/**
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* Cesium - https://github.com/CesiumGS/cesium
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*
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* Copyright 2011-2020 Cesium Contributors
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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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* Columbus View (Pat. Pend.)
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*
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* Portions licensed separately.
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* See https://github.com/CesiumGS/cesium/blob/master/LICENSE.md for full licensing details.
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*/
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define(['./when-8d13db60'], function (when) { 'use strict';
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/**
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* Formats an error object into a String. If available, uses name, message, and stack
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* properties, otherwise, falls back on toString().
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*
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* @exports formatError
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*
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* @param {*} object The item to find in the array.
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* @returns {String} A string containing the formatted error.
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*/
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function formatError(object) {
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var result;
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var name = object.name;
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var message = object.message;
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if (when.defined(name) && when.defined(message)) {
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result = name + ': ' + message;
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} else {
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result = object.toString();
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}
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var stack = object.stack;
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if (when.defined(stack)) {
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result += '\n' + stack;
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}
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return result;
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}
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// createXXXGeometry functions may return Geometry or a Promise that resolves to Geometry
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// if the function requires access to ApproximateTerrainHeights.
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// For fully synchronous functions, just wrapping the function call in a `when` Promise doesn't
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// handle errors correctly, hence try-catch
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function callAndWrap(workerFunction, parameters, transferableObjects) {
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var resultOrPromise;
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try {
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resultOrPromise = workerFunction(parameters, transferableObjects);
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return resultOrPromise; // errors handled by Promise
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} catch (e) {
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return when.when.reject(e);
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}
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}
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/**
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* Creates an adapter function to allow a calculation function to operate as a Web Worker,
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* paired with TaskProcessor, to receive tasks and return results.
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*
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* @exports createTaskProcessorWorker
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*
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* @param {createTaskProcessorWorker~WorkerFunction} workerFunction The calculation function,
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* which takes parameters and returns a result.
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* @returns {createTaskProcessorWorker~TaskProcessorWorkerFunction} A function that adapts the
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* calculation function to work as a Web Worker onmessage listener with TaskProcessor.
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*
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*
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* @example
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* function doCalculation(parameters, transferableObjects) {
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* // calculate some result using the inputs in parameters
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* return result;
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* }
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*
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* return Cesium.createTaskProcessorWorker(doCalculation);
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* // the resulting function is compatible with TaskProcessor
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*
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* @see TaskProcessor
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* @see {@link http://www.w3.org/TR/workers/|Web Workers}
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* @see {@link http://www.w3.org/TR/html5/common-dom-interfaces.html#transferable-objects|Transferable objects}
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*/
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function createTaskProcessorWorker(workerFunction) {
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var postMessage;
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return function(event) {
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var data = event.data;
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var transferableObjects = [];
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var responseMessage = {
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id : data.id,
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result : undefined,
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error : undefined
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};
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return when.when(callAndWrap(workerFunction, data.parameters, transferableObjects))
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.then(function(result) {
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responseMessage.result = result;
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})
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.otherwise(function(e) {
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if (e instanceof Error) {
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// Errors can't be posted in a message, copy the properties
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responseMessage.error = {
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name : e.name,
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message : e.message,
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stack : e.stack
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};
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} else {
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responseMessage.error = e;
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}
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})
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.always(function() {
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if (!when.defined(postMessage)) {
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postMessage = when.defaultValue(self.webkitPostMessage, self.postMessage);
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}
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if (!data.canTransferArrayBuffer) {
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transferableObjects.length = 0;
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}
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try {
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postMessage(responseMessage, transferableObjects);
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} catch (e) {
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// something went wrong trying to post the message, post a simpler
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// error that we can be sure will be cloneable
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responseMessage.result = undefined;
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responseMessage.error = 'postMessage failed with error: ' + formatError(e) + '\n with responseMessage: ' + JSON.stringify(responseMessage);
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postMessage(responseMessage);
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}
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});
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};
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}
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return createTaskProcessorWorker;
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});
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