import os

from mercurial.node import nullid

from mercurial.i18n import _

from mercurial import util, mdiff, cmdutil, scmutil

from mercurial import localrepo, changelog, manifest, filelog, revlog

class unionrevlog(revlog.revlog):

    def __init__(self, opener, indexfile, revlog2, linkmapper):

        # How it works:

        # To retrieve a revision, we just need to know the node id so we can

        # look it up in revlog2.

        #

        opener = scmutil.readonlyvfs(opener)

        revlog.revlog.__init__(self, opener, indexfile)

        self.revlog2 = revlog2

        n = len(self)

        self.repotiprev = n - 1

        for rev2 in self.revlog2:

            rev = self.revlog2.index[rev2]

            # rev numbers - in revlog2, very different from self.rev

            _start, _csize, _rsize, _base, linkrev, p1rev, p2rev, node = rev

                link = n

                link = linkmapper(linkrev)

            if node in self.nodemap:

                # this happens for the common revlog revisions

                self.bundlerevs.add(self.nodemap[node])

                continue

            text = revlog.revlog.revision(self, rev)

            # already cached

        return text

    def addrevision(self, text, transaction, link, p1=None, p2=None, d=None):

        raise NotImplementedError

    def addgroup(self, revs, linkmapper, transaction):

        raise NotImplementedError

    def strip(self, rev, minlink):

        raise NotImplementedError

    def checksize(self):

        raise NotImplementedError

class unionchangelog(unionrevlog, changelog.changelog):

    def __init__(self, opener, opener2):

        changelog.changelog.__init__(self, opener)

        linkmapper = None

        changelog2 = changelog.changelog(opener2)

        unionrevlog.__init__(self, opener, self.indexfile, changelog2,

                             linkmapper)

class unionmanifest(unionrevlog, manifest.manifest):

    def __init__(self, opener, opener2, linkmapper):

        manifest.manifest.__init__(self, opener)

        manifest2 = manifest.manifest(opener2)

        unionrevlog.__init__(self, opener, self.indexfile, manifest2,

                             linkmapper)

class unionfilelog(unionrevlog, filelog.filelog):

    def __init__(self, opener, path, opener2, linkmapper, repo):

        filelog.filelog.__init__(self, opener, path)

        filelog2 = filelog.filelog(opener2, path)

        unionrevlog.__init__(self, opener, self.indexfile, filelog2,

                             linkmapper)

        self._repo = repo

    def _file(self, f):

        self._repo.file(f)

class unionpeer(localrepo.localpeer):

    def canpush(self):

        return False

class unionrepository(localrepo.localrepository):

    def __init__(self, ui, path, path2):

        localrepo.localrepository.__init__(self, ui, path)

        self.ui.setconfig('phases', 'publish', False)

        self._url = 'union:%s+%s' % (util.expandpath(path),

        return False

    def peer(self):

        return unionpeer(self)

    def getcwd(self):

def instance(ui, path, create):

    if create:

        raise util.Abort(_('cannot create new union repository'))

    parentpath = ui.config("bundle", "mainreporoot", "")

    if not parentpath:

        # Try to make the full path relative so we get a nice, short URL.

        # In particular, we don't want temp dir names in test outputs.

        cwd = os.getcwd()

        if parentpath == cwd:

            parentpath = ''

        else:

            if parentpath.startswith(cwd):

                parentpath = parentpath[len(cwd):]

    if path.startswith('union:'):

        s = path.split(":", 1)[1].split("+", 1)

        if len(s) == 1:

            repopath, repopath2 = parentpath, s[0]