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