mirror of https://github.com/grpc/grpc-node.git
69 lines
1.8 KiB
JavaScript
69 lines
1.8 KiB
JavaScript
/*
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*
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* Copyright 2015 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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'use strict';
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var _ = require('lodash');
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/**
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* This class represents a queue of callbacks that must happen sequentially,
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* each with a specific delay after the previous event.
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*/
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function AsyncDelayQueue() {
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this.queue = [];
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this.callback_pending = false;
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}
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/**
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* Run the next callback after its corresponding delay, if there are any
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* remaining.
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*/
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AsyncDelayQueue.prototype.runNext = function() {
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var next = this.queue.shift();
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var continueCallback = _.bind(this.runNext, this);
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if (next) {
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this.callback_pending = true;
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if (next.delay === 0) {
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next.callback(continueCallback);
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} else {
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setTimeout(function() {
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next.callback(continueCallback);
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}, next.delay);
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}
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} else {
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this.callback_pending = false;
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}
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};
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/**
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* Add a callback to be called with a specific delay after now or after the
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* current last item in the queue or current pending callback, whichever is
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* latest.
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* @param {function(function())} callback The callback
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* @param {Number} The delay to apply, in milliseconds
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*/
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AsyncDelayQueue.prototype.add = function(callback, delay) {
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this.queue.push({callback: callback, delay: delay});
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if (!this.callback_pending) {
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this.runNext();
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}
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};
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module.exports = AsyncDelayQueue;
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