Re: [PATCH v4 2/2] diff: add SUBMODULE_DIFF format to display submodule diff

> diff --git a/submodule.c b/submodule.c
> index 1b5cdfb7e784..36f8fd00c3ce 100644
> --- a/submodule.c
> +++ b/submodule.c
> @@ -333,6 +333,73 @@ static void print_submodule_summary(struct rev_info *rev, FILE *f,
>  	strbuf_release(&sb);
>  }
>  
> +void show_submodule_diff(FILE *f, const char *path,
> +		const char *line_prefix,
> +		unsigned char one[20], unsigned char two[20],
> +		unsigned dirty_submodule, const char *meta,
> +		const char *a_prefix, const char *b_prefix,
> +		const char *reset)
> +{
> +	struct child_process cp = CHILD_PROCESS_INIT;
> +	struct strbuf sb = STRBUF_INIT;
> +	struct strbuf submodule_git_dir = STRBUF_INIT;
> +	const char *git_dir, *message = NULL;
> +	int create_dirty_diff = 0;
> +	FILE *diff;
> +	char c;