diff options
Diffstat (limited to 'libbe/properties.py')
| -rw-r--r-- | libbe/properties.py | 112 |
1 files changed, 97 insertions, 15 deletions
diff --git a/libbe/properties.py b/libbe/properties.py index 9292ad7..2ccc50b 100644 --- a/libbe/properties.py +++ b/libbe/properties.py @@ -26,9 +26,11 @@ and for more information on decorators. """ +import copy import types import unittest + class ValueCheckError (ValueError): def __init__(self, name, value, allowed): action = "in" # some list of allowed values @@ -130,12 +132,18 @@ def defaulting_property(default=None, null=None): if hasattr(funcs, "__call__"): funcs = funcs() fget = funcs.get("fget") + fset = funcs.get("fset") def _fget(self): value = fget(self) if value == null: return default return value + def _fset(self, value): + if value == default: + value = null + fset(self, value) funcs["fget"] = _fget + funcs["fset"] = _fset return funcs return decorator @@ -291,25 +299,48 @@ def change_hook_property(hook, mutable=False): fget = funcs.get("fget") fset = funcs.get("fset") name = funcs.get("name", "<unknown>") + def hash_value(value): # only used if mutable == True + return repr(value) + def _fget(self, new_value=None, from_fset=False): # only used if mutable == True + value = fget(self) + if not hasattr(self, "_change_hook_property_mutable_cache_hash"): + # first call to _fget for any mutable property + self._change_hook_property_mutable_cache_hash = {} + self._change_hook_property_mutable_cache_copy = {} + if name not in self._change_hook_property_mutable_cache_hash: + # first call to _fget for this particular mutable property + self._change_hook_property_mutable_cache_hash[name] = \ + hash_value(new_value) + self._change_hook_property_mutable_cache_copy[name] = \ + copy.deepcopy(new_value) + elif from_fset == True: # return cached value, and cache new value + old_hash = self._change_hook_property_mutable_cache_hash[name] + if hash_value(value) != old_hash: + value = self._change_hook_property_mutable_cache_copy[name] + self._change_hook_property_mutable_cache_hash[name] = \ + hash_value(new_value) + self._change_hook_property_mutable_cache_copy[name] = \ + copy.deepcopy(new_value) + else: # check for a change in value while we weren't looking + old_hash = self._change_hook_property_mutable_cache_hash[name] + if hash_value(value) != old_hash: + old_val=self._change_hook_property_mutable_cache_copy[name] + self._change_hook_property_mutable_cache_hash[name] = \ + hash_value(value) + self._change_hook_property_mutable_cache_copy[name] = \ + copy.deepcopy(value) + hook(self, old_val, value) + return value def _fset(self, value): - old_value = fget(self) + if mutable == True: # get cached previous value + old_value = _fget(self, new_value=value, from_fset=True) + else: + old_value = fget(self) fset(self, value) - change_detected = False if value != old_value: - change_detected = True - elif mutable == True: - if True: #hasattr(self, "_change_hook_property_mutable_cache_%s" % name): - # compare cached string with new value - #old_string = getattr(self, "_change_hook_property_mutable_cache_%s" % name) - old_string = "dummy" - #print "comparing", name, "mutable strings", old_string, repr(value) - if repr(value) != old_string: - change_detected = True - #print "testing", name, "change hook property", change_detected, value - if change_detected: hook(self, old_value, value) - if mutable == True: # cache the new value for next time - setattr(self, "_change_hook_property_mutable_cache_%s" % name, repr(value)) + if mutable == True: + funcs["fget"] = _fget funcs["fset"] = _fset return funcs return decorator @@ -508,6 +539,57 @@ class DecoratorTests(unittest.TestCase): t.x = 2 self.failUnless(t.old == 1, t.old) self.failUnless(t.new == 2, t.new) + def testChangeHookMutableProperty(self): + class Test(object): + def _hook(self, old, new): + self.old = old + self.new = new + self.hook_calls += 1 + + @Property + @change_hook_property(_hook, mutable=True) + @local_property(name="HOOKED") + def x(): return {} + t = Test() + t.hook_calls = 0 + t.x = [] + self.failUnless(t.old == None, t.old) + self.failUnless(t.new == [], t.new) + a = t.x + a.append(5) + t.x = a + self.failUnless(t.old == [], t.old) + self.failUnless(t.new == [5], t.new) + t.x = [] + self.failUnless(t.old == [5], t.old) + self.failUnless(t.new == [], t.new) + # now append without reassigning. this doesn't trigger the + # change, since we don't ever set t.x, only get it and mess + # with it. It does, however, update our t.new, since t.new = + # t.x and is not a static copy. + t.x.append(5) + self.failUnless(t.old == [5], t.old) + self.failUnless(t.new == [5], t.new) + # however, the next t.x get _will_ notice the change... + a = t.x + self.failUnless(t.old == [], t.old) + self.failUnless(t.new == [5], t.new) + self.failUnless(t.hook_calls == 5, t.hook_calls) + t.x.append(6) # this append(6) is not noticed yet + self.failUnless(t.old == [], t.old) + self.failUnless(t.new == [5,6], t.new) + self.failUnless(t.hook_calls == 5, t.hook_calls) + # this append(7) is not noticed, but the t.x get causes the + # append(6) to be noticed + t.x.append(7) + self.failUnless(t.old == [5], t.old) + self.failUnless(t.new == [5,6,7], t.new) + self.failUnless(t.hook_calls == 6, t.hook_calls) + a = t.x # now the append(7) is noticed + self.failUnless(t.old == [5,6], t.old) + self.failUnless(t.new == [5,6,7], t.new) + self.failUnless(t.hook_calls == 7, t.hook_calls) + suite = unittest.TestLoader().loadTestsFromTestCase(DecoratorTests) |