From: martin rudalics <rudalics@gmx.at>
To: Eli Zaretskii <eliz@gnu.org>
Cc: acm@muc.de, 16526@debbugs.gnu.org
Subject: bug#16526: 24.3.50; scroll-conservatively & c-mode regression
Date: Mon, 27 Jan 2014 09:20:57 +0100 [thread overview]
Message-ID: <52E616E9.2040807@gmx.at> (raw)
In-Reply-To: <831tzubqxw.fsf@gnu.org>
> After beginning-of-buffer jumps to point-min, redisplay kicks in.
> Since scroll-conservatively is set to a large value, redisplay first
> tries to see whether it can bring point into view by scrolling the
> window as little as possible. It calls try_scrolling, which at some
> point (around line 15000) tries to see whether the new location of
> point is close enough to the current window start. It does so by
> calling move_it_to, which simulates the display. While doing so,
> move_it_to hits a portion of text with font-lock properties, and calls
> JIT Lock to fontify them.
Well... try_scrolling could detect that `point' is some 15000 lines away
from the current window start so trying to scroll the window as little
as possible might not be worth the effort.
> And here's where things go awry: For some reason, the CC Mode
> fontification code decides it needs to scan the buffer backwards,
> starting from EOB. So it goes temporarily to EOB (this is why I saw
> point being there), and scans all the way back, I think in this loop
> from c-append-lower-brace-pair-to-state-cache, which is called with
> its first argument FROM set to EOB:
But it's redisplay which temporarily puts `point' at EOB and triggers
the fontification subsystem to "work" at that position?
> This loop takes a lot of time, of course, and is a waste of time,
> since eventually try_scrolling comes to the correct conclusion that
> scrolling is impossible, and instead recenters at BOB.
Are you sure that try_scrolling doesn't call this loop over and over
again?
> Why does CC Mode decide to go from EOB backwards, I don't know;
> presumably, this is decided by c-parse-state-get-strategy as part of
> c-parse-state-1.
This seems obvious. To decide whether code shall be fontified this way
or another it has to decide whether the code is part of a comment and
find that comment's start. As long as it is not aware of the fact that
`point' is already at BOB, obviously.
martin
next prev parent reply other threads:[~2014-01-27 8:20 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.12613.1390467262.10748.bug-gnu-emacs@gnu.org>
2014-01-23 8:53 ` bug#16526: 24.3.50; scroll-conservatively & c-mode regression martin rudalics
2014-01-24 15:45 ` martin rudalics
2014-01-24 20:48 ` Alan Mackenzie
[not found] ` <lbujij$1scv$1@colin.muc.de>
2014-01-25 3:50 ` Juanma Barranquero
2014-01-25 9:23 ` martin rudalics
[not found] ` <52E38286.1050306@gmx.at>
2014-01-25 10:30 ` Eli Zaretskii
2014-01-25 14:58 ` martin rudalics
[not found] ` <52E3D131.2090705@gmx.at>
2014-01-25 16:30 ` Eli Zaretskii
2014-01-25 16:48 ` martin rudalics
2014-01-25 17:29 ` Eli Zaretskii
2014-01-25 18:25 ` martin rudalics
[not found] ` <52E4019C.5080905@gmx.at>
2014-01-25 18:31 ` Eli Zaretskii
2014-01-25 18:40 ` Eli Zaretskii
2014-01-26 11:20 ` martin rudalics
[not found] ` <52E4EF61.3050404@gmx.at>
2014-01-26 17:20 ` Eli Zaretskii
2014-01-26 20:43 ` Alan Mackenzie
2014-01-27 8:21 ` martin rudalics
[not found] ` <52E61704.6050807@gmx.at>
2014-01-27 14:49 ` Stefan Monnier
[not found] ` <jwvvbx5fq2b.fsf-monnier+emacsbugs@gnu.org>
2014-01-27 17:25 ` martin rudalics
[not found] ` <52E69695.5040703@gmx.at>
2014-01-28 0:16 ` Stefan Monnier
2014-01-29 22:36 ` Alan Mackenzie
[not found] ` <20140129223626.GD3092@acm.acm>
2014-01-30 7:37 ` martin rudalics
2014-01-30 13:47 ` martin rudalics
[not found] ` <52EA57D6.5080403@gmx.at>
2014-01-30 17:15 ` Eli Zaretskii
2014-01-30 18:58 ` martin rudalics
[not found] ` <52EAA0C9.1090000@gmx.at>
2014-02-01 10:41 ` Eli Zaretskii
2014-02-02 13:18 ` martin rudalics
2014-02-02 17:40 ` Alan Mackenzie
[not found] ` <20140202174050.GA5365@acm.acm>
2014-02-02 18:07 ` Eli Zaretskii
2014-02-02 19:20 ` Alan Mackenzie
2014-02-02 20:53 ` Eli Zaretskii
2014-02-05 23:00 ` Alan Mackenzie
2014-02-06 6:01 ` Eli Zaretskii
2014-06-22 16:49 ` Eli Zaretskii
2014-06-22 19:32 ` Alan Mackenzie
2014-06-22 20:04 ` Eli Zaretskii
2014-06-25 21:32 ` Alan Mackenzie
2014-06-26 2:51 ` Stefan Monnier
2014-06-27 20:34 ` Alan Mackenzie
2014-06-27 22:33 ` Stefan Monnier
2014-06-27 22:54 ` Stefan Monnier
[not found] ` <jwv8uoim0bm.fsf-monnier+emacsbugs@gnu.org>
2014-06-28 13:00 ` Alan Mackenzie
2014-06-28 14:00 ` martin rudalics
2014-06-28 14:34 ` Stefan Monnier
[not found] ` <53AECA88.7010401@gmx.at>
2014-06-28 14:55 ` Alan Mackenzie
2014-06-28 15:12 ` Eli Zaretskii
2014-06-28 16:30 ` Alan Mackenzie
2014-06-29 8:44 ` martin rudalics
2014-06-29 9:17 ` Alan Mackenzie
2014-06-29 10:06 ` martin rudalics
[not found] ` <53AFE536.7010407@gmx.at>
2014-06-29 12:48 ` Alan Mackenzie
2014-06-29 14:18 ` martin rudalics
2014-06-29 14:41 ` Alan Mackenzie
[not found] ` <20140629144151.GD2948@acm.acm>
2014-06-29 16:01 ` martin rudalics
[not found] ` <53B03876.9070307@gmx.at>
2014-06-29 17:49 ` Alan Mackenzie
2014-06-30 7:55 ` martin rudalics
2014-06-30 13:48 ` Stefan Monnier
[not found] ` <53B117D6.1050306@gmx.at>
2014-07-02 20:05 ` Alan Mackenzie
[not found] ` <20140702200522.GB3823@acm.acm>
2014-07-03 1:57 ` Stefan Monnier
2014-07-03 8:40 ` martin rudalics
[not found] ` <jwv61jf2owy.fsf-monnier+emacsbugs@gnu.org>
2014-07-03 14:59 ` Stefan Monnier
2014-07-04 18:27 ` Alan Mackenzie
2014-07-04 19:11 ` Stefan Monnier
2014-07-04 19:43 ` Stefan Monnier
2014-07-05 2:23 ` Stefan Monnier
2014-07-06 13:48 ` Alan Mackenzie
2014-07-07 1:52 ` Stefan Monnier
2014-07-07 7:07 ` martin rudalics
[not found] ` <jwvsimevsvz.fsf-monnier+emacsbugs@gnu.org>
2014-07-07 7:07 ` martin rudalics
2014-07-05 20:25 ` Alan Mackenzie
2014-07-05 23:06 ` Stefan Monnier
2014-07-04 19:29 ` Alan Mackenzie
2014-07-05 1:52 ` Stefan Monnier
2014-07-05 7:47 ` Alan Mackenzie
2014-06-29 22:14 ` Stefan Monnier
[not found] ` <jwvionjjrn7.fsf-monnier+emacsbugs@gnu.org>
2014-07-02 18:40 ` Alan Mackenzie
[not found] ` <20140702184013.GA3823@acm.acm>
2014-07-02 19:40 ` Stefan Monnier
[not found] ` <jwvsimpksv1.fsf-monnier+emacsbugs@gnu.org>
2014-06-28 17:33 ` Alan Mackenzie
[not found] ` <20140628173334.GB2632@acm.acm>
2014-06-29 21:39 ` Stefan Monnier
2014-01-29 21:52 ` Alan Mackenzie
2014-01-30 17:16 ` Eli Zaretskii
2014-01-31 20:00 ` Alan Mackenzie
2014-01-31 20:16 ` Eli Zaretskii
2014-01-27 8:20 ` martin rudalics [this message]
2014-01-27 16:23 ` Eli Zaretskii
2014-01-27 17:26 ` martin rudalics
2014-01-26 11:19 ` martin rudalics
2014-01-25 20:27 ` bug#16526: 24.3.50; scroll-conservatively & c-mode regression. The purpose of revision 116070 Alan Mackenzie
[not found] ` <20140125202721.GA3630@acm.acm>
2014-01-25 23:02 ` Stefan Monnier
2014-01-26 3:41 ` Eli Zaretskii
2014-01-26 9:54 ` Alan Mackenzie
2014-01-26 16:33 ` Eli Zaretskii
2014-01-26 17:35 ` Eli Zaretskii
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=52E616E9.2040807@gmx.at \
--to=rudalics@gmx.at \
--cc=16526@debbugs.gnu.org \
--cc=acm@muc.de \
--cc=eliz@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).