Source Code for Module buildbot.util.eventual

 1  # This file is part of Buildbot.  Buildbot is free software: you can 
 2  # redistribute it and/or modify it under the terms of the GNU General Public 
 3  # License as published by the Free Software Foundation, version 2. 
 4  # 
 5  # This program is distributed in the hope that it will be useful, but WITHOUT 
 6  # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 
 7  # FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more 
 8  # details. 
 9  # 
10  # You should have received a copy of the GNU General Public License along with 
11  # this program; if not, write to the Free Software Foundation, Inc., 51 
12  # Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 
13  # 
14  # Copyright Buildbot Team Members 
15   
16   
17  # copied from foolscap 
18   
19  from twisted.internet import reactor, defer 
20  from twisted.python import log 
21   
22 -class _SimpleCallQueue(object): 
23   
24      _reactor = reactor 
25   
26 -    def __init__(self): 
27          self._events = [] 
28          self._flushObservers = [] 
29          self._timer = None 
30          self._in_turn = False 
31   
32 -    def append(self, cb, args, kwargs): 
33          self._events.append((cb, args, kwargs)) 
34          if not self._timer: 
35              self._timer = self._reactor.callLater(0, self._turn) 
36   
37 -    def _turn(self): 
38          self._timer = None 
39          self._in_turn = True 
40          # flush all the messages that are currently in the queue. If anything 
41          # gets added to the queue while we're doing this, those events will 
42          # be put off until the next turn. 
43          events, self._events = self._events, [] 
44          for cb, args, kwargs in events: 
45              try: 
46                  cb(*args, **kwargs) 
47              except: 
48                  log.err() 
49          self._in_turn = False 
50          if self._events and not self._timer: 
51              self._timer = self._reactor.callLater(0, self._turn) 
52          if not self._events: 
53              observers, self._flushObservers = self._flushObservers, [] 
54              for o in observers: 
55                  o.callback(None) 
56   
57 -    def flush(self): 
58          if not self._events and not self._in_turn: 
59              return defer.succeed(None) 
60          d = defer.Deferred() 
61          self._flushObservers.append(d) 
62          return d 
63   
64   
65  _theSimpleQueue = _SimpleCallQueue() 
66   
67 -def eventually(cb, *args, **kwargs): 
68      _theSimpleQueue.append(cb, args, kwargs) 
69   
70   
71 -def fireEventually(value=None): 
72      d = defer.Deferred() 
73      eventually(d.callback, value) 
74      return d 
75   
76 -def flushEventualQueue(_ignored=None): 
77      return _theSimpleQueue.flush() 
78   
79 -def _setReactor(r=None): 
80      # This sets the reactor used to schedule future events to r.  If r is None 
81      # (the default), the reactor is reset to its default value. 
82      # This should only be used for unit tests. 
83      if r is None: 
84          r = reactor 
85      _theSimpleQueue._reactor = r 
86