95 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			95 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Python
		
	
	
| # -*- coding: utf-8 -*-
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| # 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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| 
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| from six.moves import range
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| 
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| 
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| class _Entry(object):
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|     __slots__ = ["end_key", "queue"]
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| 
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|     def __init__(self, end_key):
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|         self.end_key = end_key
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|         self.queue = []
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| 
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| 
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| class WheelTimer(object):
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|     """Stores arbitrary objects that will be returned after their timers have
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|     expired.
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|     """
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| 
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|     def __init__(self, bucket_size=5000):
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|         """
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|         Args:
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|             bucket_size (int): Size of buckets in ms. Corresponds roughly to the
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|                 accuracy of the timer.
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|         """
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|         self.bucket_size = bucket_size
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|         self.entries = []
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|         self.current_tick = 0
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| 
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|     def insert(self, now, obj, then):
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|         """Inserts object into timer.
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| 
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|         Args:
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|             now (int): Current time in msec
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|             obj (object): Object to be inserted
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|             then (int): When to return the object strictly after.
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|         """
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|         then_key = int(then / self.bucket_size) + 1
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| 
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|         if self.entries:
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|             min_key = self.entries[0].end_key
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|             max_key = self.entries[-1].end_key
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| 
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|             if then_key <= max_key:
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|                 # The max here is to protect against inserts for times in the past
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|                 self.entries[max(min_key, then_key) - min_key].queue.append(obj)
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|                 return
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| 
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|         next_key = int(now / self.bucket_size) + 1
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|         if self.entries:
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|             last_key = self.entries[-1].end_key
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|         else:
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|             last_key = next_key
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| 
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|         # Handle the case when `then` is in the past and `entries` is empty.
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|         then_key = max(last_key, then_key)
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| 
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|         # Add empty entries between the end of the current list and when we want
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|         # to insert. This ensures there are no gaps.
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|         self.entries.extend(_Entry(key) for key in range(last_key, then_key + 1))
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| 
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|         self.entries[-1].queue.append(obj)
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| 
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|     def fetch(self, now):
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|         """Fetch any objects that have timed out
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| 
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|         Args:
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|             now (ms): Current time in msec
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| 
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|         Returns:
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|             list: List of objects that have timed out
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|         """
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|         now_key = int(now / self.bucket_size)
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| 
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|         ret = []
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|         while self.entries and self.entries[0].end_key <= now_key:
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|             ret.extend(self.entries.pop(0).queue)
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| 
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|         return ret
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| 
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|     def __len__(self):
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|         return sum(len(entry.queue) for entry in self.entries)
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