From: lee <lee@yun.yagibdah.de>
To: help-gnu-emacs@gnu.org
Subject: Re: iterating over a list while removing elements
Date: Thu, 20 Mar 2014 18:34:58 +0100 [thread overview]
Message-ID: <87lhw4vkn1.fsf@yun.yagibdah.de> (raw)
In-Reply-To: <slrnlijoej.9nq.joost.m.kremers@j.kremers4.news.arnhem.chello.nl> (Joost Kremers's message of "19 Mar 2014 18:28:35 GMT")
Joost Kremers <joost.m.kremers@gmail.com> writes:
> Note, BTW, that file-directory-p returns t for "." and "..". It seems to
> me that the only two names that directory-files could return that you
> really want to exclude are those two,[1] so there's no need for
> multisearch-directory-ref-p, I think. (Or is there?)
The idea is that (file-directory-p "..") may cause a file look-up which
can be avoided by string-matching. String-matching is some magnitudes
faster than file look-ups.
When I try multisearch with with a source file from a somewhat large
application that has a bunch of #includes, it takes a couple (like 15 or
so) seconds to create the list of files, and it creates 123 additional
buffers. When you look at the source of multisearch[1], you`ll see that
there can be a huge amount of look-ups, many of them on non-existing
files.
How does the disk cache deal with non-existing files? The
meta-information is probably in the cache (more or less), yet there can
be no information for non-existing files. Creating the list of files is
actually what takes most of the time. Visiting them is really fast;
searching doesn`t take long, either.
[1]: https://github.com/lee-/emacs/tree/master/multisearch
> [1] Files can have dots in their names, so what do you want to do with a
> file whose name ends in a dot? Or two? Unlikely, for sure, but not
> impossible.
Hm. I haven`t considered this possibility ... I`ll have to change the
regexps used in `multisearch-directory-ref-p' ...
Hmmmm ... I`m testing this again, and there seems to be a bug
somewhere. I`ll fix that tomorrow or so ...
--
Knowledge is volatile and fluid. Software is power.
next prev parent reply other threads:[~2014-03-20 17:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.17526.1395229207.10748.help-gnu-emacs@gnu.org>
2014-03-19 13:12 ` iterating over a list while removing elements Pascal J. Bourguignon
2014-03-19 18:28 ` Joost Kremers
2014-03-20 17:34 ` lee [this message]
2014-03-20 20:16 ` Eli Zaretskii
2014-03-21 5:25 ` lee
2014-03-20 16:33 ` lee
2014-03-19 11:39 lee
2014-03-19 12:39 ` Stefan
2014-03-20 16:02 ` lee
2014-03-19 13:11 ` Michael Albinus
2014-03-20 16:10 ` lee
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