diff --git a/mercurial/repository.py b/mercurial/repository.py --- a/mercurial/repository.py +++ b/mercurial/repository.py @@ -9,6 +9,11 @@ import abc +from .i18n import _ +from . import ( + error, +) + class _basepeer(object): """Represents a "connection" to a repository. @@ -216,5 +221,36 @@ of results in the order they were called. """ + def capable(self, name): + """Determine support for a named capability. + + Returns ``False`` if capability not supported. + + Returns ``True`` if boolean capability is supported. Returns a string + if capability support is non-boolean. + """ + caps = self.capabilities() + if name in caps: + return True + + name = '%s=' % name + for cap in caps: + if cap.startswith(name): + return cap[len(name):] + + return False + + def requirecap(self, name, purpose): + """Require a capability to be present. + + Raises a ``CapabilityError`` if the capability isn't present. + """ + if self.capable(name): + return + + raise error.CapabilityError( + _('cannot %s; remote repository does not support the %r ' + 'capability') % (purpose, name)) + class legacypeer(peer, _baselegacywirecommands): """peer but with support for legacy wire protocol commands."""