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   
 24  from six.moves import queue 
 25   
 26  LOW = 0 
 27  MEDIUM = 10 
 28  HIGH = 100 
 29   
 30  PRIORITY = { 
 31      'LOW': LOW, 
 32      'MEDIUM': MEDIUM, 
 33      'HIGH': HIGH, 
 34      } 
 35  REVERSE_PRIORITY = dict((values, key) for key, values in PRIORITY.items()) 
 36   
 37   
 38   
39 -class PrioritizedTasksQueue(queue.Queue):
40
41 - def _init(self, maxsize):
42 """Initialize the queue representation""" 43 self.maxsize = maxsize 44 # ordered list of task, from the lowest to the highest priority 45 self.queue = []
46
47 - def _put(self, item):
48 """Put a new item in the queue""" 49 for i, task in enumerate(self.queue): 50 # equivalent task 51 if task == item: 52 # if new task has a higher priority, remove the one already 53 # queued so the new priority will be considered 54 if task < item: 55 item.merge(task) 56 del self.queue[i] 57 break 58 # else keep it so current order is kept 59 task.merge(item) 60 return 61 insort_left(self.queue, item)
62
63 - def _get(self):
64 """Get an item from the queue""" 65 return self.queue.pop()
66
67 - def __iter__(self):
68 return iter(self.queue)
69
70 - def remove(self, tid):
71 """remove a specific task from the queue""" 72 # XXX acquire lock 73 for i, task in enumerate(self): 74 if task.id == tid: 75 self.queue.pop(i) 76 return 77 raise ValueError('not task of id %s in queue' % tid)
78
79 -class Task(object):
80 - def __init__(self, tid, priority=LOW):
81 # task id 82 self.id = tid 83 # task priority 84 self.priority = priority
85
86 - def __repr__(self):
87 return '<Task %s @%#x>' % (self.id, id(self))
88
89 - def __cmp__(self, other):
90 return cmp(self.priority, other.priority)
91
92 - def __lt__(self, other):
93 return self.priority < other.priority
94
95 - def __eq__(self, other):
96 return self.id == other.id
97 98 __hash__ = object.__hash__ 99
100 - def merge(self, other):
101 pass
102