143 lines
2.8 KiB
JavaScript
143 lines
2.8 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const util = require("util");
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const TOMBSTONE = {};
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const UNDEFINED_MARKER = {};
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class StackedSetMap {
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constructor(parentStack) {
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this.stack = parentStack === undefined ? [] : parentStack.slice();
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this.map = new Map();
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this.stack.push(this.map);
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}
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add(item) {
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this.map.set(item, true);
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}
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set(item, value) {
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this.map.set(item, value === undefined ? UNDEFINED_MARKER : value);
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}
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delete(item) {
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if (this.stack.length > 1) {
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this.map.set(item, TOMBSTONE);
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} else {
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this.map.delete(item);
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}
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}
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has(item) {
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const topValue = this.map.get(item);
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if (topValue !== undefined) return topValue !== TOMBSTONE;
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if (this.stack.length > 1) {
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for (var i = this.stack.length - 2; i >= 0; i--) {
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const value = this.stack[i].get(item);
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if (value !== undefined) {
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this.map.set(item, value);
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return value !== TOMBSTONE;
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}
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}
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this.map.set(item, TOMBSTONE);
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}
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return false;
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}
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get(item) {
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const topValue = this.map.get(item);
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if (topValue !== undefined) {
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return topValue === TOMBSTONE || topValue === UNDEFINED_MARKER
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? undefined
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: topValue;
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}
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if (this.stack.length > 1) {
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for (var i = this.stack.length - 2; i >= 0; i--) {
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const value = this.stack[i].get(item);
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if (value !== undefined) {
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this.map.set(item, value);
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return value === TOMBSTONE || value === UNDEFINED_MARKER
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? undefined
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: value;
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}
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}
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this.map.set(item, TOMBSTONE);
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}
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return undefined;
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}
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_compress() {
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if (this.stack.length === 1) return;
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this.map = new Map();
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for (const data of this.stack) {
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for (const pair of data) {
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if (pair[1] === TOMBSTONE) {
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this.map.delete(pair[0]);
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} else {
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this.map.set(pair[0], pair[1]);
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}
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}
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}
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this.stack = [this.map];
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}
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asArray() {
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this._compress();
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return Array.from(this.map.entries(), pair => pair[0]);
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}
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asSet() {
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return new Set(this.asArray());
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}
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asPairArray() {
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this._compress();
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return Array.from(this.map.entries(), pair =>
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/** @type {[TODO, TODO]} */ (pair[1] === UNDEFINED_MARKER
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? [pair[0], undefined]
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: pair)
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);
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}
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asMap() {
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return new Map(this.asPairArray());
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}
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get size() {
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this._compress();
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return this.map.size;
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}
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createChild() {
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return new StackedSetMap(this.stack);
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}
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get length() {
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throw new Error("This is no longer an Array");
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}
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set length(value) {
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throw new Error("This is no longer an Array");
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}
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}
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// TODO remove in webpack 5
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StackedSetMap.prototype.push = util.deprecate(
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/**
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* @deprecated
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* @this {StackedSetMap}
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* @param {any} item Item to add
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* @returns {void}
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*/
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function(item) {
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this.add(item);
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},
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"This is no longer an Array: Use add instead."
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);
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module.exports = StackedSetMap;
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