mercurial/peer.py

convert: support incremental conversion with hg subrepos

This was implied in issue3486, which specifically asked for subrepo support in
lfconvert.  Now that lfconvert uses the convert extension internally when going
to normal files, the issue is half fixed.  But now even non largefile repos
benefit when other transformations are needed.

Supporting a full subrepo tree conversion from a single command doesn't seem
reasonable, given the number of options that can be provided, and the
transformations that would need to occur when entering a subrepo (consider
'filemap' paths).  Instead, this allows the user to incrementally convert each
hg subrepo from bottom up like so:

  # so convert knows the dest type when it sees a non empty dest dir
  $ hg init converted

  $ hg convert orig/sub1 converted/sub1
  $ hg convert orig/sub2 converted/sub2
  $ hg convert orig converted

This allows different options to be applied to different subrepos more readily.
It assumes the shamap is in the default location in each converted subrepo for
simplicity.  It also allows for a subrepo to be cloned into place, in case _it_
doesn't need a conversion.  I was able to convert away from using
largefiles/bfiles in several subrepos with this mechanism.

# peer.py - repository base classes for mercurial
#
# Copyright 2005, 2006 Matt Mackall <[e-mail]>
# Copyright 2006 Vadim Gelfer <[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.

from i18n import _
import error

class peerrepository(object):

    def capable(self, name):
        '''tell whether repo supports named capability.
        return False if not supported.
        if boolean capability, return True.
        if string capability, return string.'''
        caps = self._capabilities()
        if name in caps:
            return True
        name_eq = name + '='
        for cap in caps:
            if cap.startswith(name_eq):
                return cap[len(name_eq):]
        return False

    def requirecap(self, name, purpose):
        '''raise an exception if the given capability is not present'''
        if not self.capable(name):
            raise error.CapabilityError(
                _('cannot %s; remote repository does not '
                  'support the %r capability') % (purpose, name))

    def local(self):
        '''return peer as a localrepo, or None'''
        return None

    def peer(self):
        return self

    def canpush(self):
        return True

    def close(self):
        pass