116 lines
3.6 KiB
Python
116 lines
3.6 KiB
Python
# Copyright 2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from twisted.internet import defer
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from twisted.internet.defer import Deferred
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from synapse.util.async_helpers import ReadWriteLock
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from tests import unittest
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class ReadWriteLockTestCase(unittest.TestCase):
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def _assert_called_before_not_after(self, lst, first_false):
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for i, d in enumerate(lst[:first_false]):
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self.assertTrue(d.called, msg="%d was unexpectedly false" % i)
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for i, d in enumerate(lst[first_false:]):
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self.assertFalse(
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d.called, msg="%d was unexpectedly true" % (i + first_false)
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)
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def test_rwlock(self):
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rwlock = ReadWriteLock()
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key = object()
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ds = [
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rwlock.read(key), # 0
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rwlock.read(key), # 1
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rwlock.write(key), # 2
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rwlock.write(key), # 3
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rwlock.read(key), # 4
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rwlock.read(key), # 5
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rwlock.write(key), # 6
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]
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ds = [defer.ensureDeferred(d) for d in ds]
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self._assert_called_before_not_after(ds, 2)
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with ds[0].result:
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self._assert_called_before_not_after(ds, 2)
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self._assert_called_before_not_after(ds, 2)
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with ds[1].result:
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self._assert_called_before_not_after(ds, 2)
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self._assert_called_before_not_after(ds, 3)
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with ds[2].result:
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self._assert_called_before_not_after(ds, 3)
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self._assert_called_before_not_after(ds, 4)
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with ds[3].result:
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self._assert_called_before_not_after(ds, 4)
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self._assert_called_before_not_after(ds, 6)
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with ds[5].result:
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self._assert_called_before_not_after(ds, 6)
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self._assert_called_before_not_after(ds, 6)
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with ds[4].result:
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self._assert_called_before_not_after(ds, 6)
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self._assert_called_before_not_after(ds, 7)
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with ds[6].result:
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pass
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d = defer.ensureDeferred(rwlock.write(key))
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self.assertTrue(d.called)
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with d.result:
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pass
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d = defer.ensureDeferred(rwlock.read(key))
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self.assertTrue(d.called)
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with d.result:
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pass
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def test_lock_handoff_to_nonblocking_writer(self):
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"""Test a writer handing the lock to another writer that completes instantly."""
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rwlock = ReadWriteLock()
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key = "key"
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unblock: "Deferred[None]" = Deferred()
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async def blocking_write():
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with await rwlock.write(key):
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await unblock
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async def nonblocking_write():
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with await rwlock.write(key):
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pass
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d1 = defer.ensureDeferred(blocking_write())
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d2 = defer.ensureDeferred(nonblocking_write())
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self.assertFalse(d1.called)
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self.assertFalse(d2.called)
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# Unblock the first writer. The second writer will complete without blocking.
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unblock.callback(None)
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self.assertTrue(d1.called)
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self.assertTrue(d2.called)
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# The `ReadWriteLock` should operate as normal.
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d3 = defer.ensureDeferred(nonblocking_write())
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self.assertTrue(d3.called)
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