From: Mark Harmstone <hellas@burntcomma.com>
Subject: [PATCH] user32: Support activation context class redirection in CreateWindow.
Message-Id: <5517311A.2080908@burntcomma.com>
Date: Sat, 28 Mar 2015 22:54:18 +0000

This patch implements the class redirection feature of activation contexts, as
used by version 6 of comctl32. Among other things, this is a necessary step in
fixing the behaviour seen in bug 38124.

---
 dlls/user32/win.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/dlls/user32/win.c b/dlls/user32/win.c
index 8ff3ebd..fe8c397 100644
--- a/dlls/user32/win.c
+++ b/dlls/user32/win.c
@@ -55,6 +55,17 @@ static CRITICAL_SECTION_DEBUG critsect_debug =
 };
 static CRITICAL_SECTION surfaces_section = { &critsect_debug, -1, 0, 0, 0, 0 };
 
+/* from dlls/ntdll/actctx.c */
+struct wndclass_redirect_data
+{
+    ULONG size;
+    DWORD res;
+    ULONG name_len;
+    ULONG name_offset;
+    ULONG module_len;
+    ULONG module_offset;
+};
+
 /**********************************************************************/
 
 /* helper for Get/SetWindowLong */
@@ -1292,6 +1303,39 @@ static void dump_window_styles( DWORD style, DWORD exstyle )
 #undef DUMPED_EX_STYLES
 }
 
+static BOOL get_redir_class_name(LPCWSTR className, LPWSTR redirClassName, int len)
+{
+    ATOM classatom;
+    ACTCTX_SECTION_KEYED_DATA askd;
+    WCHAR classNameStr[256];
+    struct wndclass_redirect_data* wcrd;
+
+    classatom = get_int_atom_value(className);
+    if (classatom)
+        GlobalGetAtomNameW(classatom, classNameStr, sizeof(classNameStr) / sizeof(*classNameStr));
+    else
+        strcpyW(classNameStr, className);
+
+    askd.cbSize = sizeof(askd);
+    if (FindActCtxSectionStringW(0, NULL, ACTIVATION_CONTEXT_SECTION_WINDOW_CLASS_REDIRECTION, classNameStr, &askd)) {
+        wcrd = askd.lpData;
+
+        if (wcrd->name_len == 0)
+            return FALSE;
+
+        if (wcrd->name_len > len) {
+            WARN("Redirected class name too long for buffer\n");
+            return FALSE;
+        }
+
+        memcpy(redirClassName, (unsigned char*)askd.lpData + wcrd->name_offset, wcrd->name_len);
+        redirClassName[wcrd->name_len / sizeof(WCHAR)] = 0;
+
+        return TRUE;
+    }
+
+    return FALSE;
+}
 
 /***********************************************************************
  *           WIN_CreateWindowEx
@@ -1308,6 +1352,7 @@ HWND WIN_CreateWindowEx( CREATESTRUCTW *cs, LPCWSTR className, HINSTANCE module,
     MDICREATESTRUCTW mdi_cs;
     CBT_CREATEWNDW cbtc;
     CREATESTRUCTW cbcs;
+    WCHAR redirClassName[256];
 
     TRACE("%s %s ex=%08x style=%08x %d,%d %dx%d parent=%p menu=%p inst=%p params=%p\n",
           unicode ? debugstr_w(cs->lpszName) : debugstr_a((LPCSTR)cs->lpszName),
@@ -1444,6 +1489,23 @@ HWND WIN_CreateWindowEx( CREATESTRUCTW *cs, LPCWSTR className, HINSTANCE module,
 
     /* Create the window structure */
 
+    wndPtr = NULL;
+
+    if (get_redir_class_name(className, redirClassName, sizeof(redirClassName)))
+    {
+        WNDCLASSW wc;
+
+        TRACE("Redirecting %s to %s\n", debugstr_w(className), debugstr_w(redirClassName));
+
+        wndPtr = create_window_handle( parent, owner, redirClassName, module, unicode );
+
+        if (GetLastError() == ERROR_INVALID_HANDLE && GetClassInfoW( 0, redirClassName, &wc ))
+            wndPtr = create_window_handle( parent, owner, redirClassName, module, unicode );
+
+        if (!wndPtr)
+            WARN("Could not create window of class %s\n", debugstr_w(redirClassName));
+    }
+
     if (!(wndPtr = create_window_handle( parent, owner, className, module, unicode )))
     {
         WNDCLASSW wc;