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node_modules/workerpool/src/Pool.js

@@ -0,0 +1,416 @@
+var Promise = require('./Promise');
+var WorkerHandler = require('./WorkerHandler');
+var environment = require('./environment');
+var DebugPortAllocator = require('./debug-port-allocator');
+var DEBUG_PORT_ALLOCATOR = new DebugPortAllocator();
+/**
+ * A pool to manage workers
+ * @param {String} [script]   Optional worker script
+ * @param {WorkerPoolOptions} [options]  See docs
+ * @constructor
+ */
+function Pool(script, options) {
+  if (typeof script === 'string') {
+    this.script = script || null;
+  }
+  else {
+    this.script = null;
+    options = script;
+  }
+
+  this.workers = [];  // queue with all workers
+  this.tasks = [];    // queue with tasks awaiting execution
+
+  options = options || {};
+
+  this.forkArgs = options.forkArgs || [];
+  this.forkOpts = options.forkOpts || {};
+  this.debugPortStart = (options.debugPortStart || 43210);
+  this.nodeWorker = options.nodeWorker;
+  this.workerType = options.workerType || options.nodeWorker || 'auto'
+  this.maxQueueSize = options.maxQueueSize || Infinity;
+
+  // configuration
+  if (options && 'maxWorkers' in options) {
+    validateMaxWorkers(options.maxWorkers);
+    this.maxWorkers = options.maxWorkers;
+  }
+  else {
+    this.maxWorkers = Math.max((environment.cpus || 4) - 1, 1);
+  }
+
+  if (options && 'minWorkers' in options) {
+    if(options.minWorkers === 'max') {
+      this.minWorkers = this.maxWorkers;
+    } else {
+      validateMinWorkers(options.minWorkers);
+      this.minWorkers = options.minWorkers;
+      this.maxWorkers = Math.max(this.minWorkers, this.maxWorkers);     // in case minWorkers is higher than maxWorkers
+    }
+    this._ensureMinWorkers();
+  }
+
+  this._boundNext = this._next.bind(this);
+
+
+  if (this.workerType === 'thread') {
+    WorkerHandler.ensureWorkerThreads();
+  }
+}
+
+
+/**
+ * Execute a function on a worker.
+ *
+ * Example usage:
+ *
+ *   var pool = new Pool()
+ *
+ *   // call a function available on the worker
+ *   pool.exec('fibonacci', [6])
+ *
+ *   // offload a function
+ *   function add(a, b) {
+ *     return a + b
+ *   };
+ *   pool.exec(add, [2, 4])
+ *       .then(function (result) {
+ *         console.log(result); // outputs 6
+ *       })
+ *       .catch(function(error) {
+ *         console.log(error);
+ *       });
+ *
+ * @param {String | Function} method  Function name or function.
+ *                                    If `method` is a string, the corresponding
+ *                                    method on the worker will be executed
+ *                                    If `method` is a Function, the function
+ *                                    will be stringified and executed via the
+ *                                    workers built-in function `run(fn, args)`.
+ * @param {Array} [params]  Function arguments applied when calling the function
+ * @param {ExecOptions} [options]  Options object
+ * @return {Promise.<*, Error>} result
+ */
+Pool.prototype.exec = function (method, params, options) {
+  // validate type of arguments
+  if (params && !Array.isArray(params)) {
+    throw new TypeError('Array expected as argument "params"');
+  }
+
+  if (typeof method === 'string') {
+    var resolver = Promise.defer();
+
+    if (this.tasks.length >= this.maxQueueSize) {
+      throw new Error('Max queue size of ' + this.maxQueueSize + ' reached');
+    }
+
+    // add a new task to the queue
+    var tasks = this.tasks;
+    var task = {
+      method:  method,
+      params:  params,
+      resolver: resolver,
+      timeout: null,
+      options: options
+    };
+    tasks.push(task);
+
+    // replace the timeout method of the Promise with our own,
+    // which starts the timer as soon as the task is actually started
+    var originalTimeout = resolver.promise.timeout;
+    resolver.promise.timeout = function timeout (delay) {
+      if (tasks.indexOf(task) !== -1) {
+        // task is still queued -> start the timer later on
+        task.timeout = delay;
+        return resolver.promise;
+      }
+      else {
+        // task is already being executed -> start timer immediately
+        return originalTimeout.call(resolver.promise, delay);
+      }
+    };
+
+    // trigger task execution
+    this._next();
+
+    return resolver.promise;
+  }
+  else if (typeof method === 'function') {
+    // send stringified function and function arguments to worker
+    return this.exec('run', [String(method), params]);
+  }
+  else {
+    throw new TypeError('Function or string expected as argument "method"');
+  }
+};
+
+/**
+ * Create a proxy for current worker. Returns an object containing all
+ * methods available on the worker. The methods always return a promise.
+ *
+ * @return {Promise.<Object, Error>} proxy
+ */
+Pool.prototype.proxy = function () {
+  if (arguments.length > 0) {
+    throw new Error('No arguments expected');
+  }
+
+  var pool = this;
+  return this.exec('methods')
+      .then(function (methods) {
+        var proxy = {};
+
+        methods.forEach(function (method) {
+          proxy[method] = function () {
+            return pool.exec(method, Array.prototype.slice.call(arguments));
+          }
+        });
+
+        return proxy;
+      });
+};
+
+/**
+ * Creates new array with the results of calling a provided callback function
+ * on every element in this array.
+ * @param {Array} array
+ * @param {function} callback  Function taking two arguments:
+ *                             `callback(currentValue, index)`
+ * @return {Promise.<Array>} Returns a promise which resolves  with an Array
+ *                           containing the results of the callback function
+ *                           executed for each of the array elements.
+ */
+/* TODO: implement map
+Pool.prototype.map = function (array, callback) {
+};
+*/
+
+/**
+ * Grab the first task from the queue, find a free worker, and assign the
+ * worker to the task.
+ * @protected
+ */
+Pool.prototype._next = function () {
+  if (this.tasks.length > 0) {
+    // there are tasks in the queue
+
+    // find an available worker
+    var worker = this._getWorker();
+    if (worker) {
+      // get the first task from the queue
+      var me = this;
+      var task = this.tasks.shift();
+
+      // check if the task is still pending (and not cancelled -> promise rejected)
+      if (task.resolver.promise.pending) {
+        // send the request to the worker
+        var promise = worker.exec(task.method, task.params, task.resolver, task.options)
+          .then(me._boundNext)
+          .catch(function () {
+            // if the worker crashed and terminated, remove it from the pool
+            if (worker.terminated) {
+              return me._removeWorker(worker);
+            }
+          }).then(function() {
+            me._next(); // trigger next task in the queue
+          });
+
+        // start queued timer now
+        if (typeof task.timeout === 'number') {
+          promise.timeout(task.timeout);
+        }
+      } else {
+        // The task taken was already complete (either rejected or resolved), so just trigger next task in the queue
+        me._next();
+      }
+    }
+  }
+};
+
+/**
+ * Get an available worker. If no worker is available and the maximum number
+ * of workers isn't yet reached, a new worker will be created and returned.
+ * If no worker is available and the maximum number of workers is reached,
+ * null will be returned.
+ *
+ * @return {WorkerHandler | null} worker
+ * @private
+ */
+Pool.prototype._getWorker = function() {
+  // find a non-busy worker
+  var workers = this.workers;
+  for (var i = 0; i < workers.length; i++) {
+    var worker = workers[i];
+    if (worker.busy() === false) {
+      return worker;
+    }
+  }
+
+  if (workers.length < this.maxWorkers) {
+    // create a new worker
+    worker = this._createWorkerHandler();
+    workers.push(worker);
+    return worker;
+  }
+
+  return null;
+};
+
+/**
+ * Remove a worker from the pool.
+ * Attempts to terminate worker if not already terminated, and ensures the minimum
+ * pool size is met.
+ * @param {WorkerHandler} worker
+ * @return {Promise<WorkerHandler>}
+ * @protected
+ */
+Pool.prototype._removeWorker = function(worker) {
+  DEBUG_PORT_ALLOCATOR.releasePort(worker.debugPort);
+  // _removeWorker will call this, but we need it to be removed synchronously
+  this._removeWorkerFromList(worker);
+  // If minWorkers set, spin up new workers to replace the crashed ones
+  this._ensureMinWorkers();
+  // terminate the worker (if not already terminated)
+  return new Promise(function(resolve, reject) {
+    worker.terminate(false, function(err) {
+      if (err) {
+        reject(err);
+      } else {
+        resolve(worker);
+      }
+    });
+  });
+};
+
+/**
+ * Remove a worker from the pool list.
+ * @param {WorkerHandler} worker
+ * @protected
+ */
+Pool.prototype._removeWorkerFromList = function(worker) {
+  // remove from the list with workers
+  var index = this.workers.indexOf(worker);
+  if (index !== -1) {
+    this.workers.splice(index, 1);
+  }
+};
+
+/**
+ * Close all active workers. Tasks currently being executed will be finished first.
+ * @param {boolean} [force=false]   If false (default), the workers are terminated
+ *                                  after finishing all tasks currently in
+ *                                  progress. If true, the workers will be
+ *                                  terminated immediately.
+ * @param {number} [timeout]        If provided and non-zero, worker termination promise will be rejected
+ *                                  after timeout if worker process has not been terminated.
+ * @return {Promise.<void, Error>}
+ */
+Pool.prototype.terminate = function (force, timeout) {
+  // cancel any pending tasks
+  this.tasks.forEach(function (task) {
+    task.resolver.reject(new Error('Pool terminated'));
+  });
+  this.tasks.length = 0;
+
+  var f = function (worker) {
+    this._removeWorkerFromList(worker);
+  };
+  var removeWorker = f.bind(this);
+
+  var promises = [];
+  var workers = this.workers.slice();
+  workers.forEach(function (worker) {
+    var termPromise = worker.terminateAndNotify(force, timeout)
+      .then(removeWorker);
+    promises.push(termPromise);
+  });
+  return Promise.all(promises);
+};
+
+/**
+ * Retrieve statistics on tasks and workers.
+ * @return {{totalWorkers: number, busyWorkers: number, idleWorkers: number, pendingTasks: number, activeTasks: number}} Returns an object with statistics
+ */
+Pool.prototype.stats = function () {
+  var totalWorkers = this.workers.length;
+  var busyWorkers = this.workers.filter(function (worker) {
+    return worker.busy();
+  }).length;
+
+  return {
+    totalWorkers:  totalWorkers,
+    busyWorkers:   busyWorkers,
+    idleWorkers:   totalWorkers - busyWorkers,
+
+    pendingTasks:  this.tasks.length,
+    activeTasks:   busyWorkers
+  };
+};
+
+/**
+ * Ensures that a minimum of minWorkers is up and running
+ * @protected
+ */
+Pool.prototype._ensureMinWorkers = function() {
+  if (this.minWorkers) {
+    for(var i = this.workers.length; i < this.minWorkers; i++) {
+      this.workers.push(this._createWorkerHandler());
+    }
+  }
+};
+
+/**
+ * Helper function to create a new WorkerHandler and pass all options.
+ * @return {WorkerHandler}
+ * @private
+ */
+Pool.prototype._createWorkerHandler = function () {
+  return new WorkerHandler(this.script, {
+    forkArgs: this.forkArgs,
+    forkOpts: this.forkOpts,
+    debugPort: DEBUG_PORT_ALLOCATOR.nextAvailableStartingAt(this.debugPortStart),
+    workerType: this.workerType
+  });
+}
+
+/**
+ * Ensure that the maxWorkers option is an integer >= 1
+ * @param {*} maxWorkers
+ * @returns {boolean} returns true maxWorkers has a valid value
+ */
+function validateMaxWorkers(maxWorkers) {
+  if (!isNumber(maxWorkers) || !isInteger(maxWorkers) || maxWorkers < 1) {
+    throw new TypeError('Option maxWorkers must be an integer number >= 1');
+  }
+}
+
+/**
+ * Ensure that the minWorkers option is an integer >= 0
+ * @param {*} minWorkers
+ * @returns {boolean} returns true when minWorkers has a valid value
+ */
+function validateMinWorkers(minWorkers) {
+  if (!isNumber(minWorkers) || !isInteger(minWorkers) || minWorkers < 0) {
+    throw new TypeError('Option minWorkers must be an integer number >= 0');
+  }
+}
+
+/**
+ * Test whether a variable is a number
+ * @param {*} value
+ * @returns {boolean} returns true when value is a number
+ */
+function isNumber(value) {
+  return typeof value === 'number';
+}
+
+/**
+ * Test whether a number is an integer
+ * @param {number} value
+ * @returns {boolean} Returns true if value is an integer
+ */
+function isInteger(value) {
+  return Math.round(value) == value;
+}
+
+module.exports = Pool;

node_modules/workerpool/src/Promise.js

@@ -0,0 +1,279 @@
+'use strict';
+
+/**
+ * Promise
+ *
+ * Inspired by https://gist.github.com/RubaXa/8501359 from RubaXa <trash@rubaxa.org>
+ *
+ * @param {Function} handler   Called as handler(resolve: Function, reject: Function)
+ * @param {Promise} [parent]   Parent promise for propagation of cancel and timeout
+ */
+function Promise(handler, parent) {
+  var me = this;
+
+  if (!(this instanceof Promise)) {
+    throw new SyntaxError('Constructor must be called with the new operator');
+  }
+
+  if (typeof handler !== 'function') {
+    throw new SyntaxError('Function parameter handler(resolve, reject) missing');
+  }
+
+  var _onSuccess = [];
+  var _onFail = [];
+
+  // status
+  this.resolved = false;
+  this.rejected = false;
+  this.pending = true;
+
+  /**
+   * Process onSuccess and onFail callbacks: add them to the queue.
+   * Once the promise is resolve, the function _promise is replace.
+   * @param {Function} onSuccess
+   * @param {Function} onFail
+   * @private
+   */
+  var _process = function (onSuccess, onFail) {
+    _onSuccess.push(onSuccess);
+    _onFail.push(onFail);
+  };
+
+  /**
+   * Add an onSuccess callback and optionally an onFail callback to the Promise
+   * @param {Function} onSuccess
+   * @param {Function} [onFail]
+   * @returns {Promise} promise
+   */
+  this.then = function (onSuccess, onFail) {
+    return new Promise(function (resolve, reject) {
+      var s = onSuccess ? _then(onSuccess, resolve, reject) : resolve;
+      var f = onFail    ? _then(onFail,    resolve, reject) : reject;
+
+      _process(s, f);
+    }, me);
+  };
+
+  /**
+   * Resolve the promise
+   * @param {*} result
+   * @type {Function}
+   */
+  var _resolve = function (result) {
+    // update status
+    me.resolved = true;
+    me.rejected = false;
+    me.pending = false;
+
+    _onSuccess.forEach(function (fn) {
+      fn(result);
+    });
+
+    _process = function (onSuccess, onFail) {
+      onSuccess(result);
+    };
+
+    _resolve = _reject = function () { };
+
+    return me;
+  };
+
+  /**
+   * Reject the promise
+   * @param {Error} error
+   * @type {Function}
+   */
+  var _reject = function (error) {
+    // update status
+    me.resolved = false;
+    me.rejected = true;
+    me.pending = false;
+
+    _onFail.forEach(function (fn) {
+      fn(error);
+    });
+
+    _process = function (onSuccess, onFail) {
+      onFail(error);
+    };
+
+    _resolve = _reject = function () { }
+
+    return me;
+  };
+
+  /**
+   * Cancel te promise. This will reject the promise with a CancellationError
+   * @returns {Promise} self
+   */
+  this.cancel = function () {
+    if (parent) {
+      parent.cancel();
+    }
+    else {
+      _reject(new CancellationError());
+    }
+
+    return me;
+  };
+
+  /**
+   * Set a timeout for the promise. If the promise is not resolved within
+   * the time, the promise will be cancelled and a TimeoutError is thrown.
+   * If the promise is resolved in time, the timeout is removed.
+   * @param {number} delay     Delay in milliseconds
+   * @returns {Promise} self
+   */
+  this.timeout = function (delay) {
+    if (parent) {
+      parent.timeout(delay);
+    }
+    else {
+      var timer = setTimeout(function () {
+        _reject(new TimeoutError('Promise timed out after ' + delay + ' ms'));
+      }, delay);
+
+      me.always(function () {
+        clearTimeout(timer);
+      });
+    }
+
+    return me;
+  };
+
+  // attach handler passing the resolve and reject functions
+  handler(function (result) {
+    _resolve(result);
+  }, function (error) {
+    _reject(error);
+  });
+}
+
+/**
+ * Execute given callback, then call resolve/reject based on the returned result
+ * @param {Function} callback
+ * @param {Function} resolve
+ * @param {Function} reject
+ * @returns {Function}
+ * @private
+ */
+function _then(callback, resolve, reject) {
+  return function (result) {
+    try {
+      var res = callback(result);
+      if (res && typeof res.then === 'function' && typeof res['catch'] === 'function') {
+        // method returned a promise
+        res.then(resolve, reject);
+      }
+      else {
+        resolve(res);
+      }
+    }
+    catch (error) {
+      reject(error);
+    }
+  }
+}
+
+/**
+ * Add an onFail callback to the Promise
+ * @param {Function} onFail
+ * @returns {Promise} promise
+ */
+Promise.prototype['catch'] = function (onFail) {
+  return this.then(null, onFail);
+};
+
+// TODO: add support for Promise.catch(Error, callback)
+// TODO: add support for Promise.catch(Error, Error, callback)
+
+/**
+ * Execute given callback when the promise either resolves or rejects.
+ * @param {Function} fn
+ * @returns {Promise} promise
+ */
+Promise.prototype.always = function (fn) {
+  return this.then(fn, fn);
+};
+
+/**
+ * Create a promise which resolves when all provided promises are resolved,
+ * and fails when any of the promises resolves.
+ * @param {Promise[]} promises
+ * @returns {Promise} promise
+ */
+Promise.all = function (promises){
+  return new Promise(function (resolve, reject) {
+    var remaining = promises.length,
+        results = [];
+
+    if (remaining) {
+      promises.forEach(function (p, i) {
+        p.then(function (result) {
+          results[i] = result;
+          remaining--;
+          if (remaining == 0) {
+            resolve(results);
+          }
+        }, function (error) {
+          remaining = 0;
+          reject(error);
+        });
+      });
+    }
+    else {
+      resolve(results);
+    }
+  });
+};
+
+/**
+ * Create a promise resolver
+ * @returns {{promise: Promise, resolve: Function, reject: Function}} resolver
+ */
+Promise.defer = function () {
+  var resolver = {};
+
+  resolver.promise = new Promise(function (resolve, reject) {
+    resolver.resolve = resolve;
+    resolver.reject = reject;
+  });
+
+  return resolver;
+};
+
+/**
+ * Create a cancellation error
+ * @param {String} [message]
+ * @extends Error
+ */
+function CancellationError(message) {
+  this.message = message || 'promise cancelled';
+  this.stack = (new Error()).stack;
+}
+
+CancellationError.prototype = new Error();
+CancellationError.prototype.constructor = Error;
+CancellationError.prototype.name = 'CancellationError';
+
+Promise.CancellationError = CancellationError;
+
+
+/**
+ * Create a timeout error
+ * @param {String} [message]
+ * @extends Error
+ */
+function TimeoutError(message) {
+  this.message = message || 'timeout exceeded';
+  this.stack = (new Error()).stack;
+}
+
+TimeoutError.prototype = new Error();
+TimeoutError.prototype.constructor = Error;
+TimeoutError.prototype.name = 'TimeoutError';
+
+Promise.TimeoutError = TimeoutError;
+
+
+module.exports = Promise;

node_modules/workerpool/src/WorkerHandler.js

@@ -0,0 +1,489 @@
+'use strict';
+
+var Promise = require('./Promise');
+var environment = require('./environment');
+var requireFoolWebpack = require('./requireFoolWebpack');
+
+/**
+ * Special message sent by parent which causes a child process worker to terminate itself.
+ * Not a "message object"; this string is the entire message.
+ */
+var TERMINATE_METHOD_ID = '__workerpool-terminate__';
+
+/**
+ * If sending `TERMINATE_METHOD_ID` does not cause the child process to exit in this many milliseconds,
+ * force-kill the child process.
+ */
+var CHILD_PROCESS_EXIT_TIMEOUT = 1000;
+
+function ensureWorkerThreads() {
+  var WorkerThreads = tryRequireWorkerThreads()
+  if (!WorkerThreads) {
+    throw new Error('WorkerPool: workerType = \'thread\' is not supported, Node >= 11.7.0 required')
+  }
+
+  return WorkerThreads;
+}
+
+// check whether Worker is supported by the browser
+function ensureWebWorker() {
+  // Workaround for a bug in PhantomJS (Or QtWebkit): https://github.com/ariya/phantomjs/issues/14534
+  if (typeof Worker !== 'function' && (typeof Worker !== 'object' || typeof Worker.prototype.constructor !== 'function')) {
+    throw new Error('WorkerPool: Web Workers not supported');
+  }
+}
+
+function tryRequireWorkerThreads() {
+  try {
+    return requireFoolWebpack('worker_threads');
+  } catch(error) {
+    if (typeof error === 'object' && error !== null && error.code === 'MODULE_NOT_FOUND') {
+      // no worker_threads available (old version of node.js)
+      return null;
+    } else {
+      throw error;
+    }
+  }
+}
+
+// get the default worker script
+function getDefaultWorker() {
+  if (environment.platform === 'browser') {
+    // test whether the browser supports all features that we need
+    if (typeof Blob === 'undefined') {
+      throw new Error('Blob not supported by the browser');
+    }
+    if (!window.URL || typeof window.URL.createObjectURL !== 'function') {
+      throw new Error('URL.createObjectURL not supported by the browser');
+    }
+
+    // use embedded worker.js
+    var blob = new Blob([require('./generated/embeddedWorker')], {type: 'text/javascript'});
+    return window.URL.createObjectURL(blob);
+  }
+  else {
+    // use external worker.js in current directory
+    return __dirname + '/worker.js';
+  }
+}
+
+function setupWorker(script, options) {
+  if (options.workerType === 'web') { // browser only
+    ensureWebWorker();
+    return setupBrowserWorker(script, Worker);
+  } else if (options.workerType === 'thread') { // node.js only
+    WorkerThreads = ensureWorkerThreads();
+    return setupWorkerThreadWorker(script, WorkerThreads);
+  } else if (options.workerType === 'process' || !options.workerType) { // node.js only
+    return setupProcessWorker(script, resolveForkOptions(options), requireFoolWebpack('child_process'));
+  } else { // options.workerType === 'auto' or undefined
+    if (environment.platform === 'browser') {
+      ensureWebWorker();
+      return setupBrowserWorker(script, Worker);
+    }
+    else { // environment.platform === 'node'
+      var WorkerThreads = tryRequireWorkerThreads();
+      if (WorkerThreads) {
+        return setupWorkerThreadWorker(script, WorkerThreads);
+      } else {
+        return setupProcessWorker(script, resolveForkOptions(options), requireFoolWebpack('child_process'));
+      }
+    }
+  }
+}
+
+function setupBrowserWorker(script, Worker) {
+  // create the web worker
+  var worker = new Worker(script);
+
+  worker.isBrowserWorker = true;
+  // add node.js API to the web worker
+  worker.on = function (event, callback) {
+    this.addEventListener(event, function (message) {
+      callback(message.data);
+    });
+  };
+  worker.send = function (message) {
+    this.postMessage(message);
+  };
+  return worker;
+}
+
+function setupWorkerThreadWorker(script, WorkerThreads) {
+  var worker = new WorkerThreads.Worker(script, {
+    stdout: false, // automatically pipe worker.STDOUT to process.STDOUT
+    stderr: false  // automatically pipe worker.STDERR to process.STDERR
+  });
+  worker.isWorkerThread = true;
+  // make the worker mimic a child_process
+  worker.send = function(message) {
+    this.postMessage(message);
+  };
+
+  worker.kill = function() {
+    this.terminate();
+    return true;
+  };
+
+  worker.disconnect = function() {
+    this.terminate();
+  };
+
+  return worker;
+}
+
+function setupProcessWorker(script, options, child_process) {
+  // no WorkerThreads, fallback to sub-process based workers
+  var worker = child_process.fork(
+    script,
+    options.forkArgs,
+    options.forkOpts
+  );
+
+  worker.isChildProcess = true;
+  return worker;
+}
+
+// add debug flags to child processes if the node inspector is active
+function resolveForkOptions(opts) {
+  opts = opts || {};
+
+  var processExecArgv = process.execArgv.join(' ');
+  var inspectorActive = processExecArgv.indexOf('--inspect') !== -1;
+  var debugBrk = processExecArgv.indexOf('--debug-brk') !== -1;
+
+  var execArgv = [];
+  if (inspectorActive) {
+    execArgv.push('--inspect=' + opts.debugPort);
+
+    if (debugBrk) {
+      execArgv.push('--debug-brk');
+    }
+  }
+
+  process.execArgv.forEach(function(arg) {
+    if (arg.indexOf('--max-old-space-size') > -1) {
+      execArgv.push(arg)
+    }
+  })
+
+  return Object.assign({}, opts, {
+    forkArgs: opts.forkArgs,
+    forkOpts: Object.assign({}, opts.forkOpts, {
+      execArgv: (opts.forkOpts && opts.forkOpts.execArgv || [])
+      .concat(execArgv)
+    })
+  });
+}
+
+/**
+ * Converts a serialized error to Error
+ * @param {Object} obj Error that has been serialized and parsed to object
+ * @return {Error} The equivalent Error.
+ */
+function objectToError (obj) {
+  var temp = new Error('')
+  var props = Object.keys(obj)
+
+  for (var i = 0; i < props.length; i++) {
+    temp[props[i]] = obj[props[i]]
+  }
+
+  return temp
+}
+
+/**
+ * A WorkerHandler controls a single worker. This worker can be a child process
+ * on node.js or a WebWorker in a browser environment.
+ * @param {String} [script] If no script is provided, a default worker with a
+ *                          function run will be created.
+ * @param {WorkerPoolOptions} _options See docs
+ * @constructor
+ */
+function WorkerHandler(script, _options) {
+  var me = this;
+  var options = _options || {};
+
+  this.script = script || getDefaultWorker();
+  this.worker = setupWorker(this.script, options);
+  this.debugPort = options.debugPort;
+
+  // The ready message is only sent if the worker.add method is called (And the default script is not used)
+  if (!script) {
+    this.worker.ready = true;
+  }
+
+  // queue for requests that are received before the worker is ready
+  this.requestQueue = [];
+  this.worker.on('message', function (response) {
+    if (typeof response === 'string' && response === 'ready') {
+      me.worker.ready = true;
+      dispatchQueuedRequests();
+    } else {
+      // find the task from the processing queue, and run the tasks callback
+      var id = response.id;
+      var task = me.processing[id];
+      if (task !== undefined) {
+        if (response.isEvent) {
+          if (task.options && typeof task.options.on === 'function') {
+            task.options.on(response.payload);
+          }
+        } else {
+          // remove the task from the queue
+          delete me.processing[id];
+
+          // test if we need to terminate
+          if (me.terminating === true) {
+            // complete worker termination if all tasks are finished
+            me.terminate();
+          }
+
+          // resolve the task's promise
+          if (response.error) {
+            task.resolver.reject(objectToError(response.error));
+          }
+          else {
+            task.resolver.resolve(response.result);
+          }
+        }
+      }
+    }
+  });
+
+  // reject all running tasks on worker error
+  function onError(error) {
+    me.terminated = true;
+
+    for (var id in me.processing) {
+      if (me.processing[id] !== undefined) {
+        me.processing[id].resolver.reject(error);
+      }
+    }
+    me.processing = Object.create(null);
+  }
+
+  // send all queued requests to worker
+  function dispatchQueuedRequests()
+  {
+    for(const request of me.requestQueue.splice(0)) {
+      me.worker.send(request);
+    }
+  }
+
+  var worker = this.worker;
+  // listen for worker messages error and exit
+  this.worker.on('error', onError);
+  this.worker.on('exit', function (exitCode, signalCode) {
+    var message = 'Workerpool Worker terminated Unexpectedly\n';
+
+    message += '    exitCode: `' + exitCode + '`\n';
+    message += '    signalCode: `' + signalCode + '`\n';
+
+    message += '    workerpool.script: `' +  me.script + '`\n';
+    message += '    spawnArgs: `' +  worker.spawnargs + '`\n';
+    message += '    spawnfile: `' + worker.spawnfile + '`\n'
+
+    message += '    stdout: `' + worker.stdout + '`\n'
+    message += '    stderr: `' + worker.stderr + '`\n'
+
+    onError(new Error(message));
+  });
+
+  this.processing = Object.create(null); // queue with tasks currently in progress
+
+  this.terminating = false;
+  this.terminated = false;
+  this.terminationHandler = null;
+  this.lastId = 0;
+}
+
+/**
+ * Get a list with methods available on the worker.
+ * @return {Promise.<String[], Error>} methods
+ */
+WorkerHandler.prototype.methods = function () {
+  return this.exec('methods');
+};
+
+/**
+ * Execute a method with given parameters on the worker
+ * @param {String} method
+ * @param {Array} [params]
+ * @param {{resolve: Function, reject: Function}} [resolver]
+ * @param {ExecOptions}  [options]
+ * @return {Promise.<*, Error>} result
+ */
+WorkerHandler.prototype.exec = function(method, params, resolver, options) {
+  if (!resolver) {
+    resolver = Promise.defer();
+  }
+
+  // generate a unique id for the task
+  var id = ++this.lastId;
+
+  // register a new task as being in progress
+  this.processing[id] = {
+    id: id,
+    resolver: resolver,
+    options: options
+  };
+
+  // build a JSON-RPC request
+  var request = {
+    id: id,
+    method: method,
+    params: params
+  };
+
+  if (this.terminated) {
+    resolver.reject(new Error('Worker is terminated'));
+  } else if (this.worker.ready) {
+    // send the request to the worker
+    this.worker.send(request);
+  } else {
+    this.requestQueue.push(request);
+  }
+
+  // on cancellation, force the worker to terminate
+  var me = this;
+  return resolver.promise.catch(function (error) {
+    if (error instanceof Promise.CancellationError || error instanceof Promise.TimeoutError) {
+      // remove this task from the queue. It is already rejected (hence this
+      // catch event), and else it will be rejected again when terminating
+      delete me.processing[id];
+
+      // terminate worker
+      return me.terminateAndNotify(true)
+        .then(function() {
+          throw error;
+        }, function(err) { 
+          throw err; 
+        });
+    } else {
+      throw error;
+    }
+  })
+};
+
+/**
+ * Test whether the worker is working or not
+ * @return {boolean} Returns true if the worker is busy
+ */
+WorkerHandler.prototype.busy = function () {
+  return Object.keys(this.processing).length > 0;
+};
+
+/**
+ * Terminate the worker.
+ * @param {boolean} [force=false]   If false (default), the worker is terminated
+ *                                  after finishing all tasks currently in
+ *                                  progress. If true, the worker will be
+ *                                  terminated immediately.
+ * @param {function} [callback=null] If provided, will be called when process terminates.
+ */
+WorkerHandler.prototype.terminate = function (force, callback) {
+  var me = this;
+  if (force) {
+    // cancel all tasks in progress
+    for (var id in this.processing) {
+      if (this.processing[id] !== undefined) {
+        this.processing[id].resolver.reject(new Error('Worker terminated'));
+      }
+    }
+    this.processing = Object.create(null);
+  }
+
+  if (typeof callback === 'function') {
+    this.terminationHandler = callback;
+  }
+  if (!this.busy()) {
+    // all tasks are finished. kill the worker
+    var cleanup = function(err) {
+      me.terminated = true;
+      me.worker = null;
+      me.terminating = false;
+      if (me.terminationHandler) {
+        me.terminationHandler(err, me);
+      } else if (err) {
+        throw err;
+      }
+    }
+
+    if (this.worker) {
+      if (typeof this.worker.kill === 'function') {
+        if (this.worker.killed) {
+          cleanup(new Error('worker already killed!'));
+          return;
+        }
+
+        if (this.worker.isChildProcess) {
+          var cleanExitTimeout = setTimeout(function() {
+            me.worker.kill();
+          }, CHILD_PROCESS_EXIT_TIMEOUT);
+
+          this.worker.once('exit', function() {
+            clearTimeout(cleanExitTimeout);
+            me.worker.killed = true;
+            cleanup();
+          });
+
+          if (this.worker.ready) {
+            this.worker.send(TERMINATE_METHOD_ID);
+          } else {
+            this.worker.requestQueue.push(TERMINATE_METHOD_ID)
+          }
+        } else {
+          // worker_thread
+          this.worker.kill();
+          this.worker.killed = true;
+          cleanup();
+        }
+        return;
+      }
+      else if (typeof this.worker.terminate === 'function') {
+        this.worker.terminate(); // web worker
+        this.worker.killed = true;
+      }
+      else {
+        throw new Error('Failed to terminate worker');
+      }
+    }
+    cleanup();
+  }
+  else {
+    // we can't terminate immediately, there are still tasks being executed
+    this.terminating = true;
+  }
+};
+
+/**
+ * Terminate the worker, returning a Promise that resolves when the termination has been done.
+ * @param {boolean} [force=false]   If false (default), the worker is terminated
+ *                                  after finishing all tasks currently in
+ *                                  progress. If true, the worker will be
+ *                                  terminated immediately.
+ * @param {number} [timeout]        If provided and non-zero, worker termination promise will be rejected
+ *                                  after timeout if worker process has not been terminated.
+ * @return {Promise.<WorkerHandler, Error>}
+ */
+WorkerHandler.prototype.terminateAndNotify = function (force, timeout) {
+  var resolver = Promise.defer();
+  if (timeout) {
+    resolver.promise.timeout = timeout;
+  }
+  this.terminate(force, function(err, worker) {
+    if (err) {
+      resolver.reject(err);
+    } else {
+      resolver.resolve(worker);
+    }
+  });
+  return resolver.promise;
+};
+
+module.exports = WorkerHandler;
+module.exports._tryRequireWorkerThreads = tryRequireWorkerThreads;
+module.exports._setupProcessWorker = setupProcessWorker;
+module.exports._setupBrowserWorker = setupBrowserWorker;
+module.exports._setupWorkerThreadWorker = setupWorkerThreadWorker;
+module.exports.ensureWorkerThreads = ensureWorkerThreads;

node_modules/workerpool/src/debug-port-allocator.js

@@ -0,0 +1,28 @@
+'use strict';
+
+var MAX_PORTS = 65535;
+module.exports = DebugPortAllocator;
+function DebugPortAllocator() {
+  this.ports = Object.create(null);
+  this.length = 0;
+}
+
+DebugPortAllocator.prototype.nextAvailableStartingAt = function(starting) {
+  while (this.ports[starting] === true) {
+    starting++;
+  }
+
+  if (starting >= MAX_PORTS) {
+    throw new Error('WorkerPool debug port limit reached: ' + starting + '>= ' + MAX_PORTS );
+  }
+
+  this.ports[starting] = true;
+  this.length++;
+  return starting;
+};
+
+DebugPortAllocator.prototype.releasePort = function(port) {
+  delete this.ports[port];
+  this.length--;
+};
+

node_modules/workerpool/src/environment.js

@@ -0,0 +1,36 @@
+var requireFoolWebpack = require('./requireFoolWebpack');
+
+// source: https://github.com/flexdinesh/browser-or-node
+var isNode = function (nodeProcess) {
+  return (
+    typeof nodeProcess !== 'undefined' &&
+    nodeProcess.versions != null &&
+    nodeProcess.versions.node != null
+  );
+}
+module.exports.isNode = isNode
+
+// determines the JavaScript platform: browser or node
+module.exports.platform = typeof process !== 'undefined' && isNode(process)
+  ? 'node'
+  : 'browser';
+
+// determines whether the code is running in main thread or not
+// note that in node.js we have to check both worker_thread and child_process
+var worker_threads = tryRequireFoolWebpack('worker_threads');
+module.exports.isMainThread = module.exports.platform === 'node'
+  ? ((!worker_threads || worker_threads.isMainThread) && !process.connected)
+  : typeof Window !== 'undefined';
+
+// determines the number of cpus available
+module.exports.cpus = module.exports.platform === 'browser'
+  ? self.navigator.hardwareConcurrency
+  : requireFoolWebpack('os').cpus().length;
+
+function tryRequireFoolWebpack (module) {
+  try {
+    return requireFoolWebpack(module);
+  } catch(err) {
+    return null
+  }
+}

node_modules/workerpool/src/header.js

@@ -0,0 +1,24 @@
+/**
+ * workerpool.js
+ * https://github.com/josdejong/workerpool
+ *
+ * Offload tasks to a pool of workers on node.js and in the browser.
+ *
+ * @version @@version
+ * @date    @@date
+ *
+ * @license
+ * Copyright (C) 2014-2020 Jos de Jong <wjosdejong@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy
+ * of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */

node_modules/workerpool/src/index.js

@@ -0,0 +1,41 @@
+var environment = require('./environment');
+
+/**
+ * Create a new worker pool
+ * @param {string} [script]
+ * @param {WorkerPoolOptions} [options]
+ * @returns {Pool} pool
+ */
+exports.pool = function pool(script, options) {
+  var Pool = require('./Pool');
+
+  return new Pool(script, options);
+};
+
+/**
+ * Create a worker and optionally register a set of methods to the worker.
+ * @param {Object} [methods]
+ */
+exports.worker = function worker(methods) {
+  var worker = require('./worker');
+  worker.add(methods);
+};
+
+/**
+ * Sends an event to the parent worker pool.
+ * @param {any} payload 
+ */
+exports.workerEmit = function workerEmit(payload) {
+  var worker = require('./worker');
+  worker.emit(payload);
+};
+
+/**
+ * Create a promise.
+ * @type {Promise} promise
+ */
+exports.Promise = require('./Promise');
+
+exports.platform = environment.platform;
+exports.isMainThread = environment.isMainThread;
+exports.cpus = environment.cpus;

node_modules/workerpool/src/requireFoolWebpack.js

@@ -0,0 +1,8 @@
+// source of inspiration: https://github.com/sindresorhus/require-fool-webpack
+var requireFoolWebpack = eval(
+    'typeof require !== \'undefined\' ' +
+    '? require ' +
+    ': function (module) { throw new Error(\'Module " + module + " not found.\') }'
+);
+
+module.exports = requireFoolWebpack;

node_modules/workerpool/src/types.js

@@ -0,0 +1,15 @@
+/**
+ * @typedef {Object} WorkerPoolOptions
+ * @property {number | 'max'} [minWorkers]
+ * @property {number} [maxWorkers]
+ * @property {number} [maxQueueSize]
+ * @property {'auto' | 'web' | 'process' | 'thread'} [workerType]
+ * @property {*} [forkArgs]
+ * @property {*} [forkOpts]
+ * @property {number} [debugPortStart]
+ */
+
+/**
+ * @typedef {Object} ExecOptions
+ * @property {(payload: any) => unknown} [on]
+ */

node_modules/workerpool/src/worker.js

@@ -0,0 +1,202 @@
+/**
+ * worker must be started as a child process or a web worker.
+ * It listens for RPC messages from the parent process.
+ */
+
+// source of inspiration: https://github.com/sindresorhus/require-fool-webpack
+var requireFoolWebpack = eval(
+    'typeof require !== \'undefined\'' +
+    ' ? require' +
+    ' : function (module) { throw new Error(\'Module " + module + " not found.\') }'
+);
+
+/**
+ * Special message sent by parent which causes the worker to terminate itself.
+ * Not a "message object"; this string is the entire message.
+ */
+var TERMINATE_METHOD_ID = '__workerpool-terminate__';
+
+// var nodeOSPlatform = require('./environment').nodeOSPlatform;
+
+// create a worker API for sending and receiving messages which works both on
+// node.js and in the browser
+var worker = {
+  exit: function() {}
+};
+if (typeof self !== 'undefined' && typeof postMessage === 'function' && typeof addEventListener === 'function') {
+  // worker in the browser
+  worker.on = function (event, callback) {
+    addEventListener(event, function (message) {
+      callback(message.data);
+    })
+  };
+  worker.send = function (message) {
+    postMessage(message);
+  };
+}
+else if (typeof process !== 'undefined') {
+  // node.js
+
+  var WorkerThreads;
+  try {
+    WorkerThreads = requireFoolWebpack('worker_threads');
+  } catch(error) {
+    if (typeof error === 'object' && error !== null && error.code === 'MODULE_NOT_FOUND') {
+      // no worker_threads, fallback to sub-process based workers
+    } else {
+      throw error;
+    }
+  }
+
+  if (WorkerThreads &&
+    /* if there is a parentPort, we are in a WorkerThread */
+    WorkerThreads.parentPort !== null) {
+    var parentPort  = WorkerThreads.parentPort;
+    worker.send = parentPort.postMessage.bind(parentPort);
+    worker.on = parentPort.on.bind(parentPort);
+  } else {
+    worker.on = process.on.bind(process);
+    worker.send = process.send.bind(process);
+    // register disconnect handler only for subprocess worker to exit when parent is killed unexpectedly
+    worker.on('disconnect', function () {
+      process.exit(1);
+    });
+    worker.exit = process.exit.bind(process);
+  }
+}
+else {
+  throw new Error('Script must be executed as a worker');
+}
+
+function convertError(error) {
+  return Object.getOwnPropertyNames(error).reduce(function(product, name) {
+    return Object.defineProperty(product, name, {
+	value: error[name],
+	enumerable: true
+    });
+  }, {});
+}
+
+/**
+ * Test whether a value is a Promise via duck typing.
+ * @param {*} value
+ * @returns {boolean} Returns true when given value is an object
+ *                    having functions `then` and `catch`.
+ */
+function isPromise(value) {
+  return value && (typeof value.then === 'function') && (typeof value.catch === 'function');
+}
+
+// functions available externally
+worker.methods = {};
+
+/**
+ * Execute a function with provided arguments
+ * @param {String} fn     Stringified function
+ * @param {Array} [args]  Function arguments
+ * @returns {*}
+ */
+worker.methods.run = function run(fn, args) {
+  var f = new Function('return (' + fn + ').apply(null, arguments);');
+  return f.apply(f, args);
+};
+
+/**
+ * Get a list with methods available on this worker
+ * @return {String[]} methods
+ */
+worker.methods.methods = function methods() {
+  return Object.keys(worker.methods);
+};
+
+var currentRequestId = null;
+
+worker.on('message', function (request) {
+  if (request === TERMINATE_METHOD_ID) {
+    return worker.exit(0);
+  }
+  try {
+    var method = worker.methods[request.method];
+
+    if (method) {
+      currentRequestId = request.id;
+      
+      // execute the function
+      var result = method.apply(method, request.params);
+
+      if (isPromise(result)) {
+        // promise returned, resolve this and then return
+        result
+            .then(function (result) {
+              worker.send({
+                id: request.id,
+                result: result,
+                error: null
+              });
+              currentRequestId = null;
+            })
+            .catch(function (err) {
+              worker.send({
+                id: request.id,
+                result: null,
+                error: convertError(err)
+              });
+              currentRequestId = null;
+            });
+      }
+      else {
+        // immediate result
+        worker.send({
+          id: request.id,
+          result: result,
+          error: null
+        });
+
+        currentRequestId = null;
+      }
+    }
+    else {
+      throw new Error('Unknown method "' + request.method + '"');
+    }
+  }
+  catch (err) {
+    worker.send({
+      id: request.id,
+      result: null,
+      error: convertError(err)
+    });
+  }
+});
+
+/**
+ * Register methods to the worker
+ * @param {Object} methods
+ */
+worker.register = function (methods) {
+
+  if (methods) {
+    for (var name in methods) {
+      if (methods.hasOwnProperty(name)) {
+        worker.methods[name] = methods[name];
+      }
+    }
+  }
+
+  worker.send('ready');
+
+};
+
+worker.emit = function (payload) {
+  if (currentRequestId) {
+    worker.send({
+      id: currentRequestId,
+      isEvent: true,
+      payload
+    });
+  }
+};
+
+if (typeof exports !== 'undefined') {
+  exports.add = worker.register;
+  exports.emit = worker.emit;
+}