Re: [PATCH 2/4] fast-export: improve speed by skipping blobs

> We don't care about blobs, or any object other than commits, but in
> order to find the type of object, we are parsing the whole thing, which
> is slow, specially in big repositories with lots of big files.
>
> There's no need for that, we can query the object information with
> sha1_object_info();
>
> Before this, loading the objects of a fresh emacs import, with 260598
> blobs took 14 minutes, after this patch, it takes 3 seconds.

>
> This is the way fast-import does it. Also die if the object is not
> found (like fast-import).
>
> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> ---

>  builtin/fast-export.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/builtin/fast-export.c b/builtin/fast-export.c
> index a4dee14..a5b8da8 100644
> --- a/builtin/fast-export.c
> +++ b/builtin/fast-export.c
> @@ -613,6 +613,7 @@ static void import_marks(char *input_file)
>  		char *line_end, *mark_end;
>  		unsigned char sha1[20];
>  		struct object *object;
> +		enum object_type type;
>  
>  		line_end = strchr(line, '\n');
>  		if (line[0] != ':' || !line_end)
> @@ -627,17 +628,19 @@ static void import_marks(char *input_file)
>  		if (last_idnum < mark)
>  			last_idnum = mark;
>  
> -		object = parse_object(sha1);
> -		if (!object)
> +		type = sha1_object_info(sha1, NULL);
> +		if (type < 0)
> +			die("object not found: %s", sha1_to_hex(sha1));
> +
> +		if (type != OBJ_COMMIT)
> +			/* only commits */
>  			continue;
>  
> +		object = parse_object(sha1);
> +
>  		if (object->flags & SHOWN)
>  			error("Object %s already has a mark", sha1_to_hex(sha1));
>  
> -		if (object->type != OBJ_COMMIT)
> -			/* only commits */
> -			continue;
> -
>  		mark_object(object, mark);
>  
>  		object->flags |= SHOWN;