added cycle limit checking

cyclic_contracts.py

@@ -56,33 +56,41 @@ class Transporter(object):
             for r in c.routes:
                 all_routes.append(r)
                 if routes_map.has_key(r.src):
-                    routes_map[r.src].append(r.dst)
+                    routes_map[r.src].append(r)
                 else:
-                    routes_map[r.src]= [r.dst]
-        return all_routes,routes_map
+                    routes_map[r.src]= [r]
+        for r in all_routes:
+            if not routes_map.has_key(r.dst):
+                routes_map[r.dst]= []
+        return routes_map
 
     def is_cyclic(self):
-        return circular_dep(self.routes()[1])
+        return circular_dep(self.routes())
 
-def find_loop(elem,dep_elem,deps,checked=set()):
+CYCLE_LIMIT = 3
+
+def find_loop(elem,dep_elem,deps,checked,path):
     if dep_elem in checked or not deps.has_key(dep_elem):
-        return (False,len(checked))
+        return (False,[])
     else:
         checked.add(dep_elem)
     for c in deps[dep_elem]:
-        if elem == c:
-            return (True,len(checked))
-    for c in deps[dep_elem]:
-        c_loop = find_loop(elem,c,deps,checked)
-        if c_loop[0]:
-            return c_loop
-    return (False,len(checked))
+        path.append(c)
+        if elem == c.dst and len(path) <= CYCLE_LIMIT:
+            return (True,path)
+        loop_path = find_loop(elem,c.dst,deps,checked,path)
+        if loop_path[0]:
+            return loop_path
+        else:
+            del(path[-1])
+    return (False,[])
 
 def circular_dep(deps):
     dep_state = []
     for k in deps.keys():
-        circ_dep_k = find_loop(k,k,deps,set())
+        circ_dep_k = find_loop(k,k,deps,set(),[])
+        # print path
         dep_state.append((k,circ_dep_k))
     return dep_state
 
-print Transporter.from_file('./contracts_test.txt').is_cyclic()
+print Transporter.from_file('./contracts.txt').is_cyclic()