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"use strict";
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const Promise = require("bluebird");
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const pDefer = require("p-defer");
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const defaultValue = require("default-value");
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const pListen = require("p-listen");
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module.exports = function createRequestQueue(options = {}) {
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// FIXME: Validatem, docs
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let requestBuffer = [];
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let responseBuffer = [];
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let seenError;
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let requestDrainListener = pListen();
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let responseDrainListener = pListen();
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function failAllRequests(error) {
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let failedRequests = requestBuffer;
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requestBuffer = [];
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seenError = error;
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for (let request of failedRequests) {
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request.reject(error);
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}
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}
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function handleOnMatch() {
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return Promise.try(() => {
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if (requestBuffer.length === 0) {
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requestDrainListener.notify();
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}
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if (responseBuffer.length === 0) {
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responseDrainListener.notify();
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}
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return maybeCall(options.onMatch);
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}).catch((error) => {
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failAllRequests(error);
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});
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}
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function maybeCall(func, ... args) {
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if (func != null) {
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return func(... args);
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}
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}
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return {
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pushRequest: function (onQueuedRequest) {
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if (responseBuffer.length > 0) {
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let returnValue = Promise.resolve(responseBuffer.shift());
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handleOnMatch();
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return returnValue;
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} else if (seenError !== undefined) {
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return Promise.reject(seenError);
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} else {
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let { resolve, reject, promise } = pDefer();
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requestBuffer.push({ resolve, reject });
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return Promise.try(() => {
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return maybeCall(defaultValue(onQueuedRequest, options.onQueuedRequest));
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}).then(() => {
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return promise;
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});
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}
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},
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pushResponse: function (response, onQueuedResponse) {
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if (requestBuffer.length > 0) {
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let request = requestBuffer.shift();
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request.resolve(response);
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handleOnMatch();
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} else {
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responseBuffer.push(response);
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return maybeCall(defaultValue(onQueuedResponse, options.onQueuedResponse));
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}
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},
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failAllRequests: failAllRequests,
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requestCount: function () {
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return requestBuffer.length;
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},
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responseCount: function () {
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return responseBuffer.length;
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},
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awaitRequestDrain: function () {
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if (this.requestCount() === 0) {
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return Promise.resolve();
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} else {
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return requestDrainListener.listen();
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}
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},
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awaitResponseDrain: function () {
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if (this.responseCount() === 0) {
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return Promise.resolve();
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} else {
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return responseDrainListener.listen();
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}
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}
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};
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};
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