[fpc-devel] Class field reordering

[Martin Schreiber]

On Saturday 14 July 2012 19:55:39 Sven Barth wrote:
> >
> > I sometimes need "cracker" classes in MSEide and MSEgui to fix bugs and
>
> make
>
> > extensinsions for FCL classes in order to access private fields (examples
> > TDataset, TParam, TField, TFiler, TReader, TWriter, TComponent).
> > Is it guaranteed that the local definitions have the same layout as the
> > definition in the FCL unit?
>
> Do you have current examples where you fixed bugs? Maybe these can be fixed
> at the source which might be better than making them protected (though this
> can still be done for non-bug fields where you need access to certain
> members)
>
MSEgui must work with current FPC release so sometimes it is necessary to make 
workarounds until the next FPC release with the bugfixes. As soon as possible 
I remove unneeded cracker classes.
I report all FPC bugs I find apart from the compiler crashes by partial 
compile where reproducing is difficult, needs the whole MSEide+MSEgui source 
and fixing probably would need construction of a new unit handling in FPC. 
Bugs which are Delphi compatible are not reported also. ;-)

Currently I need access to the following private FCL class fields because of 
MSEide+MSEgui extensions:

TComponent:
- FComponents
- FComponentState
- FFreeNotifies

TCollection:
- FItemClass

THandlestream:
- FHandle

TMemoryStream:
- FCapacity

TWriter:
- FPropPath
- FAncestors

TReader:
- FStream
- FLoaded

TDatabase:
- FConnected

TField:
- FValidating
- FValueBuffer
- FOffset
- FFieldno

TFielddef:
- FFieldno

TParam:
- FBound

TDataset:
- FDatasources

I hope I didn't forget anything. Suggestion:
For all FCL base classes which are used in different toolkits and which can't 
be forked without breaking precompiled third party components, namely the 
units classes and db, move *all* private fields and methods to protected and 
mark them as "Use on your own risk, can be changed everytime! Don't cry 
afterwards.".
I can not fork the listed components because of compatibility with third party 
components. On the other had I forked SQLdb completely when the workaround 
burden became too big.

Thanks, Martin