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From: Junio C Hamano <gitster@pobox.com>
To: Jonathan Nieder <jrnieder@gmail.com>
Cc: Kaartic Sivaraam <kaarticsivaraam91196@gmail.com>,
	Michael Haggerty <mhagger@alum.mit.edu>,
	Alex Riesen <raa.lkml@gmail.com>,
	git@vger.kernel.org
Subject: Re: [PATCH] for_each_string_list_item(): behave correctly for empty list
Date: Wed, 20 Sep 2017 12:54:15 +0900	[thread overview]
Message-ID: <xmqqd16mowig.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20170920023008.GB126984@aiede.mtv.corp.google.com> (Jonathan Nieder's message of "Tue, 19 Sep 2017 19:30:08 -0700")

Jonathan Nieder <jrnieder@gmail.com> writes:

> ...  But a quick test with gcc 4.8.4
> -O2 finds that at least this compiler does not contain such an
> optimization.  The overhead Michael Haggerty mentioned is real.

Still, I have a feeling that users of string_list wouldn't care 
the overhead of single pointer NULL-ness check.

 - apply.c collects conflicted paths and reports them with fprintf().

 - builtin/clean.c uses the function to walk the list of paths to be
   removed, and either does a human interaction (for "-i" codepath)
   or goes to the filesystem to remove things.

 - builtin/config.c uses it in get_urlmatch() in preparation for
   doing network-y things.

 - builtin/describe.c walks the list of exclude and include patterns
   to run wildmatch on the candidate reference name to filter it out.

 ...

In all of these examples, what happens for each item in the loop
seems to me far heavier than the overhead this macro adds.

So...



  reply	other threads:[~2017-09-20  3:54 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-15 16:00 [PATCH] for_each_string_list_item(): behave correctly for empty list Michael Haggerty
2017-09-15 18:43 ` Jonathan Nieder
2017-09-16  4:06   ` Michael Haggerty
2017-09-16 11:51     ` SZEDER Gábor
2017-09-17 10:19       ` Michael Haggerty
2017-09-19 14:38     ` Kaartic Sivaraam
2017-09-20  1:38       ` Junio C Hamano
2017-09-20  1:43         ` Jonathan Nieder
2017-09-20  5:14           ` Junio C Hamano
2017-09-20  2:30       ` Jonathan Nieder
2017-09-20  3:54         ` Junio C Hamano [this message]
2017-09-20  5:27           ` [PATCH v2] for_each_string_list_item: avoid undefined behavior " Jonathan Nieder
2017-09-20  5:40             ` Junio C Hamano
2017-09-20  7:00             ` Michael Haggerty
2017-09-20  7:40             ` Kaartic Sivaraam
2017-09-20 12:22             ` [PATCH v2] doc: camelCase the config variables to improve readability Kaartic Sivaraam
2017-09-20 16:28             ` [PATCH v2] for_each_string_list_item: avoid undefined behavior for empty list Andreas Schwab
2017-09-20 17:31               ` Jonathan Nieder
2017-09-20 21:51                 ` Andreas Schwab
2017-09-21  1:12                   ` Junio C Hamano
2017-09-21 15:39                     ` Andreas Schwab
2017-09-20  7:35         ` [PATCH] for_each_string_list_item(): behave correctly " Kaartic Sivaraam
2017-09-17  0:59 ` Junio C Hamano
2017-09-17 10:24   ` Michael Haggerty
2017-09-18  0:37     ` Junio C Hamano
2017-09-19  0:08       ` Stefan Beller
2017-09-19  6:51         ` Michael Haggerty
2017-09-19 13:38           ` SZEDER Gábor
2017-09-19 13:45             ` SZEDER Gábor

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