code.delx.au - pymsnt/blob - src/tlib/throttle.py

   1 from twisted.internet import task
   2
   3
   4
   5 class Throttler:
   6         def __init__(self, consumer, speed):
   7                 self.consumer = consumer
   8
   9                 self.buffer = ""
  10                 self.speed = speed # Bytes/second
  11                 self.canClose = False
  12
  13                 self.loopTask = task.LoopingCall(self.loopFunc)
  14                 self.loopTask.start(1.0)
  15
  16         def write(self, data):
  17                 if not self.consumer:
  18                         raise ValueError, "I/O operation on closed 'file'"
  19                 self.buffer += data
  20
  21         def close(self):
  22                 self.canClose = True
  23
  24         def error(self):
  25                 self.consumer.error()
  26                 self.consumer = None
  27                 self.buffer = None
  28                 self.loopTask.stop()
  29
  30         def loopFunc(self):
  31                 if self.canClose and len(self.buffer) == 0:
  32                         self.consumer.close()
  33                         self.consumer = None
  34                         self.loopTask.stop()
  35
  36                 else:
  37                         chunk, self.buffer = self.buffer[:self.speed], self.buffer[self.speed:]
  38                         self.consumer.write(chunk)
  39
  40
  41