From: Piotr Caban <piotr@codeweavers.com>
Subject: [PATCH 1/2] imm32: Register IME window class on first use
Message-Id: <53D9051B.1030101@codeweavers.com>
Date: Wed, 30 Jul 2014 09:45:47 -0500

---
  dlls/imm32/Makefile.in |  3 ++-
  dlls/imm32/imm.c       | 16 ++++++++++++----
  2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/dlls/imm32/Makefile.in b/dlls/imm32/Makefile.in
index b190888..4ada4cb 100644
--- a/dlls/imm32/Makefile.in
+++ b/dlls/imm32/Makefile.in
@@ -1,6 +1,7 @@
 MODULE    = imm32.dll
 IMPORTLIB = imm32
-IMPORTS   = user32 gdi32 advapi32
+IMPORTS   = gdi32 advapi32
+DELAYIMPORTS = user32
 
 C_SRCS = \
 	imm.c
diff --git a/dlls/imm32/imm.c b/dlls/imm32/imm.c
index 2fa31ac..3a80f8e 100644
--- a/dlls/imm32/imm.c
+++ b/dlls/imm32/imm.c
@@ -109,6 +109,7 @@ static const WCHAR szLayoutTextW[] = {'L','a','y','o','u','t',' ','T','e','x','t
 static const WCHAR szImeRegFmt[] = {'S','y','s','t','e','m','\\','C','u','r','r','e','n','t','C','o','n','t','r','o','l','S','e','t','\\','C','o','n','t','r','o','l','\\','K','e','y','b','o','a','r','d',' ','L','a','y','o','u','t','s','\\','%','0','8','l','x',0};
 
 static const WCHAR szwIME[] = {'I','M','E',0};
+static ATOM ime_class;
 
 static LRESULT WINAPI DefIME_WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam,
                                         LPARAM lParam);
@@ -376,7 +377,7 @@ static void IMM_RegisterMessages(void)
     WM_MSIME_DOCUMENTFEED = RegisterWindowMessageA("MSIMEDocumentFeed");
 }
 
-static void IMM_RegisterIMEClass(void)
+static BOOL WINAPI IMM_RegisterIMEClass(INIT_ONCE *once, void *param, void **context)
 {
     WNDCLASSW wndClass;
 
@@ -388,7 +389,8 @@ static void IMM_RegisterIMEClass(void)
     wndClass.hCursor = LoadCursorW(NULL, (LPWSTR)IDC_ARROW);
     wndClass.lpszClassName = szwIME;
 
-    RegisterClassW(&wndClass);
+    ime_class = RegisterClassW(&wndClass);
+    return TRUE;
 }
 
 BOOL WINAPI DllMain(HINSTANCE hInstDLL, DWORD fdwReason, LPVOID lpReserved)
@@ -401,7 +403,6 @@ BOOL WINAPI DllMain(HINSTANCE hInstDLL, DWORD fdwReason, LPVOID lpReserved)
             tlsIndex = TlsAlloc();
             if (tlsIndex == TLS_OUT_OF_INDEXES)
                 return FALSE;
-            IMM_RegisterIMEClass();
             break;
         case DLL_THREAD_ATTACH:
             break;
@@ -413,7 +414,8 @@ BOOL WINAPI DllMain(HINSTANCE hInstDLL, DWORD fdwReason, LPVOID lpReserved)
             IMM_FreeThreadData();
             IMM_FreeAllImmHkl();
             TlsFree(tlsIndex);
-            UnregisterClassW(szwIME, NULL);
+            if(ime_class)
+                UnregisterClassW(MAKEINTRESOURCEW(ime_class), NULL);
             break;
     }
     return TRUE;
@@ -1539,6 +1541,12 @@ BOOL WINAPI ImmGetConversionStatus(
  */
 HWND WINAPI ImmGetDefaultIMEWnd(HWND hWnd)
 {
+    static INIT_ONCE class_init_once = INIT_ONCE_STATIC_INIT;
+
+    InitOnceExecuteOnce(&class_init_once, IMM_RegisterIMEClass, NULL, NULL);
+    if(!ime_class)
+        return NULL;
+
     if (IMM_GetThreadData()->hwndDefault == NULL)
         IMM_GetThreadData()->hwndDefault = CreateWindowExW( WS_EX_TOOLWINDOW,
                     szwIME, NULL, WS_POPUP, 0, 0, 1, 1, 0, 0, 0, 0);