1 files changed, 88 insertions, 0 deletions
diff --git a/pym/portage/util/_async/AsyncScheduler.py b/pym/portage/util/_async/AsyncScheduler.py
new file mode 100644
index 000000000..cae45fd90
--- /dev/null
+++ b/pym/portage/util/_async/AsyncScheduler.py
@@ -0,0 +1,88 @@
+# Copyright 2012 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+from portage import os
+from _emerge.AsynchronousTask import AsynchronousTask
+from _emerge.PollScheduler import PollScheduler
+
+class AsyncScheduler(AsynchronousTask, PollScheduler):
+
+	__slots__ = ('_error_count', '_loadavg_check_id',
+		'_max_jobs', '_max_load',
+		'_remaining_tasks', '_running_tasks', '_term_check_id')
+
+	def __init__(self, max_jobs=None, max_load=None, **kwargs):
+		AsynchronousTask.__init__(self)
+		PollScheduler.__init__(self, **kwargs)
+
+		if max_jobs is None:
+			max_jobs = 1
+		self._max_jobs = max_jobs
+		self._max_load = max_load
+		self._error_count = 0
+		self._running_tasks = set()
+		self._remaining_tasks = True
+		self._term_check_id = None
+		self._loadavg_check_id = None
+
+	def _cancel(self):
+		self._terminated.set()
+		self._terminate_tasks()
+
+	def _terminate_tasks(self):
+		for task in list(self._running_tasks):
+			task.cancel()
+
+	def _next_task(self):
+		raise NotImplementedError(self)
+
+	def _keep_scheduling(self):
+		return self._remaining_tasks and not self._terminated_tasks
+
+	def _running_job_count(self):
+		return len(self._running_tasks)
+
+	def _schedule_tasks(self):
+		while self._keep_scheduling() and self._can_add_job():
+			try:
+				task = self._next_task()
+			except StopIteration:
+				self._remaining_tasks = False
+			else:
+				self._running_tasks.add(task)
+				task.scheduler = self.sched_iface
+				task.addExitListener(self._task_exit)
+				task.start()
+
+	def _task_exit(self, task):
+		self._running_tasks.discard(task)
+		if task.returncode != os.EX_OK:
+			self._error_count += 1
+		self._schedule()
+
+	def _start(self):
+		self._term_check_id = self.sched_iface.idle_add(self._termination_check)
+		if self._max_load is not None:
+			# We have to schedule periodically, in case the load
+			# average has changed since the last call.
+			self._loadavg_check_id = self.sched_iface.timeout_add(
+				self._loadavg_latency, self._schedule)
+		self._schedule()
+
+	def _wait(self):
+		# Loop while there are jobs to be scheduled.
+		while self._keep_scheduling():
+			self.sched_iface.iteration()
+
+		# Clean shutdown of previously scheduled jobs. In the
+		# case of termination, this allows for basic cleanup
+		# such as flushing of buffered output to logs.
+		while self._is_work_scheduled():
+			self.sched_iface.iteration()
+
+		if self._error_count > 0:
+			self.returncode = 1
+		else:
+			self.returncode = os.EX_OK 
+
+		return self.returncode