Re: [PATCH 08/17] provide a helper to free commit buffer

> This converts two lines into one at each caller. But more
> importantly, it abstracts the concept of freeing the buffer,
> which will make it easier to change later.
>
> Note that we also need to provide a "detach" mechanism for
> the weird case in fsck which passes the buffer back to be
> freed.

> Signed-off-by: Jeff King <peff@peff.net>
> ---
>  builtin/fsck.c       |  3 +--
>  builtin/index-pack.c |  2 +-
>  builtin/log.c        |  6 ++----
>  builtin/rev-list.c   |  3 +--
>  commit.c             | 13 +++++++++++++
>  commit.h             | 11 +++++++++++
>  6 files changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/builtin/fsck.c b/builtin/fsck.c
> index fc150c8..8aadca1 100644
> --- a/builtin/fsck.c
> +++ b/builtin/fsck.c
> @@ -310,8 +310,7 @@ static int fsck_obj(struct object *obj)
>  	if (obj->type == OBJ_COMMIT) {
>  		struct commit *commit = (struct commit *) obj;
>  
> -		free(commit->buffer);
> -		commit->buffer = NULL;
> +		free_commit_buffer(commit);
>  
>  		if (!commit->parents && show_root)
>  			printf("root %s\n", sha1_to_hex(commit->object.sha1));
> diff --git a/builtin/index-pack.c b/builtin/index-pack.c
> index 18f57de..995df39 100644
> --- a/builtin/index-pack.c
> +++ b/builtin/index-pack.c
> @@ -786,7 +786,7 @@ static void sha1_object(const void *data, struct object_entry *obj_entry,
>  			}
>  			if (obj->type == OBJ_COMMIT) {
>  				struct commit *commit = (struct commit *) obj;
> -				commit->buffer = NULL;
> +				detach_commit_buffer(commit);
>  			}
>  			obj->flags |= FLAG_CHECKED;
>  		}
> diff --git a/builtin/log.c b/builtin/log.c
> index 39e8836..226f8f2 100644
> --- a/builtin/log.c
> +++ b/builtin/log.c
> @@ -349,8 +349,7 @@ static int cmd_log_walk(struct rev_info *rev)
>  			rev->max_count++;
>  		if (!rev->reflog_info) {
>  			/* we allow cycles in reflog ancestry */
> -			free(commit->buffer);
> -			commit->buffer = NULL;
> +			free_commit_buffer(commit);
>  		}
>  		free_commit_list(commit->parents);
>  		commit->parents = NULL;
> @@ -1508,8 +1507,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
>  		    reopen_stdout(rev.numbered_files ? NULL : commit, NULL, &rev, quiet))
>  			die(_("Failed to create output files"));
>  		shown = log_tree_commit(&rev, commit);
> -		free(commit->buffer);
> -		commit->buffer = NULL;
> +		free_commit_buffer(commit);
>  
>  		/* We put one extra blank line between formatted
>  		 * patches and this flag is used by log-tree code
> diff --git a/builtin/rev-list.c b/builtin/rev-list.c
> index 9f92905..e012ebe 100644
> --- a/builtin/rev-list.c
> +++ b/builtin/rev-list.c
> @@ -173,8 +173,7 @@ static void finish_commit(struct commit *commit, void *data)
>  		free_commit_list(commit->parents);
>  		commit->parents = NULL;
>  	}
> -	free(commit->buffer);
> -	commit->buffer = NULL;
> +	free_commit_buffer(commit);
>  }
>  
>  static void finish_object(struct object *obj,
> diff --git a/commit.c b/commit.c
> index fbdc480..11a05c1 100644
> --- a/commit.c
> +++ b/commit.c
> @@ -245,6 +245,19 @@ int unregister_shallow(const unsigned char *sha1)
>  	return 0;
>  }
>  
> +void free_commit_buffer(struct commit *commit)
> +{
> +	free(commit->buffer);
> +	commit->buffer = NULL;
> +}
> +
> +const void *detach_commit_buffer(struct commit *commit)
> +{
> +	void *ret = commit->buffer;
> +	commit->buffer = NULL;
> +	return ret;
> +}
> +
>  int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
>  {
>  	const char *tail = buffer;
> diff --git a/commit.h b/commit.h
> index 4df48cb..d72ed43 100644
> --- a/commit.h
> +++ b/commit.h
> @@ -51,6 +51,17 @@ int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long s
>  int parse_commit(struct commit *item);
>  void parse_commit_or_die(struct commit *item);
>  
> +/*
> + * Free any cached object buffer associated with the commit.
> + */
> +void free_commit_buffer(struct commit *);
> +
> +/*
> + * Disassociate any cached object buffer from the commit, but do not free it.
> + * The buffer (or NULL, if none) is returned.
> + */
> +const void *detach_commit_buffer(struct commit *);
> +
>  /* Find beginning and length of commit subject. */
>  int find_commit_subject(const char *commit_buffer, const char **subject);