# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1508533875 -7200
# Node ID ecdbe127443aaadb257aeb8cf16a2ba4b3d16603
# Parent  c79242324f107488af09a43787626bf56ad8741a# Parent  102a5f873a8b3c53faf2796770ec886c5b4ee730
Merged changes from the default branch.

diff -r c79242324f10 -r ecdbe127443a imiptools/data.py
--- a/imiptools/data.py	Fri Oct 20 22:40:55 2017 +0200
+++ b/imiptools/data.py	Fri Oct 20 23:11:15 2017 +0200
@@ -1214,11 +1214,11 @@
 
     return delegators
 
-def make_rule_period(start, duration, tzid, attr):
+def make_rule_period(start, duration, attr, tzid):
 
     """
     Make a period for the rule period starting at 'start' with the given
-    'duration' employing the given 'tzid' and datetime 'attr'.
+    'duration' employing the given datetime 'attr' and 'tzid'.
     """
 
     # Determine the resolution of the period.
@@ -1232,6 +1232,44 @@
 
     return RecurringPeriod(start, end, tzid, "RRULE", attr)
 
+def get_rule_periods(rrule, start, duration, attr, tzid, end, inclusive=False):
+
+    """
+    Return periods for the given 'rrule', employing the 'start', 'duration',
+    datetime 'attr' and 'tzid'.
+
+    The specified 'end' datetime indicates the end of the window for which
+    periods shall be computed.
+
+    If 'inclusive' is set to a true value, any period occurring at the 'end'
+    will be included.
+    """
+
+    parameters = rrule and get_parameters(rrule)
+    selector = get_rule(start, rrule)
+
+    until = parameters.get("UNTIL")
+
+    if until:
+        until_dt = to_timezone(get_datetime(until, attr), tzid)
+        end = end and min(until_dt, end) or until_dt
+        inclusive = True
+
+    # Obtain period instances, starting from the main period. Since counting
+    # must start from the first period, filtering from a start date must be
+    # done after the instances have been obtained.
+
+    periods = []
+
+    for recurrence_start in selector.materialise(start, end,
+                                                 parameters.get("COUNT"),
+                                                 parameters.get("BYSETPOS"),
+                                                 inclusive):
+
+        periods.append(make_rule_period(recurrence_start, duration, attr, tzid))
+
+    return periods
+
 def get_periods(obj, start=None, end=None, inclusive=False):
 
     """
@@ -1261,35 +1299,21 @@
     if not rrule:
         periods = [main_period]
 
+    # Recurrence rules create multiple instances to be checked.
+    # Conflicts may only be assessed within a period defined by policy
+    # for the agent, with instances outside that period being considered
+    # unchecked.
+
     elif end or parameters and parameters.has_key("UNTIL") or parameters.has_key("COUNT"):
 
-        # Recurrence rules create multiple instances to be checked.
-        # Conflicts may only be assessed within a period defined by policy
-        # for the agent, with instances outside that period being considered
-        # unchecked.
+        # Define a selection period with a start point. The end will be handled
+        # in the materialisation process.
 
-        selector = get_rule(dtstart, rrule)
+        selection_period = Period(start, None)
         periods = []
 
-        until = parameters.get("UNTIL")
-        if until:
-            until_dt = to_timezone(get_datetime(until, dtstart_attr), tzid)
-            end = end and min(until_dt, end) or until_dt
-            inclusive = True
-
-        # Define a selection period with a start point. The end will be handled
-        # in the materialisation process below.
-
-        selection_period = Period(start, None)
-
-        # Obtain period instances, starting from the main period. Since counting
-        # must start from the first period, filtering from a start date must be
-        # done after the instances have been obtained.
-
-        for recurrence_start in selector.materialise(dtstart, end,
-            parameters.get("COUNT"), parameters.get("BYSETPOS"), inclusive):
-
-            period = make_rule_period(recurrence_start, main_period.get_duration(), tzid, dtstart_attr)
+        for period in get_rule_periods(rrule, dtstart,
+            main_period.get_duration(), dtstart_attr, tzid, end, inclusive):
 
             # Use the main period where it occurs.