[PATCH 1/2] comctl32/listbox: Don't update scrollbar during window creation

[Nikolay Sivov]

On 09/13/2018 06:42 PM, Fabian Maurer wrote:
> This is needed for the linked bug,
> although it doesn't fix it yet.
>
> Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=43465
> Signed-off-by: Fabian Maurer <dark.shadow4 at web.de>
> ---
>   dlls/comctl32/listbox.c       |  7 +++++++
>   dlls/comctl32/tests/listbox.c | 35 +++++++++++++++++++++++++++++++++++
>   2 files changed, 42 insertions(+)
>
> diff --git a/dlls/comctl32/listbox.c b/dlls/comctl32/listbox.c
> index 2137ef86e0..a9d1db458b 100644
> --- a/dlls/comctl32/listbox.c
> +++ b/dlls/comctl32/listbox.c
> @@ -91,6 +91,7 @@ typedef struct
>       HFONT       font;           /* Current font */
>       LCID        locale;         /* Current locale for string comparisons */
>       HEADCOMBO  *lphc;           /* ComboLBox */
> +    BOOL        got_wm_size;     /* Did we get already a WM_SIZE? */
>   } LB_DESCR;
>   

Please find a better way.

>   
> @@ -200,6 +201,10 @@ static void LISTBOX_UpdateScroll( LB_DESCR *descr )
>          the programmer use it for his/her own purposes. */
>   
>       if (descr->style & LBS_NOREDRAW) return;
> +
> +    /* When height is 0 don't update scrollbar during CreateWindowEx, that is until we receive our first WM_SIZE */
> +    if (!descr->got_wm_size && descr->height == 0) return;
> +
>       info.cbSize = sizeof(info);
>   
>       if (descr->style & LBS_MULTICOLUMN)
> @@ -2502,6 +2507,7 @@ static BOOL LISTBOX_Create( HWND hwnd, LPHEADCOMBO lphc )
>       descr->font          = 0;
>       descr->locale        = GetUserDefaultLCID();
>       descr->lphc		 = lphc;
> +    descr->got_wm_size   = FALSE;
>   
>       if( lphc )
>       {
> @@ -2887,6 +2893,7 @@ static LRESULT CALLBACK LISTBOX_WindowProc( HWND hwnd, UINT msg, WPARAM wParam,
>   
>       case WM_SIZE:
>           LISTBOX_UpdateSize( descr );
> +        descr->got_wm_size = TRUE;
>           return 0;
>       case WM_GETFONT:
>           return (LRESULT)descr->font;
> diff --git a/dlls/comctl32/tests/listbox.c b/dlls/comctl32/tests/listbox.c
> index c9d13a8d67..e3a3b42c2f 100644
> --- a/dlls/comctl32/tests/listbox.c
> +++ b/dlls/comctl32/tests/listbox.c
> @@ -2176,6 +2176,40 @@ static void test_WM_MEASUREITEM(void)
>       DestroyWindow(parent);
>   }
>   
> +static void test_WS_VSCROLL(void)
> +{
> +    HWND parent, listbox;
> +    UINT style;
> +
> +    parent = create_parent();
> +
> +    /* Listbox must always have WS_VSCROLL after creating when height 0 was specified */
> +    listbox = CreateWindowA("LISTBOX", "TestList", (LBS_STANDARD & ~LBS_SORT) | WS_CHILD | WS_VSCROLL, 0, 0, 100, 0, parent, NULL, NULL, 0);
> +    style = GetWindowLongW(listbox, GWL_STYLE);
> +    ok((style & WS_VSCROLL) != 0, "Listbox must have WS_VSCROLL\n");
> +    SendMessageA(listbox, WM_SIZE, SIZE_RESTORED, 0);
> +    style = GetWindowLongW(listbox, GWL_STYLE);
> +    ok((style & WS_VSCROLL) == 0, "Listbox must not have WS_VSCROLL\n");
> +    DestroyWindow(listbox);
> +
> +    /* Listbox must not have WS_VSCROLL after creating when height > 0 was specified */
> +    listbox = CreateWindowA("LISTBOX", "TestList", (LBS_STANDARD & ~LBS_SORT) | WS_CHILD | WS_VSCROLL, 0, 0, 100, 100, parent, NULL, NULL, 0);
> +    style = GetWindowLongW(listbox, GWL_STYLE);
> +    ok((style & WS_VSCROLL) == 0, "Listbox must not have WS_VSCROLL\n");
> +    DestroyWindow(listbox);
> +
> +    /* Adding elements must change WS_VSCROLL flag */
> +    listbox = CreateWindowA("LISTBOX", "TestList", (LBS_STANDARD & ~LBS_SORT) | WS_CHILD | WS_VSCROLL, 0, 0, 100, 0, parent, NULL, NULL, 0);
> +    SendMessageA(listbox, LB_ADDSTRING, 0, (LPARAM)"test1");
> +    style = GetWindowLongW(listbox, GWL_STYLE);
> +    ok((style & WS_VSCROLL) == 0, "Listbox must not have WS_VSCROLL\n");
> +    SendMessageA(listbox, LB_ADDSTRING, 0, (LPARAM)"test1");
> +    style = GetWindowLongW(listbox, GWL_STYLE);
> +    ok((style & WS_VSCROLL) != 0, "Listbox must have WS_VSCROLL\n");
> +

Tests are a bit artificial, because WM_SIZE is normally sent by the system.

> +    DestroyWindow(parent);
> +}
> +
>   START_TEST(listbox)
>   {
>       ULONG_PTR ctx_cookie;
> @@ -2202,6 +2236,7 @@ START_TEST(listbox)
>       test_extents();
>       test_WM_MEASUREITEM();
>       test_LB_SETSEL();
> +    test_WS_VSCROLL();
>   
>       unload_v6_module(ctx_cookie, hCtx);
>   }