text: #
  # BitBake Process based server.
  #
  # Copyright (C) 2010 Bob Foerster <robert@erafx.com>
  #
  # This program is free software; you can redistribute it and/or modify
  # it under the terms of the GNU General Public License version 2 as
  # published by the Free Software Foundation.
  #
  # This program is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License along
  # with this program; if not, write to the Free Software Foundation, Inc.,
  # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  
  """
      This module implements a multiprocessing.Process based server for bitbake.
  """
  
  import bb
  import bb.event
  import itertools
  import logging
  import multiprocessing
  import os
  import signal
  import sys
  import time
  import select
  from Queue import Empty
  from multiprocessing import Event, Process, util, Queue, Pipe, queues, Manager
  
  from . import BitBakeBaseServer, BitBakeBaseServerConnection, BaseImplServer
  
  logger = logging.getLogger('BitBake')
  
  class ServerCommunicator():
      def __init__(self, connection, event_handle):
          self.connection = connection
          self.event_handle = event_handle
  
      def runCommand(self, command):
          # @todo try/except
          self.connection.send(command)
  
          while True:
              # don't let the user ctrl-c while we're waiting for a response
              try:
                  if self.connection.poll(20):
                      return self.connection.recv()
                  else:
                      bb.fatal("Timeout while attempting to communicate with bitbake server")
              except KeyboardInterrupt:
                  pass
  
      def getEventHandle(self):
          return self.event_handle.value
  
  class EventAdapter():
      """
      Adapter to wrap our event queue since the caller (bb.event) expects to
      call a send() method, but our actual queue only has put()
      """
      def __init__(self, queue):
          self.queue = queue
  
      def send(self, event):
          try:
              self.queue.put(event)
          except Exception as err:
              print("EventAdapter puked: %s" % str(err))
  
  
  class ProcessServer(Process, BaseImplServer):
      profile_filename = "profile.log"
      profile_processed_filename = "profile.log.processed"
  
      def __init__(self, command_channel, event_queue, featurelist):
          BaseImplServer.__init__(self)
          Process.__init__(self)
          self.command_channel = command_channel
          self.event_queue = event_queue
          self.event = EventAdapter(event_queue)
          self.featurelist = featurelist
          self.quit = False
  
          self.quitin, self.quitout = Pipe()
          self.event_handle = multiprocessing.Value("i")
  
      def run(self):
          for event in bb.event.ui_queue:
              self.event_queue.put(event)
          self.event_handle.value = bb.event.register_UIHhandler(self)
  
          bb.cooker.server_main(self.cooker, self.main)
  
      def main(self):
          # Ignore SIGINT within the server, as all SIGINT handling is done by
          # the UI and communicated to us
          self.quitin.close()
          signal.signal(signal.SIGINT, signal.SIG_IGN)
          while not self.quit:
              try:
                  if self.command_channel.poll():
                      command = self.command_channel.recv()
                      self.runCommand(command)
                  if self.quitout.poll():
                      self.quitout.recv()
                      self.quit = True
  
                  self.idle_commands(.1, [self.event_queue._reader, self.command_channel, self.quitout])
              except Exception:
                  logger.exception('Running command %s', command)
  
          self.event_queue.close()
          bb.event.unregister_UIHhandler(self.event_handle.value)
          self.command_channel.close()
          self.cooker.shutdown(True)
  
      def idle_commands(self, delay, fds = []):
          nextsleep = delay
  
          for function, data in self._idlefuns.items():
              try:
                  retval = function(self, data, False)
                  if retval is False:
                      del self._idlefuns[function]
                      nextsleep = None
                  elif retval is True:
                      nextsleep = None
                  elif nextsleep is None:
                      continue
                  else:
                      fds = fds + retval
              except SystemExit:
                  raise
              except Exception:
                  logger.exception('Running idle function')
  
          if nextsleep is not None:
              select.select(fds,[],[],nextsleep)
  
      def runCommand(self, command):
          """
          Run a cooker command on the server
          """
          self.command_channel.send(self.cooker.command.runCommand(command))
  
      def stop(self):
          self.quitin.send("quit")
          self.quitin.close()
  
  class BitBakeProcessServerConnection(BitBakeBaseServerConnection):
      def __init__(self, serverImpl, ui_channel, event_queue):
          self.procserver = serverImpl
          self.ui_channel = ui_channel
          self.event_queue = event_queue
          self.connection = ServerCommunicator(self.ui_channel, self.procserver.event_handle)
          self.events = self.event_queue
  
      def sigterm_terminate(self):
          bb.error("UI received SIGTERM")
          self.terminate()
  
      def terminate(self):
          def flushevents():
              while True:
                  try:
                      event = self.event_queue.get(block=False)
                  except (Empty, IOError):
                      break
                  if isinstance(event, logging.LogRecord):
                      logger.handle(event)
  
          signal.signal(signal.SIGINT, signal.SIG_IGN)
          self.procserver.stop()
  
          while self.procserver.is_alive():
              flushevents()
              self.procserver.join(0.1)
  
          self.ui_channel.close()
          self.event_queue.close()
          self.event_queue.setexit()
  
  # Wrap Queue to provide API which isn't server implementation specific
  class ProcessEventQueue(multiprocessing.queues.Queue):
      def __init__(self, maxsize):
          multiprocessing.queues.Queue.__init__(self, maxsize)
          self.exit = False
  
      def setexit(self):
          self.exit = True
  
      def waitEvent(self, timeout):
          if self.exit:
              raise KeyboardInterrupt()
          try:
              return self.get(True, timeout)
          except Empty:
              return None
  
      def getEvent(self):
          try:
              return self.get(False)
          except Empty:
              return None
  
  
  class BitBakeServer(BitBakeBaseServer):
      def initServer(self):
          # establish communication channels.  We use bidirectional pipes for
          # ui <--> server command/response pairs
          # and a queue for server -> ui event notifications
          #
          self.ui_channel, self.server_channel = Pipe()
          self.event_queue = ProcessEventQueue(0)
          self.serverImpl = ProcessServer(self.server_channel, self.event_queue, None)
  
      def detach(self):
          self.serverImpl.start()
          return
  
      def establishConnection(self, featureset):
  
          self.connection = BitBakeProcessServerConnection(self.serverImpl, self.ui_channel, self.event_queue)
  
          _, error = self.connection.connection.runCommand(["setFeatures", featureset])
          if error:
              logger.error("Unable to set the cooker to the correct featureset: %s" % error)
              raise BaseException(error)
          signal.signal(signal.SIGTERM, lambda i, s: self.connection.sigterm_terminate())
          return self.connection
  