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author | Sylvain Thenault <sylvain.thenault@logilab.fr> | 2008-12-01 11:36:51 +0100 |
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committer | Sylvain Thenault <sylvain.thenault@logilab.fr> | 2008-12-01 11:36:51 +0100 |
commit | 33239a3d2d6c35ec56a506afb47991afcf65e54a (patch) | |
tree | ec87751ba9f22df21f71e222c190b3c24b8b16bd /tasksqueue.py | |
parent | 65c478e1645131acc92cf160df7712146ce043f4 (diff) | |
download | logilab-common-33239a3d2d6c35ec56a506afb47991afcf65e54a.tar.gz |
new module containing a class to handle prioritized tasks queue
Diffstat (limited to 'tasksqueue.py')
-rw-r--r-- | tasksqueue.py | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/tasksqueue.py b/tasksqueue.py new file mode 100644 index 0000000..75ade01 --- /dev/null +++ b/tasksqueue.py @@ -0,0 +1,74 @@ +"""Prioritized tasks queue + +:organization: Logilab +:copyright: 2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved. +:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr +""" +__docformat__ = "restructuredtext en" + +from bisect import insort_left +from Queue import Queue + +LOW = 0 +MEDIUM = 10 +HIGH = 100 + + +class PrioritizedTasksQueue(Queue): + + def _init(self, maxsize): + """Initialize the queue representation""" + self.maxsize = maxsize + # ordered list of task, from the lowest to the highest priority + self.queue = [] + + def _put(self, item): + """Put a new item in the queue""" + for i, task in enumerate(self.queue): + # equivalent task + if task == item: + # if new task has a higher priority, remove the one already + # queued so the new priority will be considered + if task < item: + item.merge(task) + del self.queue[i] + break + # else keep it so current order is kept + task.merge(item) + return + insort_left(self.queue, item) + + def _get(self): + """Get an item from the queue""" + return self.queue.pop() + + def __iter__(self): + return iter(self.queue) + + def remove(self, tid): + """remove a specific task from the queue""" + # XXX acquire lock + for i, task in enumerate(self): + if task.id == tid: + self.queue.pop(i) + return + raise ValueError('not task of id %s in queue' % tid) + +class Task(object): + def __init__(self, tid, priority=LOW): + # task id + self.id = tid + # task priority + self.priority = priority + + def __repr__(self): + return '<Task %s @%#x>' % (self.id, id(self)) + + def __cmp__(self, other): + return cmp(self.priority, other.priority) + + def __eq__(self, other): + return self.id == other.id + + def merge(self, other): + pass |