1 files changed, 103 insertions, 0 deletions
diff --git a/indra/lib/python/indra/ipc/compatibility.py b/indra/lib/python/indra/ipc/compatibility.py
new file mode 100644
index 0000000000..a430e46ab4
--- /dev/null
+++ b/indra/lib/python/indra/ipc/compatibility.py
@@ -0,0 +1,103 @@
+"""\
+@file compatibility.py
+@brief Classes that manage compatibility states.
+
+Copyright (c) 2007, Linden Research, Inc.
+$License$
+"""
+
+
+"""Compatibility combination table:
+
+    I   M   O   N   S
+    --  --  --  --  --
+I:  I   I   I   I   I
+M:  I   M   M   M   M   
+O:  I   M   O   M   O
+N:  I   M   M   N   N
+S:  I   M   O   N   S
+
+"""
+
+class _Compatibility(object):
+    def __init__(self, reason):
+        self.reasons = [ ]
+        if reason:
+            self.reasons.append(reason)
+        
+    def combine(self, other):
+        if self._level() <= other._level():
+            return self._buildclone(other)
+        else:
+            return other._buildclone(self)
+    
+    def prefix(self, leadin):
+        self.reasons = [ leadin + r for r in self.reasons ] 
+    
+    def same(self):         return self._level() >=  1
+    def deployable(self):   return self._level() >   0
+    def resolved(self):     return self._level() >  -1
+    def compatible(self):   return self._level() >  -2
+    
+    def explain(self):
+        return self.__class__.__name__ + "\n" + "\n".join(self.reasons) + "\n"
+        
+    def _buildclone(self, other=None):
+        c = self._buildinstance()
+        c.reasons = self.reasons
+        if other:
+            c.reasons = c.reasons + other.reasons
+        return c
+        
+    def _buildinstance(self):
+        return self.__class__(None)
+
+#    def _level(self):
+#        raise RuntimeError('implement in subclass')
+
+
+class Incompatible(_Compatibility):
+    def _level(self):
+        return -2
+
+class Mixed(_Compatibility):
+    def __init__(self, *inputs):
+        _Compatibility.__init__(self, None)
+        for i in inputs:
+            self.reasons += i.reasons
+                    
+    def _buildinstance(self):
+        return self.__class__()
+        
+    def _level(self):
+        return -1
+
+class _Aged(_Compatibility):
+    def combine(self, other):
+        if self._level() == other._level():
+            return self._buildclone(other)
+        if int(self._level()) == int(other._level()):
+            return Mixed(self, other)
+        return _Compatibility.combine(self, other)
+
+class Older(_Aged):
+    def _level(self):
+        return -0.25
+    
+class Newer(_Aged):
+    def _level(self):
+        return 0.25
+
+class Same(_Compatibility):
+    def __init__(self):
+        _Compatibility.__init__(self, None)
+    
+    def _buildinstance(self):
+        return self.__class__()
+        
+    def _level(self):
+        return 1
+
+
+
+