Modify system to use proper patterns rather than just strings and blanks

2 files changed, 58 insertions, 47 deletions

diff --git a/category.py b/category.py
index 51a36b8..61458dc 100644
--- a/category.py
+++ b/category.py
@@ -1,5 +1,7 @@
 __docformat__ = 'restructuredtext'
 
+from pattern import Pattern
+
 class Category:
     """
     A Category is a "set" of states. The category specifies a name, certain
@@ -13,26 +15,38 @@ class Category:
         Categories are constructed with a `name` and a series of keyword
         arguments. `name` is a string. Each keyword argument that is specified
         is the name of a state argument a state must posess to be considered to
-        be a member of the category. If the value of the keyword argument is
-        `None` then the state argument can have any value, otherwise the value is a string
-        and specifies a mandatory value for the state argument.
+        be a member of the category. The value of the keyword arguments are
+        patterns that must match the value of the state argument.
         """
         self.args = args
         self.name = name
 
     def equiv(self, other):
         """
-        Returns True if any state in the Category `other` is in this Category. Note that
-        this is *intransitive*; ``a.equiv(b)`` is not the same as ``b.equiv(a)``.
+        A Category is equivalent to another Category if:
+        - The other category mandates the same or more arguments
+        - The intersection of the two is nonempty
+        Its an odd relationship, brought about to match expected user behavior
         """
         if self.name != other.name: return False
         for key, value in self.args.iteritems():
             if not other.args.has_key(key): return False
-            if value == None: continue
-            if other.args[key] == None: continue
-            if not other.args[key] == value: return False
+            if not other.args[key].intersect(value).nonempty(): return False
         return True
-    
+
+    def subtract(self, other):
+        """
+        returns a set of categories that, when combined, include all states
+        that are in `self` but *not* in `other`
+        """
+        retval = set()
+        for key, value in other.args.iteritems():
+            args = {}
+            for k, v in self.args.iteritems(): args[k] = v
+            args[key].intersect(value.complement())
+            if args[key].nonempty():
+                retval.add(Category(self.name, **args))
+
     def intersect(self, other):
         """
         Returns a new category consisting only of states that are in this
@@ -45,28 +59,19 @@ class Category:
                 args[key] = other.args[key]
             elif not other.args.has_key(key):
                 args[key] = self.args[key]
-            elif self.args[key] == None:
-                args[key] = other.args[key]
-            elif other.args[key] == None:
-                args[key] = self.args[key]
-            elif self.args[key] != other.args[key]:
-                return None
-            else: # self.args[key] == other.args[key]
-                args[key] = self.args[key]
+            else:
+                val = self.args[key].intersect(other.args[key])
+                if not val.nonempty():
+                    return None
+                args[key] = val
         return Category(self.name, **args)
 
     def __str__(self):
-        string = self.name + "("
-        had = False
-        for key, val in self.args.iteritems():
-            if had:
-                string += ", "
-            had = True
-            if val == None:
-                string += "%%%s" % key
-            else:
-                string += "%s: %s" % (key, val)
-        return string + ")"
+        return "%s(%s)" % (
+            self.name,
+            ", ".join(["%s: %s" % (key, val) \
+                    for key, val in self.args.iteritems()])
+            )
 
     def __repr__(self):
         return self.__str__()
@@ -95,8 +100,10 @@ class Category:
         """
         args = {}
         for key, value in self.args.iteritems():
-            if value != None or not info.has_key(key):
+            if not info.has_key(key):
                 args[key] = value
-            else:
+            elif not value.singular():
                 args[key] = info[key]
+            else:
+                args[key] = value
         return Category(self.name, **args)
diff --git a/statemachine.py b/statemachine.py
index 5c396eb..cc90793 100644
--- a/statemachine.py
+++ b/statemachine.py
@@ -1,6 +1,7 @@
 __docformat__ = 'restructuredtext'
 
 from category import Category
+from pattern import Pattern
 
 class StateMachine:
     """
@@ -20,10 +21,11 @@ class StateMachine:
         Move states in the given Category `cat` from down to up.
         """
         found = None
-        for dependency in self.get_applicable_deps(cat):
+        for (match, dependency) in self.get_applicable_deps(cat):
             res = self.get_satisfied_states(cat, dependency)
+            print dependency, res
             if len(res) == 0:
-                return False
+                res = cat.subtract(match)
             if found == None:
                 found = res
             else:
@@ -44,18 +46,12 @@ class StateMachine:
         least one category in the returned list.
         """
         retval = set()
-        found = set()
         for x in cats1:
             for y in cats2:
-                if x == y: continue
                 inter = x.intersect(y)
                 if inter != None:
                     retval.add(inter)
-                    found.add(x)
-                    found.add(y)
-        if len(found) == 0:
-            return cats1 & cats2
-        return (retval | ((cats1 & cats2) - found))
+        return retval
 
     def add_hold(self, cat):
         """
@@ -85,15 +81,23 @@ class StateMachine:
         retval = []
         for (x, y) in self.deps:
             if x.equiv(cat):
-                retval.append(y.fill(cat.intersect(x).args))
+                retval.append((x, y.fill(cat.intersect(x).args)))
         return retval
 
+    def __str__(self):
+        return "\n".join(["%s: %s" % (v, k) for k, v in self.holds.iteritems()])
+
+    def __repr__(self):
+        return str(self)
+
 if __name__ == "__main__":
     sm = StateMachine()
-    sm.deps.append((Category("mounted", type="nfs"), Category("network_up")))
-    sm.deps.append((Category("mounted", uuid=None, devname=None, label=None), Category("found_disk", uuid=None, devname=None, label=None)))
-    sm.deps.append((Category("mounted", uuid=None, devname=None, label=None), Category("vol_conf", uuid=None, devname=None, label=None)))
-    sm.assert_state(Category("vol_conf", uuid=None, devname=None, label="myroot", type="ext3", mountpoint="/"))
-    sm.assert_state(Category("found_disk", uuid="d3adb3ef", devname="/dev/sda", label="myroot"))
-    sm.assert_state(Category("mounted", uuid=None, type="ext3", devname=None, label=None, mountpoint=None))
-    print sm.holds
+    sm.deps.append((Category("mounted", type=Pattern(True, "nfs")), Category("network_up")))
+    sm.deps.append((Category("mounted", uuid=Pattern(False), devname=Pattern(False), label=Pattern(False), type=Pattern(False, "nfs")), Category("found_disk", uuid=Pattern(False), devname=Pattern(False), label=Pattern(False))))
+    sm.deps.append((Category("mounted", uuid=Pattern(False), devname=Pattern(False), label=Pattern(False)), Category("vol_conf", uuid=Pattern(False), devname=Pattern(False), label=Pattern(False))))
+    sm.assert_state(Category("network_up"))
+    sm.assert_state(Category("vol_conf", uuid=Pattern(False), devname=Pattern(False), label=Pattern(True, "myroot"), type=Pattern(True, "ext3"), mountpoint=Pattern(True, "/")))
+    sm.assert_state(Category("vol_conf", uuid=Pattern(False), devname=Pattern(True, "foosrv.com:/vol/home"), label=Pattern(False), type=Pattern(True, "nfs"), mountpoint=Pattern(True, "/home")))
+    sm.assert_state(Category("found_disk", uuid=Pattern(True, "d3adb3ef"), devname=Pattern(True, "/dev/sda"), label=Pattern(True, "myroot")))
+    sm.assert_state(Category("mounted", uuid=Pattern(False), type=Pattern(False), devname=Pattern(False), label=Pattern(False), mountpoint=Pattern(False)))
+    print sm