RE: LISTBOX_Directory() returns LB_OKAY for invalid directory / f ilen ame

[Krishna Murthy]

The 'le' is an integer value and not a bitwise value. This means it could
have only one error condition at a time.  The condition:
if ((le != ERROR_NO_MORE_FILES) && (le != ERROR_FILE_NOT_FOUND)) return
LB_ERR;

Could never return LB_ERR even if file was not found. Hence we have changed
to the logical OR condition which could trigger error either if no more
files or file not found:
if ((le != ERROR_NO_MORE_FILES) || (le != ERROR_FILE_NOT_FOUND)) return
LB_ERR;


Please find attached sample executable (DIRLIST.exe.zip has the executable),
which demonstrate the behavior change between windows and wine. Run the
sample and enter invalid path name or file name and press enter (click on
Display button). On windows it displays error message "DlgDirList
Failed...". Same steps when repeated on wine, it does not display this error
message because of the above logical error.

Krishna

-----Original Message-----
From: Alexandre Julliard [mailto:julliard(a)winehq.org] 
Sent: Friday, June 18, 2004 11:20 AM
To: Krishna Murthy
Cc: wine-devel(a)winehq.org
Subject: Re: LISTBOX_Directory() returns LB_OKAY for invalid directory /
filen ame

Krishna Murthy <Krishna.Murthy(a)guptaworldwide.com> writes:
> diff -u -r1.103 listbox.c
> --- wine/controls/listbox.c	1 Apr 2004 04:57:12 -0000	1.103
> +++ wine/controls/listbox.c	17 Jun 2004 21:50:20 -0000
> @@ -1760,7 +1760,7 @@
>          if ((handle = FindFirstFileW(filespec, &entry)) ==
> INVALID_HANDLE_VALUE)
>          {
>        int le = GetLastError();
> -            if ((le != ERROR_NO_MORE_FILES) && (le !=
> ERROR_FILE_NOT_FOUND)) return LB_ERR;
> +            if ((le != ERROR_NO_MORE_FILES) || (le != 
> + ERROR_FILE_NOT_FOUND)) return LB_ERR;

This makes the test completely useless, it can't be right.

--
Alexandre Julliard
julliard(a)winehq.org

LISTBOX_Directory() returns LB_OKAY for invalid directory / f ilen ame

[Dimitrie O. Paun]

On Tue, Jun 22, 2004 at 11:08:28AM -0700, Krishna Murthy wrote:
> The 'le' is an integer value and not a bitwise value. This means it could
> have only one error condition at a time.

Right. Because of this fact:
> if ((le != ERROR_NO_MORE_FILES) || (le != ERROR_FILE_NOT_FOUND)) return
> LB_ERR;

Will always return LB_ERR. Proof:

     (le != ERROR_NO_MORE_FILES) || (le != ERROR_FILE_NOT_FOUND)  
## by deMorgan's Law 
== !((le == ERROR_NO_MORE_FILES) && (le == ERROR_FILE_NOT_FOUND))
## by transitivity
== !(ERROR_NO_MORE_FILES == ERROR_FILE_NOT_FOUND) 
## by the definition of these error codes
== !(18 == 2)
## different numbers are not equal
== !(FALSE)
## by negation
== TRUE

;)

-- 
Dimi.

P.S. I haven't done a formal proof since I was doing my M.Sc. at UofT :)