webpack/lib/CacheFacade.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports 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 { forEachBail } = require("enhanced-resolve");
const asyncLib = require("neo-async");
const getLazyHashedEtag = require("./cache/getLazyHashedEtag");
const mergeEtags = require("./cache/mergeEtags");

/** @typedef {import("./Cache")} Cache */
/** @typedef {import("./Cache").Etag} Etag */
/** @typedef {import("./cache/getLazyHashedEtag").HashableObject} HashableObject */
/** @typedef {import("./util/Hash").HashFunction} HashFunction */

/**
 * Defines the callback cache callback.
 * @template T
 * @callback CallbackCache
 * @param {(Error | null)=} err
 * @param {(T | null)=} result
 * @returns {void}
 */

/**
 * Defines the callback normal error cache callback.
 * @template T
 * @callback CallbackNormalErrorCache
 * @param {(Error | null)=} err
 * @param {T=} result
 * @returns {void}
 */

class MultiItemCache {
	/**
	 * Creates an instance of MultiItemCache.
	 * @param {ItemCacheFacade[]} items item caches
	 */
	constructor(items) {
		this._items = items;
		// @ts-expect-error expected - returns the single ItemCacheFacade when passed an array of length 1
		// eslint-disable-next-line no-constructor-return
		if (items.length === 1) return /** @type {ItemCacheFacade} */ (items[0]);
	}

	/**
	 * Returns value.
	 * @template T
	 * @param {CallbackCache<T>} callback signals when the value is retrieved
	 * @returns {void}
	 */
	get(callback) {
		forEachBail(this._items, (item, callback) => item.get(callback), callback);
	}

	/**
	 * Returns promise with the data.
	 * @template T
	 * @returns {Promise<T>} promise with the data
	 */
	getPromise() {
		/**
		 * Returns promise with the data.
		 * @param {number} i index
		 * @returns {Promise<T>} promise with the data
		 */
		const next = (i) =>
			this._items[i].getPromise().then((result) => {
				if (result !== undefined) return result;
				if (++i < this._items.length) return next(i);
			});
		return next(0);
	}

	/**
	 * Processes the provided data.
	 * @template T
	 * @param {T} data the value to store
	 * @param {CallbackCache<void>} callback signals when the value is stored
	 * @returns {void}
	 */
	store(data, callback) {
		asyncLib.each(
			this._items,
			(item, callback) => item.store(data, callback),
			callback
		);
	}

	/**
	 * Stores the provided data.
	 * @template T
	 * @param {T} data the value to store
	 * @returns {Promise<void>} promise signals when the value is stored
	 */
	storePromise(data) {
		return Promise.all(this._items.map((item) => item.storePromise(data))).then(
			() => {}
		);
	}
}

class ItemCacheFacade {
	/**
	 * Creates an instance of ItemCacheFacade.
	 * @param {Cache} cache the root cache
	 * @param {string} name the child cache item name
	 * @param {Etag | null} etag the etag
	 */
	constructor(cache, name, etag) {
		this._cache = cache;
		this._name = name;
		this._etag = etag;
	}

	/**
	 * Returns value.
	 * @template T
	 * @param {CallbackCache<T>} callback signals when the value is retrieved
	 * @returns {void}
	 */
	get(callback) {
		this._cache.get(this._name, this._etag, callback);
	}

	/**
	 * Returns promise with the data.
	 * @template T
	 * @returns {Promise<T>} promise with the data
	 */
	getPromise() {
		return new Promise((resolve, reject) => {
			this._cache.get(this._name, this._etag, (err, data) => {
				if (err) {
					reject(err);
				} else {
					resolve(data);
				}
			});
		});
	}

	/**
	 * Processes the provided data.
	 * @template T
	 * @param {T} data the value to store
	 * @param {CallbackCache<void>} callback signals when the value is stored
	 * @returns {void}
	 */
	store(data, callback) {
		this._cache.store(this._name, this._etag, data, callback);
	}

	/**
	 * Stores the provided data.
	 * @template T
	 * @param {T} data the value to store
	 * @returns {Promise<void>} promise signals when the value is stored
	 */
	storePromise(data) {
		return new Promise((resolve, reject) => {
			this._cache.store(this._name, this._etag, data, (err) => {
				if (err) {
					reject(err);
				} else {
					resolve();
				}
			});
		});
	}

	/**
	 * Processes the provided computer.
	 * @template T
	 * @param {(callback: CallbackNormalErrorCache<T>) => void} computer function to compute the value if not cached
	 * @param {CallbackNormalErrorCache<T>} callback signals when the value is retrieved
	 * @returns {void}
	 */
	provide(computer, callback) {
		this.get((err, cacheEntry) => {
			if (err) return callback(err);
			if (cacheEntry !== undefined) return cacheEntry;
			computer((err, result) => {
				if (err) return callback(err);
				this.store(result, (err) => {
					if (err) return callback(err);
					callback(null, result);
				});
			});
		});
	}

	/**
	 * Returns promise with the data.
	 * @template T
	 * @param {() => Promise<T> | T} computer function to compute the value if not cached
	 * @returns {Promise<T>} promise with the data
	 */
	async providePromise(computer) {
		const cacheEntry = await this.getPromise();
		if (cacheEntry !== undefined) return cacheEntry;
		const result = await computer();
		await this.storePromise(result);
		return result;
	}
}

class CacheFacade {
	/**
	 * Creates an instance of CacheFacade.
	 * @param {Cache} cache the root cache
	 * @param {string} name the child cache name
	 * @param {HashFunction=} hashFunction the hash function to use
	 */
	constructor(cache, name, hashFunction) {
		this._cache = cache;
		this._name = name;
		this._hashFunction = hashFunction;
	}

	/**
	 * Returns child cache.
	 * @param {string} name the child cache name#
	 * @returns {CacheFacade} child cache
	 */
	getChildCache(name) {
		return new CacheFacade(
			this._cache,
			`${this._name}|${name}`,
			this._hashFunction
		);
	}

	/**
	 * Returns item cache.
	 * @param {string} identifier the cache identifier
	 * @param {Etag | null} etag the etag
	 * @returns {ItemCacheFacade} item cache
	 */
	getItemCache(identifier, etag) {
		return new ItemCacheFacade(
			this._cache,
			`${this._name}|${identifier}`,
			etag
		);
	}

	/**
	 * Gets lazy hashed etag.
	 * @param {HashableObject} obj an hashable object
	 * @returns {Etag} an etag that is lazy hashed
	 */
	getLazyHashedEtag(obj) {
		return getLazyHashedEtag(obj, this._hashFunction);
	}

	/**
	 * Merges the provided values into a single result.
	 * @param {Etag} a an etag
	 * @param {Etag} b another etag
	 * @returns {Etag} an etag that represents both
	 */
	mergeEtags(a, b) {
		return mergeEtags(a, b);
	}

	/**
	 * Returns value.
	 * @template T
	 * @param {string} identifier the cache identifier
	 * @param {Etag | null} etag the etag
	 * @param {CallbackCache<T>} callback signals when the value is retrieved
	 * @returns {void}
	 */
	get(identifier, etag, callback) {
		this._cache.get(`${this._name}|${identifier}`, etag, callback);
	}

	/**
	 * Returns promise with the data.
	 * @template T
	 * @param {string} identifier the cache identifier
	 * @param {Etag | null} etag the etag
	 * @returns {Promise<T>} promise with the data
	 */
	getPromise(identifier, etag) {
		return new Promise((resolve, reject) => {
			this._cache.get(`${this._name}|${identifier}`, etag, (err, data) => {
				if (err) {
					reject(err);
				} else {
					resolve(data);
				}
			});
		});
	}

	/**
	 * Processes the provided identifier.
	 * @template T
	 * @param {string} identifier the cache identifier
	 * @param {Etag | null} etag the etag
	 * @param {T} data the value to store
	 * @param {CallbackCache<void>} callback signals when the value is stored
	 * @returns {void}
	 */
	store(identifier, etag, data, callback) {
		this._cache.store(`${this._name}|${identifier}`, etag, data, callback);
	}

	/**
	 * Stores the provided identifier.
	 * @template T
	 * @param {string} identifier the cache identifier
	 * @param {Etag | null} etag the etag
	 * @param {T} data the value to store
	 * @returns {Promise<void>} promise signals when the value is stored
	 */
	storePromise(identifier, etag, data) {
		return new Promise((resolve, reject) => {
			this._cache.store(`${this._name}|${identifier}`, etag, data, (err) => {
				if (err) {
					reject(err);
				} else {
					resolve();
				}
			});
		});
	}

	/**
	 * Processes the provided identifier.
	 * @template T
	 * @param {string} identifier the cache identifier
	 * @param {Etag | null} etag the etag
	 * @param {(callback: CallbackNormalErrorCache<T>) => void} computer function to compute the value if not cached
	 * @param {CallbackNormalErrorCache<T>} callback signals when the value is retrieved
	 * @returns {void}
	 */
	provide(identifier, etag, computer, callback) {
		this.get(identifier, etag, (err, cacheEntry) => {
			if (err) return callback(err);
			if (cacheEntry !== undefined) return cacheEntry;
			computer((err, result) => {
				if (err) return callback(err);
				this.store(identifier, etag, result, (err) => {
					if (err) return callback(err);
					callback(null, result);
				});
			});
		});
	}

	/**
	 * Returns promise with the data.
	 * @template T
	 * @param {string} identifier the cache identifier
	 * @param {Etag | null} etag the etag
	 * @param {() => Promise<T> | T} computer function to compute the value if not cached
	 * @returns {Promise<T>} promise with the data
	 */
	async providePromise(identifier, etag, computer) {
		const cacheEntry = await this.getPromise(identifier, etag);
		if (cacheEntry !== undefined) return cacheEntry;
		const result = await computer();
		await this.storePromise(identifier, etag, result);
		return result;
	}
}

module.exports = CacheFacade;
module.exports.ItemCacheFacade = ItemCacheFacade;
module.exports.MultiItemCache = MultiItemCache;