From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Jonathan Tan <jonathantanmy@google.com>, git@vger.kernel.org
Subject: Re: [RFC/PATCH 1/3] mailinfo: refactor commit message processing
Date: Fri, 16 Sep 2016 14:46:41 -0700 [thread overview]
Message-ID: <20160916214641.ib7khsl3fbtn6smg@sigill.intra.peff.net> (raw)
In-Reply-To: <xmqqoa3nk6a5.fsf@gitster.mtv.corp.google.com>
On Fri, Sep 16, 2016 at 12:12:50PM -0700, Junio C Hamano wrote:
> > +static int check_header_raw(struct mailinfo *mi,
> > + char *buf, size_t len,
> > + struct strbuf *hdr_data[], int overwrite) {
> > + const struct strbuf sb = {0, len, buf};
> > + return check_header(mi, &sb, hdr_data, overwrite);
> > +}
>
> IIUC, this is a helper for callers that do not have a strbuf but
> instead have <buf, len> pair to perform the same check_header() the
> callers that have strbuf can do.
>
> As check_header() uses the strbuf as a read-only entity, wrapping
> the <buf, len> pair in a temporary strbuf like this is safe.
>
> The incoming <buf> should conceptually be "const char *", but it's
> OK.
I think the "right" way to do this would be to continue taking a "char
*", and then strbuf_attach() it. That saves us from unexpectedly
violating any strbuf invariants.
If our assumption that check_header() does not touch the
contents turns out to be wrong, neither strategy would inform our
caller, though. I think you'd want something like:
assert(sb.buf == buf);
after check_header() returns (though I guess we are in theory protected
by the "const").
That being said...
> If check_header() didn't call any helper function that gets passed
> &sb as a strbuf, or if convertiong the helper function to take a
> <buf, len> pair instead, I would actually suggest refactoring this
> the other way around, though. That is, move the implementation of
> check_header() to this function, updating its reference to line->buf
> and line->len to reference to <buf> and <len>, and then make
> check_header() a thin wrapper that does
>
> check_header(mi, const struct strbuf *line,
> struct strbuf *hdr_data[], int overwrite)
> {
> return check_header_raw(mi, line->buf, line->len,
> hdr_data, overwrite);
> }
This is _way_ better, and it looks like check_header() could handle it
easily. Looking at it, I also suspect the cascading if in that function
could be made more pleasant by modeling cmp_header()'s interface after
skip_prefix_mem(), but that is totally orthogonal and optional.
-Peff
next prev parent reply other threads:[~2016-09-16 21:46 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-02 19:58 [PATCH] sequencer: support folding in rfc2822 footer Jonathan Tan
2016-09-03 2:23 ` Junio C Hamano
2016-09-06 22:08 ` Jonathan Tan
2016-09-06 23:30 ` Jonathan Tan
2016-09-07 6:38 ` Jeff King
2016-09-16 17:37 ` [RFC/PATCH 0/3] handle multiline in-body headers Jonathan Tan
2016-09-16 18:29 ` Junio C Hamano
2016-09-16 17:37 ` [RFC/PATCH 1/3] mailinfo: refactor commit message processing Jonathan Tan
2016-09-16 19:12 ` Junio C Hamano
2016-09-16 21:46 ` Jeff King [this message]
2016-09-16 17:37 ` [RFC/PATCH 2/3] mailinfo: correct malformed test example Jonathan Tan
2016-09-16 19:19 ` Junio C Hamano
2016-09-16 22:42 ` Jonathan Tan
2016-09-16 22:55 ` Junio C Hamano
2016-09-17 0:31 ` Jonathan Tan
2016-09-17 3:48 ` Junio C Hamano
2016-09-16 17:37 ` [RFC/PATCH 3/3] mailinfo: handle in-body header continuations Jonathan Tan
2016-09-16 20:17 ` Junio C Hamano
2016-09-16 20:49 ` Jonathan Tan
2016-09-16 20:59 ` Junio C Hamano
2016-09-16 22:36 ` Jonathan Tan
2016-09-16 23:04 ` Junio C Hamano
2016-09-17 0:22 ` Jonathan Tan
2016-09-16 21:51 ` Jeff King
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