From: Jacek Caban <jacek@codeweavers.com>
Subject: urlmon: Unregister window class on DLL unload.
Message-Id: <52FCC6E8.6090006@codeweavers.com>
Date: Thu, 13 Feb 2014 14:21:44 +0100

---
 dlls/urlmon/bindprot.c    | 64
+++++++++++++++++++++++++++++++----------------
 dlls/urlmon/urlmon_main.c |  1 +
 dlls/urlmon/urlmon_main.h |  1 +
 3 files changed, 45 insertions(+), 21 deletions(-)

diff --git a/dlls/urlmon/bindprot.c b/dlls/urlmon/bindprot.c
index b11856b..dc0d7cd 100644
--- a/dlls/urlmon/bindprot.c
+++ b/dlls/urlmon/bindprot.c
@@ -83,15 +83,50 @@ static LRESULT WINAPI notif_wnd_proc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM
     return DefWindowProcW(hwnd, msg, wParam, lParam);
 }
 
+static const WCHAR wszURLMonikerNotificationWindow[] =
+    {'U','R','L',' ','M','o','n','i','k','e','r',' ',
+     'N','o','t','i','f','i','c','a','t','i','o','n',' ','W','i','n','d','o','w',0};
+
+static ATOM notif_wnd_class;
+
+static CRITICAL_SECTION notif_wnd_class_cs;
+static CRITICAL_SECTION_DEBUG notif_wnd_class_cs_dbg = {
+    0, 0, &notif_wnd_class_cs,
+    { &notif_wnd_class_cs_dbg.ProcessLocksList, &notif_wnd_class_cs_dbg.ProcessLocksList },
+    0, 0, { (DWORD_PTR)(__FILE__ ": notif_wnd_class") }
+};
+static CRITICAL_SECTION notif_wnd_class_cs = { &notif_wnd_class_cs_dbg, -1, 0, 0, 0, 0 };
+
+static BOOL ensure_notif_wnd_class(void)
+{
+    EnterCriticalSection(&notif_wnd_class_cs);
+
+    if(!notif_wnd_class) {
+        static WNDCLASSEXW wndclass = {
+            sizeof(wndclass), 0, notif_wnd_proc, 0, 0,
+            NULL, NULL, NULL, NULL, NULL,
+            wszURLMonikerNotificationWindow, NULL
+        };
+
+        wndclass.hInstance = hProxyDll;
+        notif_wnd_class = RegisterClassExW(&wndclass);
+    }
+
+    LeaveCriticalSection(&notif_wnd_class_cs);
+
+    return notif_wnd_class != 0;
+}
+
+void unregister_notif_wnd_class(void)
+{
+    if(notif_wnd_class)
+        UnregisterClassW(MAKEINTRESOURCEW(notif_wnd_class), hProxyDll);
+}
+
 HWND get_notif_hwnd(void)
 {
-    static ATOM wnd_class = 0;
     tls_data_t *tls_data;
 
-    static const WCHAR wszURLMonikerNotificationWindow[] =
-        {'U','R','L',' ','M','o','n','i','k','e','r',' ',
-         'N','o','t','i','f','i','c','a','t','i','o','n',' ','W','i','n','d','o','w',0};
-
     tls_data = get_tls_data();
     if(!tls_data)
         return NULL;
@@ -101,23 +136,10 @@ HWND get_notif_hwnd(void)
         return tls_data->notif_hwnd;
     }
 
-    if(!wnd_class) {
-        static WNDCLASSEXW wndclass = {
-            sizeof(wndclass), 0,
-            notif_wnd_proc, 0, 0,
-            NULL, NULL, NULL, NULL, NULL,
-            wszURLMonikerNotificationWindow,
-            NULL
-        };
-
-        wndclass.hInstance = hProxyDll;
-
-        wnd_class = RegisterClassExW(&wndclass);
-        if (!wnd_class && GetLastError() == ERROR_CLASS_ALREADY_EXISTS)
-            wnd_class = 1;
-    }
+    if(!ensure_notif_wnd_class())
+        return NULL;
 
-    tls_data->notif_hwnd = CreateWindowExW(0, wszURLMonikerNotificationWindow,
+    tls_data->notif_hwnd = CreateWindowExW(0, MAKEINTRESOURCEW(notif_wnd_class),
             wszURLMonikerNotificationWindow, 0, 0, 0, 0, 0, HWND_MESSAGE,
             NULL, hProxyDll, NULL);
     if(tls_data->notif_hwnd)
diff --git a/dlls/urlmon/urlmon_main.c b/dlls/urlmon/urlmon_main.c
index 7b3f1fd..1204a62 100644
--- a/dlls/urlmon/urlmon_main.c
+++ b/dlls/urlmon/urlmon_main.c
@@ -139,6 +139,7 @@ static void process_detach(void)
 
     free_session();
     free_tls_list();
+    unregister_notif_wnd_class();
 }
 
 /***********************************************************************
diff --git a/dlls/urlmon/urlmon_main.h b/dlls/urlmon/urlmon_main.h
index faab45a..14a4f08 100644
--- a/dlls/urlmon/urlmon_main.h
+++ b/dlls/urlmon/urlmon_main.h
@@ -225,6 +225,7 @@ typedef struct {
 
 tls_data_t *get_tls_data(void) DECLSPEC_HIDDEN;
 
+void unregister_notif_wnd_class(void) DECLSPEC_HIDDEN;
 HWND get_notif_hwnd(void) DECLSPEC_HIDDEN;
 void release_notif_hwnd(HWND) DECLSPEC_HIDDEN;