Re: [PATCH 00/17] Refactor chunk-format into an API

> This version also changes the approach to use a more dynamic interaction
> with a struct chunkfile pointer. This idea is credited to Taylor Blau [2],
> but I started again from scratch. I also go further to make struct chunkfile
> anonymous to API consumers. It is defined only in chunk-format.c, which
> should hopefully deter future users from interacting with that data
> directly.
>
> [2] https://lore.kernel.org/git/X8%2FI%2FRzXZksio+ri@nand.local/

> This combined API is beneficial to reduce duplicated logic. Or rather, to
> ensure that similar file formats have similar protections against bad data.
> The multi-pack-index code did not have as many guards as the commit-graph
> code did, but now they both share a common base that checks for things like
> duplicate chunks or offsets outside the size of the file.

> Here are some stats for the end-to-end change:
>
>  * 638 insertions(+), 456 deletions(-).
>  * commit-graph.c: 171 insertions(+), 192 deletions(-)
>  * midx.c: 196 insertions(+), 260 deletions(-)
>
> While there is an overall increase to the code size, the consumers do get a
> bit smaller. Boilerplate things like abstracting method to match
> chunk_write_fn and chunk_read_fn make up a lot of these insertions. The
> "interesting" code gets a lot smaller and cleaner.