[sane-devel] [RFC][PATCH] sanei configuration framework extension

[stef]

Le Monday 23 June 2008 22:06:30 m. allan noah, vous avez écrit :
> On Mon, Jun 23, 2008 at 3:36 PM, stef <stef.dev at free.fr> wrote:
> > Le Thursday 19 June 2008 15:36:59 m. allan noah, vous avez écrit :
> >> pretty good, but i have two comments:
> >>
> >> 1. i think calling the struct SANE_Config instead of something with
> >> sanei in it, makes it look too much like something that should be in
> >> the SANE standard, instead of the internal-use function that it is.
> >>
> >> 2. some backends seem to have dozens of options, that struct is going
> >> to become quite large if it is extending to hold everything. does it
> >> instead make more sense for the callback to be run for each line
> >> extracted from the file, with a flag indicating that it was an option
> >> instead of an attach line?
> >>
> >> allan
> >
> >        Hello,
> >
> >        here's a new take at config option parsing. The struct is now
> > called SANEI_Config, and holds an array of SANE_Option_Descriptor and an
> > array of placeholder for the values of the options.
>
> brilliant. enables us to reuse lots of code, and keep a familiar
> interface. bravo.
>
> > To parse options, a backend first
> > creates a list of the options it wants using SANE_Option_Descriptor.
>
> great.
>
> > Then it calls sanei_configure_initialize() which creates the
> > placeholders. When the SANEI_Config is ready, the backend calls
> > sanei_configure_attach() which opens the configuration, parse it
> > according to the given descriptors. Whenever a line no recognized as an
> > option is met, the
> > sanei_configure_attach() calls the backend provided
> > (*attach)(SANEI_Config *, char *devname) attach function. This backend
> > specific function calls the usb/scsi/parport attach functions allready
> > provided by sanei library. As a parameter it has the currently parsed
> > options in the config struct and so may use them during the attach. A
> > sanei_configure_get_value() helper is given to access the values of the
> > options.
> >        Once parsing is done, there is a sanei_configure_dispose()
> > function to release allocated ressources.
>
> i would rather that the backend provided the placeholder memory if
> possible, for two reasons: 1. to keep all the memory allocations in
> one place, 2. so that the placeholders can be pre-loaded with default
> values by the backend.
>
> >        By doing this way, configuration is parsed only with the options
> > the backend needs. The existing sanei_check_value() may be reused to
> > check if constraints are respected.  Only a couple options that need a
> > complex syntax couldn't be handled right now (such as 'calibrate
> > /path/name port' from canon_pp) but could be handled by a
> > SANE_TYPE_STRING_LIST to be created.
> >
> >        The appended patch currently only manage SANE_TYPE_STRING options
> > and as been tested with a modified rts8891 backend.
>
> this sounds quite good- thank you very much for taking on the task!
>
> allan
> --
> "The truth is an offense, but not a sin"

	Hello,

	here's the patch modified like you suggest. Now both descriptors and 
placeholders are given by the backend. There is no need for a free'ing 
function anymore.

Regards,
	Stef

-------------- next part --------------
A non-text attachment was scrubbed...
Name: proposal.patch.gz
Type: application/x-gzip
Size: 4750 bytes
Desc: not available
Url : http://lists.alioth.debian.org/pipermail/sane-devel/attachments/20080625/411eb2c4/attachment.bin