diff options
| -rw-r--r-- | synapse/util/wheel_timer.py | 88 | ||||
| -rw-r--r-- | tests/util/test_wheel_timer.py | 74 |
2 files changed, 162 insertions, 0 deletions
diff --git a/synapse/util/wheel_timer.py b/synapse/util/wheel_timer.py new file mode 100644 index 0000000000..b447b2456c --- /dev/null +++ b/synapse/util/wheel_timer.py @@ -0,0 +1,88 @@ +# -*- coding: utf-8 -*- +# Copyright 2016 OpenMarket Ltd +# +# 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. + + +class _Entry(object): + __slots__ = ["end_key", "queue"] + + def __init__(self, end_key): + self.end_key = end_key + self.queue = [] + + +class WheelTimer(object): + """Stores arbitrary objects that will be returned after their timers have + expired. + """ + + def __init__(self, bucket_size=5000): + """ + Args: + bucket_size (int): Size of buckets in ms. Corresponds roughly to the + accuracy of the timer. + """ + self.bucket_size = bucket_size + self.entries = [] + self.current_tick = 0 + + def insert(self, now, obj, then): + """Inserts object into timer. + + Args: + now (int): Current time in msec + obj (object): Object to be inserted + then (int): When to return the object strictly after. + """ + then_key = int(then / self.bucket_size) + 1 + for entry in self.entries: + # Add to first bucket we find. This should gracefully handle inserts + # for times in the past. + if entry.end_key >= then_key: + entry.queue.append(obj) + return + + next_key = int(now / self.bucket_size) + 1 + if self.entries: + last_key = self.entries[-1].end_key + else: + last_key = next_key + + # Handle the case when `then` is in the past and `entries` is empty. + then_key = max(last_key, then_key) + + # Add empty entries between the end of the current list and when we want + # to insert. This ensures there are no gaps. + self.entries.extend( + _Entry(key) for key in xrange(last_key, then_key + 1) + ) + + self.entries[-1].queue.append(obj) + + def fetch(self, now): + """Fetch any objects that have timed out + + Args: + now (ms): Current time in msec + + Returns: + list: List of objects that have timed out + """ + now_key = int(now / self.bucket_size) + + ret = [] + while self.entries and self.entries[0].end_key <= now_key: + ret.extend(self.entries.pop(0).queue) + + return ret diff --git a/tests/util/test_wheel_timer.py b/tests/util/test_wheel_timer.py new file mode 100644 index 0000000000..c44567e52e --- /dev/null +++ b/tests/util/test_wheel_timer.py @@ -0,0 +1,74 @@ +# -*- coding: utf-8 -*- +# Copyright 2016 OpenMarket Ltd +# +# 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 .. import unittest + +from synapse.util.wheel_timer import WheelTimer + + +class WheelTimerTestCase(unittest.TestCase): + def test_single_insert_fetch(self): + wheel = WheelTimer(bucket_size=5) + + obj = object() + wheel.insert(100, obj, 150) + + self.assertListEqual(wheel.fetch(101), []) + self.assertListEqual(wheel.fetch(110), []) + self.assertListEqual(wheel.fetch(120), []) + self.assertListEqual(wheel.fetch(130), []) + self.assertListEqual(wheel.fetch(149), []) + self.assertListEqual(wheel.fetch(156), [obj]) + self.assertListEqual(wheel.fetch(170), []) + + def test_mutli_insert(self): + wheel = WheelTimer(bucket_size=5) + + obj1 = object() + obj2 = object() + obj3 = object() + wheel.insert(100, obj1, 150) + wheel.insert(105, obj2, 130) + wheel.insert(106, obj3, 160) + + self.assertListEqual(wheel.fetch(110), []) + self.assertListEqual(wheel.fetch(135), [obj2]) + self.assertListEqual(wheel.fetch(149), []) + self.assertListEqual(wheel.fetch(158), [obj1]) + self.assertListEqual(wheel.fetch(160), []) + self.assertListEqual(wheel.fetch(200), [obj3]) + self.assertListEqual(wheel.fetch(210), []) + + def test_insert_past(self): + wheel = WheelTimer(bucket_size=5) + + obj = object() + wheel.insert(100, obj, 50) + self.assertListEqual(wheel.fetch(120), [obj]) + + def test_insert_past_mutli(self): + wheel = WheelTimer(bucket_size=5) + + obj1 = object() + obj2 = object() + obj3 = object() + wheel.insert(100, obj1, 150) + wheel.insert(100, obj2, 140) + wheel.insert(100, obj3, 50) + self.assertListEqual(wheel.fetch(110), [obj3]) + self.assertListEqual(wheel.fetch(120), []) + self.assertListEqual(wheel.fetch(147), [obj2]) + self.assertListEqual(wheel.fetch(200), [obj1]) + self.assertListEqual(wheel.fetch(240), []) |