Source Code for Module common.tasksqueue

  1  # copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved. 
  2  # contact http://www.logilab.fr/ -- mailto:contact@logilab.fr 
  3  # 
  4  # This file is part of logilab-common. 
  5  # 
  6  # logilab-common is free software: you can redistribute it and/or modify it under 
  7  # the terms of the GNU Lesser General Public License as published by the Free 
  8  # Software Foundation, either version 2.1 of the License, or (at your option) any 
  9  # later version. 
 10  # 
 11  # logilab-common is distributed in the hope that it will be useful, but WITHOUT 
 12  # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 
 13  # FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more 
 14  # details. 
 15  # 
 16  # You should have received a copy of the GNU Lesser General Public License along 
 17  # with logilab-common.  If not, see <http://www.gnu.org/licenses/>. 
 18  """Prioritized tasks queue""" 
 19   
 20  __docformat__ = "restructuredtext en" 
 21   
 22  from bisect import insort_left 
 23  from queue import Queue 
 24   
 25  LOW = 0 
 26  MEDIUM = 10 
 27  HIGH = 100 
 28   
 29  PRIORITY = { 
 30      'LOW': LOW, 
 31      'MEDIUM': MEDIUM, 
 32      'HIGH': HIGH, 
 33      } 
 34  REVERSE_PRIORITY = dict((values, key) for key, values in PRIORITY.items()) 
 35   
 36   
 37   
 38 -class PrioritizedTasksQueue(Queue): 
 39   
 40 -    def _init(self, maxsize): 
 41          """Initialize the queue representation""" 
 42          self.maxsize = maxsize 
 43          # ordered list of task, from the lowest to the highest priority 
 44          self.queue = [] 
 45   
 46 -    def _put(self, item): 
 47          """Put a new item in the queue""" 
 48          for i, task in enumerate(self.queue): 
 49              # equivalent task 
 50              if task == item: 
 51                  # if new task has a higher priority, remove the one already 
 52                  # queued so the new priority will be considered 
 53                  if task < item: 
 54                      item.merge(task) 
 55                      del self.queue[i] 
 56                      break 
 57                  # else keep it so current order is kept 
 58                  task.merge(item) 
 59                  return 
 60          insort_left(self.queue, item) 
 61   
 62 -    def _get(self): 
 63          """Get an item from the queue""" 
 64          return self.queue.pop() 
 65   
 66 -    def __iter__(self): 
 67          return iter(self.queue) 
 68   
 69 -    def remove(self, tid): 
 70          """remove a specific task from the queue""" 
 71          # XXX acquire lock 
 72          for i, task in enumerate(self): 
 73              if task.id == tid: 
 74                  self.queue.pop(i) 
 75                  return 
 76          raise ValueError('not task of id %s in queue' % tid) 
 77   
 78 -class Task(object): 
 79 -    def __init__(self, tid, priority=LOW): 
 80          # task id 
 81          self.id = tid 
 82          # task priority 
 83          self.priority = priority 
 84   
 85 -    def __repr__(self): 
 86          return '<Task %s @%#x>' % (self.id, id(self)) 
 87   
 88 -    def __cmp__(self, other): 
 89          return cmp(self.priority, other.priority) 
 90   
 91 -    def __lt__(self, other): 
 92          return self.priority < other.priority 
 93   
 94 -    def __eq__(self, other): 
 95          return self.id == other.id 
 96   
 97      __hash__ = object.__hash__ 
 98   
 99 -    def merge(self, other): 
100          pass 
101