webpack/lib/ModuleGraph.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 util = require("util");
const ExportsInfo = require("./ExportsInfo");
const ModuleGraphConnection = require("./ModuleGraphConnection");
const HarmonyImportDependency = require("./dependencies/HarmonyImportDependency");
const { ImportPhaseUtils } = require("./dependencies/ImportPhase");
const SortableSet = require("./util/SortableSet");
const WeakTupleMap = require("./util/WeakTupleMap");
const { sortWithSourceOrder } = require("./util/comparators");

/** @typedef {import("./Compilation").ModuleMemCaches} ModuleMemCaches */
/** @typedef {import("./DependenciesBlock")} DependenciesBlock */
/** @typedef {import("./Dependency")} Dependency */
/** @typedef {import("./ExportsInfo").ExportInfo} ExportInfo */
/** @typedef {import("./ExportsInfo").ExportInfoName} ExportInfoName */
/** @typedef {import("./Module")} Module */
/** @typedef {import("./ModuleProfile")} ModuleProfile */
/** @typedef {import("./RequestShortener")} RequestShortener */
/** @typedef {import("./util/runtime").RuntimeSpec} RuntimeSpec */
/** @typedef {import("./dependencies/HarmonyImportSideEffectDependency")} HarmonyImportSideEffectDependency */
/** @typedef {import("./dependencies/HarmonyImportSpecifierDependency")} HarmonyImportSpecifierDependency */
/** @typedef {import("./util/comparators").DependencySourceOrder} DependencySourceOrder */

/**
 * Defines the optimization bailout function callback.
 * @callback OptimizationBailoutFunction
 * @param {RequestShortener} requestShortener
 * @returns {string}
 */

/** @type {Iterable<ModuleGraphConnection>} */
const EMPTY_SET = new Set();

/**
 * Gets connections by key.
 * @template {Module | null | undefined} T
 * @param {SortableSet<ModuleGraphConnection>} set input
 * @param {(connection: ModuleGraphConnection) => T} getKey function to extract key from connection
 * @returns {ReadonlyMap<T, ReadonlyArray<ModuleGraphConnection>>} mapped by key
 */
const getConnectionsByKey = (set, getKey) => {
	/** @type {Map<T, ModuleGraphConnection[]>} */
	const map = new Map();
	/** @type {T | 0} */
	let lastKey = 0;
	/** @type {ModuleGraphConnection[] | undefined} */
	let lastList;
	for (const connection of set) {
		const key = getKey(connection);
		if (lastKey === key) {
			/** @type {ModuleGraphConnection[]} */
			(lastList).push(connection);
		} else {
			lastKey = key;
			const list = map.get(key);
			if (list !== undefined) {
				lastList = list;
				list.push(connection);
			} else {
				const list = [connection];
				lastList = list;
				map.set(key, list);
			}
		}
	}
	return map;
};

/**
 * Gets connections by origin module.
 * @param {SortableSet<ModuleGraphConnection>} set input
 * @returns {ReadonlyMap<Module | undefined | null, ReadonlyArray<ModuleGraphConnection>>} mapped by origin module
 */
const getConnectionsByOriginModule = (set) =>
	getConnectionsByKey(set, (connection) => connection.originModule);

/**
 * Gets connections by module.
 * @param {SortableSet<ModuleGraphConnection>} set input
 * @returns {ReadonlyMap<Module | undefined, ReadonlyArray<ModuleGraphConnection>>} mapped by module
 */
const getConnectionsByModule = (set) =>
	getConnectionsByKey(set, (connection) => connection.module);

/** @typedef {SortableSet<ModuleGraphConnection>} IncomingConnections */
/** @typedef {SortableSet<ModuleGraphConnection>} OutgoingConnections */
/** @typedef {Module | null | undefined} Issuer */
/** @typedef {(string | OptimizationBailoutFunction)[]} OptimizationBailouts */

class ModuleGraphModule {
	constructor() {
		/** @type {IncomingConnections} */
		this.incomingConnections = new SortableSet();
		/** @type {OutgoingConnections | undefined} */
		this.outgoingConnections = undefined;
		/** @type {Issuer} */
		this.issuer = undefined;
		/** @type {OptimizationBailouts} */
		this.optimizationBailout = [];
		/** @type {ExportsInfo} */
		this.exports = new ExportsInfo();
		/** @type {number | null} */
		this.preOrderIndex = null;
		/** @type {number | null} */
		this.postOrderIndex = null;
		/** @type {number | null} */
		this.depth = null;
		/** @type {ModuleProfile | undefined} */
		this.profile = undefined;
		/** @type {boolean} */
		this.async = false;
		/** @type {ModuleGraphConnection[] | undefined} */
		this._unassignedConnections = undefined;
	}
}

/** @typedef {(moduleGraphConnection: ModuleGraphConnection) => boolean} FilterConnection */

/** @typedef {EXPECTED_OBJECT} MetaKey */

/** @typedef {import("./dependencies/CommonJsExportRequireDependency").idsSymbol} CommonJsExportRequireDependencyIDsSymbol */
/** @typedef {import("./dependencies/HarmonyImportSpecifierDependency").idsSymbol} HarmonyImportSpecifierDependencyIDsSymbol */
/** @typedef {import("./dependencies/HarmonyExportImportedSpecifierDependency").idsSymbol} HarmonyExportImportedSpecifierDependencyIDsSymbol */

/**
 * Defines the known meta type used by this module.
 * @typedef {object} KnownMeta
 * @property {Map<Module, string>=} importVarMap
 * @property {Map<Module, string>=} deferredImportVarMap
 */

/** @typedef {KnownMeta & Record<CommonJsExportRequireDependencyIDsSymbol | HarmonyImportSpecifierDependencyIDsSymbol | HarmonyExportImportedSpecifierDependencyIDsSymbol, string[]> & Record<string, EXPECTED_ANY>} Meta */

class ModuleGraph {
	constructor() {
		/**
		 * @type {WeakMap<Dependency, ModuleGraphConnection | null>}
		 * @private
		 */
		this._dependencyMap = new WeakMap();
		/**
		 * @type {Map<Module, ModuleGraphModule>}
		 * @private
		 */
		this._moduleMap = new Map();
		/**
		 * @type {WeakMap<MetaKey, Meta>}
		 * @private
		 */
		this._metaMap = new WeakMap();
		/**
		 * @type {WeakTupleMap<EXPECTED_ANY[], EXPECTED_ANY> | undefined}
		 * @private
		 */
		this._cache = undefined;
		/**
		 * @type {ModuleMemCaches | undefined}
		 * @private
		 */
		this._moduleMemCaches = undefined;

		/**
		 * @type {string | undefined}
		 * @private
		 */
		this._cacheStage = undefined;

		/**
		 * @type {WeakMap<Dependency, DependencySourceOrder>}
		 * @private
		 */
		this._dependencySourceOrderMap = new WeakMap();

		/**
		 * @type {Set<Module>}
		 * @private
		 */
		this._modulesNeedingSort = new Set();
	}

	/**
	 * Get module graph module.
	 * @param {Module} module the module
	 * @returns {ModuleGraphModule} the internal module
	 */
	_getModuleGraphModule(module) {
		let mgm = this._moduleMap.get(module);
		if (mgm === undefined) {
			mgm = new ModuleGraphModule();
			this._moduleMap.set(module, mgm);
		}
		return mgm;
	}

	/**
	 * Updates parents using the provided dependency.
	 * @param {Dependency} dependency the dependency
	 * @param {DependenciesBlock} block parent block
	 * @param {Module} module parent module
	 * @param {number=} indexInBlock position in block
	 * @returns {void}
	 */
	setParents(dependency, block, module, indexInBlock = -1) {
		dependency._parentDependenciesBlockIndex = indexInBlock;
		dependency._parentDependenciesBlock = block;
		dependency._parentModule = module;
	}

	/**
	 * Sets parent dependencies block index.
	 * @param {Dependency} dependency the dependency
	 * @param {number} index the index
	 * @returns {void}
	 */
	setParentDependenciesBlockIndex(dependency, index) {
		dependency._parentDependenciesBlockIndex = index;
	}

	/**
	 * Gets parent module.
	 * @param {Dependency} dependency the dependency
	 * @returns {Module | undefined} parent module
	 */
	getParentModule(dependency) {
		return dependency._parentModule;
	}

	/**
	 * Returns parent block.
	 * @param {Dependency} dependency the dependency
	 * @returns {DependenciesBlock | undefined} parent block
	 */
	getParentBlock(dependency) {
		return dependency._parentDependenciesBlock;
	}

	/**
	 * Gets parent block index.
	 * @param {Dependency} dependency the dependency
	 * @returns {number} index
	 */
	getParentBlockIndex(dependency) {
		return dependency._parentDependenciesBlockIndex;
	}

	/**
	 * Sets resolved module.
	 * @param {Module | null} originModule the referencing module
	 * @param {Dependency} dependency the referencing dependency
	 * @param {Module} module the referenced module
	 * @returns {void}
	 */
	setResolvedModule(originModule, dependency, module) {
		const connection = new ModuleGraphConnection(
			originModule,
			dependency,
			module,
			undefined,
			dependency.weak,
			dependency.getCondition(this)
		);
		const connections = this._getModuleGraphModule(module).incomingConnections;
		connections.add(connection);
		if (originModule) {
			const mgm = this._getModuleGraphModule(originModule);
			if (mgm._unassignedConnections === undefined) {
				mgm._unassignedConnections = [];
			}
			mgm._unassignedConnections.push(connection);
			if (mgm.outgoingConnections === undefined) {
				mgm.outgoingConnections = new SortableSet();
			}
			mgm.outgoingConnections.add(connection);
		} else {
			this._dependencyMap.set(dependency, connection);
		}
	}

	/**
	 * Updates module using the provided dependency.
	 * @param {Dependency} dependency the referencing dependency
	 * @param {Module} module the referenced module
	 * @returns {void}
	 */
	updateModule(dependency, module) {
		const connection =
			/** @type {ModuleGraphConnection} */
			(this.getConnection(dependency));
		if (connection.module === module) return;
		const newConnection = connection.clone();
		newConnection.module = module;
		this._dependencyMap.set(dependency, newConnection);
		connection.setActive(false);
		const originMgm = this._getModuleGraphModule(
			/** @type {Module} */ (connection.originModule)
		);
		/** @type {OutgoingConnections} */
		(originMgm.outgoingConnections).add(newConnection);
		const targetMgm = this._getModuleGraphModule(module);
		targetMgm.incomingConnections.add(newConnection);
	}

	/**
	 * Updates parent using the provided dependency.
	 * @param {Dependency} dependency the need update dependency
	 * @param {ModuleGraphConnection=} connection the target connection
	 * @param {Module=} parentModule the parent module
	 * @returns {void}
	 */
	updateParent(dependency, connection, parentModule) {
		if (this._dependencySourceOrderMap.has(dependency)) {
			return;
		}
		if (!connection || !parentModule) {
			return;
		}
		const originDependency = connection.dependency;

		// src/index.js
		// import { c } from "lib/c" -> c = 0
		// import { a, b } from "lib" -> a and b have the same source order -> a = b = 1
		// import { d } from "lib/d" -> d = 2
		const currentSourceOrder =
			/** @type {HarmonyImportSideEffectDependency | HarmonyImportSpecifierDependency} */
			(dependency).sourceOrder;

		// lib/index.js (reexport)
		// import { a } from "lib/a" -> a = 0
		// import { b } from "lib/b" -> b = 1
		const originSourceOrder =
			/** @type {HarmonyImportSideEffectDependency | HarmonyImportSpecifierDependency} */
			(originDependency).sourceOrder;
		if (
			typeof currentSourceOrder === "number" &&
			typeof originSourceOrder === "number"
		) {
			// src/index.js
			// import { c } from "lib/c" -> c = 0
			// import { a } from "lib/a" -> a = 1.0 = 1(main) + 0.0(sub)
			// import { b } from "lib/b" -> b = 1.1 = 1(main) + 0.1(sub)
			// import { d } from "lib/d" -> d = 2
			this._dependencySourceOrderMap.set(dependency, {
				main: currentSourceOrder,
				sub: originSourceOrder
			});

			// Save for later batch sorting
			this._modulesNeedingSort.add(parentModule);
		}
	}

	/**
	 * Finish update parent.
	 * @returns {void}
	 */
	finishUpdateParent() {
		if (this._modulesNeedingSort.size === 0) {
			return;
		}
		for (const mod of this._modulesNeedingSort) {
			// If dependencies like HarmonyImportSideEffectDependency and HarmonyImportSpecifierDependency have a SourceOrder,
			// we sort based on it; otherwise, we preserve the original order.
			sortWithSourceOrder(
				mod.dependencies,
				this._dependencySourceOrderMap,
				(dep, index) => this.setParentDependenciesBlockIndex(dep, index)
			);
		}
		this._modulesNeedingSort.clear();
	}

	/**
	 * Removes connection.
	 * @param {Dependency} dependency the referencing dependency
	 * @returns {void}
	 */
	removeConnection(dependency) {
		const connection =
			/** @type {ModuleGraphConnection} */
			(this.getConnection(dependency));
		const targetMgm = this._getModuleGraphModule(connection.module);
		targetMgm.incomingConnections.delete(connection);
		const originMgm = this._getModuleGraphModule(
			/** @type {Module} */ (connection.originModule)
		);
		/** @type {OutgoingConnections} */
		(originMgm.outgoingConnections).delete(connection);
		this._dependencyMap.set(dependency, null);
	}

	/**
	 * Adds the provided dependency to the module graph.
	 * @param {Dependency} dependency the referencing dependency
	 * @param {string} explanation an explanation
	 * @returns {void}
	 */
	addExplanation(dependency, explanation) {
		const connection =
			/** @type {ModuleGraphConnection} */
			(this.getConnection(dependency));
		connection.addExplanation(explanation);
	}

	/**
	 * Clones module attributes.
	 * @param {Module} sourceModule the source module
	 * @param {Module} targetModule the target module
	 * @returns {void}
	 */
	cloneModuleAttributes(sourceModule, targetModule) {
		const oldMgm = this._getModuleGraphModule(sourceModule);
		const newMgm = this._getModuleGraphModule(targetModule);
		newMgm.postOrderIndex = oldMgm.postOrderIndex;
		newMgm.preOrderIndex = oldMgm.preOrderIndex;
		newMgm.depth = oldMgm.depth;
		newMgm.exports = oldMgm.exports;
		newMgm.async = oldMgm.async;
	}

	/**
	 * Removes module attributes.
	 * @param {Module} module the module
	 * @returns {void}
	 */
	removeModuleAttributes(module) {
		const mgm = this._getModuleGraphModule(module);
		mgm.postOrderIndex = null;
		mgm.preOrderIndex = null;
		mgm.depth = null;
		mgm.async = false;
	}

	/**
	 * Removes all module attributes.
	 * @returns {void}
	 */
	removeAllModuleAttributes() {
		for (const mgm of this._moduleMap.values()) {
			mgm.postOrderIndex = null;
			mgm.preOrderIndex = null;
			mgm.depth = null;
			mgm.async = false;
		}
	}

	/**
	 * Move module connections.
	 * @param {Module} oldModule the old referencing module
	 * @param {Module} newModule the new referencing module
	 * @param {FilterConnection} filterConnection filter predicate for replacement
	 * @returns {void}
	 */
	moveModuleConnections(oldModule, newModule, filterConnection) {
		if (oldModule === newModule) return;
		const oldMgm = this._getModuleGraphModule(oldModule);
		const newMgm = this._getModuleGraphModule(newModule);
		// Outgoing connections
		const oldConnections = oldMgm.outgoingConnections;
		if (oldConnections !== undefined) {
			if (newMgm.outgoingConnections === undefined) {
				newMgm.outgoingConnections = new SortableSet();
			}
			const newConnections = newMgm.outgoingConnections;
			for (const connection of oldConnections) {
				if (filterConnection(connection)) {
					connection.originModule = newModule;
					newConnections.add(connection);
					oldConnections.delete(connection);
				}
			}
		}
		// Incoming connections
		const oldConnections2 = oldMgm.incomingConnections;
		const newConnections2 = newMgm.incomingConnections;
		for (const connection of oldConnections2) {
			if (filterConnection(connection)) {
				connection.module = newModule;
				newConnections2.add(connection);
				oldConnections2.delete(connection);
			}
		}
	}

	/**
	 * Copies outgoing module connections.
	 * @param {Module} oldModule the old referencing module
	 * @param {Module} newModule the new referencing module
	 * @param {FilterConnection} filterConnection filter predicate for replacement
	 * @returns {void}
	 */
	copyOutgoingModuleConnections(oldModule, newModule, filterConnection) {
		if (oldModule === newModule) return;
		const oldMgm = this._getModuleGraphModule(oldModule);
		const newMgm = this._getModuleGraphModule(newModule);
		// Outgoing connections
		const oldConnections = oldMgm.outgoingConnections;
		if (oldConnections !== undefined) {
			if (newMgm.outgoingConnections === undefined) {
				newMgm.outgoingConnections = new SortableSet();
			}
			const newConnections = newMgm.outgoingConnections;
			for (const connection of oldConnections) {
				if (filterConnection(connection)) {
					const newConnection = connection.clone();
					newConnection.originModule = newModule;
					newConnections.add(newConnection);
					if (newConnection.module !== undefined) {
						const otherMgm = this._getModuleGraphModule(newConnection.module);
						otherMgm.incomingConnections.add(newConnection);
					}
				}
			}
		}
	}

	/**
	 * Adds the provided module to the module graph.
	 * @param {Module} module the referenced module
	 * @param {string} explanation an explanation why it's referenced
	 * @returns {void}
	 */
	addExtraReason(module, explanation) {
		const connections = this._getModuleGraphModule(module).incomingConnections;
		connections.add(new ModuleGraphConnection(null, null, module, explanation));
	}

	/**
	 * Gets resolved module.
	 * @param {Dependency} dependency the dependency to look for a referenced module
	 * @returns {Module | null} the referenced module
	 */
	getResolvedModule(dependency) {
		const connection = this.getConnection(dependency);
		return connection !== undefined ? connection.resolvedModule : null;
	}

	/**
	 * Returns the connection.
	 * @param {Dependency} dependency the dependency to look for a referenced module
	 * @returns {ModuleGraphConnection | undefined} the connection
	 */
	getConnection(dependency) {
		const connection = this._dependencyMap.get(dependency);
		if (connection === undefined) {
			const module = this.getParentModule(dependency);
			if (module !== undefined) {
				const mgm = this._getModuleGraphModule(module);
				if (
					mgm._unassignedConnections &&
					mgm._unassignedConnections.length !== 0
				) {
					/** @type {undefined | ModuleGraphConnection} */
					let foundConnection;
					for (const connection of mgm._unassignedConnections) {
						this._dependencyMap.set(
							/** @type {Dependency} */ (connection.dependency),
							connection
						);
						if (connection.dependency === dependency) {
							foundConnection = connection;
						}
					}
					mgm._unassignedConnections.length = 0;
					if (foundConnection !== undefined) {
						return foundConnection;
					}
				}
			}
			this._dependencyMap.set(dependency, null);
			return;
		}
		return connection === null ? undefined : connection;
	}

	/**
	 * Returns the referenced module.
	 * @param {Dependency} dependency the dependency to look for a referenced module
	 * @returns {Module | null} the referenced module
	 */
	getModule(dependency) {
		const connection = this.getConnection(dependency);
		return connection !== undefined ? connection.module : null;
	}

	/**
	 * Returns the referencing module.
	 * @param {Dependency} dependency the dependency to look for a referencing module
	 * @returns {Module | null} the referencing module
	 */
	getOrigin(dependency) {
		const connection = this.getConnection(dependency);
		return connection !== undefined ? connection.originModule : null;
	}

	/**
	 * Gets resolved origin.
	 * @param {Dependency} dependency the dependency to look for a referencing module
	 * @returns {Module | null} the original referencing module
	 */
	getResolvedOrigin(dependency) {
		const connection = this.getConnection(dependency);
		return connection !== undefined ? connection.resolvedOriginModule : null;
	}

	/**
	 * Gets incoming connections.
	 * @param {Module} module the module
	 * @returns {Iterable<ModuleGraphConnection>} reasons why a module is included
	 */
	getIncomingConnections(module) {
		const connections = this._getModuleGraphModule(module).incomingConnections;
		return connections;
	}

	/**
	 * Gets outgoing connections.
	 * @param {Module} module the module
	 * @returns {Iterable<ModuleGraphConnection>} list of outgoing connections
	 */
	getOutgoingConnections(module) {
		const connections = this._getModuleGraphModule(module).outgoingConnections;
		return connections === undefined ? EMPTY_SET : connections;
	}

	/**
	 * Gets incoming connections by origin module.
	 * @param {Module} module the module
	 * @returns {ReadonlyMap<Module | undefined | null, ReadonlyArray<ModuleGraphConnection>>} reasons why a module is included, in a map by source module
	 */
	getIncomingConnectionsByOriginModule(module) {
		const connections = this._getModuleGraphModule(module).incomingConnections;
		return connections.getFromUnorderedCache(getConnectionsByOriginModule);
	}

	/**
	 * Gets outgoing connections by module.
	 * @param {Module} module the module
	 * @returns {ReadonlyMap<Module | undefined, ReadonlyArray<ModuleGraphConnection>> | undefined} connections to modules, in a map by module
	 */
	getOutgoingConnectionsByModule(module) {
		const connections = this._getModuleGraphModule(module).outgoingConnections;
		return connections === undefined
			? undefined
			: connections.getFromUnorderedCache(getConnectionsByModule);
	}

	/**
	 * Returns the module profile.
	 * @param {Module} module the module
	 * @returns {ModuleProfile | undefined} the module profile
	 */
	getProfile(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.profile;
	}

	/**
	 * Updates profile using the provided module.
	 * @param {Module} module the module
	 * @param {ModuleProfile | undefined} profile the module profile
	 * @returns {void}
	 */
	setProfile(module, profile) {
		const mgm = this._getModuleGraphModule(module);
		mgm.profile = profile;
	}

	/**
	 * Returns the issuer module.
	 * @param {Module} module the module
	 * @returns {Issuer} the issuer module
	 */
	getIssuer(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.issuer;
	}

	/**
	 * Updates issuer using the provided module.
	 * @param {Module} module the module
	 * @param {Module | null} issuer the issuer module
	 * @returns {void}
	 */
	setIssuer(module, issuer) {
		const mgm = this._getModuleGraphModule(module);
		mgm.issuer = issuer;
	}

	/**
	 * Sets issuer if unset.
	 * @param {Module} module the module
	 * @param {Module | null} issuer the issuer module
	 * @returns {void}
	 */
	setIssuerIfUnset(module, issuer) {
		const mgm = this._getModuleGraphModule(module);
		if (mgm.issuer === undefined) mgm.issuer = issuer;
	}

	/**
	 * Gets optimization bailout.
	 * @param {Module} module the module
	 * @returns {OptimizationBailouts} optimization bailouts
	 */
	getOptimizationBailout(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.optimizationBailout;
	}

	/**
	 * Gets provided exports.
	 * @param {Module} module the module
	 * @returns {null | true | ExportInfoName[]} the provided exports
	 */
	getProvidedExports(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.exports.getProvidedExports();
	}

	/**
	 * Checks whether this module graph is export provided.
	 * @param {Module} module the module
	 * @param {ExportInfoName | ExportInfoName[]} exportName a name of an export
	 * @returns {boolean | null} true, if the export is provided by the module.
	 * null, if it's unknown.
	 * false, if it's not provided.
	 */
	isExportProvided(module, exportName) {
		const mgm = this._getModuleGraphModule(module);
		const result = mgm.exports.isExportProvided(exportName);
		return result === undefined ? null : result;
	}

	/**
	 * Returns info about the exports.
	 * @param {Module} module the module
	 * @returns {ExportsInfo} info about the exports
	 */
	getExportsInfo(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.exports;
	}

	/**
	 * Returns info about the export.
	 * @param {Module} module the module
	 * @param {string} exportName the export
	 * @returns {ExportInfo} info about the export
	 */
	getExportInfo(module, exportName) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.exports.getExportInfo(exportName);
	}

	/**
	 * Gets read only export info.
	 * @param {Module} module the module
	 * @param {string} exportName the export
	 * @returns {ExportInfo} info about the export (do not modify)
	 */
	getReadOnlyExportInfo(module, exportName) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.exports.getReadOnlyExportInfo(exportName);
	}

	/**
	 * Returns the used exports.
	 * @param {Module} module the module
	 * @param {RuntimeSpec} runtime the runtime
	 * @returns {false | true | SortableSet<string> | null} the used exports
	 * false: module is not used at all.
	 * true: the module namespace/object export is used.
	 * SortableSet<string>: these export names are used.
	 * empty SortableSet<string>: module is used but no export.
	 * null: unknown, worst case should be assumed.
	 */
	getUsedExports(module, runtime) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.exports.getUsedExports(runtime);
	}

	/**
	 * Gets pre order index.
	 * @param {Module} module the module
	 * @returns {number | null} the index of the module
	 */
	getPreOrderIndex(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.preOrderIndex;
	}

	/**
	 * Gets post order index.
	 * @param {Module} module the module
	 * @returns {number | null} the index of the module
	 */
	getPostOrderIndex(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.postOrderIndex;
	}

	/**
	 * Sets pre order index.
	 * @param {Module} module the module
	 * @param {number} index the index of the module
	 * @returns {void}
	 */
	setPreOrderIndex(module, index) {
		const mgm = this._getModuleGraphModule(module);
		mgm.preOrderIndex = index;
	}

	/**
	 * Sets pre order index if unset.
	 * @param {Module} module the module
	 * @param {number} index the index of the module
	 * @returns {boolean} true, if the index was set
	 */
	setPreOrderIndexIfUnset(module, index) {
		const mgm = this._getModuleGraphModule(module);
		if (mgm.preOrderIndex === null) {
			mgm.preOrderIndex = index;
			return true;
		}
		return false;
	}

	/**
	 * Sets post order index.
	 * @param {Module} module the module
	 * @param {number} index the index of the module
	 * @returns {void}
	 */
	setPostOrderIndex(module, index) {
		const mgm = this._getModuleGraphModule(module);
		mgm.postOrderIndex = index;
	}

	/**
	 * Sets post order index if unset.
	 * @param {Module} module the module
	 * @param {number} index the index of the module
	 * @returns {boolean} true, if the index was set
	 */
	setPostOrderIndexIfUnset(module, index) {
		const mgm = this._getModuleGraphModule(module);
		if (mgm.postOrderIndex === null) {
			mgm.postOrderIndex = index;
			return true;
		}
		return false;
	}

	/**
	 * Returns the depth of the module.
	 * @param {Module} module the module
	 * @returns {number | null} the depth of the module
	 */
	getDepth(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.depth;
	}

	/**
	 * Updates depth using the provided module.
	 * @param {Module} module the module
	 * @param {number} depth the depth of the module
	 * @returns {void}
	 */
	setDepth(module, depth) {
		const mgm = this._getModuleGraphModule(module);
		mgm.depth = depth;
	}

	/**
	 * Sets depth if lower.
	 * @param {Module} module the module
	 * @param {number} depth the depth of the module
	 * @returns {boolean} true, if the depth was set
	 */
	setDepthIfLower(module, depth) {
		const mgm = this._getModuleGraphModule(module);
		if (mgm.depth === null || mgm.depth > depth) {
			mgm.depth = depth;
			return true;
		}
		return false;
	}

	/**
	 * Checks whether this module graph is async.
	 * @param {Module} module the module
	 * @returns {boolean} true, if the module is async
	 */
	isAsync(module) {
		const mgm = this._getModuleGraphModule(module);
		return mgm.async;
	}

	/**
	 * Checks whether this module graph is deferred.
	 * @param {Module} module the module
	 * @returns {boolean} true, if the module is used as a deferred module at least once
	 */
	isDeferred(module) {
		if (this.isAsync(module)) return false;
		const connections = this.getIncomingConnections(module);
		for (const connection of connections) {
			if (
				!connection.dependency ||
				!(connection.dependency instanceof HarmonyImportDependency)
			) {
				continue;
			}
			if (ImportPhaseUtils.isDefer(connection.dependency.phase)) return true;
		}
		return false;
	}

	/**
	 * Updates async using the provided module.
	 * @param {Module} module the module
	 * @returns {void}
	 */
	setAsync(module) {
		const mgm = this._getModuleGraphModule(module);
		mgm.async = true;
	}

	/**
	 * Returns metadata.
	 * @param {MetaKey} thing any thing
	 * @returns {Meta} metadata
	 */
	getMeta(thing) {
		let meta = this._metaMap.get(thing);
		if (meta === undefined) {
			meta = /** @type {Meta} */ (Object.create(null));
			this._metaMap.set(thing, meta);
		}
		return meta;
	}

	/**
	 * Gets meta if existing.
	 * @param {MetaKey} thing any thing
	 * @returns {Meta | undefined} metadata
	 */
	getMetaIfExisting(thing) {
		return this._metaMap.get(thing);
	}

	/**
	 * Processes the provided cache stage.
	 * @param {string=} cacheStage a persistent stage name for caching
	 */
	freeze(cacheStage) {
		this._cache = new WeakTupleMap();
		this._cacheStage = cacheStage;
	}

	unfreeze() {
		this._cache = undefined;
		this._cacheStage = undefined;
	}

	/**
	 * Returns computed value or cached.
	 * @template {EXPECTED_ANY[]} T
	 * @template R
	 * @param {(moduleGraph: ModuleGraph, ...args: T) => R} fn computer
	 * @param {T} args arguments
	 * @returns {R} computed value or cached
	 */
	cached(fn, ...args) {
		if (this._cache === undefined) return fn(this, ...args);
		return this._cache.provide(fn, ...args, () => fn(this, ...args));
	}

	/**
	 * Sets module mem caches.
	 * @param {ModuleMemCaches} moduleMemCaches mem caches for modules for better caching
	 */
	setModuleMemCaches(moduleMemCaches) {
		this._moduleMemCaches = moduleMemCaches;
	}

	/**
	 * Dependency cache provide.
	 * @template {Dependency} D
	 * @template {EXPECTED_ANY[]} ARGS
	 * @template R
	 * @param {D} dependency dependency
	 * @param {[...ARGS, (moduleGraph: ModuleGraph, dependency: D, ...args: ARGS) => R]} args arguments, last argument is a function called with moduleGraph, dependency, ...args
	 * @returns {R} computed value or cached
	 */
	dependencyCacheProvide(dependency, ...args) {
		const fn =
			/** @type {(moduleGraph: ModuleGraph, dependency: D, ...args: EXPECTED_ANY[]) => R} */
			(args.pop());
		if (this._moduleMemCaches && this._cacheStage) {
			const memCache = this._moduleMemCaches.get(
				/** @type {Module} */
				(this.getParentModule(dependency))
			);
			if (memCache !== undefined) {
				return memCache.provide(dependency, this._cacheStage, ...args, () =>
					fn(this, dependency, ...args)
				);
			}
		}
		if (this._cache === undefined) return fn(this, dependency, ...args);
		return this._cache.provide(dependency, ...args, () =>
			fn(this, dependency, ...args)
		);
	}

	// TODO remove in webpack 6
	/**
	 * Gets module graph for module.
	 * @deprecated
	 * @param {Module} module the module
	 * @param {string} deprecateMessage message for the deprecation message
	 * @param {string} deprecationCode code for the deprecation
	 * @returns {ModuleGraph} the module graph
	 */
	static getModuleGraphForModule(module, deprecateMessage, deprecationCode) {
		const fn = deprecateMap.get(deprecateMessage);
		if (fn) return fn(module);
		const newFn = util.deprecate(
			/**
			 * Handles the callback logic for this hook.
			 * @param {Module} module the module
			 * @returns {ModuleGraph} the module graph
			 */
			(module) => {
				const moduleGraph = moduleGraphForModuleMap.get(module);
				if (!moduleGraph) {
					throw new Error(
						`${
							deprecateMessage
						}There was no ModuleGraph assigned to the Module for backward-compat (Use the new API)`
					);
				}
				return moduleGraph;
			},
			`${deprecateMessage}: Use new ModuleGraph API`,
			deprecationCode
		);
		deprecateMap.set(deprecateMessage, newFn);
		return newFn(module);
	}

	// TODO remove in webpack 6
	/**
	 * Sets module graph for module.
	 * @deprecated
	 * @param {Module} module the module
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @returns {void}
	 */
	static setModuleGraphForModule(module, moduleGraph) {
		moduleGraphForModuleMap.set(module, moduleGraph);
	}

	// TODO remove in webpack 6
	/**
	 * Clear module graph for module.
	 * @deprecated
	 * @param {Module} module the module
	 * @returns {void}
	 */
	static clearModuleGraphForModule(module) {
		moduleGraphForModuleMap.delete(module);
	}
}

// TODO remove in webpack 6
/** @type {WeakMap<Module, ModuleGraph>} */
const moduleGraphForModuleMap = new WeakMap();

// TODO remove in webpack 6
/** @type {Map<string, (module: Module) => ModuleGraph>} */
const deprecateMap = new Map();

module.exports = ModuleGraph;
module.exports.ModuleGraphConnection = ModuleGraphConnection;