Commit 1a72a60f by Julien Muchembled

storage: require backends to use @fallback implementation explicitly

... rather than logging when the backend does not override.
1 parent 042f5ac0
......@@ -74,7 +74,7 @@ def implements(obj, ignore=()):
assert not wrong_signature, wrong_signature
return obj
def _set_code(func):
def _stub(func):
args, varargs, varkw, _ = inspect.getargspec(func)
if varargs:
args.append("*" + varargs)
......@@ -82,16 +82,25 @@ def _set_code(func):
args.append("**" + varkw)
exec "def %s(%s): raise NotImplementedError\nf = %s" % (
func.__name__, ",".join(args), func.__name__)
func.func_code = f.func_code
return f
def abstract(func):
_set_code(func)
func.__abstract__ = 1
return func
f = _stub(func)
f.__abstract__ = 1
f.__defaults__ = func.__defaults__
f.__doc__ = func.__doc__
return f
def requires(*args):
for func in args:
_set_code(func)
# Tolerate useless abstract decoration on required method (e.g. it
# simplifies the implementation of a fallback decorator), but remove
# marker since it does not need to be implemented if it's required
# by a method that is overridden.
try:
del func.__abstract__
except AttributeError:
func.__code__ = _stub(func).__code__
def decorator(func):
func.__requires__ = args
return func
......
......@@ -33,7 +33,7 @@ from ZODB.FileStorage import FileStorage
from ..app import option_defaults
from . import buildDatabaseManager, DatabaseFailure
from .manager import DatabaseManager
from .manager import DatabaseManager, Fallback
from neo.lib import compress, logging, patch, util
from neo.lib.interfaces import implements
from neo.lib.protocol import BackendNotImplemented, MAX_TID
......@@ -692,6 +692,9 @@ class ImporterDatabaseManager(DatabaseManager):
def _fetchObject(*_):
raise AssertionError
getLastObjectTID = Fallback.getLastObjectTID.__func__
_getDataTID = Fallback._getDataTID.__func__
def getObjectHistory(self, *args, **kw):
raise BackendNotImplemented(self.getObjectHistory)
......
......@@ -26,22 +26,9 @@ from . import DatabaseFailure
READABLE = CellStates.UP_TO_DATE, CellStates.FEEDING
def lazymethod(func):
def getter(self):
cls = self.__class__
name = func.__name__
assert name not in cls.__dict__
setattr(cls, name, func(self))
return getattr(self, name)
return property(getter, doc=func.__doc__)
def fallback(func):
def warn(self):
logging.info("Fallback to generic/slow implementation of %s."
" It should be overridden by backend storage (%s).",
func.__name__, self.__class__.__name__)
return func
return lazymethod(wraps(func)(warn))
setattr(Fallback, func.__name__, func)
return abstract(func)
def splitOIDField(tid, oids):
if len(oids) % 8:
......@@ -52,6 +39,9 @@ def splitOIDField(tid, oids):
class CreationUndone(Exception):
pass
class Fallback(object):
pass
class DatabaseManager(object):
"""This class only describes an interface for database managers."""
......@@ -493,6 +483,7 @@ class DatabaseManager(object):
None if data_serial is None else util.p64(data_serial))
@fallback
@requires(_getObject)
def _fetchObject(self, oid, tid):
"""Specialized version of _getObject, for replication"""
r = self._getObject(oid, tid)
......@@ -738,6 +729,7 @@ class DatabaseManager(object):
return self._pruneData(data_id_list)
@fallback
@requires(_getObject)
def _getDataTID(self, oid, tid=None, before_tid=None):
"""
Return a 2-tuple:
......
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