Re: [PATCH v2 3/4] strbuf_setlen: don't write to strbuf_slopbuf

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 23, 2017, 21:04 UTC
Message-ID: <xmqqh8wyxag1.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <CA+sFfMdXv+nqpXmwfLTHtkRLuGkAEAwWXZCvOryVZ=aLb_UmbA@mail.gmail.com>

Brandon Casey <drafnel@gmail.com> writes:

> So is there any reason why didn't do something like the following in
> the first place?

My guess is that we didn't bother; if we cared, we would have used a single instance of const char in a read-only segment, instead of such a macro.

Show 25 quoted lines

> diff --git a/strbuf.h b/strbuf.h
> index e705b94..fcca618 100644
> --- a/strbuf.h
> +++ b/strbuf.h
> @@ -67,7 +67,7 @@ struct strbuf {
>         char *buf;
>  };
>
> -extern char strbuf_slopbuf[];
> +#define strbuf_slopbuf ""
>  #define STRBUF_INIT  { .alloc = 0, .len = 0, .buf = strbuf_slopbuf }
>
>  /**
> @@ -147,7 +147,9 @@ static inline void strbuf_setlen(struct strbuf
> *sb, size_t len)
>         if (len > (sb->alloc ? sb->alloc - 1 : 0))
>                 die("BUG: strbuf_setlen() beyond buffer");
>         sb->len = len;
> -       sb->buf[len] = '\0';
> +       if (sb->alloc) {
> +               sb->buf[len] = '\0';
> +       }
>  }
>
> -Brandon