user32: Enable IsDialogMessageA() ASCII to Unicode mapping only when the user…

user32: Enable IsDialogMessageA() ASCII to Unicode mapping only when the user default lang ID is CJK. Using GetSystemMetrics(SM_DBCSENABLED) may incorrectly enable ASCII to Unicode mapping in mixed locale environments. For example, when UserDefaultLCID is French(040c) but SystemDefaultLCID is Japanese(0411). Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55655

user32: Enable IsDialogMessageA() ASCII to Unicode mapping only when the user…
8d5d4136 · Zhiyi Zhang · Alexandre Julliard · b000b659 · 8d5d4136
Commit 8d5d4136 authored Sep 27, 2023 by Zhiyi Zhang Committed by Alexandre Julliard Sep 27, 2023
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message.c dlls/user32/message.c +9 -1

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--- a/dlls/user32/message.c
+++ b/dlls/user32/message.c
@@ -807,6 +807,14 @@ BOOL WINAPI DECLSPEC_HOTPATCH GetMessageA( MSG *msg, HWND hwnd, UINT first, UINT
    return (msg->message != WM_QUIT);
 }
+static BOOL is_cjk(void)
+{
+    int lang_id = PRIMARYLANGID(GetUserDefaultLangID());
+    if (lang_id == LANG_CHINESE || lang_id == LANG_JAPANESE || lang_id == LANG_KOREAN)
+        return TRUE;
+    return FALSE;
+}
 /***********************************************************************
 *		IsDialogMessageA (USER32.@)
@@ -817,7 +825,7 @@ BOOL WINAPI IsDialogMessageA( HWND hwndDlg, LPMSG pmsg )
    enum wm_char_mapping mapping;
    MSG msg = *pmsg;
-    mapping = GetSystemMetrics( SM_DBCSENABLED ) ? WMCHAR_MAP_ISDIALOGMESSAGE : WMCHAR_MAP_NOMAPPING;
+    mapping = is_cjk() ? WMCHAR_MAP_ISDIALOGMESSAGE : WMCHAR_MAP_NOMAPPING;
    if (!map_wparam_AtoW( msg.message, &msg.wParam, mapping ))
        return TRUE;
    return IsDialogMessageW( hwndDlg, &msg );