189 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			189 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| 'use strict';
 | |
| 
 | |
| Object.defineProperty(exports, '__esModule', {
 | |
|   value: true
 | |
| });
 | |
| exports.default = void 0;
 | |
| 
 | |
| function _defineProperty(obj, key, value) {
 | |
|   if (key in obj) {
 | |
|     Object.defineProperty(obj, key, {
 | |
|       value: value,
 | |
|       enumerable: true,
 | |
|       configurable: true,
 | |
|       writable: true
 | |
|     });
 | |
|   } else {
 | |
|     obj[key] = value;
 | |
|   }
 | |
|   return obj;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 | |
|  *
 | |
|  * This source code is licensed under the MIT license found in the
 | |
|  * LICENSE file in the root directory of this source tree.
 | |
|  */
 | |
| 
 | |
| /**
 | |
|  * Priority queue that processes tasks in natural ordering (lower priority first)
 | |
|  * accoridng to the priority computed by the function passed in the constructor.
 | |
|  *
 | |
|  * FIFO ordering isn't guaranteed for tasks with the same priority.
 | |
|  *
 | |
|  * Worker specific tasks with the same priority as a non-worker specific task
 | |
|  * are always processed first.
 | |
|  */
 | |
| class PriorityQueue {
 | |
|   constructor(_computePriority) {
 | |
|     _defineProperty(this, '_queue', []);
 | |
| 
 | |
|     _defineProperty(this, '_sharedQueue', new MinHeap());
 | |
| 
 | |
|     this._computePriority = _computePriority;
 | |
|   }
 | |
| 
 | |
|   enqueue(task, workerId) {
 | |
|     if (workerId == null) {
 | |
|       this._enqueue(task, this._sharedQueue);
 | |
|     } else {
 | |
|       const queue = this._getWorkerQueue(workerId);
 | |
| 
 | |
|       this._enqueue(task, queue);
 | |
|     }
 | |
|   }
 | |
| 
 | |
|   _enqueue(task, queue) {
 | |
|     const item = {
 | |
|       priority: this._computePriority(task.request[2], ...task.request[3]),
 | |
|       task
 | |
|     };
 | |
|     queue.add(item);
 | |
|   }
 | |
| 
 | |
|   dequeue(workerId) {
 | |
|     const workerQueue = this._getWorkerQueue(workerId);
 | |
| 
 | |
|     const workerTop = workerQueue.peek();
 | |
| 
 | |
|     const sharedTop = this._sharedQueue.peek(); // use the task from the worker queue if there's no task in the shared queue
 | |
|     // or if the priority of the worker queue is smaller or equal to the
 | |
|     // priority of the top task in the shared queue. The tasks of the
 | |
|     // worker specific queue are preferred because no other worker can pick this
 | |
|     // specific task up.
 | |
| 
 | |
|     if (
 | |
|       sharedTop == null ||
 | |
|       (workerTop != null && workerTop.priority <= sharedTop.priority)
 | |
|     ) {
 | |
|       var _workerQueue$poll$tas, _workerQueue$poll;
 | |
| 
 | |
|       return (_workerQueue$poll$tas =
 | |
|         (_workerQueue$poll = workerQueue.poll()) === null ||
 | |
|         _workerQueue$poll === void 0
 | |
|           ? void 0
 | |
|           : _workerQueue$poll.task) !== null && _workerQueue$poll$tas !== void 0
 | |
|         ? _workerQueue$poll$tas
 | |
|         : null;
 | |
|     }
 | |
| 
 | |
|     return this._sharedQueue.poll().task;
 | |
|   }
 | |
| 
 | |
|   _getWorkerQueue(workerId) {
 | |
|     let queue = this._queue[workerId];
 | |
| 
 | |
|     if (queue == null) {
 | |
|       queue = this._queue[workerId] = new MinHeap();
 | |
|     }
 | |
| 
 | |
|     return queue;
 | |
|   }
 | |
| }
 | |
| 
 | |
| exports.default = PriorityQueue;
 | |
| 
 | |
| class MinHeap {
 | |
|   constructor() {
 | |
|     _defineProperty(this, '_heap', []);
 | |
|   }
 | |
| 
 | |
|   peek() {
 | |
|     var _this$_heap$;
 | |
| 
 | |
|     return (_this$_heap$ = this._heap[0]) !== null && _this$_heap$ !== void 0
 | |
|       ? _this$_heap$
 | |
|       : null;
 | |
|   }
 | |
| 
 | |
|   add(item) {
 | |
|     const nodes = this._heap;
 | |
|     nodes.push(item);
 | |
| 
 | |
|     if (nodes.length === 1) {
 | |
|       return;
 | |
|     }
 | |
| 
 | |
|     let currentIndex = nodes.length - 1; // Bubble up the added node as long as the parent is bigger
 | |
| 
 | |
|     while (currentIndex > 0) {
 | |
|       const parentIndex = Math.floor((currentIndex + 1) / 2) - 1;
 | |
|       const parent = nodes[parentIndex];
 | |
| 
 | |
|       if (parent.priority <= item.priority) {
 | |
|         break;
 | |
|       }
 | |
| 
 | |
|       nodes[currentIndex] = parent;
 | |
|       nodes[parentIndex] = item;
 | |
|       currentIndex = parentIndex;
 | |
|     }
 | |
|   }
 | |
| 
 | |
|   poll() {
 | |
|     const nodes = this._heap;
 | |
|     const result = nodes[0];
 | |
|     const lastElement = nodes.pop(); // heap was empty or removed the last element
 | |
| 
 | |
|     if (result == null || nodes.length === 0) {
 | |
|       return result !== null && result !== void 0 ? result : null;
 | |
|     }
 | |
| 
 | |
|     let index = 0;
 | |
|     nodes[0] =
 | |
|       lastElement !== null && lastElement !== void 0 ? lastElement : null;
 | |
|     const element = nodes[0];
 | |
| 
 | |
|     while (true) {
 | |
|       let swapIndex = null;
 | |
|       const rightChildIndex = (index + 1) * 2;
 | |
|       const leftChildIndex = rightChildIndex - 1;
 | |
|       const rightChild = nodes[rightChildIndex];
 | |
|       const leftChild = nodes[leftChildIndex]; // if the left child is smaller, swap with the left
 | |
| 
 | |
|       if (leftChild != null && leftChild.priority < element.priority) {
 | |
|         swapIndex = leftChildIndex;
 | |
|       } // If the right child is smaller or the right child is smaller than the left
 | |
|       // then swap with the right child
 | |
| 
 | |
|       if (
 | |
|         rightChild != null &&
 | |
|         rightChild.priority < (swapIndex == null ? element : leftChild).priority
 | |
|       ) {
 | |
|         swapIndex = rightChildIndex;
 | |
|       }
 | |
| 
 | |
|       if (swapIndex == null) {
 | |
|         break;
 | |
|       }
 | |
| 
 | |
|       nodes[index] = nodes[swapIndex];
 | |
|       nodes[swapIndex] = element;
 | |
|       index = swapIndex;
 | |
|     }
 | |
| 
 | |
|     return result;
 | |
|   }
 | |
| }
 |