imm32: Do not let ImmDestroyContext destroy any default contexts.

dlls/imm32/imm.c

@@ -77,6 +77,7 @@ typedef struct tagInputContextData
 
         ImmHkl          *immKbd;
         UINT            lastVK;
+        BOOL            threadDefault;
         DWORD           magic;
 } InputContextData;
 
@@ -119,6 +120,7 @@ static CRITICAL_SECTION threaddata_cs = { &critsect_debug, -1, 0, 0, 0, 0 };
 #define is_kbd_ime_unicode(p)  (p->imeInfo.fdwProperty & IME_PROP_UNICODE)
 
 static BOOL IMM_DestroyContext(HIMC hIMC);
+static InputContextData* get_imc_data(HIMC hIMC);
 
 static inline WCHAR *strdupAtoW( const char *str )
 {
@@ -244,6 +246,16 @@ static IMMThreadData* IMM_GetThreadData(DWORD id)
     return data;
 }
 
+static BOOL IMM_IsDefaultContext(HIMC imc)
+{
+    InputContextData *data = get_imc_data(imc);
+
+    if (!data)
+        return FALSE;
+
+    return data->threadDefault;
+}
+
 static void IMM_FreeThreadData(void)
 {
     IMMThreadData *data;
@@ -478,6 +490,8 @@ static IMMThreadData* IMM_GetInitializedThreadData(void)
         HIMC defaultContext;
         LeaveCriticalSection(&threaddata_cs);
         defaultContext = ImmCreateContext();
+        if (defaultContext)
+            ((InputContextData*)defaultContext)->threadDefault = TRUE;
         thread_data = IMM_GetThreadData(0);
         if (!thread_data)
         {
@@ -780,11 +794,7 @@ static BOOL IMM_DestroyContext(HIMC hIMC)
  */
 BOOL WINAPI ImmDestroyContext(HIMC hIMC)
 {
-    IMMThreadData* thread_data = IMM_GetThreadData(0);
-    HIMC defaultContext = thread_data->defaultContext;
-    LeaveCriticalSection(&threaddata_cs);
-
-    if (hIMC != defaultContext)
+    if (!IMM_IsDefaultContext(hIMC))
         return IMM_DestroyContext(hIMC);
     else
         return FALSE;