namespaces: introduce a generic way to map between names and nodes
This patch begins the work to provide a way to register a namespace to handle
'names'. Benefits of this would be,
- improved templating: This would provide {name} which could output any branch,
bookmark, tag, or any extension registered namespace all without having the
extension doing any extra work
- improved tab completion: Since this provides a single source of all 'names',
tab completion would not need to know of each namespace
- changeset lookup: Similar to before, a unified place to get all 'names' will
allow finding changesets without any extension code having to reimplement
this
Also, d226fe36e362 has shown us that for internal code which expects a certain
type of method or behavior, we should provide an easy way for extensions to
check this behavior.
from mercurial import util
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()