[PATCH 02/17] shell32/autocomplete: Fix handling of Backspace and Delete so that it matches Windows

[Huw Davies]

On Wed, Sep 05, 2018 at 07:13:04PM +0300, Gabriel Ivăncescu wrote:
> On Windows, auto-append doesn't happen when the user presses Backspace or
> Delete, so remove it (not to mention it's totally wrong and full of bugs,
> see Wine-Bug). However, the autocompletion box does show up for these two
> keys, so handle that.
> 
> Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=22255
> Signed-off-by: Gabriel Ivăncescu <gabrielopcode at gmail.com>
> ---
> 
> That being said, the previous code was completely wrong even if auto
> append actually worked on Backspace or Delete. I honestly have no idea
> what it tried to accomplish... (not to mention it happens on a WM_KEYUP,
> which means the control already processed the operation itself)
> 
> Behavior compared with Windows XP SP2.
> 
>  dlls/shell32/autocomplete.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/dlls/shell32/autocomplete.c b/dlls/shell32/autocomplete.c
> index 051644a..254884b 100644
> --- a/dlls/shell32/autocomplete.c
> +++ b/dlls/shell32/autocomplete.c
> @@ -199,16 +199,6 @@ static LRESULT APIENTRY ACEditSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam,
>                          ShowWindow(This->hwndListBox, SW_HIDE);
>                          return CallWindowProcW(This->wpOrigEditProc, hwnd, uMsg, wParam, lParam);
>                      }
> -                    if (This->options & ACO_AUTOAPPEND) {
> -                        DWORD b;
> -                        SendMessageW(hwnd, EM_GETSEL, (WPARAM)&b, 0);
> -                        if (b>1) {
> -                            hwndText[b-1] = '\0';
> -                        } else {
> -                            hwndText[0] = '\0';
> -                            SetWindowTextW(hwnd, hwndText);
> -                        }
> -                    }

Right, the original code here is clearly broken.

>                      break;
>                  default:
>                      ;
> @@ -236,7 +226,9 @@ static LRESULT APIENTRY ACEditSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam,
>                      break;
>  
>                  if (!strncmpiW(hwndText, strs, len)) {
> -                    if (!filled && (This->options & ACO_AUTOAPPEND)) {
> +                    if (!filled && (This->options & ACO_AUTOAPPEND) &&
> +                        wParam != VK_BACK && wParam != VK_DELETE)
> +                    {

Special casing VK_BACK and VK_DELETE like this looks odd.  There has
to be a cleaner way.  I'm also concerned that you're about to rip this
code apart in [7/17].

>                          WCHAR buffW[255];
>  
>                          strcpyW(buffW, hwndText);
> -- 
> 1.9.1
> 
> 
>