92 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			92 lines
		
	
	
		
			2.8 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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class _Entry:
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    __slots__ = ["end_key", "queue"]
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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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class WheelTimer:
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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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    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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    def insert(self, now, obj, then):
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        """Inserts object into timer.
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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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        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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            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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        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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        # 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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        # 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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        self.entries[-1].queue.append(obj)
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    def fetch(self, now):
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        """Fetch any objects that have timed out
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        Args:
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            now (ms): Current time in msec
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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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        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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        return ret
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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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