_subkey(_In_z_ LPCTSTR szSubkey);
+
     protected:
         ///
         /// Closes a handle to the registry key.
diff --git a/src/Win.cpp b/src/Win.cpp
index cfe42e24..69d85b07 100644
--- a/src/Win.cpp
+++ b/src/Win.cpp
@@ -346,6 +346,43 @@ winstd::reg_key::~reg_key()
 }
 
 
+bool winstd::reg_key::delete_subkey(_In_z_ LPCTSTR szSubkey)
+{
+    LSTATUS s;
+
+    s = RegDeleteKey(m_h, szSubkey);
+    if (s == ERROR_SUCCESS || s == ERROR_FILE_NOT_FOUND)
+        return true;
+
+    {
+        reg_key k;
+        if (!k.open(m_h, szSubkey, 0, KEY_ENUMERATE_SUB_KEYS))
+            return false;
+        for (;;) {
+            TCHAR szName[MAX_PATH];
+            DWORD dwSize = _countof(szName);
+            s = RegEnumKeyEx(k, 0, szName, &dwSize, NULL, NULL, NULL, NULL);
+            if (s == ERROR_SUCCESS)
+                k.delete_subkey(szName);
+            else if (s == ERROR_NO_MORE_ITEMS)
+                break;
+            else {
+                SetLastError(s);
+                return false;
+            }
+        }
+    }
+
+    s = RegDeleteKey(m_h, szSubkey);
+    if (s == ERROR_SUCCESS)
+        return true;
+    else {
+        SetLastError(s);
+        return false;
+    }
+}
+
+
 void winstd::reg_key::free_internal() noexcept
 {
     RegCloseKey(m_h);