Re: [PATCH 02/11] Support GIT_TEST_GETTEXT_POISON=rot13

[Junio C Hamano <gitster@pobox.com>]

"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> +const char *gettext_maybe_rot13(const char *msgid)
> +{
> +...
> +	while (*msgid) {
> +		const char *p = strchrnul(msgid, '%'), *spec;
> +
> +		while (*p && p[1] == '%')
> +			p = strchrnul(p + 2, '%');

We are at '%', and while the next is '%' (i.e. a literal '%' is
asked), we skip these two bytes and then we go back to the
equivalent of the initialization of 'p'.  Effects?  We leave the
loop when we are at the end of the string, or at '%' that is not
followed by a '%'.

It would have been easier to understand what is going on in the loop
if there weren't duplicated strchrnul() call, perhaps

	const char *p = msgid;
	while (*(p = strchrnul(p, '%')) == '%' && p[1] == '%')
        	p += 2;

That reads "find '%' and if the next char is also '%', skip these
two and redo the loop", which would be equivalent.  And it would be
much easier to follow the logic.

> +		if (p != msgid) {

And if 'p' is different (actually we know p is the same as, or
always ahead of, msgid, so "if (msgid < p)" would be easier to
follow for readers) ...

> +			strbuf_addstr(buf, "<rot13>");
> +			while (p != msgid)

Ditto.

> +				strbuf_addch(buf, do_rot13(*(msgid++)));
> +			strbuf_addstr(buf, "</rot13>");

... we add a section of obfuscated output enclosed with an xml
looking marker.

> +		}
> +
> +		if (!*p)
> +			break;

And if we are at the end, we are done.

> +		spec = strpbrk(p + 1, "diouxXeEfFgGaAcsCSpnm%");
> +		if (!spec)
> +			BUG("Unrecognized format string: %s", p);

It is a bit surprising that things like "%.*d" and "%.7f" do not
appear in our translatable strings (or perhaps this is one of the
places why the series is marked RFH and is not complete?).

> +		strbuf_add(buf, p, spec + 1 - p);
> +		msgid = spec + 1;
> +	}
> +
> +	return buf->buf;
> +}

Anyway, thanks for a fun reading.