From: Jeff King <peff@peff.net>
Date: Tue, 12 Mar 2013 11:03:55 GMT
Subject: Re: [PATCH v2 3/4] config: make parsing stack struct independent from actual data source
Message-ID: <20130312110355.GE11340@sigill.intra.peff.net>
In-Reply-To: <20130310165940.GD1136@sandbox-ub.fritz.box>

On Sun, Mar 10, 2013 at 05:59:40PM +0100, Heiko Voigt wrote:

> diff --git a/config.c b/config.c
> index f55c43d..fe1c0e5 100644
> --- a/config.c
> +++ b/config.c
> @@ -10,20 +10,42 @@
>  #include "strbuf.h"
>  #include "quote.h"
>  
> -typedef struct config_file {
> -	struct config_file *prev;
> -	FILE *f;
> +struct config_source {
> +	struct config_source *prev;
> +	void *data;

Would a union be more appropriate here? We do not ever have to pass it
directly as a parameter, since we pass the "struct config_source" to the
method functions.

It's still possible to screw up using a union, but it's slightly harder
than screwing up using a void pointer. And I do not think we need the
run-time flexibility offered by the void pointer in this case.

> +static int config_file_fgetc(struct config_source *conf)
> +{
> +	FILE *f = conf->data;
> +	return fgetc(f);
> +}

This could become just:

  return fgetc(conf->u.f);

and so forth (might it make sense to give "f" a more descriptive name,
as we are adding other sources?).

-Peff