Python SpawnProcess.poll方法代码示例

# 需要导入模块: from _emerge.SpawnProcess import SpawnProcess [as 别名]
# 或者: from _emerge.SpawnProcess.SpawnProcess import poll [as 别名]
class _LockProcess(AbstractPollTask):
	"""
	This uses the portage.locks module to acquire a lock asynchronously,
	using a subprocess. After the lock is acquired, the process
	writes to a pipe in order to notify a poll loop running in the main
	process. The unlock() method notifies the subprocess to release the
	lock and exit.
	"""

	__slots__ = ('path',) + \
		('_acquired', '_kill_test', '_proc', '_files', '_reg_id', '_unlocked')

	def _start(self):
		in_pr, in_pw = os.pipe()
		out_pr, out_pw = os.pipe()
		self._files = {}
		self._files['pipe_in'] = in_pr
		self._files['pipe_out'] = out_pw
		fcntl.fcntl(in_pr, fcntl.F_SETFL,
			fcntl.fcntl(in_pr, fcntl.F_GETFL) | os.O_NONBLOCK)
		self._reg_id = self.scheduler.register(in_pr,
			self.scheduler.IO_IN, self._output_handler)
		self._registered = True
		self._proc = SpawnProcess(
			args=[portage._python_interpreter,
				os.path.join(portage._bin_path, 'lock-helper.py'), self.path],
				env=dict(os.environ, PORTAGE_PYM_PATH=portage._pym_path),
				fd_pipes={0:out_pr, 1:in_pw, 2:sys.stderr.fileno()},
				scheduler=self.scheduler)
		self._proc.addExitListener(self._proc_exit)
		self._proc.start()
		os.close(out_pr)
		os.close(in_pw)

	def _proc_exit(self, proc):

		if self._files is not None:
			# Close pipe_out if it's still open, since it's useless
			# after the process has exited. This helps to avoid
			# "ResourceWarning: unclosed file" since Python 3.2.
			try:
				pipe_out = self._files.pop('pipe_out')
			except KeyError:
				pass
			else:
				os.close(pipe_out)

		if proc.returncode != os.EX_OK:
			# Typically, this will happen due to the
			# process being killed by a signal.

			if not self._acquired:
				# If the lock hasn't been aquired yet, the
				# caller can check the returncode and handle
				# this failure appropriately.
				if not (self.cancelled or self._kill_test):
					writemsg_level("_LockProcess: %s\n" % \
						_("failed to acquire lock on '%s'") % (self.path,),
						level=logging.ERROR, noiselevel=-1)
				self._unregister()
				self.returncode = proc.returncode
				self.wait()
				return

			if not self.cancelled and \
				not self._unlocked:
				# We don't want lost locks going unnoticed, so it's
				# only safe to ignore if either the cancel() or
				# unlock() methods have been previously called.
				raise AssertionError("lock process failed with returncode %s" \
					% (proc.returncode,))

	def _cancel(self):
		if self._proc is not None:
			self._proc.cancel()

	def _poll(self):
		if self._proc is not None:
			self._proc.poll()
		return self.returncode

	def _output_handler(self, f, event):
		buf = None
		if event & self.scheduler.IO_IN:
			try:
				buf = os.read(self._files['pipe_in'], self._bufsize)
			except OSError as e:
				if e.errno not in (errno.EAGAIN,):
					raise
		if buf:
			self._acquired = True
			self._unregister()
			self.returncode = os.EX_OK
			self.wait()

		return True

	def _unregister(self):
		self._registered = False

#.........这里部分代码省略.........

# 需要导入模块: from _emerge.SpawnProcess import SpawnProcess [as 别名]
# 或者: from _emerge.SpawnProcess.SpawnProcess import poll [as 别名]
class _LockProcess(AbstractPollTask):
	"""
	This uses the portage.locks module to acquire a lock asynchronously,
	using a subprocess. After the lock is acquired, the process
	writes to a pipe in order to notify a poll loop running in the main
	process. The unlock() method notifies the subprocess to release the
	lock and exit.
	"""

	__slots__ = ('path',) + \
		('_acquired', '_kill_test', '_proc', '_files', '_unlock_future')

	def _start(self):
		in_pr, in_pw = os.pipe()
		out_pr, out_pw = os.pipe()
		self._files = {}
		self._files['pipe_in'] = in_pr
		self._files['pipe_out'] = out_pw

		fcntl.fcntl(in_pr, fcntl.F_SETFL,
			fcntl.fcntl(in_pr, fcntl.F_GETFL) | os.O_NONBLOCK)

		# FD_CLOEXEC is enabled by default in Python >=3.4.
		if sys.hexversion < 0x3040000:
			try:
				fcntl.FD_CLOEXEC
			except AttributeError:
				pass
			else:
				fcntl.fcntl(in_pr, fcntl.F_SETFD,
					fcntl.fcntl(in_pr, fcntl.F_GETFD) | fcntl.FD_CLOEXEC)

		self.scheduler.add_reader(in_pr, self._output_handler)
		self._registered = True
		self._proc = SpawnProcess(
			args=[portage._python_interpreter,
				os.path.join(portage._bin_path, 'lock-helper.py'), self.path],
				env=dict(os.environ, PORTAGE_PYM_PATH=portage._pym_path),
				fd_pipes={0:out_pr, 1:in_pw, 2:sys.__stderr__.fileno()},
				scheduler=self.scheduler)
		self._proc.addExitListener(self._proc_exit)
		self._proc.start()
		os.close(out_pr)
		os.close(in_pw)

	def _proc_exit(self, proc):

		if self._files is not None:
			# Close pipe_out if it's still open, since it's useless
			# after the process has exited. This helps to avoid
			# "ResourceWarning: unclosed file" since Python 3.2.
			try:
				pipe_out = self._files.pop('pipe_out')
			except KeyError:
				pass
			else:
				os.close(pipe_out)

		if proc.returncode != os.EX_OK:
			# Typically, this will happen due to the
			# process being killed by a signal.

			if not self._acquired:
				# If the lock hasn't been aquired yet, the
				# caller can check the returncode and handle
				# this failure appropriately.
				if not (self.cancelled or self._kill_test):
					writemsg_level("_LockProcess: %s\n" % \
						_("failed to acquire lock on '%s'") % (self.path,),
						level=logging.ERROR, noiselevel=-1)
				self._unregister()
				self.returncode = proc.returncode
				self._async_wait()
				return

			if not self.cancelled and \
				self._unlock_future is None:
				# We don't want lost locks going unnoticed, so it's
				# only safe to ignore if either the cancel() or
				# unlock() methods have been previously called.
				raise AssertionError("lock process failed with returncode %s" \
					% (proc.returncode,))

		if self._unlock_future is not None:
			self._unlock_future.set_result(None)

	def _cancel(self):
		if self._proc is not None:
			self._proc.cancel()

	def _poll(self):
		if self._proc is not None:
			self._proc.poll()
		return self.returncode

	def _output_handler(self):
		buf = self._read_buf(self._files['pipe_in'])
		if buf:
			self._acquired = True
			self._unregister()
#.........这里部分代码省略.........