On Fri, Jun 3, 2016 at 6:36 PM, Junio C Hamano <gitster@xxxxxxxxx> wrote:
> Eric Sunshine <sunshine@xxxxxxxxxxxxxx> writes:
>> On Thu, Jun 2, 2016 at 3:51 AM, Eric Wong <e@xxxxxxxxx> wrote:
>>> Eric Wong <e@xxxxxxxxx> wrote:
>>>> Eric Sunshine <sunshine@xxxxxxxxxxxxxx> wrote:
>>>> > On Tue, May 31, 2016 at 3:45 AM, Eric Wong <e@xxxxxxxxx> wrote:
>>>> > > Eric Sunshine <sunshine@xxxxxxxxxxxxxx> wrote:
>>>> > >> I wonder if hand-coding, rather than using a regex, could be an improvement:
>>>> > >>
>>>> > >> static int is_mboxrd_from(const char *s, size_t n)
>>>> > >> {
>>>> > >> size_t f = strlen("From ");
>>>> > >> const char *t = s + n;
>>>> > >>
>>>> > >> while (s < t && *s == '>')
>>>> > >> s++;
>>>> > >> return t - s >= f && !memcmp(s, "From ", f);
>>>> > >> }
>>>> > >>
>>>> > >> or something.
>>>> > >
>>>> > > Yikes. I mostly work in high-level languages and do my best to
>>>> > > avoid string parsing in C; so that scares me. A lot.
>>
>> As mentioned above, it's all subjective and, of course, I have a bias
>> toward the example I provided, but don't otherwise feel strongly about
>> it. I do, however, like the idea of using a simple hand-coded matching
>> function over the regex (but no so much that I would complain about
>> it). Use whatever you and Junio feel is appropriate.
>
> This is meant to be a replacement for the original that uses
> regexec(), which in turn means the string we are checking is
> guaranteed to be NUL terminated, right?
Yes, this is meant as a replacement for the regexec(), but no, there
is no guarantee that the "line" is NUL-terminated. In this case, the
'line' in pretty.c:pp_remainder() might end at a NUL or it might just
end at the next newline in the larger buffer.
The bit about sending the "line" to regexec() without taking its
logical end-of-line into account was what caught my attention in the
first place.
> static int is_mboxrd_from(const char *line) {
> return starts_with(line + strspn(line, ">"), "From ");
> }
>
> is sufficiently high-level that no longer is scary, hopefully?
That's nice and concise but unfortunately not useful for this case
where we must respect the logical end-of-line (within the larger
buffer), represented by line+linelen.
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