425 lines
13 KiB
JavaScript
425 lines
13 KiB
JavaScript
/**
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* Main content for the worker that handles the loading and execution of
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* modules within it.
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*/
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function workerBootstrap() {
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var modules = Object.create(null);
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// Handle messages for registering a module
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function registerModule(ref, callback) {
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var id = ref.id;
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var name = ref.name;
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var dependencies = ref.dependencies; if ( dependencies === void 0 ) dependencies = [];
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var init = ref.init; if ( init === void 0 ) init = function(){};
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var getTransferables = ref.getTransferables; if ( getTransferables === void 0 ) getTransferables = null;
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// Only register once
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if (modules[id]) { return }
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try {
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// If any dependencies are modules, ensure they're registered and grab their value
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dependencies = dependencies.map(function (dep) {
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if (dep && dep.isWorkerModule) {
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registerModule(dep, function (depResult) {
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if (depResult instanceof Error) { throw depResult }
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});
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dep = modules[dep.id].value;
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}
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return dep
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});
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// Rehydrate functions
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init = rehydrate(("<" + name + ">.init"), init);
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if (getTransferables) {
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getTransferables = rehydrate(("<" + name + ">.getTransferables"), getTransferables);
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}
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// Initialize the module and store its value
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var value = null;
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if (typeof init === 'function') {
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value = init.apply(void 0, dependencies);
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} else {
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console.error('worker module init function failed to rehydrate');
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}
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modules[id] = {
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id: id,
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value: value,
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getTransferables: getTransferables
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};
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callback(value);
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} catch(err) {
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if (!(err && err.noLog)) {
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console.error(err);
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}
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callback(err);
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}
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}
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// Handle messages for calling a registered module's result function
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function callModule(ref, callback) {
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var ref$1;
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var id = ref.id;
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var args = ref.args;
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if (!modules[id] || typeof modules[id].value !== 'function') {
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callback(new Error(("Worker module " + id + ": not found or its 'init' did not return a function")));
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}
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try {
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var result = (ref$1 = modules[id]).value.apply(ref$1, args);
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if (result && typeof result.then === 'function') {
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result.then(handleResult, function (rej) { return callback(rej instanceof Error ? rej : new Error('' + rej)); });
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} else {
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handleResult(result);
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}
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} catch(err) {
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callback(err);
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}
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function handleResult(result) {
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try {
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var tx = modules[id].getTransferables && modules[id].getTransferables(result);
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if (!tx || !Array.isArray(tx) || !tx.length) {
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tx = undefined; //postMessage is very picky about not passing null or empty transferables
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}
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callback(result, tx);
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} catch(err) {
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console.error(err);
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callback(err);
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}
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}
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}
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function rehydrate(name, str) {
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var result = void 0;
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self.troikaDefine = function (r) { return result = r; };
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var url = URL.createObjectURL(
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new Blob(
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[("/** " + (name.replace(/\*/g, '')) + " **/\n\ntroikaDefine(\n" + str + "\n)")],
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{type: 'application/javascript'}
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)
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);
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try {
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importScripts(url);
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} catch(err) {
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console.error(err);
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}
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URL.revokeObjectURL(url);
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delete self.troikaDefine;
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return result
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}
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// Handler for all messages within the worker
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self.addEventListener('message', function (e) {
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var ref = e.data;
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var messageId = ref.messageId;
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var action = ref.action;
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var data = ref.data;
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try {
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// Module registration
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if (action === 'registerModule') {
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registerModule(data, function (result) {
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if (result instanceof Error) {
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postMessage({
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messageId: messageId,
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success: false,
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error: result.message
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});
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} else {
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postMessage({
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messageId: messageId,
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success: true,
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result: {isCallable: typeof result === 'function'}
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});
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}
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});
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}
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// Invocation
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if (action === 'callModule') {
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callModule(data, function (result, transferables) {
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if (result instanceof Error) {
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postMessage({
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messageId: messageId,
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success: false,
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error: result.message
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});
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} else {
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postMessage({
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messageId: messageId,
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success: true,
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result: result
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}, transferables || undefined);
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}
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});
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}
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} catch(err) {
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postMessage({
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messageId: messageId,
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success: false,
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error: err.stack
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});
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}
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});
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}
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/**
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* Fallback for `defineWorkerModule` that behaves identically but runs in the main
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* thread, for when the execution environment doesn't support web workers or they
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* are disallowed due to e.g. CSP security restrictions.
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*/
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function defineMainThreadModule(options) {
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var moduleFunc = function() {
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var args = [], len = arguments.length;
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while ( len-- ) args[ len ] = arguments[ len ];
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return moduleFunc._getInitResult().then(function (initResult) {
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if (typeof initResult === 'function') {
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return initResult.apply(void 0, args)
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} else {
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throw new Error('Worker module function was called but `init` did not return a callable function')
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}
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})
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};
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moduleFunc._getInitResult = function() {
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// We can ignore getTransferables in main thread. TODO workerId?
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var dependencies = options.dependencies;
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var init = options.init;
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// Resolve dependencies
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dependencies = Array.isArray(dependencies) ? dependencies.map(function (dep) {
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if (dep) {
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// If it's a worker module, use its main thread impl
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dep = dep.onMainThread || dep;
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// If it's a main thread worker module, use its init return value
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if (dep._getInitResult) {
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dep = dep._getInitResult();
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}
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}
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return dep
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}) : [];
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// Invoke init with the resolved dependencies
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var initPromise = Promise.all(dependencies).then(function (deps) {
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return init.apply(null, deps)
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});
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// Cache the resolved promise for subsequent calls
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moduleFunc._getInitResult = function () { return initPromise; };
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return initPromise
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};
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return moduleFunc
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}
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var supportsWorkers = function () {
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var supported = false;
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// Only attempt worker initialization in browsers; elsewhere it would just be
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// noise e.g. loading into a Node environment for SSR.
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if (typeof window !== 'undefined' && typeof window.document !== 'undefined') {
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try {
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// TODO additional checks for things like importScripts within the worker?
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// Would need to be an async check.
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var worker = new Worker(
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URL.createObjectURL(new Blob([''], { type: 'application/javascript' }))
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);
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worker.terminate();
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supported = true;
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} catch (err) {
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if (typeof process !== 'undefined' && process.env.NODE_ENV === 'test') ; else {
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console.log(
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("Troika createWorkerModule: web workers not allowed; falling back to main thread execution. Cause: [" + (err.message) + "]")
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);
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}
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}
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}
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// Cached result
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supportsWorkers = function () { return supported; };
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return supported
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};
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var _workerModuleId = 0;
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var _messageId = 0;
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var _allowInitAsString = false;
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var workers = Object.create(null);
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var registeredModules = Object.create(null); //workerId -> Set<unregisterFn>
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var openRequests = Object.create(null);
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/**
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* Define a module of code that will be executed with a web worker. This provides a simple
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* interface for moving chunks of logic off the main thread, and managing their dependencies
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* among one another.
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*
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* @param {object} options
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* @param {function} options.init
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* @param {array} [options.dependencies]
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* @param {function} [options.getTransferables]
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* @param {string} [options.name]
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* @param {string} [options.workerId]
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* @return {function(...[*]): {then}}
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*/
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function defineWorkerModule(options) {
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if ((!options || typeof options.init !== 'function') && !_allowInitAsString) {
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throw new Error('requires `options.init` function')
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}
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var dependencies = options.dependencies;
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var init = options.init;
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var getTransferables = options.getTransferables;
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var workerId = options.workerId;
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var onMainThread = defineMainThreadModule(options);
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if (workerId == null) {
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workerId = '#default';
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}
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var id = "workerModule" + (++_workerModuleId);
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var name = options.name || id;
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var registrationPromise = null;
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dependencies = dependencies && dependencies.map(function (dep) {
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// Wrap raw functions as worker modules with no dependencies
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if (typeof dep === 'function' && !dep.workerModuleData) {
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_allowInitAsString = true;
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dep = defineWorkerModule({
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workerId: workerId,
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name: ("<" + name + "> function dependency: " + (dep.name)),
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init: ("function(){return (\n" + (stringifyFunction(dep)) + "\n)}")
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});
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_allowInitAsString = false;
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}
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// Grab postable data for worker modules
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if (dep && dep.workerModuleData) {
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dep = dep.workerModuleData;
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}
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return dep
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});
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function moduleFunc() {
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var args = [], len = arguments.length;
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while ( len-- ) args[ len ] = arguments[ len ];
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if (!supportsWorkers()) {
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return onMainThread.apply(void 0, args)
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}
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// Register this module if needed
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if (!registrationPromise) {
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registrationPromise = callWorker(workerId,'registerModule', moduleFunc.workerModuleData);
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var unregister = function () {
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registrationPromise = null;
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registeredModules[workerId].delete(unregister);
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}
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;(registeredModules[workerId] || (registeredModules[workerId] = new Set())).add(unregister);
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}
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// Invoke the module, returning a promise
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return registrationPromise.then(function (ref) {
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var isCallable = ref.isCallable;
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if (isCallable) {
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return callWorker(workerId,'callModule', {id: id, args: args})
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} else {
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throw new Error('Worker module function was called but `init` did not return a callable function')
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}
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})
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}
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moduleFunc.workerModuleData = {
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isWorkerModule: true,
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id: id,
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name: name,
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dependencies: dependencies,
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init: stringifyFunction(init),
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getTransferables: getTransferables && stringifyFunction(getTransferables)
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};
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moduleFunc.onMainThread = onMainThread;
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return moduleFunc
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}
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/**
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* Terminate an active Worker by a workerId that was passed to defineWorkerModule.
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* This only terminates the Worker itself; the worker module will remain available
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* and if you call it again its Worker will be respawned.
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* @param {string} workerId
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*/
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function terminateWorker(workerId) {
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// Unregister all modules that were registered in that worker
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if (registeredModules[workerId]) {
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registeredModules[workerId].forEach(function (unregister) {
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unregister();
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});
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}
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// Terminate the Worker object
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if (workers[workerId]) {
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workers[workerId].terminate();
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delete workers[workerId];
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}
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}
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/**
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* Stringifies a function into a form that can be deserialized in the worker
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* @param fn
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*/
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function stringifyFunction(fn) {
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var str = fn.toString();
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// If it was defined in object method/property format, it needs to be modified
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if (!/^function/.test(str) && /^\w+\s*\(/.test(str)) {
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str = 'function ' + str;
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}
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return str
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}
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function getWorker(workerId) {
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var worker = workers[workerId];
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if (!worker) {
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// Bootstrap the worker's content
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var bootstrap = stringifyFunction(workerBootstrap);
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// Create the worker from the bootstrap function content
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worker = workers[workerId] = new Worker(
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URL.createObjectURL(
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new Blob(
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[("/** Worker Module Bootstrap: " + (workerId.replace(/\*/g, '')) + " **/\n\n;(" + bootstrap + ")()")],
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{type: 'application/javascript'}
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)
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)
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);
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// Single handler for response messages from the worker
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worker.onmessage = function (e) {
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var response = e.data;
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var msgId = response.messageId;
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var callback = openRequests[msgId];
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if (!callback) {
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throw new Error('WorkerModule response with empty or unknown messageId')
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}
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delete openRequests[msgId];
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callback(response);
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};
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}
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return worker
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}
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// Issue a call to the worker with a callback to handle the response
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function callWorker(workerId, action, data) {
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return new Promise(function (resolve, reject) {
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var messageId = ++_messageId;
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openRequests[messageId] = function (response) {
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if (response.success) {
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resolve(response.result);
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} else {
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reject(new Error(("Error in worker " + action + " call: " + (response.error))));
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}
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};
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getWorker(workerId).postMessage({
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messageId: messageId,
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action: action,
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data: data
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});
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})
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}
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export { defineWorkerModule, stringifyFunction, terminateWorker };
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