view hgext/children.py @ 18792:10669e24eb6c

completion: add a debugpathcomplete command

The bash_completion code uses "hg status" to generate a list of
possible completions for commands that operate on files in the
working directory. In a large working directory, this can result
in a single tab-completion being very slow (several seconds) as a
result of checking the status of every file, even when there is no
need to check status or no possible matches.

The new debugpathcomplete command gains performance in a few simple
ways:

* Allow completion to operate on just a single directory. When used
  to complete the right commands, this considerably reduces the
  number of completions returned, at no loss in functionality.

* Never check the status of files. For completions that really must
  know if a file is modified, it is faster to use status:

  hg status -nm 'glob:myprefix**'

Performance:

Here are the commands used by bash_completion to complete, run in
the root of the mozilla-central working dir (~77,000 files) and
another repo (~165,000 files):

All "normal state" files (used by e.g. remove, revert):

                            mozilla    other
  status -nmcd 'glob:**'       1.77     4.10 sec
  debugpathcomplete -f -n      0.53     1.26
  debugpathcomplete -n         0.17     0.41

("-f" means "complete full paths", rather than the current directory)

Tracked files matching "a":

                            mozilla    other
  status -nmcd 'glob:a**'      0.26     0.47
  debugpathcomplete -f -n a    0.10     0.24
  debugpathcomplete -n a       0.10     0.22

We should be able to further improve completion performance once
the critbit work lands. Right now, our performance is limited by
the need to iterate over all keys in the dirstate.

# Mercurial extension to provide the 'hg children' command
#
# Copyright 2007 by Intevation GmbH <[e-mail]>
#
# Author(s):
# Thomas Arendsen Hein <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''command to display child changesets (DEPRECATED)

This extension is deprecated. You should use :hg:`log -r
"children(REV)"` instead.
'''

from mercurial import cmdutil, commands
from mercurial.commands import templateopts
from mercurial.i18n import _

testedwith = 'internal'

def children(ui, repo, file_=None, **opts):
    """show the children of the given or working directory revision

    Print the children of the working directory's revisions. If a
    revision is given via -r/--rev, the children of that revision will
    be printed. If a file argument is given, revision in which the
    file was last changed (after the working directory revision or the
    argument to --rev if given) is printed.
    """
    rev = opts.get('rev')
    if file_:
        ctx = repo.filectx(file_, changeid=rev)
    else:
        ctx = repo[rev]

    displayer = cmdutil.show_changeset(ui, repo, opts)
    for cctx in ctx.children():
        displayer.show(cctx)
    displayer.close()

cmdtable = {
    "children":
        (children,
         [('r', 'rev', '',
           _('show children of the specified revision'), _('REV')),
         ] + templateopts,
         _('hg children [-r REV] [FILE]')),
}

commands.inferrepo += " children"