Mailinglist Archive: zypp-devel (68 mails)

[Michael Andres <ma@xxxxxxx>]

On Tue, May 15, Jan Kupec wrote:

> PS: Question for Michael:
> 
> I see a lot of classes in libzypp are designed following a certain
> pattern with public API separated from implementation. Is it the Bridge
> pattern? I have not found time to learn much about it so far. Should i

Some are sort of Bridge (e.g. Resolvables, Sources, Capabilites). 

Other simply use 'Body/Handle' or PIMPL, to keep data and implementation 
details out of the public interface, to implement cheap copy or copy on 
write. 


> design YUMParser's classes that way?

It's always a good idea to decouple interface and implementation.


Look e.g. at the yum::PrimaryFileReader:

        PrimaryFileReader(
              const Pathname &primary_file,
              const ProcessPackage & callback,
              const ProgressData::ReceiverFnc & progress );


This is actually the complete public interface. A filename, 
a callback processing the parded data and optional progressreport.


If you'd move all the rest of the class to a separate implementation 
class, you could drop a lot of compiletime dependencies (e.g. the whole
xml::Reader stuff).

Then you can add/remove additional data/calbacks, whatever you need, 
without breaking binary compatibility.



-- 

cu,
    Michael Andres

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