Re: [PATCH] xdiff-interface.c: strip newline (and cr) from line before pattern matching

> POSIX doth sayeth:
>
>   "In the regular expression processing described in IEEE Std 1003.1-2001,
>    the <newline> is regarded as an ordinary character and both a period and
>    a non-matching list can match one. ... Those utilities (like grep) that
>    do not allow <newline>s to match are responsible for eliminating any
>    <newline> from strings before matching against the RE."
>
> Thus far git has not been removing the trailing newline from strings matched
> against regular expression patterns. This has the effect that (quoting
> Jonathan del Strother) "... a line containing just 'FUNCNAME' (terminated by
> a newline) will be matched by the pattern '^(FUNCNAME.$)' but not
> '^(FUNCNAME$)'", and more simply not '^FUNCNAME$'.
>
> Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
> ---
>
>
> This could be a little simpler if I knew what was guaranteed from xdiff.
> Such as whether the len elements of line were guaranteed to be newline
> terminated, or be greater than zero. But, the code in def_ff() in xemit.c
> is wrapped in 'if (len > 0)', so..
>
> -brandon
>
>
>  xdiff-interface.c |   12 +++++++++++-
>  1 files changed, 11 insertions(+), 1 deletions(-)
>
> diff --git a/xdiff-interface.c b/xdiff-interface.c
> index 8bab82e..61f5dab 100644
> --- a/xdiff-interface.c
> +++ b/xdiff-interface.c
> @@ -191,12 +191,22 @@ struct ff_regs {
>  static long ff_regexp(const char *line, long len,
>                char *buffer, long buffer_size, void *priv)
>  {
> -       char *line_buffer = xstrndup(line, len); /* make NUL terminated */
> +       char *line_buffer;
>        struct ff_regs *regs = priv;
>        regmatch_t pmatch[2];
>        int i;
>        int result = -1;
>
> +       /* Exclude terminating newline (and cr) from matching */
> +       if (len > 0 && line[len-1] == '\n') {
> +               if (len > 1 && line[len-2] == '\r')
> +                       len -= 2;
> +               else
> +                       len--;
> +       }
> +
> +       line_buffer = xstrndup(line, len); /* make NUL terminated */
> +
>        for (i = 0; i < regs->nr; i++) {
>                struct ff_reg *reg = regs->array + i;
>                if (!regexec(&reg->re, line_buffer, 2, pmatch, 0)) {
> --
> 1.6.0.2.323.g7c850
>
>