pym/_emerge/QueueScheduler.py

   1 # Copyright 1999-2012 Gentoo Foundation
   2 # Distributed under the terms of the GNU General Public License v2
   3
   4 from _emerge.PollScheduler import PollScheduler
   5
   6 class QueueScheduler(PollScheduler):
   7
   8         """
   9         Add instances of SequentialTaskQueue and then call run(). The
  10         run() method returns when no tasks remain.
  11         """
  12
  13         def __init__(self, max_jobs=None, max_load=None):
  14                 PollScheduler.__init__(self)
  15
  16                 if max_jobs is None:
  17                         max_jobs = 1
  18
  19                 self._max_jobs = max_jobs
  20                 self._max_load = max_load
  21
  22                 self._queues = []
  23                 self._schedule_listeners = []
  24
  25         def add(self, q):
  26                 self._queues.append(q)
  27
  28         def remove(self, q):
  29                 self._queues.remove(q)
  30
  31         def clear(self):
  32                 for q in self._queues:
  33                         q.clear()
  34
  35         def run(self, timeout=None):
  36
  37                 timeout_callback = None
  38                 if timeout is not None:
  39                         def timeout_callback():
  40                                 timeout_callback.timed_out = True
  41                                 raise StopIteration()
  42                         timeout_callback.timed_out = False
  43                         timeout_callback.timeout_id = self.sched_iface.timeout_add(
  44                                 timeout, timeout_callback)
  45
  46                 try:
  47                         self._main_loop()
  48                 except StopIteration:
  49                         pass
  50                 finally:
  51                         if timeout_callback is not None:
  52                                 self.sched_iface.unregister(timeout_callback.timeout_id)
  53
  54         def _schedule_tasks(self):
  55                 """
  56                 @rtype: bool
  57                 @returns: True if there may be remaining tasks to schedule,
  58                         False otherwise.
  59                 """
  60                 if self._terminated_tasks:
  61                         return False
  62
  63                 while self._can_add_job():
  64                         n = self._max_jobs - self._running_job_count()
  65                         if n < 1:
  66                                 break
  67
  68                         if not self._start_next_job(n):
  69                                 return False
  70
  71                 for q in self._queues:
  72                         if q:
  73                                 return True
  74                 return False
  75
  76         def _running_job_count(self):
  77                 job_count = 0
  78                 for q in self._queues:
  79                         job_count += len(q.running_tasks)
  80                 self._jobs = job_count
  81                 return job_count
  82
  83         def _start_next_job(self, n=1):
  84                 started_count = 0
  85                 for q in self._queues:
  86                         initial_job_count = len(q.running_tasks)
  87                         q.schedule()
  88                         final_job_count = len(q.running_tasks)
  89                         if final_job_count > initial_job_count:
  90                                 started_count += (final_job_count - initial_job_count)
  91                         if started_count >= n:
  92                                 break
  93                 return started_count
  94