webpack/lib/util/WeakTupleMap.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const isWeakKey = thing => typeof thing === "object" && thing !== null;

/**
 * @template {any[]} T
 * @template V
 */
class WeakTupleMap {
	constructor() {
		/** @private */
		this.f = 0;
		/** @private @type {any} */
		this.v = undefined;
		/** @private @type {Map<object, WeakTupleMap<T, V>> | undefined} */
		this.m = undefined;
		/** @private @type {WeakMap<object, WeakTupleMap<T, V>> | undefined} */
		this.w = undefined;
	}

	/**
	 * @param {[...T, V]} args tuple
	 * @returns {void}
	 */
	set(...args) {
		/** @type {WeakTupleMap<T, V>} */
		let node = this;
		for (let i = 0; i < args.length - 1; i++) {
			node = node._get(args[i]);
		}
		node._setValue(args[args.length - 1]);
	}

	/**
	 * @param {T} args tuple
	 * @returns {boolean} true, if the tuple is in the Set
	 */
	has(...args) {
		/** @type {WeakTupleMap<T, V>} */
		let node = this;
		for (let i = 0; i < args.length; i++) {
			node = node._peek(args[i]);
			if (node === undefined) return false;
		}
		return node._hasValue();
	}

	/**
	 * @param {T} args tuple
	 * @returns {V} the value
	 */
	get(...args) {
		/** @type {WeakTupleMap<T, V>} */
		let node = this;
		for (let i = 0; i < args.length; i++) {
			node = node._peek(args[i]);
			if (node === undefined) return undefined;
		}
		return node._getValue();
	}

	/**
	 * @param {[...T, function(): V]} args tuple
	 * @returns {V} the value
	 */
	provide(...args) {
		/** @type {WeakTupleMap<T, V>} */
		let node = this;
		for (let i = 0; i < args.length - 1; i++) {
			node = node._get(args[i]);
		}
		if (node._hasValue()) return node._getValue();
		const fn = args[args.length - 1];
		const newValue = fn(...args.slice(0, -1));
		node._setValue(newValue);
		return newValue;
	}

	/**
	 * @param {T} args tuple
	 * @returns {void}
	 */
	delete(...args) {
		/** @type {WeakTupleMap<T, V>} */
		let node = this;
		for (let i = 0; i < args.length; i++) {
			node = node._peek(args[i]);
			if (node === undefined) return;
		}
		node._deleteValue();
	}

	/**
	 * @returns {void}
	 */
	clear() {
		this.f = 0;
		this.v = undefined;
		this.w = undefined;
		this.m = undefined;
	}

	_getValue() {
		return this.v;
	}

	_hasValue() {
		return (this.f & 1) === 1;
	}

	_setValue(v) {
		this.f |= 1;
		this.v = v;
	}

	_deleteValue() {
		this.f &= 6;
		this.v = undefined;
	}

	_peek(thing) {
		if (isWeakKey(thing)) {
			if ((this.f & 4) !== 4) return undefined;
			return this.w.get(thing);
		} else {
			if ((this.f & 2) !== 2) return undefined;
			return this.m.get(thing);
		}
	}

	_get(thing) {
		if (isWeakKey(thing)) {
			if ((this.f & 4) !== 4) {
				const newMap = new WeakMap();
				this.f |= 4;
				const newNode = new WeakTupleMap();
				(this.w = newMap).set(thing, newNode);
				return newNode;
			}
			const entry = this.w.get(thing);
			if (entry !== undefined) {
				return entry;
			}
			const newNode = new WeakTupleMap();
			this.w.set(thing, newNode);
			return newNode;
		} else {
			if ((this.f & 2) !== 2) {
				const newMap = new Map();
				this.f |= 2;
				const newNode = new WeakTupleMap();
				(this.m = newMap).set(thing, newNode);
				return newNode;
			}
			const entry = this.m.get(thing);
			if (entry !== undefined) {
				return entry;
			}
			const newNode = new WeakTupleMap();
			this.m.set(thing, newNode);
			return newNode;
		}
	}
}

module.exports = WeakTupleMap;