dnschain/src/lib/stacked-scheduler.coffee

A blockchain-based DNS + HTTPS server that fixes HTTPS security, and more!

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dnschain
http://dnschain.net

Copyright (c) 2014 okTurtles Foundation

This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at http://mozilla.org/MPL/2.0/.

###

# TODO: go through 'TODO's!

module.exports = (dnschain) ->
    # expose these into our namespace
    for k of dnschain.globals
        eval "var #{k} = dnschain.globals.#{k};"

    class StackedScheduler
        constructor: ({@stackedDelay}) ->
            @stackedDelay ?= 2000 # 2 seconds by default
            @tasks = {}
            @nextRunTime = Date.now()
            @taskCounter = 0

        cancelAll: (runCallback=false)->
            for key, task of @tasks
                clearTimeout(task.tid)
                task.callback() if runCallback
                delete @tasks[key]

        schedule: (callback) ->
            diffMillis = @nextRunTime - Date.now()
            @nextRunTime += @stackedDelay - Math.min(diffMillis, 0)
            nonce = @taskCounter++
            @tasks[nonce] =
                callback: callback # for 'cancelAll'
                tid: setTimeout =>
                    delete @tasks[nonce]
                    callback()
                , Math.max diffMillis, 0