[GRASS-dev] G_check_input_output() and fully qualified output map name

[Martin Landa]

Hi Hamish,

2007/10/31, Hamish <hamish_nospam at yahoo.com>:
> Martin Landa wrote:
> > I realized a strange behaviour of r.buffer, e.g.
> >
> > $ r.buffer in=e out=e d=1
> >
> > No error, input and output is the same...
>
> r.buffer uses
>    opt2 = G_define_standard_option(G_OPT_R_OUTPUT);
>
> which defines
>    Opt->gisprompt    = "new,cell,raster";
>
> the parser does check that the given name doesn't already exist.
> Have you set the --overwrite enviro variable to be always on?
>
> For the above example I get:
>   ERROR: option <output>: <e> exists.
>
>
> Presumably if you abuse --overwrite you get what you asked for.

Hm, right I used GRASS_OVERWITE=1. But anyway why not use
G_check_input_output() in r.buffer and other modules with input/output
raster/vector maps? To avoid the same input and output?

>
> > $ r.buffer in=e out=e at user1 d=1
> > Illegal filename. Character <@> not allowed.
> > ERROR: <e at user> is an illegal file name
> >
> > Why so restrictive? The current mapset is 'user1'.
>
> output maps can only be written to the current mapset*. Allowing '@' is
> redundant, requires code (ie additional habitat for bugs) to check that
> what's after the '@' matches G_mapset(), and might put ideas in people's
> heads that 'output=map at other_mapset' isn't banned.

Right, my question was based on GUI work. You can select from a dialog
as the output existing map from the current mapset (which is always
given as 'map at mapset'). Of course '@mapset' can be removed when
creating command string in GUI or to extend G_check_input_output() to
check also for fully qualified map name.

> [*] i.rectify is the exception, it writes to the target mapset which
> was set with i.target
>
>
> I agree that the error message could be better.
> If it were me, I'd keep it simple with something like
>
> if ( G_legal_filename(output) == -1 ) {
>    if(strchr(output, '@'))
>       G_fatal_error(_("Output map name should not include a mapset"));
>    ...

Martin

>
>
> Hamish
>


-- 
Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *