webpack/lib/ids/IdHelpers.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 createHash = require("../util/createHash");
const { makePathsRelative } = require("../util/identifier");
const numberHash = require("../util/numberHash");

/** @typedef {import("../Chunk")} Chunk */
/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../Compilation")} Compilation */
/** @typedef {import("../Module")} Module */
/** @typedef {typeof import("../util/Hash")} Hash */

/**
 * @param {string} str string to hash
 * @param {number} len max length of the hash
 * @param {string | Hash} hashFunction hash function to use
 * @returns {string} hash
 */
const getHash = (str, len, hashFunction) => {
	const hash = createHash(hashFunction);
	hash.update(str);
	const digest = /** @type {string} */ (hash.digest("hex"));
	return digest.substr(0, len);
};

/**
 * @param {string} str the string
 * @returns {string} string prefixed by an underscore if it is a number
 */
const avoidNumber = str => {
	// max length of a number is 21 chars, bigger numbers a written as "...e+xx"
	if (str.length > 21) return str;
	const firstChar = str.charCodeAt(0);
	// skip everything that doesn't look like a number
	// charCodes: "-": 45, "1": 49, "9": 57
	if (firstChar < 49) {
		if (firstChar !== 45) return str;
	} else if (firstChar > 57) {
		return str;
	}
	if (str === +str + "") {
		return `_${str}`;
	}
	return str;
};

/**
 * @param {string} request the request
 * @returns {string} id representation
 */
const requestToId = request => {
	return request
		.replace(/^(\.\.?\/)+/, "")
		.replace(/(^[.-]|[^a-zA-Z0-9_-])+/g, "_");
};
exports.requestToId = requestToId;

/**
 * @param {string} string the string
 * @param {string} delimiter separator for string and hash
 * @param {string | Hash} hashFunction hash function to use
 * @returns {string} string with limited max length to 100 chars
 */
const shortenLongString = (string, delimiter, hashFunction) => {
	if (string.length < 100) return string;
	return (
		string.slice(0, 100 - 6 - delimiter.length) +
		delimiter +
		getHash(string, 6, hashFunction)
	);
};

/**
 * @param {Module} module the module
 * @param {string} context context directory
 * @param {Object=} associatedObjectForCache an object to which the cache will be attached
 * @returns {string} short module name
 */
const getShortModuleName = (module, context, associatedObjectForCache) => {
	const libIdent = module.libIdent({ context, associatedObjectForCache });
	if (libIdent) return avoidNumber(libIdent);
	const nameForCondition = module.nameForCondition();
	if (nameForCondition)
		return avoidNumber(
			makePathsRelative(context, nameForCondition, associatedObjectForCache)
		);
	return "";
};
exports.getShortModuleName = getShortModuleName;

/**
 * @param {string} shortName the short name
 * @param {Module} module the module
 * @param {string} context context directory
 * @param {string | Hash} hashFunction hash function to use
 * @param {Object=} associatedObjectForCache an object to which the cache will be attached
 * @returns {string} long module name
 */
const getLongModuleName = (
	shortName,
	module,
	context,
	hashFunction,
	associatedObjectForCache
) => {
	const fullName = getFullModuleName(module, context, associatedObjectForCache);
	return `${shortName}?${getHash(fullName, 4, hashFunction)}`;
};
exports.getLongModuleName = getLongModuleName;

/**
 * @param {Module} module the module
 * @param {string} context context directory
 * @param {Object=} associatedObjectForCache an object to which the cache will be attached
 * @returns {string} full module name
 */
const getFullModuleName = (module, context, associatedObjectForCache) => {
	return makePathsRelative(
		context,
		module.identifier(),
		associatedObjectForCache
	);
};
exports.getFullModuleName = getFullModuleName;

/**
 * @param {Chunk} chunk the chunk
 * @param {ChunkGraph} chunkGraph the chunk graph
 * @param {string} context context directory
 * @param {string} delimiter delimiter for names
 * @param {string | Hash} hashFunction hash function to use
 * @param {Object=} associatedObjectForCache an object to which the cache will be attached
 * @returns {string} short chunk name
 */
const getShortChunkName = (
	chunk,
	chunkGraph,
	context,
	delimiter,
	hashFunction,
	associatedObjectForCache
) => {
	const modules = chunkGraph.getChunkRootModules(chunk);
	const shortModuleNames = modules.map(m =>
		requestToId(getShortModuleName(m, context, associatedObjectForCache))
	);
	chunk.idNameHints.sort();
	const chunkName = Array.from(chunk.idNameHints)
		.concat(shortModuleNames)
		.filter(Boolean)
		.join(delimiter);
	return shortenLongString(chunkName, delimiter, hashFunction);
};
exports.getShortChunkName = getShortChunkName;

/**
 * @param {Chunk} chunk the chunk
 * @param {ChunkGraph} chunkGraph the chunk graph
 * @param {string} context context directory
 * @param {string} delimiter delimiter for names
 * @param {string | Hash} hashFunction hash function to use
 * @param {Object=} associatedObjectForCache an object to which the cache will be attached
 * @returns {string} short chunk name
 */
const getLongChunkName = (
	chunk,
	chunkGraph,
	context,
	delimiter,
	hashFunction,
	associatedObjectForCache
) => {
	const modules = chunkGraph.getChunkRootModules(chunk);
	const shortModuleNames = modules.map(m =>
		requestToId(getShortModuleName(m, context, associatedObjectForCache))
	);
	const longModuleNames = modules.map(m =>
		requestToId(
			getLongModuleName("", m, context, hashFunction, associatedObjectForCache)
		)
	);
	chunk.idNameHints.sort();
	const chunkName = Array.from(chunk.idNameHints)
		.concat(shortModuleNames, longModuleNames)
		.filter(Boolean)
		.join(delimiter);
	return shortenLongString(chunkName, delimiter, hashFunction);
};
exports.getLongChunkName = getLongChunkName;

/**
 * @param {Chunk} chunk the chunk
 * @param {ChunkGraph} chunkGraph the chunk graph
 * @param {string} context context directory
 * @param {Object=} associatedObjectForCache an object to which the cache will be attached
 * @returns {string} full chunk name
 */
const getFullChunkName = (
	chunk,
	chunkGraph,
	context,
	associatedObjectForCache
) => {
	if (chunk.name) return chunk.name;
	const modules = chunkGraph.getChunkRootModules(chunk);
	const fullModuleNames = modules.map(m =>
		makePathsRelative(context, m.identifier(), associatedObjectForCache)
	);
	return fullModuleNames.join();
};
exports.getFullChunkName = getFullChunkName;

/**
 * @template K
 * @template V
 * @param {Map<K, V[]>} map a map from key to values
 * @param {K} key key
 * @param {V} value value
 * @returns {void}
 */
const addToMapOfItems = (map, key, value) => {
	let array = map.get(key);
	if (array === undefined) {
		array = [];
		map.set(key, array);
	}
	array.push(value);
};

/**
 * @param {Compilation} compilation the compilation
 * @returns {Set<string>} used module ids as strings
 */
const getUsedModuleIds = compilation => {
	const chunkGraph = compilation.chunkGraph;

	/** @type {Set<string>} */
	const usedIds = new Set();
	if (compilation.usedModuleIds) {
		for (const id of compilation.usedModuleIds) {
			usedIds.add(id + "");
		}
	}

	for (const module of compilation.modules) {
		const moduleId = chunkGraph.getModuleId(module);
		if (moduleId !== null) {
			usedIds.add(moduleId + "");
		}
	}

	return usedIds;
};
exports.getUsedModuleIds = getUsedModuleIds;

/**
 * @param {Compilation} compilation the compilation
 * @returns {Set<string>} used chunk ids as strings
 */
const getUsedChunkIds = compilation => {
	/** @type {Set<string>} */
	const usedIds = new Set();
	if (compilation.usedChunkIds) {
		for (const id of compilation.usedChunkIds) {
			usedIds.add(id + "");
		}
	}

	for (const chunk of compilation.chunks) {
		const chunkId = chunk.id;
		if (chunkId !== null) {
			usedIds.add(chunkId + "");
		}
	}

	return usedIds;
};
exports.getUsedChunkIds = getUsedChunkIds;

/**
 * @template T
 * @param {Iterable<T>} items list of items to be named
 * @param {function(T): string} getShortName get a short name for an item
 * @param {function(T, string): string} getLongName get a long name for an item
 * @param {function(T, T): -1|0|1} comparator order of items
 * @param {Set<string>} usedIds already used ids, will not be assigned
 * @param {function(T, string): void} assignName assign a name to an item
 * @returns {T[]} list of items without a name
 */
const assignNames = (
	items,
	getShortName,
	getLongName,
	comparator,
	usedIds,
	assignName
) => {
	/** @type {Map<string, T[]>} */
	const nameToItems = new Map();

	for (const item of items) {
		const name = getShortName(item);
		addToMapOfItems(nameToItems, name, item);
	}

	/** @type {Map<string, T[]>} */
	const nameToItems2 = new Map();

	for (const [name, items] of nameToItems) {
		if (items.length > 1 || !name) {
			for (const item of items) {
				const longName = getLongName(item, name);
				addToMapOfItems(nameToItems2, longName, item);
			}
		} else {
			addToMapOfItems(nameToItems2, name, items[0]);
		}
	}

	/** @type {T[]} */
	const unnamedItems = [];

	for (const [name, items] of nameToItems2) {
		if (!name) {
			for (const item of items) {
				unnamedItems.push(item);
			}
		} else if (items.length === 1 && !usedIds.has(name)) {
			assignName(items[0], name);
			usedIds.add(name);
		} else {
			items.sort(comparator);
			let i = 0;
			for (const item of items) {
				while (nameToItems2.has(name + i) && usedIds.has(name + i)) i++;
				assignName(item, name + i);
				usedIds.add(name + i);
				i++;
			}
		}
	}

	unnamedItems.sort(comparator);
	return unnamedItems;
};
exports.assignNames = assignNames;

/**
 * @template T
 * @param {T[]} items list of items to be named
 * @param {function(T): string} getName get a name for an item
 * @param {function(T, T): -1|0|1} comparator order of items
 * @param {function(T, number): boolean} assignId assign an id to an item
 * @param {number[]} ranges usable ranges for ids
 * @param {number} expandFactor factor to create more ranges
 * @param {number} extraSpace extra space to allocate, i. e. when some ids are already used
 * @returns {void}
 */
const assignDeterministicIds = (
	items,
	getName,
	comparator,
	assignId,
	ranges = [10],
	expandFactor = 10,
	extraSpace = 0
) => {
	items.sort(comparator);

	// max 5% fill rate
	const optimalRange = Math.min(
		Math.ceil(items.length * 20) + extraSpace,
		Number.MAX_SAFE_INTEGER
	);

	let i = 0;
	let range = ranges[i];
	while (range < optimalRange) {
		i++;
		if (i < ranges.length) {
			range = Math.min(ranges[i], Number.MAX_SAFE_INTEGER);
		} else {
			range = Math.min(range * expandFactor, Number.MAX_SAFE_INTEGER);
		}
	}

	for (const item of items) {
		const ident = getName(item);
		let id;
		let i = 0;
		do {
			id = numberHash(ident + i++, range);
		} while (!assignId(item, id));
	}
};
exports.assignDeterministicIds = assignDeterministicIds;

/**
 * @param {Iterable<Module>} modules the modules
 * @param {Compilation} compilation the compilation
 * @returns {void}
 */
const assignAscendingModuleIds = (modules, compilation) => {
	const chunkGraph = compilation.chunkGraph;

	const usedIds = getUsedModuleIds(compilation);

	let nextId = 0;
	let assignId;
	if (usedIds.size > 0) {
		assignId = module => {
			if (chunkGraph.getModuleId(module) === null) {
				while (usedIds.has(nextId + "")) nextId++;
				chunkGraph.setModuleId(module, nextId++);
			}
		};
	} else {
		assignId = module => {
			if (chunkGraph.getModuleId(module) === null) {
				chunkGraph.setModuleId(module, nextId++);
			}
		};
	}
	for (const module of modules) {
		assignId(module);
	}
};
exports.assignAscendingModuleIds = assignAscendingModuleIds;

/**
 * @param {Iterable<Chunk>} chunks the chunks
 * @param {Compilation} compilation the compilation
 * @returns {void}
 */
const assignAscendingChunkIds = (chunks, compilation) => {
	const usedIds = getUsedChunkIds(compilation);

	let nextId = 0;
	if (usedIds.size > 0) {
		for (const chunk of chunks) {
			if (chunk.id === null) {
				while (usedIds.has(nextId + "")) nextId++;
				chunk.id = nextId;
				chunk.ids = [nextId];
				nextId++;
			}
		}
	} else {
		for (const chunk of chunks) {
			if (chunk.id === null) {
				chunk.id = nextId;
				chunk.ids = [nextId];
				nextId++;
			}
		}
	}
};
exports.assignAscendingChunkIds = assignAscendingChunkIds;