Re: [PATCH v5 1/5] bulk-checkin: extract abstract `bulk_checkin_source`

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 27, 2023, 23:12 UTC
Message-ID: <xmqqpm0zoe23.fsf@gitster.g>
In-Reply-To: <20231025073736.GB2145145@coredump.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 12 quoted lines

> Alternatively, I think some of our other OO code just leaves room for
> a type-specific void pointer, like:
>
>   struct bulk_checkin_source {
> 	...the usual stuff...
>
> 	void *magic_type_data;
>   };
>
> and then the init_bulk_checkin_source_from_fd() function allocates its
> own heap struct for the magic_type_data field and sticks the int in
> there.

Yup. All the pros-and-cons makes sense. I earlier said I found this a good place to stop, exactly because the full OO with

    struct specific_subclass {
	struct vtbl *vtbl;
	struct base_class common_data_specific_to_instance;
	... other instance specific data members here ...;
    }

would require us to add too many supporting infrastructure struct types; with only a few subclasses in use, it is a bit too much to justify.