Source Code for Module EDThreading

 1  # -*- coding: utf8 -*- 
 2  # 
 3  #    Project: The EDNA Kernel 
 4  #             http://www.edna-site.org 
 5  # 
 6  #    File: "$Id:$" 
 7  # 
 8  #    Copyright (C) 2012-2012 European Synchrotron Radiation Facility 
 9  #                            Grenoble, France 
10  # 
11  #    Principal authors: Jérôme Kieffer (jerome.kieffer@esrf.fr) 
12  #  
13  # 
14  #    This program is free software: you can redistribute it and/or modify 
15  #    it under the terms of the GNU Lesser General Public License as published 
16  #    by the Free Software Foundation, either version 3 of the License, or 
17  #    (at your option) any later version. 
18  # 
19  #    This program is distributed in the hope that it will be useful, 
20  #    but WITHOUT ANY WARRANTY; without even the implied warranty of 
21  #    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
22  #    GNU Lesser General Public License for more details. 
23  # 
24  #    You should have received a copy of the GNU General Public License 
25  #    and the GNU Lesser General Public License  along with this program.   
26  #    If not, see <http://www.gnu.org/licenses/>. 
27  # 
28   
29  """ 
30  Set an environment variable "EDNA_LOCK" to help debugging  
31  any dead-locks- inside EDNA  
32  """ 
33   
34  __authors__ = [ "Jérôme Kieffer" ] 
35  __contact__ = "jerome.kieffer@esrf.fr" 
36  __license__ = "LGPLv3+" 
37  __copyright__ = "European Synchrotron Radiation Facility, Grenoble, France" 
38  __date__ = "20120401" 
39  import uuid, sys, os, traceback 
40  import threading 
41  _Semaphore = threading._Semaphore 
42   
43  if os.environ.get("EDNA_LOCK", False): 
44 -    class Semaphore(_Semaphore): 
45          """ 
46          threading.Semaphore like class with helper for fighting dead-locks 
47          """ 
48 -        def __init__(self, *arg, **kwarg): 
49              _Semaphore.__init__(self, *arg, **kwarg) 
50              self.blocked = [] 
51   
52 -        def acquire(self, *arg, **kwarg): 
53              if self._Semaphore__value == 0: 
54                  uid = uuid.uuid4() 
55                  self.blocked.append(uid) 
56                  sys.stderr.write("Blocking sem %s" % 
57                                   os.linesep.join([str(uid)] + \ 
58                                          traceback.format_stack()[:-1] + [""])) 
59              return _Semaphore.acquire(self, *arg, **kwarg) 
60   
61 -        def release(self, *arg, **kwarg): 
62              if self.blocked: 
63                  try: 
64                      uid = self.blocked.pop() 
65                  except Exception: 
66                      pass 
67                  else: 
68                      sys.stderr.write("Released sem %s %s" % (uid, os.linesep)) 
69              _Semaphore.release(self, *arg, **kwarg) 
70   
71 -        def __enter__(self): 
72              self.acquire() 
73              return self 
74   
75 -        def __exit__(self, *arg, **kwarg): 
76              self.release() 
77  else: 
78      Semaphore = threading.Semaphore 
79