Add bring_down method to state machine, complete with depsolve

1 files changed, 18 insertions, 0 deletions

diff --git a/statemachine.py b/statemachine.py
index 54a325c..a708e5b 100644
--- a/statemachine.py
+++ b/statemachine.py
@@ -67,6 +67,21 @@ class StateMachine:
                 return
         self.up.add(cat)
 
+    def bring_down(self, cat):
+        """
+        Bring a currently "up" state down.
+        """
+        to_drop = set([ x for x in self.up if x.subset_of(cat) ])
+        if None in to_drop: to_drop.remove(None)
+        if len(to_drop) == 0: return False
+        for (dependent, dependency) in self.deps:
+            match = set([dependency.intersect(x) for x in to_drop])
+            if None in match: match.remove(None)
+            if match != None:
+                for item in match:
+                    self.bring_down(dependent.fill(item.args))
+        self.up -= to_drop
+
     def get_satisfied_states(self, dependents, dependencies):
         """
         Given that states in `dependents` depend on states in `dependencies`,
@@ -107,3 +122,6 @@ if __name__ == "__main__":
     sm.bring_up(Category("found_disk", uuid=Pattern(True, "d3adb3ef"), devname=Pattern(True, "/dev/sda"), label=Pattern(True, "myroot")))
     sm.bring_up(Category("mounted", uuid=Pattern(False), type=Pattern(False), devname=Pattern(False), label=Pattern(False), mountpoint=Pattern(False)))
     print sm
+    print "--"
+    sm.bring_down(Category("network_up"))
+    print sm