Add utility function to compute diffs between two objects (converted to dicts)

3 files changed, 101 insertions, 1 deletions

diff --git a/pykolab/xml/__init__.py b/pykolab/xml/__init__.py
index 20b7e9f..3ca52b2 100644
--- a/pykolab/xml/__init__.py
+++ b/pykolab/xml/__init__.py
@@ -19,6 +19,7 @@ from todo import todo_from_ical
 from todo import todo_from_string
 from todo import todo_from_message
 
+from utils import compute_diff
 from utils import to_dt
 
 __all__ = [
@@ -34,6 +35,7 @@ __all__ = [
         "todo_from_ical",
         "todo_from_string",
         "todo_from_message",
+        "compute_diff",
         "to_dt",
     ]
 
diff --git a/pykolab/xml/utils.py b/pykolab/xml/utils.py
index aa05e11..35d7578 100644
--- a/pykolab/xml/utils.py
+++ b/pykolab/xml/utils.py
@@ -2,6 +2,8 @@ import datetime
 import pytz
 import kolabformat
 from dateutil.tz import tzlocal
+from collections import OrderedDict
+
 
 def to_dt(dt):
     """
@@ -109,3 +111,68 @@ def to_cdatetime(_datetime, with_timezone=True, as_utc=False):
         _cdatetime.setUTC(True)
 
     return _cdatetime
+
+
+def compute_diff(a, b, reduced=False):
+    """
+        List the differences between two given dicts
+    """
+    diff = []
+
+    properties = a.keys()
+    properties.extend([x for x in b.keys() if x not in properties])
+
+    for prop in properties:
+        aa = a[prop] if a.has_key(prop) else None
+        bb = b[prop] if b.has_key(prop) else None
+
+        # compare two lists
+        if isinstance(aa, list) or isinstance(bb, list):
+            if not isinstance(aa, list):
+                aa = [aa]
+            if not isinstance(bb, list):
+                bb = [bb]
+            index = 0
+            length = max(len(aa), len(bb))
+            while index < length:
+                aai = aa[index] if index < len(aa) else None
+                bbi = bb[index] if index < len(bb) else None
+                if not aai == bbi:
+                    if reduced:
+                        (old, new) = reduce_properties(aai, bbi)
+                    else:
+                        (old, new) = (aai, bbi)
+                    diff.append(OrderedDict([('property', prop), ('index', index), ('old', old), ('new', new)]))
+                index += 1
+
+        # the two properties differ
+        elif not aa.__class__ == bb.__class__ or not aa == bb:
+            if reduced:
+                (old, new) = reduce_properties(aa, bb)
+            else:
+                (old, new) = (aa, bb)
+            diff.append(OrderedDict([('property', prop), ('old', old), ('new', new)]))
+
+    return diff
+
+
+def reduce_properties(aa, bb):
+    """
+        Compares two given structs and removes equal values in bb
+    """
+    if not isinstance(aa, dict) or not isinstance(bb, dict):
+        return (aa, bb)
+
+    properties = aa.keys()
+    properties.extend([x for x in bb.keys() if x not in properties])
+
+    for prop in properties:
+        if not aa.has_key(prop) or not bb.has_key(prop):
+            continue
+        if isinstance(aa[prop], dict) and isinstance(bb[prop], dict):
+            (aa[prop], bb[prop]) = reduce_properties(aa[prop], bb[prop])
+        if aa[prop] == bb[prop]:
+            # del aa[prop]
+            del bb[prop]
+
+    return (aa, bb)
diff --git a/tests/unit/test-003-event.py b/tests/unit/test-003-event.py
index d9e05fa..6a9fd4f 100644
--- a/tests/unit/test-003-event.py
+++ b/tests/unit/test-003-event.py
@@ -14,6 +14,8 @@ from pykolab.xml import InvalidEventDateError
 from pykolab.xml import event_from_ical
 from pykolab.xml import event_from_string
 from pykolab.xml import event_from_message
+from pykolab.xml import compute_diff
+from collections import OrderedDict
 
 ical_event = """
 BEGIN:VEVENT
@@ -223,7 +225,7 @@ xml_event = """
                 <text>alarm 2</text>
               </description>
               <attendee>
-                  <cal-address>mailto:%3Cjohn.die%40example.org%3E</cal-address>
+                  <cal-address>mailto:%3Cjohn.doe%40example.org%3E</cal-address>
               </attendee>
               <trigger>
                 <parameters>
@@ -615,6 +617,35 @@ END:VEVENT
         self.assertEqual(data['alarm'][1]['trigger']['value'], '-P1D')
         self.assertEqual(len(data['alarm'][1]['attendee']), 1)
 
+    def test_026_compute_diff(self):
+        e1 = event_from_string(xml_event)
+        e2 = event_from_string(xml_event)
+
+        e2.set_summary("test2")
+        e2.set_end(e1.get_end() + datetime.timedelta(hours=2))
+        e2.set_sequence(e1.get_sequence() + 1)
+        e2.set_attendee_participant_status("jane@example.org", "DECLINED")
+        e2.set_lastmodified()
+
+        diff = compute_diff(e1.to_dict(), e2.to_dict(), True)
+        self.assertEqual(len(diff), 5)
+
+        ps = self._find_prop_in_list(diff, 'summary')
+        self.assertIsInstance(ps, OrderedDict)
+        self.assertEqual(ps['new'], "test2")
+
+        pa = self._find_prop_in_list(diff, 'attendee')
+        self.assertIsInstance(pa, OrderedDict)
+        self.assertEqual(pa['index'], 0)
+        self.assertEqual(pa['new'], dict(partstat='DECLINED'))
+
+
+    def _find_prop_in_list(self, diff, name):
+        for prop in diff:
+            if prop['property'] == name:
+                return prop
+        return None
+
 
 if __name__ == '__main__':
     unittest.main()