mirror of https://github.com/grpc/grpc-node.git
80 lines
2.7 KiB
JavaScript
80 lines
2.7 KiB
JavaScript
/*
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*
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* Copyright 2015, Google Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Google Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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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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setTimeout(function() {
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next.callback(continueCallback);
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}, next.delay);
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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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