Re: [PATCH 0/2] MR10235: gdiplus: Validate window handle in has_gdi_dc

[Esme Povirk (＠madewokherd)]

Esme Povirk (@madewokherd) commented about dlls/gdiplus/gdiplus_private.h:
> static inline BOOL has_gdi_dc(GpGraphics *graphics)
>  {
> -    return graphics->hdc != NULL || graphics->owndc;
> +    return graphics->hdc != NULL || (graphics->owndc && IsWindow(graphics->hwnd));

This would add a non-obvious corner case. We generally assume that there are only a few valid Graphics object types: Metafile recording, Bitmap, HWND, and HDC, and that has_gdi_dc divides them cleanly (Metafile/Bitmap do not have a DC, and HWND/HDC do).

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https://gitlab.winehq.org/wine/wine/-/merge_requests/10235#note_131305