hgext/children.py

log: remove increasing windows usage in fastpath

The purpose of increasing windows is to allow backwards iteration on the
filelog  at a reasonable cost.
But is it needed?
 - if follow is False, we have no reason to iterate backwards.
   We basically just want to walk the complete filelog and yield all revisions
   within the revision range. We can do this forward or
   backwards, as it only reads the index.
 - when follow is True, we need to examine the contents of the filelog, and to
   do this efficiently we need to read the filelog forward.
   And on the other hand, to track ancestors and copies, we need to process
   revisions backwards. But is it necessary to use increasing windows
   for this?
   We can iterate over the complete filelog forward, stack the revisions, and
   read the reversed(pile), it does the same thing with a more readable code.

# 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'''

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


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]')),
}