Subject: Re: [PATCH 07/10] grep/pcre2: use pcre2_maketables_free() function

From: Junio C Hamano <[email-masked]>
Date: Wed, 03 Mar 2021 16:16:13 -0800

Ævar Arnfjörð Bjarmason  <[email-masked]> writes:

> Make use of the pcre2_maketables_free() function to free the memory
> allocated by pcre2_maketables(). At first sight it's strange that
> 10da030ab75 (grep: avoid leak of chartables in PCRE2, 2019-10-16)
> which added the free() call here doesn't make use of the pcre2_free()
> the author introduced in the preceding commit in 513f2b0bbd4 (grep:
> make PCRE2 aware of custom allocator, 2019-10-16).
>
> The reason is that at the time the function didn't exist. It was first
> introduced in PCREv2 version 10.34, released on 2019-11-21.
>
> Let's make use of it behind a macro. I don't think this matters for
> anything to do with custom allocators, but it makes our use of PCREv2
> more discoverable. At some distant point in the future we'll be able
> to drop the version guard, as nobody will be running a version older
> than 10.34.

OK.  The same comment about the macro that happens to be OK only
because 10 and 11 are consecutive applies here.

>
> Signed-off-by: Ævar Arnfjörð Bjarmason <[email-masked]>
> ---
>  grep.c | 4 ++++
>  grep.h | 3 +++
>  2 files changed, 7 insertions(+)
>
> diff --git a/grep.c b/grep.c
> index e58044474d..c63dbff4b2 100644
> --- a/grep.c
> +++ b/grep.c
> @@ -490,7 +490,11 @@ static void free_pcre2_pattern(struct grep_pat *p)
>  	pcre2_compile_context_free(p->pcre2_compile_context);
>  	pcre2_code_free(p->pcre2_pattern);
>  	pcre2_match_data_free(p->pcre2_match_data);
> +#ifdef GIT_PCRE2_VERSION_10_34_OR_HIGHER
> +	pcre2_maketables_free(pcre2_global_context, p->pcre2_tables);
> +#else
>  	free((void *)p->pcre2_tables);
> +#endif
>  }
>  #else /* !USE_LIBPCRE2 */
>  static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt)
> diff --git a/grep.h b/grep.h
> index 54e52042cb..64666e9204 100644
> --- a/grep.h
> +++ b/grep.h
> @@ -7,6 +7,9 @@
>  #if (PCRE2_MAJOR >= 10 && PCRE2_MINOR >= 36) || PCRE2_MAJOR >= 11
>  #define GIT_PCRE2_VERSION_10_36_OR_HIGHER
>  #endif
> +#if (PCRE2_MAJOR >= 10 && PCRE2_MINOR >= 34) || PCRE2_MAJOR >= 11
> +#define GIT_PCRE2_VERSION_10_34_OR_HIGHER
> +#endif
>  #else
>  typedef int pcre2_code;
>  typedef int pcre2_match_data;