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