mirror of https://github.com/webpack/webpack.git
123 lines
2.6 KiB
JavaScript
123 lines
2.6 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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has(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;
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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 ? undefined : topValue;
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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 ? undefined : 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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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 => pair[1] === UNDEFINED_MARKER ? [pair[0], undefined] : pair);
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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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StackedSetMap.prototype.push = util.deprecate(function(item) {
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this.add(item);
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}, "This is no longer an Array: Use add instead.");
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module.exports = StackedSetMap;
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