On Mon, Aug 15, 2016 at 06:44:26PM +0200, Pino Toscano wrote: > On Monday, 15 August 2016 16:26:51 CEST Richard W.M. Jones wrote: > > On Mon, Aug 15, 2016 at 04:48:29PM +0200, Pino Toscano wrote: > > > Create an object hierarchy to represent different bootloaders for Linux > > > guests, moving the separate handling of grub1 and grub2 in different > > > classes: this isolates the code for each type of bootloader together, > > > instead of scattering it all around. > > > > > > This is mostly code refactoring, with no actual behaviour change. > > > --- > > > po/POTFILES-ml | 1 + > > > v2v/Makefile.am | 2 + > > > v2v/bootloaders.ml | 317 > > > +++++++++++++++++++++++++++++++++++++++++++++++++++ > > > v2v/bootloaders.mli | 44 +++++++ > > > > Is this really "bootloaders"? It's more like "linux_bootloaders", > > unless this might one day be extended to include NTLDR. > > OK, make sense -- I will rename it. > > > > +class virtual bootloader = object > > > + method virtual name : string > > > + method virtual augeas_device_patterns : string list > > > + method virtual list_kernels : unit -> string list > > > + method virtual set_default_kernel : string -> unit > > > + method set_augeas_configuration () = false > > > + method virtual configure_console : unit -> unit > > > + method virtual remove_console : unit -> unit > > > + method update () = () > > > +end > > > > I think you'll also find that you don't need to use inheritance at > > all. You can just declare bootloader as a class type and declare two > > (unrelated) classes which implement the class type. They won't be > > able to inherit the two trivial non-virtual functions, but IMHO that's > > a feature. > > Using inheritance helps here to spot typos in methods, and also when > implementing subclasses it'll be spotted if a method is not implemented.
I'm fairly sure they're equivalent in terms of safety actually. I would have to try it to be sure. > > I still don't much see the point versus an implementation which used a > > type Bootloader.t declared as: > > > > type t = Grub1 of <any local data grub1 needs> > > | Grub2 of <any local data grub2 needs> > > > > (and not exposed through the mli file). As this is to some extent my > > personal preference, I'll let it slide. > > I did this approach as well, and it turns out that: > * every method is basically a giant "match t with Grub1 _ | Grub2 _", > which makes it ugly to read: this is also because the code shared > between one bootloader implementation and another is not really much, > and currently only the "remove_hd_prefix" function is > * the implementation of a bootloader is scattered all around, so > looking at what is done for a bootloader means looking everywhere > * passing a data type when calling every method is basically like > what is done in C to mimim OOP; hence if I have to do something that > resembles OOP but not actually doing it, then it will be a suboptimal > implementation than OO (IMHO at least) Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW _______________________________________________ Libguestfs mailing list [email protected] https://www.redhat.com/mailman/listinfo/libguestfs
