/
AcquireMutex.py
59 lines (53 loc) · 2.25 KB
/
AcquireMutex.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
# Copyright (C) 2007 Samuel Abels
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,MA 02110-1301 USA
from SpiffWorkflow.Task import Task
from SpiffWorkflow.exceptions import WorkflowException
from SpiffWorkflow.specs.TaskSpec import TaskSpec
class AcquireMutex(TaskSpec):
"""
This class implements a task that acquires a mutex (lock), protecting
a section of the workflow from being accessed by other sections.
If more than one input is connected, the task performs an implicit
multi merge.
If more than one output is connected, the task performs an implicit
parallel split.
"""
def __init__(self, parent, name, mutex, **kwargs):
"""
Constructor.
@type parent: TaskSpec
@param parent: A reference to the parent task spec.
@type name: str
@param name: The name of the task spec.
@type mutex: str
@param mutex: The name of the mutex that should be acquired.
@type kwargs: dict
@param kwargs: See L{SpiffWorkflow.specs.TaskSpec}.
"""
assert mutex is not None
TaskSpec.__init__(self, parent, name, **kwargs)
self.mutex = mutex
def _update_state_hook(self, my_task):
mutex = my_task.workflow._get_mutex(self.mutex)
if mutex.testandset():
return True
my_task._set_state(Task.WAITING)
return False
def serialize(self, serializer):
return serializer._serialize_acquire_mutex(self)
@classmethod
def deserialize(self, serializer, wf_spec, s_state):
return serializer._deserialize_acquire_mutex(wf_spec, s_state)