[Nepomuk] Nepomuk Core - Questions & Patches

[Vishesh Handa]

Hey Sebastian

On Mon, May 24, 2010 at 1:45 PM, Sebastian Trüg <trueg at kde.org> wrote:

> Hi Vishesh,
>
> I don't really see how this can work. After all the same resource could
> still be accessed in two different ways. For example we have this resource:
>
> nepomuk:/res/foobar
>    nao:identifier "foobar" .
>
> Now the code:
>
> Resource r1( QUrl("nepomuk:/res/foobar" ) );
> Resource r2( "foobar" );
>
> At this point determineUri has not been called for any resource yet and
> as far as RM is concerned those are different resources with 2 different
> RDs.
>

You're right. I forgot that determineUri has to be called at least once. :-(
I think we should add a test for this.

Hmm, so we still need some kind of proxies. I guess it's time to combine
determineUri() and load().

- Vishesh Handa


>
> Be aware though that I did not look at your patch in detail yet. I will
> do that later. So I might have missed something. :)
>
> Cheers,
> Sebastian
>
> On 05/23/2010 05:54 PM, Vishesh Handa wrote:
> >
> > On Sun, May 23, 2010 at 8:20 PM, Sebastian Trüg <trueg at kde.org
> > <mailto:trueg at kde.org>> wrote:
> >
> >     On 05/23/2010 04:23 PM, Vishesh Handa wrote:
> >     >     > One way of solving both the problems is to derive
> >     ResourceData from
> >     >     > QObject. And then call deleteLater() instead of "delete
> >     this". (Patch
> >     >     > attached)
> >     >
> >     >     oh, no, please don't. Totally useless overhead. It is much
> >     simpler to
> >     >     make the mutex recursive.
> >     >
> >     >
> >     > Well then we need a better way of solving the "delete this"
> problem.
> >     > When you say moving "it" into Resource, do you mean determineUri()
> or
> >     > replaceWith() ?
> >
> >     I mean all calls of determineUri().
> >     Example:
> >     ResourceData::removeProperty calls determineUri. Instead determineUri
> >     should be called in Resource::removeProperty.
> >
> >
> > I'm sorry. I don't understand. Isn't it the same thing? If A calls B or
> > B is called inside A?
> >
> >
> >     The only problem here is load. But I recently thought that it could
> be
> >     merged into determineUri (or the other way around). After all most
> >     resources do not have more than - say - 20 properties. That is
> quickly
> >     loaded and would avoid performing yet another query. What I mean is
> that
> >     in determineUri
> >
> >     select distinct ?r ?o where {
> >     { ?r nie:url <uri> . }
> >     UNION { <uri> ?p ?o . } } LIMIT 1
> >
> >     could become something like
> >
> >     select distinct ?r ?pp ?oo where {
> >     { ?r nie:url <uri> .
> >     ?r ?pp ?oo . FILTER(?r!=<uri> . }
> >     UNION { <uri> ?p ?o . <uri> ?pp ?oo . }
> >
> >     to determine the URI AND load all properties at the same time.
> >     Just an idea I had when I thought about ways to spped it all up...
> >
> >
> > Seems logical. But then you call determineUri everywhere? I guess we
> > could make it determineAndLoad(). :-)
> >
> > ---------------------------
> >
> > I had another idea on how to get rid of the proxy mess. I was going to
> > tell you about it later, as its aim was to get rid of the nasty lists
> > and determineUri mess, but it seems as though it would solve the proxy
> > problem as well. (Nice side effect!)
> >
> > The ResourceManagerPrivate has 2 sets of lists. I'm going to call them
> > INIT-LIST (m_initializedData) and the HALF-INIT list (m_uriKickoffData &
> > m_idKickoffData). Whenever a Resource is created by the RMP::data()
> > function, it checks if it is present INIT-LIST or HALF-init list, and
> > accordingly gives us a RD (ResourceData).
> >
> > A RD can go into the HALF-INIT lists in 4 ways - (look at determineUri)
> > --- KickOffId
> > ------- nepomuk://res/ stored as a string
> > ------- nao:identifier
> >
> > --- KickOffUri
> > -------- nie:url
> > -------- nepomuk://res/
> >
> > *Proposal :*
> > Remove the KickOffId completely. And make KickOffUri contain the
> > nao:identifier as well. When determineUri is being called, say
> > m_kickOffUri is the nepomuk resource uri, it should add itself to the
> > INIT-LIST and it should add all other ways of getting Initialized to the
> > HALF-INIT list ( nao:identifier and nie:url ) This way RMP:data() will
> > always returns the correct RD* and a proxy wouldn't be required.
> >
> > determineUri would be a lot simpler -
> >
> > if( m_kickOffUri.isValid() ) {
> >       // check for nepomuk://res/
> >       // check for nie:url and the filex crap which I don't understand
> > } else {
> >      // check for nao:identifier
> > }
> >
> > An additional thing we could do is to make removeProperty() removing the
> > corresponding RD from the HALF-INIT list if the property being removed
> > is nao:identifier or nie::url. (addProperty should check for the same)/
> >
> > I hope I've been clear enough.
> >
> > - Vishesh Handa
> >
> >
> >     Cheers,
> >     Sebastian
> >
> >
>
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