Index: translate/storage/cpo.py
===================================================================
--- translate/storage/cpo.py	(revision 7740)
+++ translate/storage/cpo.py	(working copy)
@@ -134,12 +134,18 @@
 gpo.po_message_msgid_plural.restype = STRING
 gpo.po_message_msgstr.restype = STRING
 gpo.po_message_msgstr_plural.restype = STRING
+gpo.po_message_prev_msgid.restype = STRING
+gpo.po_message_prev_msgid.restype = STRING
+gpo.po_message_prev_msgid_plural.restype = STRING
 
 # Message (set methods)
 gpo.po_message_set_comments.argtypes = [c_int, STRING]
 gpo.po_message_set_extracted_comments.argtypes = [c_int, STRING]
 gpo.po_message_set_fuzzy.argtypes = [c_int, c_int]
 gpo.po_message_set_msgctxt.argtypes = [c_int, STRING]
+gpo.po_message_set_prev_msgctxt.argtypes = [c_int, STRING]
+gpo.po_message_set_prev_msgid.argtypes = [c_int, STRING]
+gpo.po_message_set_prev_msgid_plural.argtypes = [c_int, STRING]
 
 # Setup the po_xerror_handler
 xerror_handler = po_xerror_handler()
@@ -181,6 +187,72 @@
         gpo.po_message_set_msgid_plural(self._gpo_message, msgid_plural)
     msgid_plural = property(None, setmsgid_plural)
 
+    def setprev_context(self, msgid_context):
+        """Set the previous context for this message"""
+        gpo.po_message_set_prev_msgctxt(self._gpo_message, msgid_context)
+
+    def getprev_context(self):
+        """Get the previous context for this message, if any """
+        prev_ctxt = gpo.po_message_prev_msgctxt(self._gpo_message)
+        if not prev_ctxt:
+            return ""
+        return prev_ctxt
+
+    prev_context = property(getprev_context, setprev_context)
+
+    def setprev_source(self, prev_source):
+        """Set msgid as a previous msgid for this message"""
+        if isinstance(prev_source, multistring):
+            prev_source = prev_source.strings
+        if isinstance(prev_source, unicode):
+            prev_source = prev_source.encode(self._encoding)
+        if isinstance(prev_source, list):
+            if  len(prev_source) > 1:
+                self.prev_plural = str(prev_source[1])
+
+            prev_source = str(prev_source[0])
+
+        self.source = ""
+        print prev_source, type(prev_source)
+        gpo.po_message_set_prev_msgid(self._gpo_message, prev_source)
+
+    def getprev_source(self):
+        """Get the previous msgid for this message, if any"""
+        prev_source = gpo.po_message_prev_msgid(self._gpo_message)
+        if not prev_source:
+            return ""
+        return prev_source
+
+    prev_source = property(getprev_source, setprev_source)
+
+    def setprev_plural(self, msgid_plural):
+        """Set a given msgid_plural as a previous plural"""
+        if isinstance(msgid_plural, list):
+            msgid_plural = "".join(msgid_plural)
+        gpo.po_message_set_prev_msgid_plural(self._gpo_message, msgid_plural)
+
+    def getprev_plural(self):
+        """Get the previous plural for this message, if any"""
+        prev_plural = gpo.po_message_prev_msgid_plural(self._gpo_message)
+        if not prev_plural:
+            return ""
+        return prev_plural
+
+    prev_plural = property(getprev_plural, setprev_plural)
+
+    def set_as_previous(self):
+        """Sets the current msgid as previous message. Then, the current
+        msgid could be filled with a new msgid. Note that, if a unit
+        contains a previous msgid, it also is marked as fuzzy (to keep the
+        same behavior as msgmerge).
+        """
+        if not self.target:
+            return
+
+        self.markfuzzy()
+        self.prev_context = gpo.po_message_msgctxt(self._gpo_message)
+        self.prev_source = self.source
+
     def getsource(self):
         def remove_msgid_comments(text):
             if not text:
Index: translate/storage/test_cpo.py
===================================================================
--- translate/storage/test_cpo.py	(revision 7740)
+++ translate/storage/test_cpo.py	(working copy)
@@ -72,6 +72,62 @@
         unit.addnote("# Double commented comment")
         assert unit.getnotes() == "# Double commented comment"
 
+    def test_previous_source(self):
+        """tests if we handle previous msgid properly"""
+        unit = self.UnitClass("Cat")
+        assert unit.prev_source == ""
+
+        unit.prev_source = "Feline"
+        assert unit.prev_source == "Feline"
+
+        unit.prev_source = ""
+        assert unit.prev_source == ""
+
+    def test_previous_context(self):
+        """tests if we handle previous context messages properly"""
+        unit = self.UnitClass("Cat")
+        assert unit.prev_context == ""
+
+        context = "A sort of a cute animal"
+        unit.prev_context = context
+        assert unit.prev_context == context
+
+        unit.prev_context = ""
+        assert unit.prev_context == ""
+
+    def test_previous_plural(self):
+        """tests if we handle previous plural properly"""
+        unit = self.UnitClass("Cat")
+        assert unit.prev_plural == ""
+
+        unit.prev_plural = "Cats"
+        assert unit.prev_plural == "Cats"
+
+        unit.prev_plural = ""
+        assert unit.prev_plural == ""
+
+    def test_set_as_previous(self):
+        """tests if we set previous messages properly"""
+        # This is just a sanity test, for a more complete test look
+        # at convert/test_pot2po.py
+        unit = self.UnitClass("Test %d")
+        unit.msgid_plural = ["Tests %d"]
+        unit.target = ["Teste %d", "Testes %d"]
+        unit.set_as_previous()
+        unit.source = "Test %s"
+        test_unit = '''#, fuzzy\n#| msgid "Test %d"\n#| msgid_plural "Tests %d"
+msgid "Test %s"\nmsgstr "Teste %d"\n'''
+        assert str(unit) == test_unit
+        assert unit.isfuzzy()
+
+        # without a target, the unit remain the same
+        unit2 = self.UnitClass("Other")
+        unit2.msgid_plural = ["Others"]
+        expected = str(unit2)
+        unit2.set_as_previous()
+        assert str(unit2) == expected
+
+
 class TestCPOFile(test_po.TestPOFile):
     StoreClass = cpo.pofile
     def test_msgidcomments(self):