diff: Add slots to diff wrappers to reduce memory size.

For #127

setools/diff/bounds.py

@@ -95,6 +95,8 @@ class BoundsWrapper(Wrapper):
 
     """Wrap *bounds for diff purposes."""
 
+    __slots__ = ("ruletype", "parent", "child")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype

setools/diff/conditional.py

@@ -23,6 +23,8 @@ class ConditionalExprWrapper(Wrapper):
 
     """Wrap conditional policy expressions to allow comparisons by truth table."""
 
+    __slots__ = ("truth_table")
+
     def __init__(self, cond):
         self.origin = cond
         self.truth_table = cond.truth_table()

setools/diff/constraints.py

@@ -186,6 +186,8 @@ class ConstraintWrapper(Wrapper):
 
     """Wrap constraints for diff purposes."""
 
+    __slots__ = ("ruletype", "tclass", "perms", "expr")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype

setools/diff/context.py

@@ -26,6 +26,8 @@ class ContextWrapper(Wrapper):
 
     """Wrap contexts to allow comparisons."""
 
+    __slots__ = ("user", "role", "type_", "range_")
+
     def __init__(self, ctx):
         self.origin = ctx
         self.user = SymbolWrapper(ctx.user)

setools/diff/default.py

@@ -96,6 +96,8 @@ class DefaultWrapper(Wrapper):
 
     """Wrap default_* to allow comparisons."""
 
+    __slots__ = ("ruletype", "tclass")
+
     def __init__(self, default):
         self.origin = default
         self.ruletype = default.ruletype

setools/diff/difference.py

@@ -133,9 +133,10 @@ class Wrapper(object):
 
     """Base class for policy object wrappers."""
 
-    origin = None
+    __slots__ = ("origin", "key")
 
     def __repr__(self):
+        # pylint: disable=no-member
         return "<{0.__class__.__name__}(Wrapping {1})>".format(self, repr(self.origin))
 
     def __hash__(self):
@@ -159,12 +160,15 @@ class SymbolWrapper(Wrapper):
     on its name.
     """
 
+    __slots__ = ("name")
+
     def __init__(self, symbol):
         self.origin = symbol
         self.name = str(symbol)
+        self.key = hash(self.name)
 
     def __hash__(self):
-        return hash(self.name)
+        return self.key
 
     def __lt__(self, other):
         return self.name < other.name

setools/diff/fsuse.py

@@ -72,6 +72,8 @@ class FSUseWrapper(Wrapper):
 
     """Wrap fs_use_* rules to allow set operations."""
 
+    __slots__ = ("ruletype", "fs", "context")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype

setools/diff/genfscon.py

@@ -72,6 +72,8 @@ class GenfsconWrapper(Wrapper):
 
     """Wrap genfscon rules to allow set operations."""
 
+    __slots__ = ("fs", "path", "filetype", "context")
+
     def __init__(self, rule):
         self.origin = rule
         self.fs = rule.fs

setools/diff/mls.py

@@ -169,6 +169,8 @@ class LevelDeclWrapper(Wrapper):
 
     """Wrap level declarations to allow comparisons."""
 
+    __slots__ = ("sensitivity")
+
     def __init__(self, level):
         self.origin = level
         self.sensitivity = SymbolWrapper(level.sensitivity)
@@ -190,6 +192,8 @@ class LevelWrapper(Wrapper):
 
     """Wrap levels to allow comparisons."""
 
+    __slots__ = ("sensitivity", "categories")
+
     def __init__(self, level):
         self.origin = level
         self.sensitivity = SymbolWrapper(level.sensitivity)
@@ -215,6 +219,8 @@ class RangeWrapper(Wrapper):
     to levels between the low and high levels of the range.
     """
 
+    __slots__ = ("low", "high")
+
     def __init__(self, range_):
         self.origin = range_
         self.low = LevelWrapper(range_.low)

setools/diff/mlsrules.py

@@ -104,6 +104,8 @@ class MLSRuleWrapper(Wrapper):
 
     """Wrap MLS rules to allow set operations."""
 
+    __slots__ = ("ruletype", "source", "target", "tclass")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype

setools/diff/netifcon.py

@@ -87,6 +87,8 @@ class NetifconWrapper(Wrapper):
 
     """Wrap netifcon statements for diff purposes."""
 
+    __slots__ = ("netif")
+
     def __init__(self, ocon):
         self.origin = ocon
         self.netif = ocon.netif

setools/diff/nodecon.py

@@ -71,6 +71,8 @@ class NodeconWrapper(Wrapper):
 
     """Wrap nodecon statements for diff purposes."""
 
+    __slots__ = ("ip_version", "address", "netmask")
+
     def __init__(self, ocon):
         self.origin = ocon
         self.ip_version = ocon.ip_version

setools/diff/portcon.py

@@ -71,6 +71,8 @@ class PortconWrapper(Wrapper):
 
     """Wrap portcon statements for diff purposes."""
 
+    __slots__ = ("protocol", "low", "high")
+
     def __init__(self, ocon):
         self.origin = ocon
         self.protocol = ocon.protocol

setools/diff/rbacrules.py

@@ -123,6 +123,8 @@ class RoleAllowWrapper(Wrapper):
 
     """Wrap role allow rules to allow set operations."""
 
+    __slots__ = ("ruletype", "source", "target")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype
@@ -146,6 +148,8 @@ class RoleTransitionWrapper(Wrapper):
 
     """Wrap role_transition rules to allow set operations."""
 
+    __slots__ = ("ruletype", "source", "target", "tclass")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype

setools/diff/terules.py

@@ -297,6 +297,8 @@ class AVRuleWrapper(Wrapper):
 
     """Wrap access vector rules to allow set operations."""
 
+    __slots__ = ("ruletype", "source", "target", "tclass", "conditional", "conditional_block")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype
@@ -332,6 +334,8 @@ class AVRuleXpermWrapper(Wrapper):
 
     """Wrap extended permission access vector rules to allow set operations."""
 
+    __slots__ = ("ruletype", "source", "target", "tclass", "xperm_type")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype
@@ -360,6 +364,9 @@ class TERuleWrapper(Wrapper):
 
     """Wrap type_* rules to allow set operations."""
 
+    __slots__ = ("ruletype", "source", "target", "tclass", "conditional", "conditional_block",
+                 "filename")
+
     def __init__(self, rule):
         self.origin = rule
         self.ruletype = rule.ruletype