diff options
Diffstat (limited to 'synapse')
| -rw-r--r-- | synapse/events/__init__.py | 144 |
1 files changed, 79 insertions, 65 deletions
diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py index a842661a90..512254f65d 100644 --- a/synapse/events/__init__.py +++ b/synapse/events/__init__.py @@ -37,6 +37,65 @@ from synapse.util.frozenutils import freeze USE_FROZEN_DICTS = strtobool(os.environ.get("SYNAPSE_USE_FROZEN_DICTS", "0")) +class DictProperty: + """An object property which delegates to the `_dict` within its parent object.""" + + __slots__ = ["key"] + + def __init__(self, key: str): + self.key = key + + def __get__(self, instance, owner=None): + # if the property is accessed as a class property rather than an instance + # property, return the property itself rather than the value + if instance is None: + return self + try: + return instance._dict[self.key] + except KeyError as e1: + # We want this to look like a regular attribute error (mostly so that + # hasattr() works correctly), so we convert the KeyError into an + # AttributeError. + # + # To exclude the KeyError from the traceback, we explicitly + # 'raise from e1.__context__' (which is better than 'raise from None', + # becuase that would omit any *earlier* exceptions). + # + raise AttributeError( + "'%s' has no '%s' property" % (type(instance), self.key) + ) from e1.__context__ + + def __set__(self, instance, v): + instance._dict[self.key] = v + + def __delete__(self, instance): + try: + del instance._dict[self.key] + except KeyError as e1: + raise AttributeError( + "'%s' has no '%s' property" % (type(instance), self.key) + ) from e1.__context__ + + +class DefaultDictProperty(DictProperty): + """An extension of DictProperty which provides a default if the property is + not present in the parent's _dict. + + Note that this means that hasattr() on the property always returns True. + """ + + __slots__ = ["default"] + + def __init__(self, key, default): + super().__init__(key) + self.default = default + + def __get__(self, instance, owner=None): + if instance is None: + return self + return instance._dict.get(self.key, self.default) + + class _EventInternalMetadata(object): def __init__(self, internal_metadata_dict): self.__dict__ = dict(internal_metadata_dict) @@ -117,51 +176,6 @@ class _EventInternalMetadata(object): return getattr(self, "redacted", False) -_SENTINEL = object() - - -def _event_dict_property(key, default=_SENTINEL): - """Creates a new property for the given key that delegates access to - `self._event_dict`. - - The default is used if the key is missing from the `_event_dict`, if given, - otherwise an AttributeError will be raised. - - Note: If a default is given then `hasattr` will always return true. - """ - - # We want to be able to use hasattr with the event dict properties. - # However, (on python3) hasattr expects AttributeError to be raised. Hence, - # we need to transform the KeyError into an AttributeError - - def getter_raises(self): - try: - return self._event_dict[key] - except KeyError: - raise AttributeError(key) - - def getter_default(self): - return self._event_dict.get(key, default) - - def setter(self, v): - try: - self._event_dict[key] = v - except KeyError: - raise AttributeError(key) - - def delete(self): - try: - del self._event_dict[key] - except KeyError: - raise AttributeError(key) - - if default is _SENTINEL: - # No default given, so use the getter that raises - return property(getter_raises, setter, delete) - else: - return property(getter_default, setter, delete) - - class EventBase(object): def __init__( self, @@ -175,23 +189,23 @@ class EventBase(object): self.unsigned = unsigned self.rejected_reason = rejected_reason - self._event_dict = event_dict + self._dict = event_dict self.internal_metadata = _EventInternalMetadata(internal_metadata_dict) - auth_events = _event_dict_property("auth_events") - depth = _event_dict_property("depth") - content = _event_dict_property("content") - hashes = _event_dict_property("hashes") - origin = _event_dict_property("origin") - origin_server_ts = _event_dict_property("origin_server_ts") - prev_events = _event_dict_property("prev_events") - redacts = _event_dict_property("redacts", None) - room_id = _event_dict_property("room_id") - sender = _event_dict_property("sender") - state_key = _event_dict_property("state_key") - type = _event_dict_property("type") - user_id = _event_dict_property("sender") + auth_events = DictProperty("auth_events") + depth = DictProperty("depth") + content = DictProperty("content") + hashes = DictProperty("hashes") + origin = DictProperty("origin") + origin_server_ts = DictProperty("origin_server_ts") + prev_events = DictProperty("prev_events") + redacts = DefaultDictProperty("redacts", None) + room_id = DictProperty("room_id") + sender = DictProperty("sender") + state_key = DictProperty("state_key") + type = DictProperty("type") + user_id = DictProperty("sender") @property def event_id(self) -> str: @@ -205,13 +219,13 @@ class EventBase(object): return hasattr(self, "state_key") and self.state_key is not None def get_dict(self) -> JsonDict: - d = dict(self._event_dict) + d = dict(self._dict) d.update({"signatures": self.signatures, "unsigned": dict(self.unsigned)}) return d def get(self, key, default=None): - return self._event_dict.get(key, default) + return self._dict.get(key, default) def get_internal_metadata_dict(self): return self.internal_metadata.get_dict() @@ -233,16 +247,16 @@ class EventBase(object): raise AttributeError("Unrecognized attribute %s" % (instance,)) def __getitem__(self, field): - return self._event_dict[field] + return self._dict[field] def __contains__(self, field): - return field in self._event_dict + return field in self._dict def items(self): - return list(self._event_dict.items()) + return list(self._dict.items()) def keys(self): - return six.iterkeys(self._event_dict) + return six.iterkeys(self._dict) def prev_event_ids(self): """Returns the list of prev event IDs. The order matches the order |