[repo, undo] Finish repository-side implementation of the undo feature (closes #893940)
1) Changes API for undo_transaction in order to raise an exception:
the previous API returned a sequence of error, the user of the API
needed to be careful to check explicitly. We change this for it to
raise an UndoException with the list of errors as an attribute.
2) The server-side support for undoing update actions is finished
3) The configuration for `undo-support` is now a simple boolean
Beware of the costs, both in DB space and in number of requests
on the RDBMS backend, once this feture is activated.
4) Adds a txuuid param/attribute to the existing NoSuchTransaction
exception.
# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb. If not, see <http://www.gnu.org/licenses/>.
"""CubicWeb is a generic framework to quickly build applications which describes
relations between entitites.
"""
from __future__ import with_statement
__docformat__ = "restructuredtext en"
# ignore the pygments UserWarnings
import warnings
warnings.filterwarnings('ignore', category=UserWarning,
message='.*was already imported',
module='.*pygments')
import __builtin__
# '_' is available in builtins to mark internationalized string but should
# not be used to do the actual translation
if not hasattr(__builtin__, '_'):
__builtin__._ = unicode
CW_SOFTWARE_ROOT = __path__[0]
import sys, os, logging
from StringIO import StringIO
from logilab.common.logging_ext import set_log_methods
if os.environ.get('APYCOT_ROOT'):
logging.basicConfig(level=logging.CRITICAL)
else:
logging.basicConfig()
from cubicweb.__pkginfo__ import version as __version__
set_log_methods(sys.modules[__name__], logging.getLogger('cubicweb'))
# make all exceptions accessible from the package
from cubicweb._exceptions import *
from logilab.common.registry import ObjectNotFound, NoSelectableObject, RegistryNotFound
# convert eid to the right type, raise ValueError if it's not a valid eid
typed_eid = int
#def log_thread(f, w, a):
# print f.f_code.co_filename, f.f_code.co_name
#import threading
#threading.settrace(log_thread)
class Binary(StringIO):
"""customize StringIO to make sure we don't use unicode"""
def __init__(self, buf=''):
assert isinstance(buf, (str, buffer)), \
"Binary objects must use raw strings, not %s" % buf.__class__
StringIO.__init__(self, buf)
def write(self, data):
assert isinstance(data, (str, buffer)), \
"Binary objects must use raw strings, not %s" % data.__class__
StringIO.write(self, data)
def to_file(self, fobj):
"""write a binary to disk
the writing is performed in a safe way for files stored on
Windows SMB shares
"""
pos = self.tell()
self.seek(0)
if sys.platform == 'win32':
while True:
# the 16kB chunksize comes from the shutil module
# in stdlib
chunk = self.read(16*1024)
if not chunk:
break
fobj.write(chunk)
else:
fobj.write(self.read())
self.seek(pos)
@staticmethod
def from_file(filename):
"""read a file and returns its contents in a Binary
the reading is performed in a safe way for files stored on
Windows SMB shares
"""
binary = Binary()
with open(filename, 'rb') as fobj:
if sys.platform == 'win32':
while True:
# the 16kB chunksize comes from the shutil module
# in stdlib
chunk = fobj.read(16*1024)
if not chunk:
break
binary.write(chunk)
else:
binary.write(fobj.read())
binary.seek(0)
return binary
# use this dictionary to rename entity types while keeping bw compat
ETYPE_NAME_MAP = {}
# XXX cubic web cube migration map. See if it's worth keeping this mecanism
# to help in cube renaming
CW_MIGRATION_MAP = {}
def neg_role(role):
if role == 'subject':
return 'object'
return 'subject'
def role(obj):
try:
return obj.role
except AttributeError:
return neg_role(obj.target)
def target(obj):
try:
return obj.target
except AttributeError:
return neg_role(obj.role)
class CubicWebEventManager(object):
"""simple event / callback manager.
Typical usage to register a callback::
>>> from cubicweb import CW_EVENT_MANAGER
>>> CW_EVENT_MANAGER.bind('after-registry-reload', mycallback)
Typical usage to emit an event::
>>> from cubicweb import CW_EVENT_MANAGER
>>> CW_EVENT_MANAGER.emit('after-registry-reload')
emit() accepts an additional context parameter that will be passed
to the callback if specified (and only in that case)
"""
def __init__(self):
self.callbacks = {}
def bind(self, event, callback, *args, **kwargs):
self.callbacks.setdefault(event, []).append( (callback, args, kwargs) )
def emit(self, event, context=None):
for callback, args, kwargs in self.callbacks.get(event, ()):
if context is None:
callback(*args, **kwargs)
else:
callback(context, *args, **kwargs)
CW_EVENT_MANAGER = CubicWebEventManager()
def onevent(event, *args, **kwargs):
"""decorator to ease event / callback binding
>>> from cubicweb import onevent
>>> @onevent('before-registry-reload')
... def mycallback():
... print 'hello'
...
>>>
"""
def _decorator(func):
CW_EVENT_MANAGER.bind(event, func, *args, **kwargs)
return func
return _decorator