--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/runtime/Worker.py Tue Aug 21 16:11:02 2018 +0200
@@ -0,0 +1,110 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# This file is part of Beremiz runtime.
+#
+# Copyright (C) 2018: Edouard TISSERANT
+#
+# See COPYING.Runtime file for copyrights details.
+
+from __future__ import absolute_import
+import thread
+from threading import Lock, Condition
+
+class job(object):
+ """
+ job to be executed by a worker
+ """
+ def __init__(self, call, *args, **kwargs):
+ self.job = (call, args, kwargs)
+ self.result = None
+ self.success = False
+ self.exc_info = None
+
+ def do(self):
+ """
+ do the job by executing the call, and deal with exceptions
+ """
+ try:
+ call, args, kwargs = self.job
+ self.result = call(*args, **kwargs)
+ self.success = True
+ except Exception:
+ self.success = False
+ self.exc_info = sys.exc_info()
+
+
+class worker(object):
+ """
+ serialize main thread load/unload of PLC shared objects
+ """
+ def __init__(self):
+ # Only one job at a time
+ self._finish = False
+ self._threadID = None
+ self.mutex = Lock()
+ self.todo = Condition(self.mutex)
+ self.done = Condition(self.mutex)
+ self.free = Condition(self.mutex)
+ self.job = None
+
+ def runloop(self, *args, **kwargs):
+ """
+ meant to be called by worker thread (blocking)
+ """
+ self._threadID = thread.get_ident()
+ if args or kwargs:
+ job(*args, **kwargs).do()
+ # result is ignored
+ self.mutex.acquire()
+ while not self._finish:
+ self.todo.wait()
+ if self.job is not None:
+ self.job.do()
+ self.done.notify()
+ else:
+ self.free.notify()
+ self.mutex.release()
+
+ def call(self, *args, **kwargs):
+ """
+ creates a job, execute it in worker thread, and deliver result.
+ if job execution raise exception, re-raise same exception
+ meant to be called by non-worker threads, but this is accepted.
+ blocking until job done
+ """
+
+ _job = job(*args, **kwargs)
+
+ if self._threadID == thread.get_ident() or self._threadID is None:
+ # if caller is worker thread execute immediately
+ _job.do()
+ else:
+ # otherwise notify and wait for completion
+ self.mutex.acquire()
+
+ while self.job is not None:
+ self.free.wait()
+
+ self.job = _job
+ self.todo.notify()
+ self.done.wait()
+ _job = self.job
+ self.job = None
+ self.mutex.release()
+
+ if _job.success:
+ return _job.result
+ else:
+ raise _job.exc_info[0], _job.exc_info[1], _job.exc_info[2]
+
+ def quit(self):
+ """
+ unblocks main thread, and terminate execution of runloop()
+ """
+ # mark queue
+ self._finish = True
+ self.mutex.acquire()
+ self.job = None
+ self.todo.notify()
+ self.mutex.release()