buildbot/util.py

   1 # -*- test-case-name: buildbot.test.test_util -*-
   2
   3 from twisted.internet.defer import Deferred
   4 from twisted.spread import pb
   5 import time
   6
   7 def now():
   8     #return int(time.time())
   9     return time.time()
  10
  11 def earlier(old, new):
  12     # minimum of two things, but "None" counts as +infinity
  13     if old:
  14         if new < old:
  15             return new
  16         return old
  17     return new
  18
  19 def later(old, new):
  20     # maximum of two things, but "None" counts as -infinity
  21     if old:
  22         if new > old:
  23             return new
  24         return old
  25     return new
  26
  27 class CancelableDeferred(Deferred):
  28     """I am a version of Deferred that can be canceled by calling my
  29     .cancel() method. After being canceled, no callbacks or errbacks will be
  30     executed.
  31     """
  32     def __init__(self):
  33         Deferred.__init__(self)
  34         self.canceled = 0
  35     def cancel(self):
  36         self.canceled = 1
  37     def _runCallbacks(self):
  38         if self.canceled:
  39             self.callbacks = []
  40             return
  41         Deferred._runCallbacks(self)
  42
  43 def ignoreStaleRefs(failure):
  44     """d.addErrback(util.ignoreStaleRefs)"""
  45     r = failure.trap(pb.DeadReferenceError, pb.PBConnectionLost)
  46     return None
  47
  48 class _None:
  49     pass
  50
  51 class ComparableMixin:
  52     """Specify a list of attributes that are 'important'. These will be used
  53     for all comparison operations."""
  54
  55     compare_attrs = []
  56
  57     def __hash__(self):
  58         alist = [self.__class__] + \
  59                 [getattr(self, name, _None) for name in self.compare_attrs]
  60         return hash(tuple(alist))
  61
  62     def __cmp__(self, them):
  63         if cmp(type(self), type(them)):
  64             return cmp(type(self), type(them))
  65         if cmp(self.__class__, them.__class__):
  66             return cmp(self.__class__, them.__class__)
  67         assert self.compare_attrs == them.compare_attrs
  68         self_list= [getattr(self, name, _None) for name in self.compare_attrs]
  69         them_list= [getattr(them, name, _None) for name in self.compare_attrs]
  70         return cmp(self_list, them_list)