Package logilab :: Package common :: Module tasksqueue
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Source Code for Module logilab.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.iteritems()) 
 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 - def merge(self, other):
98 pass
99