Source Code for Module osh.command.timer

  1  # osh 
  2  # Copyright (C) Jack Orenstein <jao@geophile.com> 
  3  # 
  4  # This program is free software; you can redistribute it and/or modify 
  5  # it under the terms of the GNU General Public License as published by 
  6  # the Free Software Foundation; either version 2 of the License, or 
  7  # (at your option) any later version. 
  8  # 
  9  # This program is distributed in the hope that it will be useful, 
 10  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 11  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 12  # GNU General Public License for more details. 
 13  # 
 14  # You should have received a copy of the GNU General Public License 
 15  # along with this program; if not, write to the Free Software 
 16  # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 
 17   
 18  """C{timer [-t] INTERVAL} 
 19       
 20  Generates a sequence of timestamps, separated in time by the specified C{INTERVAL} 
 21  (approximately). The C{INTERVAL} format is:: 
 22       
 23      HH:MM:SS 
 24   
 25  where C{HH} is hours, C{MM} is minutes, C{SS} is seconds.  C{HH:} and 
 26  C{HH:MM:} may be omitted. 
 27   
 28  B{Examples}:: 
 29   
 30      INTERVAL        meaning 
 31      ----------------------------- 
 32      5               5 seconds 
 33      1:30            1 minute, 30 seconds 
 34      1:00:00         1 hour 
 35   
 36  The output timestamp is time in seconds since 1/1/1970. If C{-t} is specified, 
 37  then the output timestamp is a tuple, matching what is returned by 
 38  C{time.gmtime()} and C{time.localtime()}: (year, month, day of month, 
 39  hour, minute, second, day of week, day of year, dst). 
 40   
 41  Notes: 
 42      - month is 1-based (January = 1, February = 2, ...) 
 43      - day of month is 1-based. 
 44      - second can go as high as 61 due to leap-seconds. 
 45      - day of week is 0-based, Monday = 0. 
 46      - day of year is 1-based. 
 47      - dst is 1 if Daylight Savings Time is in effect, 0 otherwise. 
 48  """ 
 49   
 50  import threading 
 51  import time 
 52   
 53  import osh.core 
 54   
 55  Option = osh.args.Option 
 56   
 57  # CLI 
 58 -def _timer(): 
 59      return _Timer() 
 60   
 61  # API 
 62 -def timer(interval, tupleoutput = False): 
 63      """Generates a sequence of timestamps, separated in time by the 
 64      specified C{interval} (approximately). The C{interval} format is 
 65      C{HH:MM:SS}, where C{HH} is hours, C{MM} is minutes, C{SS} is 
 66      seconds. C{HH:} and C{HH:MM:} may be omitted. Output items are 
 67      numbers representing seconds since 1/1/1970, if tupleoutput is False, 
 68      a tuple of (year, month, day of month, 
 69      hour, minute, second, day of week, day of year, dst) otherwise. 
 70      """ 
 71      args = [] 
 72      if tupleoutput: 
 73          args.append(Option('-t')) 
 74      return _Timer().process_args(interval) 
 75   
 76 -class _Timer(osh.core.Generator): 
 77   
 78      _tupleoutput = None 
 79      _metronome = None 
 80      _lock = None 
 81      _now = None 
 82      _done = False 
 83   
 84      # object interface 
 85   
 86 -    def __init__(self): 
 87          osh.core.Generator.__init__(self, 't' ,(1, 1)) 
 88   
 89   
 90      # BaseOp interface 
 91       
 92 -    def doc(self): 
 93          return __doc__ 
 94   
 95 -    def setup(self): 
 96          args = self.args() 
 97          self._tupleoutput = args.flag('-t') 
 98          if args.has_next(): 
 99              interval = self.parse_interval(args.next_string()) 
100              if args.has_next(): 
101                  self.usage() 
102              self._metronome = _Metronome(interval, self) 
103              self._lock = threading.Condition() 
104          else: 
105              self.usage() 
106   
107   
108      # Generator interface 
109       
110 -    def execute(self): 
111          # Timer events are generated by the metronome class, which is a separate 
112          # thread. This keeps the intervals close to what is specified. If the 
113          # timer is run in the current thread, then the interval would control 
114          # the time between completion of downstream computing (invoked by self.send) 
115          # and the next timer event. 
116          self._metronome.start() 
117          while not self._done: 
118              self._lock.acquire() 
119              while self._now is None: 
120                  # If the timeout is omitted from the wait call, then ctrl-c 
121                  # cannot interrupt. The threading module implements wait 
122                  # differently if a timeout is specified, waking up periodically. 
123                  self._lock.wait(1.0) 
124              now = self._now 
125              if (not self._tupleoutput): 
126                  now = time.mktime(now) 
127              self._now = None 
128              self._lock.release() 
129              self.send(now) 
130   
131      # For use by this module 
132   
133 -    def parse_interval(self, interval): 
134          colon1 = interval.find(':') 
135          colon2 = -1 
136          if colon1 > 0: 
137              colon2 = interval.find(':', colon1 + 1) 
138          # Normalize 
139          if colon1 < 0: 
140              # No colons 
141              interval = '0:0:' + interval 
142          elif colon2 < 0: 
143              # One colon 
144              interval = '0:' + interval 
145          colon1 = interval.find(':') 
146          colon2 = interval.find(':', colon1 + 1) 
147          HH = int(interval[:colon1]) 
148          MM = int(interval[colon1 + 1 : colon2]) 
149          SS = int(interval[colon2 + 1 :]) 
150          return HH * 3600 + MM * 60 + SS 
151   
152 -    def register_tick(self): 
153          self._lock.acquire() 
154          self._now = time.localtime() 
155          self._lock.notifyAll() 
156          self._lock.release() 
157   
158 -class _Metronome(threading.Thread): 
159   
160      _interval = None 
161      _timer = None 
162       
163 -    def __init__(self, interval, timer): 
164          threading.Thread.__init__(self) 
165          self._interval = interval 
166          self._timer = timer 
167          self.setDaemon(True) 
168   
169 -    def run(self): 
170          while True: 
171              self._timer.register_tick() 
172              time.sleep(self._interval) 
173