Re: [PATCH 2/4] shared/gatt: Add function to check if handle was found in database

[Szymon Janc <szymon.janc@tieto.com>]

Hi Luiz,

On Friday 30 of May 2014 11:32:34 Luiz Augusto von Dentz wrote:
> Hi Marcin,
> 
> On Fri, May 30, 2014 at 8:51 AM, Marcin Kraglak
> <marcin.kraglak@tieto.com> wrote:
> > It will return true if attribute with given handle exists in db, otherwise
> > false.
> > ---
> >  src/shared/gatt-db.c | 18 ++++++++++++++++++
> >  src/shared/gatt-db.h |  1 +
> >  2 files changed, 19 insertions(+)
> >
> > diff --git a/src/shared/gatt-db.c b/src/shared/gatt-db.c
> > index 998e93e..de1de57 100644
> > --- a/src/shared/gatt-db.c
> > +++ b/src/shared/gatt-db.c
> > @@ -758,3 +758,21 @@ uint32_t gatt_db_get_attribute_permissions(struct gatt_db *db, uint16_t handle)
> >
> >         return attribute->permissions;
> >  }
> > +
> > +bool gatt_db_has_attribute(struct gatt_db *db, uint16_t handle)
> > +{
> > +       struct gatt_db_attribute *attribute;
> > +       struct gatt_db_service *service;
> > +       uint16_t service_handle;
> > +
> > +       service = queue_find(db->services, find_service_for_handle,
> > +                                                       INT_TO_PTR(handle));
> > +       if (!service)
> > +               return false;
> > +
> > +       service_handle = service->attributes[0]->handle;
> > +
> > +       attribute = service->attributes[handle - service_handle];
> > +
> > +       return attribute ? true : false;
> > +}
> > diff --git a/src/shared/gatt-db.h b/src/shared/gatt-db.h
> > index f2f2f4d..ca36d32 100644
> > --- a/src/shared/gatt-db.h
> > +++ b/src/shared/gatt-db.h
> > @@ -93,3 +93,4 @@ const bt_uuid_t *gatt_db_get_attribute_type(struct gatt_db *db,
> >  uint16_t gatt_db_get_end_handle(struct gatt_db *db, uint16_t handle);
> >
> >  uint32_t gatt_db_get_attribute_permissions(struct gatt_db *db, uint16_t handle);
> > +bool gatt_db_has_attribute(struct gatt_db *db, uint16_t handle);
> > --
> > 1.9.0
> 
> This kind of API design is inefficient since it normally gonna cause
> double lookup and in any case gatt_db_get_attribute_permissions needs
> a fix since right now it cannot really tell if an error happen.
> Perhaps we could change the return to int and have another parameter
> to hold the permissions value or we can create an API for attribute
> themselves e.g. gatt_db_get_attribute + gatt_attribute_get_permission.
> 

For now I think we can fix only gatt_db_get_attribute_permissions() as you
suggested. But I agree that on long run having attribute API would be nice.

-- 
Best regards, 
Szymon Janc