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单线程环境下实现多个定时任务

代码解析

以下是实现单线程环境下多个定时任务的Python代码示例：

#!/usr/bin/env python
from heapq import *
from threading import Timer
import threading
import uuid
import time
import datetime
import sys
import math
global TimerStamp
global TimerTimes
class CancelFail(Exception):
    pass
class Slot(object):
    def __init__(self, period=0, interval=1, function=None, args=[], kwargs={}):
        self.period = period
        self.pc = 0
        self.interval = interval
        self.fire = 0
        self.id = uuid.uuid1()
        self.function = function
        self.args = args
        self.kwargs = kwargs
class NewTimer(object):
    def __init__(self, resolution=1000):
        global TimerStamp
        TimerStamp = int(time.time() * 1000)
        self.nofire = sys.maxint
        self.firestamp = self.nofire + TimerStamp
        self.resolution = resolution
        self.lock = threading.RLock()
        self.wait = dict()
        self.ready = dict()
        self._start()
    def _addToReadyList(self, slot, firestamp):
        box = dict([(slot.id, slot)])
        if not self.ready.has_key(firestamp):
            self.ready.update([(firestamp, box)])
        else:
            boxs = self.ready.get(firestamp)
            boxs.update(box)
    def _delFromReadyList(self, slot):
        boxs = self.ready.get(slot.fire)
        if boxs:
            if slot.id in boxs:
                boxs.pop(slot.id)
                if not boxs:
                    self.ready.pop(slot.fire)
    def _start(self):
        current_time = int(time.time() * 1000)
        self.nofire = current_time
        self.firestamp = self.nofire + self.resolution
        self._schedule()
    def _schedule(self):
        current_time = int(time.time() * 1000)
        if self.firestamp <= current_time:
            self._handleExpired()
        if self.firestamp <= current_time:
            self._processReadyTasks()
    def _handleExpired(self):
        current_time = int(time.time() * 1000)
        self.nofire = current_time
        self.firestamp = self.nofire + self.resolution
        self._schedule()
    def _processReadyTasks(self):
        current_time = int(time.time() * 1000)
        while self.firestamp <= current_time:
            if self.ready:
                firestamp, slots = next(iter(self.ready.items()))
                if firestamp <= current_time:
                    self._executeTask(firestamp, slots)
                    self._delFromReadyList(slots[0])
                    self._handleExpired()
                else:
                    break
    def _executeTask(self, firestamp, slot):
        try:
            slot.function(**slot.kwargs)
        except CancelFail:
            pass
    def set_timeout(self, milliseconds=1000, callback=None, *args, **kwargs):
        slot = Slot(period=0, interval=1, function=callback, args=args, kwargs=kwargs)
        self._schedule()
        return slot
    def cancel(self, slot):
        slot.fire = 0
        if slot.id in self.wait:
            self.wait[slot.id].cancel()
        self._delFromReadyList(slot)

代码说明

该代码实现了在单线程环境下管理多个定时任务的功能。通过使用优先队列（heapq）和主线程处理定时任务的方式，确保了定时任务能够高效执行。

核心原理

主要功能

优化说明

通过上述实现，可以在单线程环境下高效管理和执行多个定时任务。

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