[virt-tools-list] [libosinfo 3/3] API to retrieve checksum for driver files

[Christophe Fergeau]

On Wed, Dec 12, 2012 at 04:04:04PM +0200, Zeeshan Ali (Khattak) wrote:
> On Wed, Dec 12, 2012 at 11:13 AM, Christophe Fergeau
> <cfergeau at redhat.com> wrote:
> > On Wed, Dec 12, 2012 at 03:21:30AM +0200, Zeeshan Ali (Khattak) wrote:
> >> From: "Zeeshan Ali (Khattak)" <zeeshanak at gnome.org>
> >>
> >> Keeping this API agnostic of MD5 so that we can later switch to another
> >> hashing alogirthm without breaking the API.
> >
> > algorithm
> >
> >>  /**
> >> + * osinfo_device_driver_get_file_checksum:
> >> + * @driver: a #OsinfoDeviceDriver instance
> >> + * @file: The name of the driver file for which checksum is requested
> >> + * @checksum_type: (out) (allow-none): place-holder to return type of the
> >> + *                                     checksum into, or NULL
> >> + *
> >> + * Retrieves the expected checksum for the given driver file @file.
> >> + *
> >> + * Returns: The file checksum
> >> + */
> >> +const gchar *osinfo_device_driver_get_file_checksum(OsinfoDeviceDriver *driver,
> >> +                                                    const gchar *file,
> >> +                                                    GChecksumType *checksum_type)
> >
> > I'd prefer a
> > gboolean osinfo_device_driver_check_file(OsinfoDeviceDriver *driver, const char *file, GError **error);
> > rather than forcing every app to do md5/sha1/... checks by hands while we
> > can easily do it for them.
> 
> Thats the idea I started with but then I thought checksum might have
> some other uses.

s/uses/abuses? ;) Apps who want to get to the checksum can always use raw
osinfo_entity calls, so I'm not sure we need to promote this use in the
API.

> Also what if app wants/needs to check data before
> pushing it into a file (this is what I'm doing in Boxes). Since glib
> doesn't provide simple API for computing checksum for a file (only for
> a buffer in memory), perhaps its a good idea to provide this
> _check_file() API in addition to exposing checksum to app. Keep in
> mind that _check_file() does I/O and therefore we must provide async
> variant too then.

Ah, good points. gboolean osinfo_device_driver_check_file_data(OsinfoDeviceDriver
*driver, const guint8 *data, gsize len, GError **error) would work for me
to, and would avoid the need for async variants.

Christophe
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