Re: [PATCH 1/6] give "nbuf" strbuf a more meaningful name

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Jan 31, 2016, 11:54 UTC
Message-ID: <alpine.DEB.2.20.1601311245170.2964@virtualbox>
In-Reply-To: <20160131112526.GA5116@sigill.intra.peff.net>

Hi Peff,

On Sun, 31 Jan 2016, Jeff King wrote:

Show 10 quoted lines

> > It's a shame that we can't just factor out this common
> > code, but I don't think it's quite long enough to merit
> > the boilerplate. The interesting part of each function
> > happens inside the loop. If C had lambdas, we could do
> > something like:
> > 
> >   foreach_path_from(stdin, nul_term_line) {
> >         /* now do something interesting with "buf"
> >            and some other local variables */
> >   }

Technically, we do not have to do lambdas for that paradigm, we could introduce a new data type and a reader, i.e. something like this:

struct path_reader {
	FILE *in;
	int nul_term_line;
	struct strbuf path;
};
#define PATH_READER_INIT { NULL, STRBUF_INIT };

int read_next_path(struct path_reader *reader, FILE *in, int nul_term_line)
{
	if (!reader->in) {
		... [initialize] ...
	}

	... [read and possibly unquote path] ...
}

void cleanup_path_reader(struct path_reader *reader)
{
	if (reader->in) {
		fclose(reader->in);
		reader->in = NULL;
	}

	strbuf_release(&reader->buf);
}

And then the repeated code could be replaced by something like this:

	struct path_reader path_reader = PATH_READER_INIT;

	while (read_next_path(&reader, stdin, 1)) {
		... [work with reader->path.buf] ...
	}

	cleanup_path_reader();

Probably this is actually not limited to path names, so the functions should be renamed...

(totally untested, of course...)

Ciao, Dscho