Mercurial > hg
view hgext/pager.py @ 30561:7c0c722d568d
bdiff: early pruning of common prefix before doing expensive computations
It seems quite common that files don't change completely. New lines are often
pretty much appended, and modifications will often only change a small section
of the file which on average will be in the middle.
There can thus be a big win by pruning a common prefix before starting the more
expensive search for longest common substrings.
Worst case, it will scan through a long sequence of similar bytes without
encountering a newline. Splitlines will then have to do the same again ...
twice for each side. If similar lines are found, splitlines will save the
double iteration and hashing of the lines ... plus there will be less lines to
find common substrings in.
This change might in some cases make the algorith pick shorter or less optimal
common substrings. We can't have the cake and eat it.
This make hg --time bundle --base null -r 4.0 go from 14.5 to 15 s - a 3%
increase.
On mozilla-unified:
perfbdiff -m 3041e4d59df2
! wall 0.053088 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) to
! wall 0.024618 comb 0.020000 user 0.020000 sys 0.000000 (best of 116)
perfbdiff 0e9928989e9c --alldata --count 10
! wall 0.702075 comb 0.700000 user 0.700000 sys 0.000000 (best of 15) to
! wall 0.579235 comb 0.580000 user 0.580000 sys 0.000000 (best of 18)
author | Mads Kiilerich <madski@unity3d.com> |
---|---|
date | Wed, 16 Nov 2016 19:45:35 +0100 |
parents | 39d13b8c101d |
children | a150173da1c1 |
line wrap: on
line source
# pager.py - display output using a pager # # Copyright 2008 David Soria Parra <dsp@php.net> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. # # To load the extension, add it to your configuration file: # # [extension] # pager = # # Run 'hg help pager' to get info on configuration. '''browse command output with an external pager To set the pager that should be used, set the application variable:: [pager] pager = less -FRX If no pager is set, the pager extensions uses the environment variable $PAGER. If neither pager.pager, nor $PAGER is set, no pager is used. You can disable the pager for certain commands by adding them to the pager.ignore list:: [pager] ignore = version, help, update You can also enable the pager only for certain commands using pager.attend. Below is the default list of commands to be paged:: [pager] attend = annotate, cat, diff, export, glog, log, qdiff Setting pager.attend to an empty value will cause all commands to be paged. If pager.attend is present, pager.ignore will be ignored. Lastly, you can enable and disable paging for individual commands with the attend-<command> option. This setting takes precedence over existing attend and ignore options and defaults:: [pager] attend-cat = false To ignore global commands like :hg:`version` or :hg:`help`, you have to specify them in your user configuration file. To control whether the pager is used at all for an individual command, you can use --pager=<value>:: - use as needed: `auto`. - require the pager: `yes` or `on`. - suppress the pager: `no` or `off` (any unrecognized value will also work). ''' from __future__ import absolute_import import atexit import os import signal import subprocess import sys from mercurial.i18n import _ from mercurial import ( cmdutil, commands, dispatch, extensions, util, ) # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should # be specifying the version(s) of Mercurial they are tested with, or # leave the attribute unspecified. testedwith = 'ships-with-hg-core' def _runpager(ui, p): pager = subprocess.Popen(p, shell=True, bufsize=-1, close_fds=util.closefds, stdin=subprocess.PIPE, stdout=util.stdout, stderr=util.stderr) # back up original file objects and descriptors olduifout = ui.fout oldstdout = util.stdout stdoutfd = os.dup(util.stdout.fileno()) stderrfd = os.dup(util.stderr.fileno()) # create new line-buffered stdout so that output can show up immediately ui.fout = util.stdout = newstdout = os.fdopen(util.stdout.fileno(), 'wb', 1) os.dup2(pager.stdin.fileno(), util.stdout.fileno()) if ui._isatty(util.stderr): os.dup2(pager.stdin.fileno(), util.stderr.fileno()) @atexit.register def killpager(): if util.safehasattr(signal, "SIGINT"): signal.signal(signal.SIGINT, signal.SIG_IGN) pager.stdin.close() ui.fout = olduifout util.stdout = oldstdout # close new stdout while it's associated with pager; otherwise stdout # fd would be closed when newstdout is deleted newstdout.close() # restore original fds: stdout is open again os.dup2(stdoutfd, util.stdout.fileno()) os.dup2(stderrfd, util.stderr.fileno()) pager.wait() def uisetup(ui): if '--debugger' in sys.argv or not ui.formatted(): return # chg has its own pager implementation argv = sys.argv[:] if 'chgunix' in dispatch._earlygetopt(['--cmdserver'], argv): return def pagecmd(orig, ui, options, cmd, cmdfunc): p = ui.config("pager", "pager", os.environ.get("PAGER")) usepager = False always = util.parsebool(options['pager']) auto = options['pager'] == 'auto' if not p: pass elif always: usepager = True elif not auto: usepager = False else: attend = ui.configlist('pager', 'attend', attended) ignore = ui.configlist('pager', 'ignore') cmds, _ = cmdutil.findcmd(cmd, commands.table) for cmd in cmds: var = 'attend-%s' % cmd if ui.config('pager', var): usepager = ui.configbool('pager', var) break if (cmd in attend or (cmd not in ignore and not attend)): usepager = True break setattr(ui, 'pageractive', usepager) if usepager: ui.setconfig('ui', 'formatted', ui.formatted(), 'pager') ui.setconfig('ui', 'interactive', False, 'pager') if util.safehasattr(signal, "SIGPIPE"): signal.signal(signal.SIGPIPE, signal.SIG_DFL) _runpager(ui, p) return orig(ui, options, cmd, cmdfunc) # Wrap dispatch._runcommand after color is loaded so color can see # ui.pageractive. Otherwise, if we loaded first, color's wrapped # dispatch._runcommand would run without having access to ui.pageractive. def afterloaded(loaded): extensions.wrapfunction(dispatch, '_runcommand', pagecmd) extensions.afterloaded('color', afterloaded) def extsetup(ui): commands.globalopts.append( ('', 'pager', 'auto', _("when to paginate (boolean, always, auto, or never)"), _('TYPE'))) attended = ['annotate', 'cat', 'diff', 'export', 'glog', 'log', 'qdiff']