#!/usr/bin/env python

# -*- coding: utf-8 -*-

class TopicManager(object):

"""Acts as a factory for topic branch names, and a registry for

mapping both individual commits and merges of commits to topic

branch names.

This ensures we always know onto which topic branch to explode

(cherry-pick) a new commit.

"""

i = 0

topics = {}

commits = {}

def __init__(self, template, logger):

self.template = template

self.logger = logger

def lookup(self, *commits):

name = self._name_for(*commits)

return self.topics.get(name)

def register(self, *commits):

new = self.next()

self.assign(new, *commits)

return new

def _assign(self, topic, *commits):

name = self._name_for(*commits)

self.topics[name] = topic

self.commits[topic] = name

self.logger.debug(" Assigned %s to %s" % (topic, name))

def assign(self, topic, *commits):

old_commits = self.commits.get(topic)

if old_commits:

self.unassign(topic, old_commits)

self._assign(topic, *commits)

def unassign(self, topic, commits):

del self.topics[commits]

del self.commits[topic]

self.logger.debug(" Unassigned %s from %s" % (topic, commits))

def _name_for(self, *commits):

return ' '.join(sorted(commits))

def next(self):

self.i += 1

return self.template % self.i