RFC: Detecting the wine prefix

[Paul Chitescu]

On Friday 16 July 2010 12:32:33 pm Michael Stefaniuc wrote:
> Hello Paul,
> 
> Paul Chitescu wrote:
> > I would want to implement a change in where the wine prefix is assumed by 
> > default.
> > 
> > The current behavior of only considering WINEPREFIX is cumbersome and 
risky. 
> > Slip a finger, forget a letter and you end running a potential disastrous 
> > command in the wrong prefix. I ruined my main prefix by accidenatlly running 
> > "winetricks ie6" in it...
> > 
> > To fix that I use a wrapper script (unimaginatively named "win") that 
detects 
> > the proper prefix from the current directory and calls wine or other 
programs 
> > (winecfg, wineserver, winetricks, etc.) after setting WINEPREFIX. I am 
> > satisfied by this wrapper but has several disadvantages:
> > - You need to remember to run it instead of wine.
> > - You may paste a command from somewhere and forget to add "win" in front.
> > - Needs to be distributed.
> > 
> > The proposed solution is to incorporate the prefix detection logic in wine 
> > itself so no wrapper is needed.
> > 
> > The modified behavior would be like this:
> > - If WINEPREFIX is set obey that, user knows better. This is also required 
to 
> > create a new prefix.
> > - Starting from current working directory descend towards root looking for 
a 
> > directory that:
> > 	1. Has a dosdevices/ subdirectory and a system.reg file
> >    or
> > 	2. Has a .wine symlink pointing to a directory matching condition 1.
> >    or
> > 	3. Holds a .wine regular file whose content is the name of a directory 
> > matching condition 1.
> > - If a valid prefix (matches condition 1. above) is found use it for wine
> > - Else use the default ~/.wine
> > 
> > The extra checks 2. and 3. are to be able to handle the case when the 
current 
> > directory is on a path that is symlinked from inside the prefix. In 
particular 
> > test 3. is used when the files are on a FAT (or other symlink incapable) 
> > partition. I have several wine prefixes whose "Program Files" is located on 
a 
> > much larger FAT32 partition shared with you know what.
> > 
> > What do you think about this? Should I go on coding it?
> I like the idea as it follows the DWIM (Do What I Mean) principle.
> But the working directory shouldn't be the primary means to detect what
> WINEPREFIX to use. That should be inherited first from the location of
> the Win32 binary that is run. E.g. working on multiple regression bugs I
> have used a separate git tree as well as a separate WINEPREFIX per bug.
> My CWD was always the SRCDIR/BUILDIR thus useless to find the WINEPREFIX
> but the path to the binary always had the WINEPREFIX informations in it:
>   ./wine ~/wine/prefixes/21409/drive_c/Program\ Files/foo/foo.exe
> 
> The "descend towards root" is used extensively by git so that one can
> provide a good inspiration on how to do it, especially the corner cases.
> 
> bye
> 	michael

Right.

<can-of-worms>
A problem here would be to detect an executable name is present on the command 
line - and not only for wine but for other commands like winedbg and 
wineconsole too.
</can-of-worms>

Paul