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##
# Copyright (c) 2015-2016 Apple Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
##
from twisted.internet.defer import inlineCallbacks, returnValue
from twisted.python.failure import Failure
from datetime import datetime
@inlineCallbacks
def inTransaction(transactionCreator, operation, label="jobqueue.inTransaction", **kwargs):
"""
Perform the given operation in a transaction, committing or aborting as
required.
@param transactionCreator: a 0-arg callable that returns an
L{IAsyncTransaction}
@param operation: a 1-arg callable that takes an L{IAsyncTransaction} and
returns a value.
@param label: label to be used with the transaction.
@return: a L{Deferred} that fires with C{operation}'s result or fails with
its error, unless there is an error creating, aborting or committing
the transaction.
"""
txn = transactionCreator(label=label)
try:
result = yield operation(txn, **kwargs)
except:
f = Failure()
yield txn.abort()
returnValue(f)
else:
yield txn.commit()
returnValue(result)
def astimestamp(v):
"""
Convert the given datetime to a POSIX timestamp.
"""
return (v - datetime.utcfromtimestamp(0)).total_seconds()
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