Source Code for Module buildbot.dnotify

  1   
  2  # spiv wants this 
  3   
  4  import fcntl, signal 
  5   
  6 -class DNotify_Handler: 
  7 -    def __init__(self): 
  8          self.watchers = {} 
  9          self.installed = 0 
 10 -    def install(self): 
 11          if self.installed: 
 12              return 
 13          signal.signal(signal.SIGIO, self.fire) 
 14          self.installed = 1 
 15 -    def uninstall(self): 
 16          if not self.installed: 
 17              return 
 18          signal.signal(signal.SIGIO, signal.SIG_DFL) 
 19          self.installed = 0 
 20 -    def add(self, watcher): 
 21          self.watchers[watcher.fd.fileno()] = watcher 
 22          self.install() 
 23 -    def remove(self, watcher): 
 24          if self.watchers.has_key(watcher.fd.fileno()): 
 25              del(self.watchers[watcher.fd.fileno()]) 
 26              if not self.watchers: 
 27                  self.uninstall() 
 28 -    def fire(self, signum, frame): 
 29          # this is the signal handler 
 30          # without siginfo_t, we must fire them all 
 31          for watcher in self.watchers.values(): 
 32              watcher.callback() 
 33               
 34 -class DNotify: 
 35      DN_ACCESS = fcntl.DN_ACCESS  # a file in the directory was read 
 36      DN_MODIFY = fcntl.DN_MODIFY  # a file was modified (write,truncate) 
 37      DN_CREATE = fcntl.DN_CREATE  # a file was created 
 38      DN_DELETE = fcntl.DN_DELETE  # a file was unlinked 
 39      DN_RENAME = fcntl.DN_RENAME  # a file was renamed 
 40      DN_ATTRIB = fcntl.DN_ATTRIB  # a file had attributes changed (chmod,chown) 
 41   
 42      handler = [None] 
 43       
 44 -    def __init__(self, dirname, callback=None, 
 45                   flags=[DN_MODIFY,DN_CREATE,DN_DELETE,DN_RENAME]): 
 46   
 47          """This object watches a directory for changes. The .callback 
 48          attribute should be set to a function to be run every time something 
 49          happens to it. Be aware that it will be called more times than you 
 50          expect.""" 
 51   
 52          if callback: 
 53              self.callback = callback 
 54          else: 
 55              self.callback = self.fire 
 56          self.dirname = dirname 
 57          self.flags = reduce(lambda x, y: x | y, flags) | fcntl.DN_MULTISHOT 
 58          self.fd = open(dirname, "r") 
 59          # ideally we would move the notification to something like SIGRTMIN, 
 60          # (to free up SIGIO) and use sigaction to have the signal handler 
 61          # receive a structure with the fd number. But python doesn't offer 
 62          # either. 
 63          if not self.handler[0]: 
 64              self.handler[0] = DNotify_Handler() 
 65          self.handler[0].add(self) 
 66          fcntl.fcntl(self.fd, fcntl.F_NOTIFY, self.flags) 
 67 -    def remove(self): 
 68          self.handler[0].remove(self) 
 69          self.fd.close() 
 70 -    def fire(self): 
 71          print self.dirname, "changed!" 
 72   
 73 -def test_dnotify1(): 
 74      d = DNotify(".") 
 75      while 1: 
 76          signal.pause() 
 77   
 78 -def test_dnotify2(): 
 79      # create ./foo/, create/delete files in ./ and ./foo/ while this is 
 80      # running. Notice how both notifiers are fired when anything changes; 
 81      # this is an unfortunate side-effect of the lack of extended sigaction 
 82      # support in Python. 
 83      count = [0] 
 84      d1 = DNotify(".") 
 85      def fire1(count=count, d1=d1): 
 86          print "./ changed!", count[0] 
 87          count[0] += 1 
 88          if count[0] > 5: 
 89              d1.remove() 
 90              del(d1) 
 91      # change the callback, since we can't define it until after we have the 
 92      # dnotify object. Hmm, unless we give the dnotify to the callback. 
 93      d1.callback = fire1 
 94      def fire2(): print "foo/ changed!" 
 95      d2 = DNotify("foo", fire2) 
 96      while 1: 
 97          signal.pause() 
 98           
 99       
100  if __name__ == '__main__': 
101      test_dnotify2() 
102