Source Code for Module logilab.common.tasksqueue

 1  # copyright 2003-2010 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  :organization: Logilab 
21   
22   
23  """ 
24  __docformat__ = "restructuredtext en" 
25   
26  from bisect import insort_left 
27  from Queue import Queue 
28   
29  LOW = 0 
30  MEDIUM = 10 
31  HIGH = 100 
32   
33  REVERSE_PRIORITY = { 
34      0: 'LOW', 
35      10: 'MEDIUM', 
36      100: 'HIGH' 
37      } 
38   
39   
40 -class PrioritizedTasksQueue(Queue): 
41   
42 -    def _init(self, maxsize): 
43          """Initialize the queue representation""" 
44          self.maxsize = maxsize 
45          # ordered list of task, from the lowest to the highest priority 
46          self.queue = [] 
47   
48 -    def _put(self, item): 
49          """Put a new item in the queue""" 
50          for i, task in enumerate(self.queue): 
51              # equivalent task 
52              if task == item: 
53                  # if new task has a higher priority, remove the one already 
54                  # queued so the new priority will be considered 
55                  if task < item: 
56                      item.merge(task) 
57                      del self.queue[i] 
58                      break 
59                  # else keep it so current order is kept 
60                  task.merge(item) 
61                  return 
62          insort_left(self.queue, item) 
63   
64 -    def _get(self): 
65          """Get an item from the queue""" 
66          return self.queue.pop() 
67   
68 -    def __iter__(self): 
69          return iter(self.queue) 
70   
71 -    def remove(self, tid): 
72          """remove a specific task from the queue""" 
73          # XXX acquire lock 
74          for i, task in enumerate(self): 
75              if task.id == tid: 
76                  self.queue.pop(i) 
77                  return 
78          raise ValueError('not task of id %s in queue' % tid) 
79   
80 -class Task(object): 
81 -    def __init__(self, tid, priority=LOW): 
82          # task id 
83          self.id = tid 
84          # task priority 
85          self.priority = priority 
86   
87 -    def __repr__(self): 
88          return '<Task %s @%#x>' % (self.id, id(self)) 
89   
90 -    def __cmp__(self, other): 
91          return cmp(self.priority, other.priority) 
92   
93 -    def __eq__(self, other): 
94          return self.id == other.id 
95   
96 -    def merge(self, other): 
97          pass 
98