de36b2aaba
Note that Prettier, purposely, has only limited [configuration options](https://prettier.io/docs/en/options.html). The configuration file is based on [the one in `mozilla central`](https://searchfox.org/mozilla-central/source/.prettierrc) with just a few additions (to avoid future breakage if the defaults ever changes). Prettier is being used for a couple of reasons: - To be consistent with `mozilla-central`, where Prettier is already in use across the tree. - To ensure a *consistent* coding style everywhere, which is automatically enforced during linting (since Prettier is used as an ESLint plugin). This thus ends "all" formatting disussions once and for all, removing the need for review comments on most stylistic matters. Many ESLint options are now redundant, and I've tried my best to remove all the now unnecessary options (but I may have missed some). Note also that since Prettier considers the `printWidth` option as a guide, rather than a hard rule, this patch resorts to a small hack in the ESLint config to ensure that *comments* won't become too long. *Please note:* This patch is generated automatically, by appending the `--fix` argument to the ESLint call used in the `gulp lint` task. It will thus require some additional clean-up, which will be done in a *separate* commit. (On a more personal note, I'll readily admit that some of the changes Prettier makes are *extremely* ugly. However, in the name of consistency we'll probably have to live with that.)
586 lines
17 KiB
JavaScript
586 lines
17 KiB
JavaScript
/* Copyright 2018 Mozilla Foundation
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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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/* eslint no-var: error, prefer-const: error */
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import {
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AbortException,
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assert,
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createPromiseCapability,
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MissingPDFException,
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UnexpectedResponseException,
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UnknownErrorException,
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} from "./util";
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const CallbackKind = {
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UNKNOWN: 0,
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DATA: 1,
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ERROR: 2,
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};
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const StreamKind = {
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UNKNOWN: 0,
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CANCEL: 1,
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CANCEL_COMPLETE: 2,
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CLOSE: 3,
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ENQUEUE: 4,
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ERROR: 5,
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PULL: 6,
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PULL_COMPLETE: 7,
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START_COMPLETE: 8,
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};
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function wrapReason(reason) {
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if (
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typeof PDFJSDev === "undefined" ||
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PDFJSDev.test("!PRODUCTION || TESTING")
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) {
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assert(
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reason instanceof Error ||
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(typeof reason === "object" && reason !== null),
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'wrapReason: Expected "reason" to be a (possibly cloned) Error.'
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);
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}
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if (typeof reason !== "object" || reason === null) {
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return reason;
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}
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switch (reason.name) {
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case "AbortException":
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return new AbortException(reason.message);
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case "MissingPDFException":
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return new MissingPDFException(reason.message);
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case "UnexpectedResponseException":
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return new UnexpectedResponseException(reason.message, reason.status);
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case "UnknownErrorException":
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return new UnknownErrorException(reason.message, reason.details);
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default:
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return new UnknownErrorException(reason.message, reason.toString());
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}
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}
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class MessageHandler {
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constructor(sourceName, targetName, comObj) {
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this.sourceName = sourceName;
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this.targetName = targetName;
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this.comObj = comObj;
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this.callbackId = 1;
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this.streamId = 1;
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this.postMessageTransfers = true;
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this.streamSinks = Object.create(null);
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this.streamControllers = Object.create(null);
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this.callbackCapabilities = Object.create(null);
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this.actionHandler = Object.create(null);
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this._onComObjOnMessage = event => {
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const data = event.data;
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if (data.targetName !== this.sourceName) {
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return;
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}
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if (data.stream) {
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this._processStreamMessage(data);
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return;
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}
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if (data.callback) {
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const callbackId = data.callbackId;
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const capability = this.callbackCapabilities[callbackId];
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if (!capability) {
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throw new Error(`Cannot resolve callback ${callbackId}`);
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}
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delete this.callbackCapabilities[callbackId];
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if (data.callback === CallbackKind.DATA) {
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capability.resolve(data.data);
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} else if (data.callback === CallbackKind.ERROR) {
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capability.reject(wrapReason(data.reason));
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} else {
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throw new Error("Unexpected callback case");
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}
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return;
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}
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const action = this.actionHandler[data.action];
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if (!action) {
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throw new Error(`Unknown action from worker: ${data.action}`);
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}
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if (data.callbackId) {
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const sourceName = this.sourceName;
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const targetName = data.sourceName;
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new Promise(function(resolve) {
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resolve(action(data.data));
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}).then(
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function(result) {
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comObj.postMessage({
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sourceName,
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targetName,
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callback: CallbackKind.DATA,
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callbackId: data.callbackId,
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data: result,
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});
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},
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function(reason) {
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comObj.postMessage({
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sourceName,
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targetName,
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callback: CallbackKind.ERROR,
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callbackId: data.callbackId,
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reason: wrapReason(reason),
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});
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}
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);
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return;
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}
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if (data.streamId) {
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this._createStreamSink(data);
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return;
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}
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action(data.data);
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};
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comObj.addEventListener("message", this._onComObjOnMessage);
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}
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on(actionName, handler) {
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if (
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typeof PDFJSDev === "undefined" ||
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PDFJSDev.test("!PRODUCTION || TESTING")
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) {
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assert(
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typeof handler === "function",
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'MessageHandler.on: Expected "handler" to be a function.'
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);
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}
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const ah = this.actionHandler;
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if (ah[actionName]) {
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throw new Error(`There is already an actionName called "${actionName}"`);
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}
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ah[actionName] = handler;
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}
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/**
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* Sends a message to the comObj to invoke the action with the supplied data.
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* @param {string} actionName - Action to call.
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* @param {JSON} data - JSON data to send.
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* @param {Array} [transfers] - List of transfers/ArrayBuffers.
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*/
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send(actionName, data, transfers) {
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this._postMessage(
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{
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sourceName: this.sourceName,
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targetName: this.targetName,
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action: actionName,
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data,
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},
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transfers
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);
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}
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/**
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* Sends a message to the comObj to invoke the action with the supplied data.
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* Expects that the other side will callback with the response.
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* @param {string} actionName - Action to call.
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* @param {JSON} data - JSON data to send.
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* @param {Array} [transfers] - List of transfers/ArrayBuffers.
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* @returns {Promise} Promise to be resolved with response data.
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*/
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sendWithPromise(actionName, data, transfers) {
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const callbackId = this.callbackId++;
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const capability = createPromiseCapability();
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this.callbackCapabilities[callbackId] = capability;
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try {
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this._postMessage(
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{
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sourceName: this.sourceName,
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targetName: this.targetName,
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action: actionName,
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callbackId,
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data,
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},
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transfers
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);
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} catch (ex) {
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capability.reject(ex);
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}
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return capability.promise;
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}
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/**
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* Sends a message to the comObj to invoke the action with the supplied data.
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* Expect that the other side will callback to signal 'start_complete'.
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* @param {string} actionName - Action to call.
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* @param {JSON} data - JSON data to send.
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* @param {Object} queueingStrategy - Strategy to signal backpressure based on
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* internal queue.
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* @param {Array} [transfers] - List of transfers/ArrayBuffers.
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* @returns {ReadableStream} ReadableStream to read data in chunks.
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*/
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sendWithStream(actionName, data, queueingStrategy, transfers) {
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const streamId = this.streamId++;
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const sourceName = this.sourceName;
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const targetName = this.targetName;
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const comObj = this.comObj;
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return new ReadableStream(
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{
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start: controller => {
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const startCapability = createPromiseCapability();
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this.streamControllers[streamId] = {
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controller,
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startCall: startCapability,
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pullCall: null,
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cancelCall: null,
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isClosed: false,
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};
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this._postMessage(
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{
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sourceName,
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targetName,
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action: actionName,
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streamId,
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data,
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desiredSize: controller.desiredSize,
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},
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transfers
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);
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// Return Promise for Async process, to signal success/failure.
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return startCapability.promise;
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},
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pull: controller => {
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const pullCapability = createPromiseCapability();
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this.streamControllers[streamId].pullCall = pullCapability;
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.PULL,
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streamId,
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desiredSize: controller.desiredSize,
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});
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// Returning Promise will not call "pull"
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// again until current pull is resolved.
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return pullCapability.promise;
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},
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cancel: reason => {
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assert(reason instanceof Error, "cancel must have a valid reason");
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const cancelCapability = createPromiseCapability();
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this.streamControllers[streamId].cancelCall = cancelCapability;
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this.streamControllers[streamId].isClosed = true;
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.CANCEL,
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streamId,
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reason: wrapReason(reason),
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});
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// Return Promise to signal success or failure.
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return cancelCapability.promise;
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},
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},
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queueingStrategy
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);
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}
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/**
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* @private
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*/
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_createStreamSink(data) {
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const self = this;
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const action = this.actionHandler[data.action];
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const streamId = data.streamId;
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const sourceName = this.sourceName;
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const targetName = data.sourceName;
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const comObj = this.comObj;
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const streamSink = {
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enqueue(chunk, size = 1, transfers) {
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if (this.isCancelled) {
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return;
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}
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const lastDesiredSize = this.desiredSize;
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this.desiredSize -= size;
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// Enqueue decreases the desiredSize property of sink,
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// so when it changes from positive to negative,
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// set ready as unresolved promise.
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if (lastDesiredSize > 0 && this.desiredSize <= 0) {
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this.sinkCapability = createPromiseCapability();
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this.ready = this.sinkCapability.promise;
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}
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self._postMessage(
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{
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sourceName,
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targetName,
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stream: StreamKind.ENQUEUE,
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streamId,
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chunk,
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},
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transfers
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);
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},
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close() {
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if (this.isCancelled) {
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return;
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}
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this.isCancelled = true;
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.CLOSE,
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streamId,
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});
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delete self.streamSinks[streamId];
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},
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error(reason) {
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assert(reason instanceof Error, "error must have a valid reason");
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if (this.isCancelled) {
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return;
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}
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this.isCancelled = true;
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.ERROR,
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streamId,
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reason: wrapReason(reason),
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});
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},
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sinkCapability: createPromiseCapability(),
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onPull: null,
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onCancel: null,
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isCancelled: false,
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desiredSize: data.desiredSize,
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ready: null,
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};
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streamSink.sinkCapability.resolve();
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streamSink.ready = streamSink.sinkCapability.promise;
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this.streamSinks[streamId] = streamSink;
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new Promise(function(resolve) {
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resolve(action(data.data, streamSink));
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}).then(
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function() {
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.START_COMPLETE,
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streamId,
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success: true,
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});
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},
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function(reason) {
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.START_COMPLETE,
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streamId,
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reason: wrapReason(reason),
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});
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}
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);
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}
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/**
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* @private
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*/
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_processStreamMessage(data) {
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const streamId = data.streamId;
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const sourceName = this.sourceName;
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const targetName = data.sourceName;
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const comObj = this.comObj;
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switch (data.stream) {
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case StreamKind.START_COMPLETE:
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if (data.success) {
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this.streamControllers[streamId].startCall.resolve();
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} else {
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this.streamControllers[streamId].startCall.reject(
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wrapReason(data.reason)
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);
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}
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break;
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case StreamKind.PULL_COMPLETE:
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if (data.success) {
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this.streamControllers[streamId].pullCall.resolve();
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} else {
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this.streamControllers[streamId].pullCall.reject(
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wrapReason(data.reason)
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);
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}
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break;
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case StreamKind.PULL:
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// Ignore any pull after close is called.
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if (!this.streamSinks[streamId]) {
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.PULL_COMPLETE,
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streamId,
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success: true,
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});
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break;
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}
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// Pull increases the desiredSize property of sink,
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// so when it changes from negative to positive,
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// set ready property as resolved promise.
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if (
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this.streamSinks[streamId].desiredSize <= 0 &&
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data.desiredSize > 0
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) {
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this.streamSinks[streamId].sinkCapability.resolve();
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}
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// Reset desiredSize property of sink on every pull.
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this.streamSinks[streamId].desiredSize = data.desiredSize;
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const { onPull } = this.streamSinks[data.streamId];
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new Promise(function(resolve) {
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resolve(onPull && onPull());
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}).then(
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function() {
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.PULL_COMPLETE,
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streamId,
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success: true,
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});
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},
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function(reason) {
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.PULL_COMPLETE,
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streamId,
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reason: wrapReason(reason),
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});
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}
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);
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break;
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case StreamKind.ENQUEUE:
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assert(
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this.streamControllers[streamId],
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"enqueue should have stream controller"
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);
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if (this.streamControllers[streamId].isClosed) {
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break;
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}
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this.streamControllers[streamId].controller.enqueue(data.chunk);
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break;
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case StreamKind.CLOSE:
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assert(
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this.streamControllers[streamId],
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"close should have stream controller"
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);
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if (this.streamControllers[streamId].isClosed) {
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break;
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}
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this.streamControllers[streamId].isClosed = true;
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this.streamControllers[streamId].controller.close();
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this._deleteStreamController(streamId);
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break;
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case StreamKind.ERROR:
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assert(
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this.streamControllers[streamId],
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"error should have stream controller"
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);
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this.streamControllers[streamId].controller.error(
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wrapReason(data.reason)
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);
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this._deleteStreamController(streamId);
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break;
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case StreamKind.CANCEL_COMPLETE:
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if (data.success) {
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this.streamControllers[streamId].cancelCall.resolve();
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} else {
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this.streamControllers[streamId].cancelCall.reject(
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wrapReason(data.reason)
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);
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}
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this._deleteStreamController(streamId);
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break;
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case StreamKind.CANCEL:
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if (!this.streamSinks[streamId]) {
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break;
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}
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const { onCancel } = this.streamSinks[data.streamId];
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new Promise(function(resolve) {
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resolve(onCancel && onCancel(wrapReason(data.reason)));
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}).then(
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function() {
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comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.CANCEL_COMPLETE,
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streamId,
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success: true,
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});
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},
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function(reason) {
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|
comObj.postMessage({
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sourceName,
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targetName,
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stream: StreamKind.CANCEL_COMPLETE,
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|
streamId,
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reason: wrapReason(reason),
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});
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|
}
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);
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this.streamSinks[streamId].sinkCapability.reject(
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wrapReason(data.reason)
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);
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this.streamSinks[streamId].isCancelled = true;
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delete this.streamSinks[streamId];
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break;
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default:
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throw new Error("Unexpected stream case");
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}
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}
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|
/**
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|
* @private
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|
*/
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|
async _deleteStreamController(streamId) {
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|
// Delete the `streamController` only when the start, pull, and cancel
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|
// capabilities have settled, to prevent `TypeError`s.
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|
await Promise.all(
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|
[
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this.streamControllers[streamId].startCall,
|
|
this.streamControllers[streamId].pullCall,
|
|
this.streamControllers[streamId].cancelCall,
|
|
].map(function(capability) {
|
|
return capability && capability.promise.catch(function() {});
|
|
})
|
|
);
|
|
delete this.streamControllers[streamId];
|
|
}
|
|
|
|
/**
|
|
* Sends raw message to the comObj.
|
|
* @param {Object} message - Raw message.
|
|
* @param transfers List of transfers/ArrayBuffers, or undefined.
|
|
* @private
|
|
*/
|
|
_postMessage(message, transfers) {
|
|
if (transfers && this.postMessageTransfers) {
|
|
this.comObj.postMessage(message, transfers);
|
|
} else {
|
|
this.comObj.postMessage(message);
|
|
}
|
|
}
|
|
|
|
destroy() {
|
|
this.comObj.removeEventListener("message", this._onComObjOnMessage);
|
|
}
|
|
}
|
|
|
|
export { MessageHandler };
|