Hugh McMaster : reg: Don't enumerate a registry key for subkeys if we know the key does not have subkeys.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 33cfc644a055a9bc88253ae8d8c824ad603e7a02
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=33cfc644a055a9bc88253ae8d8c824ad603e7a02

Author: Hugh McMaster <hugh.mcmaster at outlook.com>
Date:   Wed Apr 28 19:19:32 2021 +1000

reg: Don't enumerate a registry key for subkeys if we know the key does not have subkeys.

Signed-off-by: Hugh McMaster <hugh.mcmaster at outlook.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 programs/reg/query.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/programs/reg/query.c b/programs/reg/query.c
index 66e54548688..7e42719faf9 100644
--- a/programs/reg/query.c
+++ b/programs/reg/query.c
@@ -213,7 +213,7 @@ static int query_value(HKEY hkey, WCHAR *value_name, WCHAR *path, BOOL recurse)
 static int query_all(HKEY hkey, WCHAR *path, BOOL recurse, BOOL recursing)
 {
     LONG rc;
-    DWORD num_values;
+    DWORD num_subkeys, num_values;
     DWORD max_value_len = 256, value_len;
     DWORD max_data_bytes = 2048, data_size;
     DWORD subkey_len;
@@ -222,8 +222,8 @@ static int query_all(HKEY hkey, WCHAR *path, BOOL recurse, BOOL recursing)
     BYTE *data;
     HKEY subkey;
 
-    rc = RegQueryInfoKeyW(hkey, NULL, NULL, NULL, NULL, NULL, NULL,
-                          &num_values, NULL, NULL, NULL, NULL);
+    rc = RegQueryInfoKeyW(hkey, NULL, NULL, NULL, &num_subkeys, NULL,
+                          NULL, &num_values, NULL, NULL, NULL, NULL);
     if (rc) return 1;
 
     if (num_values || recursing)
@@ -265,6 +265,9 @@ static int query_all(HKEY hkey, WCHAR *path, BOOL recurse, BOOL recursing)
     if (i || recursing)
         output_string(newlineW);
 
+    if (!num_subkeys)
+        return 0;
+
     subkey_name = malloc(MAX_SUBKEY_LEN * sizeof(WCHAR));
 
     path_len = lstrlenW(path);