todolist.py

#!/usr/bin/env python
#
# Copyright (c) 2020 Poul-Henning Kamp <phk@phk.freebsd.dk>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.


import time
import bisect

class TodoJob():
    ''' Something to happen later '''

    def __init__(self, up, when, what):
        self.when = when
        self.what = what
        self.up = up

    def __lt__(self, other):
        return self.when < other.when

    def dt(self):
        return self.when - time.time()

    def doit(self):
        self.what()

class ToDo():

    ''' Get things done '''

    def __init__(self):
        self.todo_list = []

    def schedule(self, when, what):
        if when < 10000:
            when += time.time()
        j = TodoJob(self, when, what)
        bisect.insort(self.todo_list, j)
        return j

    def cancel(self, j):
        try:
            self.todo_list.remove(j)
        except ValueError:
            pass

    def next_timeout(self):
        while self.todo_list:
            j = self.todo_list[0]
            dt = j.dt()
            if dt > 0:
                return dt
            self.todo_list.pop(0)
            j.doit()
        return 3