libzypp related queries

Hi,
I had some queries regarding some libzypp functions.

1.) I want to retrieve information regarding packages such as size,
version of the package. How can I get this information?

2.) I am using defaultLoadSystem( "/" ) for a particular function. I
am getting the error 'zypp instance already created'. I havent called
getZypp() anywhere before this line. I just loaded some repositories
into the pool using RepoManager, and that was in some other module.
How can I avoid this error?

Regards,.
Saurabh

On Friday 27 July 2012 13:36:04 Saurabh Sood wrote:
> Hi,
> I had some queries regarding some libzypp functions.
>
> 1.) I want to retrieve information regarding packages such as size,
> version of the package. How can I get this information?Common attributes are available via class ResObject[Resolvable]. 
To acces if from a PoolItem you can use:

	ResObject::constPtr PooolItem::resolvable() const;
  or    ResObject::constPtr operator->() const;

  Example:
	PooolItem pi;
	pi.resolvable()->size();
  or	pi->size();

  (or from a sat::Solvable:
	sat::Solvable s;
	PooolItem pi( s );
	...)

Attributes specific to packages/patch/pattern/product are available via the 
coresponding classes Package[ResObject[Resolvable]]. To test whether a 
ResObject actually refers to a e.g. Package use 'isKind':

	ResObject::constPtr obj;
	if ( isKind<Package>( obj ) )
  or	if ( obj->isKind<Package>() )
  or	if ( obj->isKind( ResKind::package ) )

	PooolItem pi;
	if ( pi->isKind<Package>() )
  or	if ( pi->isKind( ResKind::package )
	
To convert use 'asKind':

	ResObject::constPtr obj;
	Package::constPtr pkg( asKind<Package>( obj ) );
  or	Package::constPtr pkg( obj->asKind<Package>() );

	PooolItem pi;
	Package::constPtr pkg( asKind<Package>( pi.resolvable() ) );
  or	Package::constPtr pkg( pi->asKind<Package>() );


'asKind' performs a dynamic cast, so it returns a nullptr if the object is not 
of the right type. 'isKind' simply tests whether 'asKinf' returned a nullptr. 
In doubt use asKind and test for a nullptr.

	ResObject::constPtr obj;
	Package::constPtr pkg( asKind<Package>( obj ) );	// one cast
	if ( pkg )
	{
	  ...

	ResObject::constPtr obj;
	if ( isKind<Package>( obj ) )				// 1st cast
	{
	  Package::constPtr pkg( asKind<Package>( obj ) );	// 2nd cast
	  ...> 2.) I am using defaultLoadSystem( "/" ) for a particular function. I
> am getting the error 'zypp instance already created'. I havent called
> getZypp() anywhere before this line. I just loaded some repositories
> into the pool using RepoManager, and that was in some other module.There are a actions which may call getZypp() internally. You should call 
defaultLoadSystem before doing anything else, or do the setup manually.-- 

cu,
    Michael Andres

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