Re: comctl32: Use strcmpW instead of pointer comparison to ensure treeview updates correctly

[Nikolay Sivov]

On 10/19/2014 20:01, Dan Bassi wrote:
> Hi Nikolay. In uTorrent, the Treeview box on the left doesn't update 
> under Wine unless the box is clicked (whereas under Windows, it 
> updates automatically without clicking).
>
> I later traced the error to the "item_changed()" function in 
> comctl32/treeview.c, which was (incorrectly) detecting the text as 
> never having changed. This patch seems to fix that behaviour.
>
> Please let me know your thoughts. Many thanks.

What I mean is that we need more tests in comctl32/tests/treeview.c to 
prove that patch is correct. The fact that it fixes some case with some 
application is not enough.
> On Sun, Oct 19, 2014 at 4:49 PM, Nikolay Sivov <[e-mail] 
> > wrote:
> On 10/19/2014 18:44, Dan Bassi wrote:
>
>     +    /* Old text is a null pointer due to HeapAlloc() failing,
>     therefore unable to perform strcmpW so assume text has changed */
>     +    if (!tiOld->pszText)
>     +       return TRUE;
>     +
>
> I don't think you should necessary assume it's changed.
>
>           /* Text has changed and it's not a callback */
>     -    if ((tvChange->mask & TVIF_TEXT) && (tiOld->pszText !=
>     tiNew->pszText) &&
>     +    if ((tvChange->mask & TVIF_TEXT) &&
>     (strcmpW(tiOld->pszText, tiNew->pszText) != 0) &&
>             tiNew->pszText != LPSTR_TEXTCALLBACKW)
>             return TRUE;
>
> This is wrong, you can't compare if it's a special callback value.
>
>     +    originalItem.pszText = HeapAlloc(GetProcessHeap(), 0,
>     originalItem.cchTextMax * sizeof(WCHAR));
>
> Normally comctl32 code uses Alloc()/Free() functions.
>
> This patch needs tests first, those tests should cover all
> possible combinations regarding callback cases, different pointers
> but same data,
> same data but different pointers, maybe something else.