webpack/lib/util/hash/BulkUpdateHash.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 Alexander Akait @alexander-akait
*/

"use strict";

const Hash = require("../Hash");
const { digest, update } = require("./hash-digest");

/** @typedef {import("../../../declarations/WebpackOptions").HashDigest} Encoding */
/** @typedef {() => Hash} HashFactory */

const BULK_SIZE = 3;

// We are using an object instead of a Map as this will stay static during the runtime
// so access to it can be optimized by v8
/** @type {{ [key: string]: Map<string, string> }} */
const digestCaches = {};

class BulkUpdateHash extends Hash {
	/**
	 * @param {Hash | HashFactory} hashOrFactory function to create a hash
	 * @param {string=} hashKey key for caching
	 */
	constructor(hashOrFactory, hashKey) {
		super();
		/** @type {undefined | string} */
		this.hashKey = hashKey;
		if (typeof hashOrFactory === "function") {
			/** @type {undefined | HashFactory} */
			this.hashFactory = hashOrFactory;
			/** @type {undefined | Hash} */
			this.hash = undefined;
		} else {
			/** @type {undefined | HashFactory} */
			this.hashFactory = undefined;
			/** @type {undefined | Hash} */
			this.hash = hashOrFactory;
		}
		/** @type {string} */
		this.buffer = "";
	}

	/**
	 * Update hash {@link https://nodejs.org/api/crypto.html#crypto_hash_update_data_inputencoding}
	 * @overload
	 * @param {string | Buffer} data data
	 * @returns {Hash} updated hash
	 */
	/**
	 * Update hash {@link https://nodejs.org/api/crypto.html#crypto_hash_update_data_inputencoding}
	 * @overload
	 * @param {string} data data
	 * @param {Encoding} inputEncoding data encoding
	 * @returns {Hash} updated hash
	 */
	/**
	 * Update hash {@link https://nodejs.org/api/crypto.html#crypto_hash_update_data_inputencoding}
	 * @param {string | Buffer} data data
	 * @param {Encoding=} inputEncoding data encoding
	 * @returns {Hash} updated hash
	 */
	update(data, inputEncoding) {
		if (
			inputEncoding !== undefined ||
			typeof data !== "string" ||
			data.length > BULK_SIZE
		) {
			if (this.hash === undefined) {
				this.hash = /** @type {HashFactory} */ (this.hashFactory)();
			}
			if (this.buffer.length > 0) {
				update(this.hash, this.buffer);
				this.buffer = "";
			}
			if (typeof data === "string" && inputEncoding) {
				update(this.hash, data, inputEncoding);
			} else {
				update(this.hash, data);
			}
		} else {
			this.buffer += data;
			if (this.buffer.length > BULK_SIZE) {
				if (this.hash === undefined) {
					this.hash = /** @type {HashFactory} */ (this.hashFactory)();
				}
				update(this.hash, this.buffer);
				this.buffer = "";
			}
		}
		return this;
	}

	/**
	 * Calculates the digest {@link https://nodejs.org/api/crypto.html#crypto_hash_digest_encoding}
	 * @overload
	 * @returns {Buffer} digest
	 */
	/**
	 * Calculates the digest {@link https://nodejs.org/api/crypto.html#crypto_hash_digest_encoding}
	 * @overload
	 * @param {Encoding} encoding encoding of the return value
	 * @returns {string} digest
	 */
	/**
	 * Calculates the digest {@link https://nodejs.org/api/crypto.html#crypto_hash_digest_encoding}
	 * @param {Encoding=} encoding encoding of the return value
	 * @returns {string | Buffer} digest
	 */
	digest(encoding) {
		/** @type {undefined | Map<string, string | Buffer>} */
		let digestCache;
		const buffer = this.buffer;
		if (this.hash === undefined) {
			// short data for hash, we can use caching
			const cacheKey = `${this.hashKey}-${encoding}`;
			digestCache = digestCaches[cacheKey];
			if (digestCache === undefined) {
				digestCache = digestCaches[cacheKey] = new Map();
			}
			const cacheEntry = digestCache.get(buffer);
			if (cacheEntry !== undefined) return cacheEntry;
			this.hash = /** @type {HashFactory} */ (this.hashFactory)();
		}

		if (buffer.length > 0) {
			update(this.hash, buffer);
		}
		if (!encoding) {
			const result = digest(this.hash, undefined, Boolean(this.hashKey));
			if (digestCache !== undefined) {
				digestCache.set(buffer, result);
			}
			return result;
		}
		const result = digest(this.hash, encoding, Boolean(this.hashKey));
		if (digestCache !== undefined) {
			digestCache.set(buffer, result);
		}
		return result;
	}
}

module.exports = BulkUpdateHash;