Re: [PATCH v2] Refactor recv_sideband()

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 28, 2016, 05:20 UTC
Message-ID: <xmqqy45panyw.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <146705966655.11886.6547584744094511110@typhoon>

Lukas Fleischer <lfleischer@lfos.de> writes:

> I do not see how using fwrite() buys us anything. Neither fwrite() nor
> fputs() nor fprintf() guarantee to call write() only once.

That is not the point.

Your first attempt split what used to be a single fprintf(), which (as Nico explained) ordinarily will result in an atomic write as long as you are feeding a reasonable size buf, into two calls, _guaranteeing_ that it will _not_ be atomic. That was a bad change.

By accumulating things in strbuf (instead of char[] with hand-rolled counting logic like the original before your patch) and feeding the result out to a single fprintf(stderr, "%s", buf.buf), you will not be making anything _worse_ compared to the code before your patch. At the same time, you _are_ making the logic to accumulate the output to a buffer far easier to read, which would be a net plus.