Add initial version of Hint/HintCollection classes.

These classes encapsulate information about individual hints, with
HintCollection providing a convenient wrapper around a set of hints.

Signed-off-by: Adam D. Barratt <adam@adam-barratt.org.uk>

hints.py

@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+
+# Copyright (C) 2011 Adam D. Barratt <adsb@debian.org>
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+from migrationitem import HintItem
+
+class HintCollection:
+    def __init__(self):
+        self._hints = []
+
+    def __getitem__(self, type=None, onlyactive=True):
+        return self.hints(type, onlyactive)
+
+    def hints(self, type=None, onlyactive=True):
+        if type:
+            return [ hint for hint in self._hints if hint.type == type and (hint.active or onlyactive)]
+        else:
+            return self._hints[:]
+
+    def add_hint(self, hint, user):
+        self._hints.append(Hint(hint, user))
+
+class Hint:
+    def __init__(self, hint, user):
+        self._user = user
+        self._active = True
+        self._days = None
+        if isinstance(hint, list):
+            self._type = hint[0]
+            self._packages = hint[1:]
+        else:
+            self._type, self._packages = hint.split(' ', 2)
+
+        if self._type == 'age-days':
+            if isinstance(hint, list):
+                self._days = self._packages[0]
+                self._packages = self._packages[1:]
+            else:
+                self._days, self._packages = self._packages.split(' ', 2)
+
+        self._packages = [HintItem(x) for x in self._packages]
+
+    def set_active(self, active):
+        self._active = active
+
+    @property
+    def type(self):
+        return self._type
+
+    @property
+    def packages(self):
+        return self._packages
+
+    @property
+    def active(self):
+        return self._active