[Libguestfs] [PATCH v7 4/6] v2v: Add general mechanism for input and output options (-io/-oo).

[Richard W.M. Jones]

On Fri, Mar 23, 2018 at 02:09:58PM +0100, Pino Toscano wrote:
> Here I'd do the check of the options (both input and output) by
> prefixes, i.e. things like:
> 
>   List.iter (
>     fun key ->
>       if not (String.is_prefix key "vddk-") ||
>          not (List.mem key vddk_option_keys) then
>         error (f_"-it vddk: ‘-io %s’ is not a valid input option") key
>   ) keys;
> 
> So most probably adding a simple function to get the prefix of options
> per-input and per-output mode, and using it to check.

Yeah I didn't necessarily want to restrict the options to use a
particular prefix.  For example it might be worth allowing -o
rhv-upload to use both rhv- and ovirt- prefixes.

In any case this is actually checked already by the individual
modules, so I don't think adding another check gains much except
complexity.

BTW when I sat down this morning I thought: why didn't I implement
this using methods on the input/output object?  The answer (after a
bit of trying to rewrite it that way) is that we don't have the fully
created objects until it's too late to set the options.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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