From: Jeff King <peff@peff.net>
To: Kevin Daudt <me@ikke.info>
Cc: git@vger.kernel.org, Swift Geek <swiftgeek@gmail.com>,
Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH] mailinfo: unescape quoted-pair in header fields
Date: Mon, 19 Sep 2016 20:57:11 -0700 [thread overview]
Message-ID: <20160920035710.qw2byl3qeqwih7t5@sigill.intra.peff.net> (raw)
In-Reply-To: <20160919105133.GA10901@ikke.info>
On Mon, Sep 19, 2016 at 12:51:33PM +0200, Kevin Daudt wrote:
> > I didn't look in the RFC. Is:
> >
> > From: my \"name\" <foo@example.com>
> >
> > really the same as:
> >
> > From: "my \\\"name\\\"" <foo@example.com>
> >
> > ? That seems weird, but I think it may be that the former is simply
> > bogus (you are not supposed to use backslashes outside of the quoted
> > section at all).
>
> Correct, the quoted-pair (escape sequence) can only occur in a quoted
> string or a comment. Even more so, the display name *needs* to be quoted
> when consisting of more then one word according to the RFC.
Hmm. So, I guess a follow-up question is: what would it be OK to do if
we see a quoted-pair outside of quotes? If the top one above violates
the RFC, it seems like stripping the backslashes would be a reasonable
outcome.
So if that's the case, do we actually need to care if we see any
parenthesized comments? I think we should just leave comments in place
either way, so syntactically they are only interesting insofar as we
replace quoted pairs or not.
IOW, I wonder if:
while ((c = *in++)) {
switch (c) {
case '\\':
if (!*in)
return 0; /* ignore trailing backslash */
/* quoted pair */
strbuf_addch(out, *in++);
break;
case '"':
/*
* This may be starting or ending a quoted section,
* but we do not care whether we are in such a section.
* We _do_ need to remove the quotes, though, as they
* are syntactic.
*/
break;
default:
/*
* Anything else is a normal character we keep. These
* _might_ be violating the RFC if they are magic
* characters outside of a quoted section, but we'd
* rather be liberal and pass them through.
*/
strbuf_addch(out, c);
break;
}
}
would work. I certainly do not mind following the RFC more closely, but
AFAICT the very simple code above gives a pretty forgiving outcome.
> > This is obviously getting pretty silly, but if we are going to follow
> > the RFC, I think you actually have to do a recursive parse, and keep
> > track of an arbitrary depth of context.
> >
> > I dunno. This method probably covers most cases in practice, and it's
> > easy to reason about.
>
> The problem is, how do you differentiate between nested comments, and
> escaped braces within a comment after one run?
I'm not sure what you mean. Escaped characters are always handled first
in your loop. Can you give an example (although if you agree with what I
wrote above, it may not be worth discussing further)?
-Peff
next prev parent reply other threads:[~2016-09-20 3:57 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-16 21:02 [PATCH] mailinfo: unescape quoted-pair in header fields Kevin Daudt
2016-09-16 22:22 ` Jeff King
2016-09-19 10:51 ` Kevin Daudt
2016-09-20 3:57 ` Jeff King [this message]
2016-09-21 16:07 ` Junio C Hamano
2016-09-19 18:54 ` [PATCH v2 0/2] Handle escape characters in From field Kevin Daudt
2016-09-25 21:08 ` [PATCH v3 1/2] t5100-mailinfo: replace common path prefix with variable Kevin Daudt
2016-09-25 21:08 ` [PATCH v3 2/2] mailinfo: unescape quoted-pair in header fields Kevin Daudt
2016-09-26 19:11 ` Junio C Hamano
2016-09-26 19:26 ` Junio C Hamano
2016-09-26 19:44 ` Kevin Daudt
2016-09-26 22:23 ` Junio C Hamano
2016-09-27 10:26 ` Kevin Daudt
2016-09-26 19:06 ` [PATCH v3 1/2] t5100-mailinfo: replace common path prefix with variable Junio C Hamano
2016-09-28 19:49 ` [PATCH v4 0/2] Handle RFC2822 quoted-pairs in From header Kevin Daudt
2016-09-28 19:52 ` [PATCH v4 1/2] t5100-mailinfo: replace common path prefix with variable Kevin Daudt
2016-09-28 20:21 ` Junio C Hamano
2016-09-28 20:27 ` Kevin Daudt
2016-09-28 19:52 ` [PATCH v4 2/2] mailinfo: unescape quoted-pair in header fields Kevin Daudt
2016-09-19 18:54 ` [PATCH v2 1/2] t5100-mailinfo: replace common path prefix with variable Kevin Daudt
2016-09-19 21:16 ` Junio C Hamano
2016-09-20 3:59 ` Jeff King
2016-09-19 18:54 ` [PATCH v2 2/2] mailinfo: unescape quoted-pair in header fields Kevin Daudt
2016-09-19 21:24 ` Junio C Hamano
2016-09-19 22:04 ` Junio C Hamano
2016-09-20 4:28 ` Jeff King
2016-09-21 11:09 ` Jeff King
2016-09-22 22:17 ` Junio C Hamano
2016-09-23 4:15 ` Jeff King
2016-09-25 20:17 ` Kevin Daudt
2016-09-25 22:38 ` Jakub Narębski
2016-09-26 5:02 ` Kevin Daudt
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