On Tue, Jan 29, 2013 at 09:35:12AM -0800, Junio C Hamano wrote: > Jeff King <p...@peff.net> writes: > > > +static void write_meta_header(struct metapack_writer *mw, const char *id, > > + uint32_t version) > > +{ > > + version = htonl(version); > > + > > + sha1write(mw->out, "META", 4); > > + sha1write(mw->out, "\0\0\0\1", 4); > > + sha1write(mw->out, mw->pack->sha1, 20); > > + sha1write(mw->out, id, 4); > > + sha1write(mw->out, &version, 4); > > +} > > It seems that you are very close to actually having a plumbing that > could also do the pack .idx files. Until/unless that can be done, I > am not sure how much benefit we would be getting from a file format > that records a subtype "id" and a generic "META" type, instead of > just a single "id" as the type ehader. But it is OK to use 8 extra > bytes if we can potentially gain something later.
Yeah, I considered going that route. I had initially envisioned having a generic META file type that provided some services (like fixed-size records), and then having individual subtypes below that. But as I simplified the design, the META format became pretty much pointless. I left it in as the 8 bytes are not really a big problem, and it means we can treat metapacks generically in some cases without necessarily knowing what is in them. But I don't have a specific use case in mind, so perhaps it is just useless and confusing. I don't mind simplifying. > Shouldn't id be validated with at least something like > > if (strlen(id) < 3) > die("Bad id: %s", id); > > to catch a call > > write_meta_header(&mw, "me", 47); > > that will stuff 'm', 'e', NUL and the garbage the compiler/linker > combo has placed after that constant string in the 4-byte id field? Yes, the id does need to be at least 4 bytes. Since the id is intended to be a static string, I had planned to just document the requirement in the API documentation. I don't mind putting in a run-time check. I had originally had a separate "id" parameter that could be "char id[4]", but found that it was just redundant with the "name" parameter: you ended up passing ("commit", "CMIT") or similar. > > + strbuf_addstr(&path, pack_idx); > > + strbuf_chompstr(&path, ".idx"); > > + strbuf_addch(&path, '.'); > > + strbuf_addstr(&path, name); > > Your chompstr() does not even validate if the given name ends with > ".idx", Yeah, my intent was that it would be liberal in its input (i.e., take just "pack-*"). E.g., you can run "git metapack pack/pack-XXXX". > so this sounds like a glorified way to say > > strbuf_splice(&path, path->len - strlen("idx"), strlen("idx"), > name, strlen(name)); > > to me. Yup, though my version handles edge cases by not chomping (e.g., what does splice do when path->len is less than 3?). > > +void metapack_writer_finish(struct metapack_writer *mw) > > +{ > > + const char *tmp = mw->out->name; > > + > > + sha1close(mw->out, NULL, CSUM_FSYNC); > > + if (rename(tmp, mw->path)) > > + die_errno("unable to rename temporary metapack file"); > > Who is responsible for running adjust_shared_perm()? The caller, or > this function? I didn't think about it at all, but it seems pretty obvious to me that this function should do so. Thanks for pointing it out. -Peff -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html