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node_modules/webpack/lib/util/createHash.js

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+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const Hash = require("./Hash");
+
+const BULK_SIZE = 2000;
+
+// 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
+const digestCaches = {};
+
+class BulkUpdateDecorator extends Hash {
+	/**
+	 * @param {Hash | function(): Hash} hashOrFactory function to create a hash
+	 * @param {string=} hashKey key for caching
+	 */
+	constructor(hashOrFactory, hashKey) {
+		super();
+		this.hashKey = hashKey;
+		if (typeof hashOrFactory === "function") {
+			this.hashFactory = hashOrFactory;
+			this.hash = undefined;
+		} else {
+			this.hashFactory = undefined;
+			this.hash = hashOrFactory;
+		}
+		this.buffer = "";
+	}
+
+	/**
+	 * Update hash {@link https://nodejs.org/api/crypto.html#crypto_hash_update_data_inputencoding}
+	 * @param {string|Buffer} data data
+	 * @param {string=} inputEncoding data encoding
+	 * @returns {this} updated hash
+	 */
+	update(data, inputEncoding) {
+		if (
+			inputEncoding !== undefined ||
+			typeof data !== "string" ||
+			data.length > BULK_SIZE
+		) {
+			if (this.hash === undefined) this.hash = this.hashFactory();
+			if (this.buffer.length > 0) {
+				this.hash.update(this.buffer);
+				this.buffer = "";
+			}
+			this.hash.update(data, inputEncoding);
+		} else {
+			this.buffer += data;
+			if (this.buffer.length > BULK_SIZE) {
+				if (this.hash === undefined) this.hash = this.hashFactory();
+				this.hash.update(this.buffer);
+				this.buffer = "";
+			}
+		}
+		return this;
+	}
+
+	/**
+	 * Calculates the digest {@link https://nodejs.org/api/crypto.html#crypto_hash_digest_encoding}
+	 * @param {string=} encoding encoding of the return value
+	 * @returns {string|Buffer} digest
+	 */
+	digest(encoding) {
+		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 = this.hashFactory();
+		}
+		if (buffer.length > 0) {
+			this.hash.update(buffer);
+		}
+		const digestResult = this.hash.digest(encoding);
+		const result =
+			typeof digestResult === "string" ? digestResult : digestResult.toString();
+		if (digestCache !== undefined) {
+			digestCache.set(buffer, result);
+		}
+		return result;
+	}
+}
+
+/* istanbul ignore next */
+class DebugHash extends Hash {
+	constructor() {
+		super();
+		this.string = "";
+	}
+
+	/**
+	 * Update hash {@link https://nodejs.org/api/crypto.html#crypto_hash_update_data_inputencoding}
+	 * @param {string|Buffer} data data
+	 * @param {string=} inputEncoding data encoding
+	 * @returns {this} updated hash
+	 */
+	update(data, inputEncoding) {
+		if (typeof data !== "string") data = data.toString("utf-8");
+		if (data.startsWith("debug-digest-")) {
+			data = Buffer.from(data.slice("debug-digest-".length), "hex").toString();
+		}
+		this.string += `[${data}](${new Error().stack.split("\n", 3)[2]})\n`;
+		return this;
+	}
+
+	/**
+	 * Calculates the digest {@link https://nodejs.org/api/crypto.html#crypto_hash_digest_encoding}
+	 * @param {string=} encoding encoding of the return value
+	 * @returns {string|Buffer} digest
+	 */
+	digest(encoding) {
+		return "debug-digest-" + Buffer.from(this.string).toString("hex");
+	}
+}
+
+let crypto = undefined;
+let createXXHash64 = undefined;
+let createMd4 = undefined;
+let BatchedHash = undefined;
+
+/**
+ * Creates a hash by name or function
+ * @param {string | typeof Hash} algorithm the algorithm name or a constructor creating a hash
+ * @returns {Hash} the hash
+ */
+module.exports = algorithm => {
+	if (typeof algorithm === "function") {
+		return new BulkUpdateDecorator(() => new algorithm());
+	}
+	switch (algorithm) {
+		// TODO add non-cryptographic algorithm here
+		case "debug":
+			return new DebugHash();
+		case "xxhash64":
+			if (createXXHash64 === undefined) {
+				createXXHash64 = require("./hash/xxhash64");
+				if (BatchedHash === undefined) {
+					BatchedHash = require("./hash/BatchedHash");
+				}
+			}
+			return new BatchedHash(createXXHash64());
+		case "md4":
+			if (createMd4 === undefined) {
+				createMd4 = require("./hash/md4");
+				if (BatchedHash === undefined) {
+					BatchedHash = require("./hash/BatchedHash");
+				}
+			}
+			return new BatchedHash(createMd4());
+		case "native-md4":
+			if (crypto === undefined) crypto = require("crypto");
+			return new BulkUpdateDecorator(() => crypto.createHash("md4"), "md4");
+		default:
+			if (crypto === undefined) crypto = require("crypto");
+			return new BulkUpdateDecorator(
+				() => crypto.createHash(algorithm),
+				algorithm
+			);
+	}
+};