view mercurial/namespaces.py @ 23579:e1c39f207719

subrepo: drop the 'ui' parameter to revert()

This no longer needs to be explicitly passed because the subrepo object tracks
the 'ui' reference since fcbc66b5da6a.  See the change to 'archive' for details
about the differences between the output level in the root repo and subrepo 'ui'
object.

The only use for 'ui' in revert is to emit status and warning messages, and to
check the verbose flag prior to printing the action to be performed on a file.

The local repo's ui was already being used to print a warning message in
wctx.forget() and for 'ui.slash' when walking dirstate in the repo.status()
call.  Unlike other methods where the matcher is passed along and narrowed, a
new matcher is created in each repo, and therefore the bad() method already used
the local repo's ui.

from i18n import _
from mercurial import util

def tolist(val):
    """
    a convenience method to return an empty list instead of None
    """
    if val is None:
        return []
    else:
        return [val]

class namespaces(object):
    """
    provides an interface to register a generic many-to-many mapping between
    some (namespaced) names and nodes. The goal here is to control the
    pollution of jamming things into tags or bookmarks (in extension-land) and
    to simplify internal bits of mercurial: log output, tab completion, etc.

    More precisely, we define a list of names (the namespace) and  a mapping of
    names to nodes. This name mapping returns a list of nodes.

    Furthermore, each name mapping will be passed a name to lookup which might
    not be in its domain. In this case, each method should return an empty list
    and not raise an error.

    We'll have a dictionary '_names' where each key is a namespace and
    its value is a dictionary of functions:
      'namemap': function that takes a name and returns a list of nodes
    """

    _names_version = 0

    def __init__(self):
        self._names = util.sortdict()

        addns = self.addnamespace

        # we need current mercurial named objects (bookmarks, tags, and
        # branches) to be initialized somewhere, so that place is here
        addns("bookmarks",
              lambda repo, name: tolist(repo._bookmarks.get(name)))

        addns("tags",
              lambda repo, name: tolist(repo._tagscache.tags.get(name)))

        addns("branches",
              lambda repo, name: tolist(repo.branchtip(name)))

    def addnamespace(self, namespace, namemap, order=None):
        """
        register a namespace

        namespace: the name to be registered (in plural form)
        namemap: function that inputs a node, output name(s)
        order: optional argument to specify the order of namespaces
               (e.g. 'branches' should be listed before 'bookmarks')
        """
        val = {'namemap': namemap}
        if order is not None:
            self._names.insert(order, namespace, val)
        else:
            self._names[namespace] = val

    def singlenode(self, repo, name):
        """
        Return the 'best' node for the given name. Best means the first node
        in the first nonempty list returned by a name-to-nodes mapping function
        in the defined precedence order.

        Raises a KeyError if there is no such node.
        """
        for ns, v in self._names.iteritems():
            n = v['namemap'](repo, name)
            if n:
                # return max revision number
                if len(n) > 1:
                    cl = repo.changelog
                    maxrev = max(cl.rev(node) for node in n)
                    return cl.node(maxrev)
                return n[0]
        raise KeyError(_('no such name: %s') % name)