Re: [CLucene-dev] Ownership of objects

[Ben v. K. <bva...@gm...>]

Hi Rolf,

You're right, but there are so few places where this rule is used -
that is, most of the time clucene returns a new object, so following
the rule in inverse would mean that everything would be being passed
by reference.

I think that actually the best solution to this problem is to document
it, which i have started to do (any helpers? :)

ben

On 9/27/05, mai...@rs... <mai...@rs...> wrote:
> Hello all,
>
> I'm new to CLucene, and while browsing through the header files, I found =
that there is no documentation of ownership rules for objects passed to / r=
eceived from CLucene API.
> Searching through the mailing list, I came across a message by Mr. van Kl=
inken, where he writes the following:
>
> BEGIN citation
> Good point Robert, and it is something that i have been thinking about. I=
 have tried to build a rule into clucene (though i have probably broken thi=
s rule a few times), is that if the function  returns a reference, then it =
is an internal object and should not be  deleted (like hits.doc), and if a =
method takes a reference, then this  function is 'consuming' the object (li=
ke Document.Add), and therefore  the object passed should not be deleted.
> END citation
>
> I find it interesting that objects passed by reference are to be deleted =
by CLucene, and objects passed as pointers are not. Generally I see people =
define the rule just the other way round: An object passed by reference sta=
ys owned by the caller; if passed by pointer, ownership is transferred to t=
he method being called. To me this seems more logical, and would be consist=
ent with the rule that if a reference is returned, the object is still owne=
d by the method that returns it, and if a pointer is returned (except const=
 pointers), the ownership is transferred.
>
> Is there any special reason why in CLucene it would be the other way roun=
d? To me it looks quite strange if I see code like this:
> void method(SomeObject& obj)
> {
>   ...
>   delete &obj; // <<< this really looks strange...
> }
>
> Just being curious
>
> Rolf Sch=E4uble
>
>
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