FM / lib

/var/www/flurhymez/node_modules/webpack/lib/

/var/www/flurhymez/node_modules/webpack/lib

Name	Size	Mode	Actions
asset/	-	0755	rm
async-modules/	-	0755	rm
cache/	-	0755	rm
config/	-	0755	rm
container/	-	0755	rm
debug/	-	0755	rm
dependencies/	-	0755	rm
electron/	-	0755	rm
errors/	-	0755	rm
esm/	-	0755	rm
hmr/	-	0755	rm
ids/	-	0755	rm
javascript/	-	0755	rm
json/	-	0755	rm
library/	-	0755	rm
logging/	-	0755	rm
node/	-	0755	rm
optimize/	-	0755	rm
performance/	-	0755	rm
prefetch/	-	0755	rm
rules/	-	0755	rm
runtime/	-	0755	rm
schemes/	-	0755	rm
serialization/	-	0755	rm
sharing/	-	0755	rm
stats/	-	0755	rm
util/	-	0755	rm
wasm/	-	0755	rm
wasm-async/	-	0755	rm
wasm-sync/	-	0755	rm
web/	-	0755	rm
webworker/	-	0755	rm
AbstractMethodError.js	1133	0644	edit dl rm
APIPlugin.js	5835	0644	edit dl rm
AsyncDependenciesBlock.js	2930	0644	edit dl rm
AsyncDependencyToInitialChunkError.js	913	0644	edit dl rm
AutomaticPrefetchPlugin.js	1491	0644	edit dl rm
BannerPlugin.js	2755	0644	edit dl rm
buildChunkGraph.js	44463	0644	edit dl rm
Cache.js	3967	0644	edit dl rm
CacheFacade.js	8676	0644	edit dl rm
CaseSensitiveModulesWarning.js	2106	0644	edit dl rm
Chunk.js	21501	0644	edit dl rm
ChunkGraph.js	50519	0644	edit dl rm
ChunkGroup.js	15121	0644	edit dl rm
ChunkRenderError.js	657	0644	edit dl rm
ChunkTemplate.js	3992	0644	edit dl rm
CleanPlugin.js	9943	0644	edit dl rm
cli.js	15619	0644	edit dl rm
CodeGenerationError.js	619	0644	edit dl rm
CodeGenerationResults.js	4463	0644	edit dl rm
CommentCompilationWarning.js	729	0644	edit dl rm
CompatibilityPlugin.js	4645	0644	edit dl rm
Compilation.js	159031	0644	edit dl rm
Compiler.js	34663	0644	edit dl rm
ConcatenationScope.js	4636	0644	edit dl rm
ConcurrentCompilationError.js	441	0644	edit dl rm
ConditionalInitFragment.js	3445	0644	edit dl rm
ConstPlugin.js	14769	0644	edit dl rm
ContextExclusionPlugin.js	797	0644	edit dl rm
ContextModule.js	32377	0644	edit dl rm
ContextModuleFactory.js	11185	0644	edit dl rm
ContextReplacementPlugin.js	4720	0644	edit dl rm
DefinePlugin.js	16671	0644	edit dl rm
DelegatedModule.js	7237	0644	edit dl rm
DelegatedModuleFactoryPlugin.js	2337	0644	edit dl rm
DelegatedPlugin.js	1015	0644	edit dl rm
DependenciesBlock.js	2589	0644	edit dl rm
Dependency.js	9338	0644	edit dl rm
DependencyTemplate.js	2094	0644	edit dl rm
DependencyTemplates.js	1716	0644	edit dl rm
DllEntryPlugin.js	1277	0644	edit dl rm
DllModule.js	4493	0644	edit dl rm
DllModuleFactory.js	1008	0644	edit dl rm
DllPlugin.js	1702	0644	edit dl rm
DllReferencePlugin.js	5132	0644	edit dl rm
DynamicEntryPlugin.js	2035	0644	edit dl rm
EntryOptionPlugin.js	2779	0644	edit dl rm
EntryPlugin.js	1737	0644	edit dl rm
Entrypoint.js	3025	0644	edit dl rm
EnvironmentPlugin.js	1743	0644	edit dl rm
ErrorHelpers.js	1454	0644	edit dl rm
EvalDevToolModulePlugin.js	3296	0644	edit dl rm
EvalSourceMapDevToolPlugin.js	6335	0644	edit dl rm
ExportsInfo.js	43994	0644	edit dl rm
ExportsInfoApiPlugin.js	2072	0644	edit dl rm
ExternalModule.js	21521	0644	edit dl rm
ExternalModuleFactoryPlugin.js	7219	0644	edit dl rm
ExternalsPlugin.js	899	0644	edit dl rm
FileSystemInfo.js	103021	0644	edit dl rm
FlagAllModulesAsUsedPlugin.js	1451	0644	edit dl rm
FlagDependencyExportsPlugin.js	13222	0644	edit dl rm
FlagDependencyUsagePlugin.js	10998	0644	edit dl rm
FlagEntryExportAsUsedPlugin.js	1373	0644	edit dl rm
formatLocation.js	1781	0644	edit dl rm
Generator.js	4571	0644	edit dl rm
GraphHelpers.js	1074	0644	edit dl rm
HarmonyLinkingError.js	357	0644	edit dl rm
HookWebpackError.js	2070	0644	edit dl rm
HotModuleReplacementPlugin.js	26338	0644	edit dl rm
HotUpdateChunk.js	353	0644	edit dl rm
IgnoreErrorModuleFactory.js	1048	0644	edit dl rm
IgnorePlugin.js	2253	0644	edit dl rm
IgnoreWarningsPlugin.js	964	0644	edit dl rm
index.js	15926	0644	edit dl rm
InitFragment.js	4647	0644	edit dl rm
InvalidDependenciesModuleWarning.js	1874	0644	edit dl rm
JavascriptMetaInfoPlugin.js	2079	0644	edit dl rm
LibManifestPlugin.js	3116	0644	edit dl rm
LibraryTemplatePlugin.js	1588	0644	edit dl rm
LoaderOptionsPlugin.js	1857	0644	edit dl rm
LoaderTargetPlugin.js	747	0644	edit dl rm
MainTemplate.js	10391	0644	edit dl rm
Module.js	29686	0644	edit dl rm
ModuleBuildError.js	1626	0644	edit dl rm
ModuleDependencyError.js	1107	0644	edit dl rm
ModuleDependencyWarning.js	1222	0644	edit dl rm
ModuleError.js	1202	0644	edit dl rm
ModuleFactory.js	1427	0644	edit dl rm
ModuleFilenameHelpers.js	8060	0644	edit dl rm
ModuleGraph.js	24568	0644	edit dl rm
ModuleGraphConnection.js	5209	0644	edit dl rm
ModuleInfoHeaderPlugin.js	7174	0644	edit dl rm
ModuleNotFoundError.js	2610	0644	edit dl rm
ModuleParseError.js	3332	0644	edit dl rm
ModuleProfile.js	2440	0644	edit dl rm
ModuleRestoreError.js	957	0644	edit dl rm
ModuleStoreError.js	951	0644	edit dl rm
ModuleTemplate.js	3999	0644	edit dl rm
ModuleWarning.js	1280	0644	edit dl rm
MultiCompiler.js	16038	0644	edit dl rm
MultiStats.js	4222	0644	edit dl rm
MultiWatching.js	1466	0644	edit dl rm
NodeStuffInWebError.js	843	0644	edit dl rm
NodeStuffPlugin.js	5071	0644	edit dl rm
NoEmitOnErrorsPlugin.js	713	0644	edit dl rm
NoModeWarning.js	663	0644	edit dl rm
NormalModule.js	41829	0644	edit dl rm
NormalModuleFactory.js	31753	0644	edit dl rm
NormalModuleReplacementPlugin.js	1883	0644	edit dl rm
NullFactory.js	628	0644	edit dl rm
OptimizationStages.js	204	0644	edit dl rm
OptionsApply.js	201	0644	edit dl rm
Parser.js	968	0644	edit dl rm
PrefetchPlugin.js	1048	0644	edit dl rm
ProgressPlugin.js	17255	0644	edit dl rm
ProvidePlugin.js	2890	0644	edit dl rm
RawModule.js	4634	0644	edit dl rm
RecordIdsPlugin.js	6821	0644	edit dl rm
RequestShortener.js	755	0644	edit dl rm
RequireJsStuffPlugin.js	1904	0644	edit dl rm
ResolverFactory.js	4947	0644	edit dl rm
RuntimeGlobals.js	8510	0644	edit dl rm
RuntimeModule.js	5751	0644	edit dl rm
RuntimePlugin.js	13009	0644	edit dl rm
RuntimeTemplate.js	28186	0644	edit dl rm
SelfModuleFactory.js	384	0644	edit dl rm
SingleEntryPlugin.js	161	0644	edit dl rm
SizeFormatHelpers.js	583	0644	edit dl rm
SourceMapDevToolModuleOptionsPlugin.js	1325	0644	edit dl rm
SourceMapDevToolPlugin.js	17012	0644	edit dl rm
Stats.js	2003	0644	edit dl rm
Template.js	12789	0644	edit dl rm
TemplatedPathPlugin.js	7988	0644	edit dl rm
UnhandledSchemeError.js	833	0644	edit dl rm
UnsupportedFeatureWarning.js	780	0644	edit dl rm
UseStrictPlugin.js	1645	0644	edit dl rm
validateSchema.js	6395	0644	edit dl rm
WarnCaseSensitiveModulesPlugin.js	1410	0644	edit dl rm
WarnDeprecatedOptionPlugin.js	1275	0644	edit dl rm
WarnNoModeSetPlugin.js	545	0644	edit dl rm
WatchIgnorePlugin.js	2930	0644	edit dl rm
Watching.js	12467	0644	edit dl rm
webpack.js	5085	0644	edit dl rm
WebpackError.js	1377	0644	edit dl rm
WebpackIsIncludedPlugin.js	2420	0644	edit dl rm
WebpackOptionsApply.js	24711	0644	edit dl rm
WebpackOptionsDefaulter.js	470	0644	edit dl rm

Edit: /var/www/flurhymez/node_modules/webpack/lib/FileSystemInfo.js (103021B)

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const { create: createResolver } = require("enhanced-resolve");
const asyncLib = require("neo-async");
const AsyncQueue = require("./util/AsyncQueue");
const StackedCacheMap = require("./util/StackedCacheMap");
const createHash = require("./util/createHash");
const { join, dirname, relative, lstatReadlinkAbsolute } = require("./util/fs");
const makeSerializable = require("./util/makeSerializable");
const processAsyncTree = require("./util/processAsyncTree");

/** @typedef {import("./WebpackError")} WebpackError */
/** @typedef {import("./logging/Logger").Logger} Logger */
/** @typedef {typeof import("./util/Hash")} Hash */
/** @typedef {import("./util/fs").IStats} IStats */
/** @typedef {import("./util/fs").InputFileSystem} InputFileSystem */

const supportsEsm = +process.versions.modules >= 83;

let FS_ACCURACY = 2000;

const EMPTY_SET = new Set();

const RBDT_RESOLVE_CJS = 0;
const RBDT_RESOLVE_ESM = 1;
const RBDT_RESOLVE_DIRECTORY = 2;
const RBDT_RESOLVE_CJS_FILE = 3;
const RBDT_RESOLVE_CJS_FILE_AS_CHILD = 4;
const RBDT_RESOLVE_ESM_FILE = 5;
const RBDT_DIRECTORY = 6;
const RBDT_FILE = 7;
const RBDT_DIRECTORY_DEPENDENCIES = 8;
const RBDT_FILE_DEPENDENCIES = 9;

const INVALID = Symbol("invalid");

/**
 * @typedef {Object} FileSystemInfoEntry
 * @property {number} safeTime
 * @property {number=} timestamp
 */

/**
 * @typedef {Object} ResolvedContextFileSystemInfoEntry
 * @property {number} safeTime
 * @property {string=} timestampHash
 */

/**
 * @typedef {Object} ContextFileSystemInfoEntry
 * @property {number} safeTime
 * @property {string=} timestampHash
 * @property {ResolvedContextFileSystemInfoEntry=} resolved
 * @property {Set<string>=} symlinks
 */

/**
 * @typedef {Object} TimestampAndHash
 * @property {number} safeTime
 * @property {number=} timestamp
 * @property {string} hash
 */

/**
 * @typedef {Object} ResolvedContextTimestampAndHash
 * @property {number} safeTime
 * @property {string=} timestampHash
 * @property {string} hash
 */

/**
 * @typedef {Object} ContextTimestampAndHash
 * @property {number} safeTime
 * @property {string=} timestampHash
 * @property {string} hash
 * @property {ResolvedContextTimestampAndHash=} resolved
 * @property {Set<string>=} symlinks
 */

/**
 * @typedef {Object} ContextHash
 * @property {string} hash
 * @property {string=} resolved
 * @property {Set<string>=} symlinks
 */

/**
 * @typedef {Object} SnapshotOptimizationEntry
 * @property {Snapshot} snapshot
 * @property {number} shared
 * @property {Set<string>} snapshotContent
 * @property {Set<SnapshotOptimizationEntry>} children
 */

/**
 * @typedef {Object} ResolveBuildDependenciesResult
 * @property {Set<string>} files list of files
 * @property {Set<string>} directories list of directories
 * @property {Set<string>} missing list of missing entries
 * @property {Map<string, string | false>} resolveResults stored resolve results
 * @property {Object} resolveDependencies dependencies of the resolving
 * @property {Set<string>} resolveDependencies.files list of files
 * @property {Set<string>} resolveDependencies.directories list of directories
 * @property {Set<string>} resolveDependencies.missing list of missing entries
 */

const DONE_ITERATOR_RESULT = new Set().keys().next();

// cspell:word tshs
// Tsh = Timestamp + Hash
// Tshs = Timestamp + Hash combinations

class SnapshotIterator {
	constructor(next) {
		this.next = next;
	}
}

class SnapshotIterable {
	constructor(snapshot, getMaps) {
		this.snapshot = snapshot;
		this.getMaps = getMaps;
	}

[Symbol.iterator]() {
		let state = 0;
		/** @type {IterableIterator<string>} */
		let it;
		/** @type {(Snapshot) => (Map<string, any> | Set<string>)[]} */
		let getMaps;
		/** @type {(Map<string, any> | Set<string>)[]} */
		let maps;
		/** @type {Snapshot} */
		let snapshot;
		let queue;
		return new SnapshotIterator(() => {
			for (;;) {
				switch (state) {
					case 0:
						snapshot = this.snapshot;
						getMaps = this.getMaps;
						maps = getMaps(snapshot);
						state = 1;
					/* falls through */
					case 1:
						if (maps.length > 0) {
							const map = maps.pop();
							if (map !== undefined) {
								it = map.keys();
								state = 2;
							} else {
								break;
							}
						} else {
							state = 3;
							break;
						}
					/* falls through */
					case 2: {
						const result = it.next();
						if (!result.done) return result;
						state = 1;
						break;
					}
					case 3: {
						const children = snapshot.children;
						if (children !== undefined) {
							if (children.size === 1) {
								// shortcut for a single child
								// avoids allocation of queue
								for (const child of children) snapshot = child;
								maps = getMaps(snapshot);
								state = 1;
								break;
							}
							if (queue === undefined) queue = [];
							for (const child of children) {
								queue.push(child);
							}
						}
						if (queue !== undefined && queue.length > 0) {
							snapshot = queue.pop();
							maps = getMaps(snapshot);
							state = 1;
							break;
						} else {
							state = 4;
						}
					}
					/* falls through */
					case 4:
						return DONE_ITERATOR_RESULT;
				}
			}
		});
	}
}

class Snapshot {
	constructor() {
		this._flags = 0;
		/** @type {number | undefined} */
		this.startTime = undefined;
		/** @type {Map<string, FileSystemInfoEntry | null> | undefined} */
		this.fileTimestamps = undefined;
		/** @type {Map<string, string | null> | undefined} */
		this.fileHashes = undefined;
		/** @type {Map<string, TimestampAndHash | string | null> | undefined} */
		this.fileTshs = undefined;
		/** @type {Map<string, ResolvedContextFileSystemInfoEntry | null> | undefined} */
		this.contextTimestamps = undefined;
		/** @type {Map<string, string | null> | undefined} */
		this.contextHashes = undefined;
		/** @type {Map<string, ResolvedContextTimestampAndHash | null> | undefined} */
		this.contextTshs = undefined;
		/** @type {Map<string, boolean> | undefined} */
		this.missingExistence = undefined;
		/** @type {Map<string, string> | undefined} */
		this.managedItemInfo = undefined;
		/** @type {Set<string> | undefined} */
		this.managedFiles = undefined;
		/** @type {Set<string> | undefined} */
		this.managedContexts = undefined;
		/** @type {Set<string> | undefined} */
		this.managedMissing = undefined;
		/** @type {Set<Snapshot> | undefined} */
		this.children = undefined;
	}

hasStartTime() {
		return (this._flags & 1) !== 0;
	}

setStartTime(value) {
		this._flags = this._flags | 1;
		this.startTime = value;
	}

setMergedStartTime(value, snapshot) {
		if (value) {
			if (snapshot.hasStartTime()) {
				this.setStartTime(Math.min(value, snapshot.startTime));
			} else {
				this.setStartTime(value);
			}
		} else {
			if (snapshot.hasStartTime()) this.setStartTime(snapshot.startTime);
		}
	}

hasFileTimestamps() {
		return (this._flags & 2) !== 0;
	}

setFileTimestamps(value) {
		this._flags = this._flags | 2;
		this.fileTimestamps = value;
	}

hasFileHashes() {
		return (this._flags & 4) !== 0;
	}

setFileHashes(value) {
		this._flags = this._flags | 4;
		this.fileHashes = value;
	}

hasFileTshs() {
		return (this._flags & 8) !== 0;
	}

setFileTshs(value) {
		this._flags = this._flags | 8;
		this.fileTshs = value;
	}

hasContextTimestamps() {
		return (this._flags & 0x10) !== 0;
	}

setContextTimestamps(value) {
		this._flags = this._flags | 0x10;
		this.contextTimestamps = value;
	}

hasContextHashes() {
		return (this._flags & 0x20) !== 0;
	}

setContextHashes(value) {
		this._flags = this._flags | 0x20;
		this.contextHashes = value;
	}

hasContextTshs() {
		return (this._flags & 0x40) !== 0;
	}

setContextTshs(value) {
		this._flags = this._flags | 0x40;
		this.contextTshs = value;
	}

hasMissingExistence() {
		return (this._flags & 0x80) !== 0;
	}

setMissingExistence(value) {
		this._flags = this._flags | 0x80;
		this.missingExistence = value;
	}

hasManagedItemInfo() {
		return (this._flags & 0x100) !== 0;
	}

setManagedItemInfo(value) {
		this._flags = this._flags | 0x100;
		this.managedItemInfo = value;
	}

hasManagedFiles() {
		return (this._flags & 0x200) !== 0;
	}

setManagedFiles(value) {
		this._flags = this._flags | 0x200;
		this.managedFiles = value;
	}

hasManagedContexts() {
		return (this._flags & 0x400) !== 0;
	}

setManagedContexts(value) {
		this._flags = this._flags | 0x400;
		this.managedContexts = value;
	}

hasManagedMissing() {
		return (this._flags & 0x800) !== 0;
	}

setManagedMissing(value) {
		this._flags = this._flags | 0x800;
		this.managedMissing = value;
	}

hasChildren() {
		return (this._flags & 0x1000) !== 0;
	}

setChildren(value) {
		this._flags = this._flags | 0x1000;
		this.children = value;
	}

addChild(child) {
		if (!this.hasChildren()) {
			this.setChildren(new Set());
		}
		this.children.add(child);
	}

serialize({ write }) {
		write(this._flags);
		if (this.hasStartTime()) write(this.startTime);
		if (this.hasFileTimestamps()) write(this.fileTimestamps);
		if (this.hasFileHashes()) write(this.fileHashes);
		if (this.hasFileTshs()) write(this.fileTshs);
		if (this.hasContextTimestamps()) write(this.contextTimestamps);
		if (this.hasContextHashes()) write(this.contextHashes);
		if (this.hasContextTshs()) write(this.contextTshs);
		if (this.hasMissingExistence()) write(this.missingExistence);
		if (this.hasManagedItemInfo()) write(this.managedItemInfo);
		if (this.hasManagedFiles()) write(this.managedFiles);
		if (this.hasManagedContexts()) write(this.managedContexts);
		if (this.hasManagedMissing()) write(this.managedMissing);
		if (this.hasChildren()) write(this.children);
	}

deserialize({ read }) {
		this._flags = read();
		if (this.hasStartTime()) this.startTime = read();
		if (this.hasFileTimestamps()) this.fileTimestamps = read();
		if (this.hasFileHashes()) this.fileHashes = read();
		if (this.hasFileTshs()) this.fileTshs = read();
		if (this.hasContextTimestamps()) this.contextTimestamps = read();
		if (this.hasContextHashes()) this.contextHashes = read();
		if (this.hasContextTshs()) this.contextTshs = read();
		if (this.hasMissingExistence()) this.missingExistence = read();
		if (this.hasManagedItemInfo()) this.managedItemInfo = read();
		if (this.hasManagedFiles()) this.managedFiles = read();
		if (this.hasManagedContexts()) this.managedContexts = read();
		if (this.hasManagedMissing()) this.managedMissing = read();
		if (this.hasChildren()) this.children = read();
	}

/**
	 * @param {function(Snapshot): (ReadonlyMap<string, any> | ReadonlySet<string>)[]} getMaps first
	 * @returns {Iterable<string>} iterable
	 */
	_createIterable(getMaps) {
		return new SnapshotIterable(this, getMaps);
	}

/**
	 * @returns {Iterable<string>} iterable
	 */
	getFileIterable() {
		return this._createIterable(s => [
			s.fileTimestamps,
			s.fileHashes,
			s.fileTshs,
			s.managedFiles
		]);
	}

/**
	 * @returns {Iterable<string>} iterable
	 */
	getContextIterable() {
		return this._createIterable(s => [
			s.contextTimestamps,
			s.contextHashes,
			s.contextTshs,
			s.managedContexts
		]);
	}

/**
	 * @returns {Iterable<string>} iterable
	 */
	getMissingIterable() {
		return this._createIterable(s => [s.missingExistence, s.managedMissing]);
	}
}

makeSerializable(Snapshot, "webpack/lib/FileSystemInfo", "Snapshot");

const MIN_COMMON_SNAPSHOT_SIZE = 3;

/**
 * @template T
 */
class SnapshotOptimization {
	/**
	 * @param {function(Snapshot): boolean} has has value
	 * @param {function(Snapshot): Map<string, T> | Set<string>} get get value
	 * @param {function(Snapshot, Map<string, T> | Set<string>): void} set set value
	 * @param {boolean=} useStartTime use the start time of snapshots
	 * @param {boolean=} isSet value is an Set instead of a Map
	 */
	constructor(has, get, set, useStartTime = true, isSet = false) {
		this._has = has;
		this._get = get;
		this._set = set;
		this._useStartTime = useStartTime;
		this._isSet = isSet;
		/** @type {Map<string, SnapshotOptimizationEntry>} */
		this._map = new Map();
		this._statItemsShared = 0;
		this._statItemsUnshared = 0;
		this._statSharedSnapshots = 0;
		this._statReusedSharedSnapshots = 0;
	}

getStatisticMessage() {
		const total = this._statItemsShared + this._statItemsUnshared;
		if (total === 0) return undefined;
		return `${
			this._statItemsShared && Math.round((this._statItemsShared * 100) / total)
		}% (${this._statItemsShared}/${total}) entries shared via ${
			this._statSharedSnapshots
		} shared snapshots (${
			this._statReusedSharedSnapshots + this._statSharedSnapshots
		} times referenced)`;
	}

clear() {
		this._map.clear();
		this._statItemsShared = 0;
		this._statItemsUnshared = 0;
		this._statSharedSnapshots = 0;
		this._statReusedSharedSnapshots = 0;
	}

/**
	 * @param {Snapshot} newSnapshot snapshot
	 * @param {Set<string>} capturedFiles files to snapshot/share
	 * @returns {void}
	 */
	optimize(newSnapshot, capturedFiles) {
		/**
		 * @param {SnapshotOptimizationEntry} entry optimization entry
		 * @returns {void}
		 */
		const increaseSharedAndStoreOptimizationEntry = entry => {
			if (entry.children !== undefined) {
				entry.children.forEach(increaseSharedAndStoreOptimizationEntry);
			}
			entry.shared++;
			storeOptimizationEntry(entry);
		};
		/**
		 * @param {SnapshotOptimizationEntry} entry optimization entry
		 * @returns {void}
		 */
		const storeOptimizationEntry = entry => {
			for (const path of entry.snapshotContent) {
				const old = this._map.get(path);
				if (old.shared < entry.shared) {
					this._map.set(path, entry);
				}
				capturedFiles.delete(path);
			}
		};

/** @type {SnapshotOptimizationEntry} */
		let newOptimizationEntry = undefined;

const capturedFilesSize = capturedFiles.size;

/** @type {Set<SnapshotOptimizationEntry> | undefined} */
		const optimizationEntries = new Set();

for (const path of capturedFiles) {
			const optimizationEntry = this._map.get(path);
			if (optimizationEntry === undefined) {
				if (newOptimizationEntry === undefined) {
					newOptimizationEntry = {
						snapshot: newSnapshot,
						shared: 0,
						snapshotContent: undefined,
						children: undefined
					};
				}
				this._map.set(path, newOptimizationEntry);
				continue;
			} else {
				optimizationEntries.add(optimizationEntry);
			}
		}

optimizationEntries: for (const optimizationEntry of optimizationEntries) {
			const snapshot = optimizationEntry.snapshot;
			if (optimizationEntry.shared > 0) {
				// It's a shared snapshot
				// We can't change it, so we can only use it when all files match
				// and startTime is compatible
				if (
					this._useStartTime &&
					newSnapshot.startTime &&
					(!snapshot.startTime || snapshot.startTime > newSnapshot.startTime)
				) {
					continue;
				}
				const nonSharedFiles = new Set();
				const snapshotContent = optimizationEntry.snapshotContent;
				const snapshotEntries = this._get(snapshot);
				for (const path of snapshotContent) {
					if (!capturedFiles.has(path)) {
						if (!snapshotEntries.has(path)) {
							// File is not shared and can't be removed from the snapshot
							// because it's in a child of the snapshot
							continue optimizationEntries;
						}
						nonSharedFiles.add(path);
						continue;
					}
				}
				if (nonSharedFiles.size === 0) {
					// The complete snapshot is shared
					// add it as child
					newSnapshot.addChild(snapshot);
					increaseSharedAndStoreOptimizationEntry(optimizationEntry);
					this._statReusedSharedSnapshots++;
				} else {
					// Only a part of the snapshot is shared
					const sharedCount = snapshotContent.size - nonSharedFiles.size;
					if (sharedCount < MIN_COMMON_SNAPSHOT_SIZE) {
						// Common part it too small
						continue optimizationEntries;
					}
					// Extract common timestamps from both snapshots
					let commonMap;
					if (this._isSet) {
						commonMap = new Set();
						for (const path of /** @type {Set<string>} */ (snapshotEntries)) {
							if (nonSharedFiles.has(path)) continue;
							commonMap.add(path);
							snapshotEntries.delete(path);
						}
					} else {
						commonMap = new Map();
						const map = /** @type {Map<string, T>} */ (snapshotEntries);
						for (const [path, value] of map) {
							if (nonSharedFiles.has(path)) continue;
							commonMap.set(path, value);
							snapshotEntries.delete(path);
						}
					}
					// Create and attach snapshot
					const commonSnapshot = new Snapshot();
					if (this._useStartTime) {
						commonSnapshot.setMergedStartTime(newSnapshot.startTime, snapshot);
					}
					this._set(commonSnapshot, commonMap);
					newSnapshot.addChild(commonSnapshot);
					snapshot.addChild(commonSnapshot);
					// Create optimization entry
					const newEntry = {
						snapshot: commonSnapshot,
						shared: optimizationEntry.shared + 1,
						snapshotContent: new Set(commonMap.keys()),
						children: undefined
					};
					if (optimizationEntry.children === undefined)
						optimizationEntry.children = new Set();
					optimizationEntry.children.add(newEntry);
					storeOptimizationEntry(newEntry);
					this._statSharedSnapshots++;
				}
			} else {
				// It's a unshared snapshot
				// We can extract a common shared snapshot
				// with all common files
				const snapshotEntries = this._get(snapshot);
				if (snapshotEntries === undefined) {
					// Incomplete snapshot, that can't be used
					continue optimizationEntries;
				}
				let commonMap;
				if (this._isSet) {
					commonMap = new Set();
					const set = /** @type {Set<string>} */ (snapshotEntries);
					if (capturedFiles.size < set.size) {
						for (const path of capturedFiles) {
							if (set.has(path)) commonMap.add(path);
						}
					} else {
						for (const path of set) {
							if (capturedFiles.has(path)) commonMap.add(path);
						}
					}
				} else {
					commonMap = new Map();
					const map = /** @type {Map<string, T>} */ (snapshotEntries);
					for (const path of capturedFiles) {
						const ts = map.get(path);
						if (ts === undefined) continue;
						commonMap.set(path, ts);
					}
				}

if (commonMap.size < MIN_COMMON_SNAPSHOT_SIZE) {
					// Common part it too small
					continue optimizationEntries;
				}
				// Create and attach snapshot
				const commonSnapshot = new Snapshot();
				if (this._useStartTime) {
					commonSnapshot.setMergedStartTime(newSnapshot.startTime, snapshot);
				}
				this._set(commonSnapshot, commonMap);
				newSnapshot.addChild(commonSnapshot);
				snapshot.addChild(commonSnapshot);
				// Remove files from snapshot
				for (const path of commonMap.keys()) snapshotEntries.delete(path);
				const sharedCount = commonMap.size;
				this._statItemsUnshared -= sharedCount;
				this._statItemsShared += sharedCount;
				// Create optimization entry
				storeOptimizationEntry({
					snapshot: commonSnapshot,
					shared: 2,
					snapshotContent: new Set(commonMap.keys()),
					children: undefined
				});
				this._statSharedSnapshots++;
			}
		}
		const unshared = capturedFiles.size;
		this._statItemsUnshared += unshared;
		this._statItemsShared += capturedFilesSize - unshared;
	}
}

/* istanbul ignore next */
/**
 * @param {number} mtime mtime
 */
const applyMtime = mtime => {
	if (FS_ACCURACY > 1 && mtime % 2 !== 0) FS_ACCURACY = 1;
	else if (FS_ACCURACY > 10 && mtime % 20 !== 0) FS_ACCURACY = 10;
	else if (FS_ACCURACY > 100 && mtime % 200 !== 0) FS_ACCURACY = 100;
	else if (FS_ACCURACY > 1000 && mtime % 2000 !== 0) FS_ACCURACY = 1000;
};

/**
 * @template T
 * @template K
 * @param {Map<T, K>} a source map
 * @param {Map<T, K>} b joining map
 * @returns {Map<T, K>} joined map
 */
const mergeMaps = (a, b) => {
	if (!b || b.size === 0) return a;
	if (!a || a.size === 0) return b;
	const map = new Map(a);
	for (const [key, value] of b) {
		map.set(key, value);
	}
	return map;
};

/**
 * @template T
 * @template K
 * @param {Set<T, K>} a source map
 * @param {Set<T, K>} b joining map
 * @returns {Set<T, K>} joined map
 */
const mergeSets = (a, b) => {
	if (!b || b.size === 0) return a;
	if (!a || a.size === 0) return b;
	const map = new Set(a);
	for (const item of b) {
		map.add(item);
	}
	return map;
};

/**
 * Finding file or directory to manage
 * @param {string} managedPath path that is managing by {@link FileSystemInfo}
 * @param {string} path path to file or directory
 * @returns {string|null} managed item
 * @example
 * getManagedItem(
 *   '/Users/user/my-project/node_modules/',
 *   '/Users/user/my-project/node_modules/package/index.js'
 * ) === '/Users/user/my-project/node_modules/package'
 * getManagedItem(
 *   '/Users/user/my-project/node_modules/',
 *   '/Users/user/my-project/node_modules/package1/node_modules/package2'
 * ) === '/Users/user/my-project/node_modules/package1/node_modules/package2'
 * getManagedItem(
 *   '/Users/user/my-project/node_modules/',
 *   '/Users/user/my-project/node_modules/.bin/script.js'
 * ) === null // hidden files are disallowed as managed items
 * getManagedItem(
 *   '/Users/user/my-project/node_modules/',
 *   '/Users/user/my-project/node_modules/package'
 * ) === '/Users/user/my-project/node_modules/package'
 */
const getManagedItem = (managedPath, path) => {
	let i = managedPath.length;
	let slashes = 1;
	let startingPosition = true;
	loop: while (i < path.length) {
		switch (path.charCodeAt(i)) {
			case 47: // slash
			case 92: // backslash
				if (--slashes === 0) break loop;
				startingPosition = true;
				break;
			case 46: // .
				// hidden files are disallowed as managed items
				// it's probably .yarn-integrity or .cache
				if (startingPosition) return null;
				break;
			case 64: // @
				if (!startingPosition) return null;
				slashes++;
				break;
			default:
				startingPosition = false;
				break;
		}
		i++;
	}
	if (i === path.length) slashes--;
	// return null when path is incomplete
	if (slashes !== 0) return null;
	// if (path.slice(i + 1, i + 13) === "node_modules")
	if (
		path.length >= i + 13 &&
		path.charCodeAt(i + 1) === 110 &&
		path.charCodeAt(i + 2) === 111 &&
		path.charCodeAt(i + 3) === 100 &&
		path.charCodeAt(i + 4) === 101 &&
		path.charCodeAt(i + 5) === 95 &&
		path.charCodeAt(i + 6) === 109 &&
		path.charCodeAt(i + 7) === 111 &&
		path.charCodeAt(i + 8) === 100 &&
		path.charCodeAt(i + 9) === 117 &&
		path.charCodeAt(i + 10) === 108 &&
		path.charCodeAt(i + 11) === 101 &&
		path.charCodeAt(i + 12) === 115
	) {
		// if this is the end of the path
		if (path.length === i + 13) {
			// return the node_modules directory
			// it's special
			return path;
		}
		const c = path.charCodeAt(i + 13);
		// if next symbol is slash or backslash
		if (c === 47 || c === 92) {
			// Managed subpath
			return getManagedItem(path.slice(0, i + 14), path);
		}
	}
	return path.slice(0, i);
};

/**
 * @template {ContextFileSystemInfoEntry | ContextTimestampAndHash} T
 * @param {T} entry entry
 * @returns {T["resolved"] | undefined} the resolved entry
 */
const getResolvedTimestamp = entry => {
	if (entry === null) return null;
	if (entry.resolved !== undefined) return entry.resolved;
	return entry.symlinks === undefined ? entry : undefined;
};

/**
 * @param {ContextHash} entry entry
 * @returns {string | undefined} the resolved entry
 */
const getResolvedHash = entry => {
	if (entry === null) return null;
	if (entry.resolved !== undefined) return entry.resolved;
	return entry.symlinks === undefined ? entry.hash : undefined;
};

const addAll = (source, target) => {
	for (const key of source) target.add(key);
};

/**
 * Used to access information about the filesystem in a cached way
 */
class FileSystemInfo {
	/**
	 * @param {InputFileSystem} fs file system
	 * @param {Object} options options
	 * @param {Iterable<string | RegExp>=} options.managedPaths paths that are only managed by a package manager
	 * @param {Iterable<string | RegExp>=} options.immutablePaths paths that are immutable
	 * @param {Logger=} options.logger logger used to log invalid snapshots
	 * @param {string | Hash=} options.hashFunction the hash function to use
	 */
	constructor(
		fs,
		{
			managedPaths = [],
			immutablePaths = [],
			logger,
			hashFunction = "md4"
		} = {}
	) {
		this.fs = fs;
		this.logger = logger;
		this._remainingLogs = logger ? 40 : 0;
		this._loggedPaths = logger ? new Set() : undefined;
		this._hashFunction = hashFunction;
		/** @type {WeakMap<Snapshot, boolean | (function(WebpackError=, boolean=): void)[]>} */
		this._snapshotCache = new WeakMap();
		this._fileTimestampsOptimization = new SnapshotOptimization(
			s => s.hasFileTimestamps(),
			s => s.fileTimestamps,
			(s, v) => s.setFileTimestamps(v)
		);
		this._fileHashesOptimization = new SnapshotOptimization(
			s => s.hasFileHashes(),
			s => s.fileHashes,
			(s, v) => s.setFileHashes(v),
			false
		);
		this._fileTshsOptimization = new SnapshotOptimization(
			s => s.hasFileTshs(),
			s => s.fileTshs,
			(s, v) => s.setFileTshs(v)
		);
		this._contextTimestampsOptimization = new SnapshotOptimization(
			s => s.hasContextTimestamps(),
			s => s.contextTimestamps,
			(s, v) => s.setContextTimestamps(v)
		);
		this._contextHashesOptimization = new SnapshotOptimization(
			s => s.hasContextHashes(),
			s => s.contextHashes,
			(s, v) => s.setContextHashes(v),
			false
		);
		this._contextTshsOptimization = new SnapshotOptimization(
			s => s.hasContextTshs(),
			s => s.contextTshs,
			(s, v) => s.setContextTshs(v)
		);
		this._missingExistenceOptimization = new SnapshotOptimization(
			s => s.hasMissingExistence(),
			s => s.missingExistence,
			(s, v) => s.setMissingExistence(v),
			false
		);
		this._managedItemInfoOptimization = new SnapshotOptimization(
			s => s.hasManagedItemInfo(),
			s => s.managedItemInfo,
			(s, v) => s.setManagedItemInfo(v),
			false
		);
		this._managedFilesOptimization = new SnapshotOptimization(
			s => s.hasManagedFiles(),
			s => s.managedFiles,
			(s, v) => s.setManagedFiles(v),
			false,
			true
		);
		this._managedContextsOptimization = new SnapshotOptimization(
			s => s.hasManagedContexts(),
			s => s.managedContexts,
			(s, v) => s.setManagedContexts(v),
			false,
			true
		);
		this._managedMissingOptimization = new SnapshotOptimization(
			s => s.hasManagedMissing(),
			s => s.managedMissing,
			(s, v) => s.setManagedMissing(v),
			false,
			true
		);
		/** @type {StackedCacheMap<string, FileSystemInfoEntry | "ignore" | null>} */
		this._fileTimestamps = new StackedCacheMap();
		/** @type {Map<string, string>} */
		this._fileHashes = new Map();
		/** @type {Map<string, TimestampAndHash | string>} */
		this._fileTshs = new Map();
		/** @type {StackedCacheMap<string, ContextFileSystemInfoEntry | "ignore" | null>} */
		this._contextTimestamps = new StackedCacheMap();
		/** @type {Map<string, ContextHash>} */
		this._contextHashes = new Map();
		/** @type {Map<string, ContextTimestampAndHash>} */
		this._contextTshs = new Map();
		/** @type {Map<string, string>} */
		this._managedItems = new Map();
		/** @type {AsyncQueue<string, string, FileSystemInfoEntry | null>} */
		this.fileTimestampQueue = new AsyncQueue({
			name: "file timestamp",
			parallelism: 30,
			processor: this._readFileTimestamp.bind(this)
		});
		/** @type {AsyncQueue<string, string, string | null>} */
		this.fileHashQueue = new AsyncQueue({
			name: "file hash",
			parallelism: 10,
			processor: this._readFileHash.bind(this)
		});
		/** @type {AsyncQueue<string, string, ContextFileSystemInfoEntry | null>} */
		this.contextTimestampQueue = new AsyncQueue({
			name: "context timestamp",
			parallelism: 2,
			processor: this._readContextTimestamp.bind(this)
		});
		/** @type {AsyncQueue<string, string, ContextHash | null>} */
		this.contextHashQueue = new AsyncQueue({
			name: "context hash",
			parallelism: 2,
			processor: this._readContextHash.bind(this)
		});
		/** @type {AsyncQueue<string, string, ContextTimestampAndHash | null>} */
		this.contextTshQueue = new AsyncQueue({
			name: "context hash and timestamp",
			parallelism: 2,
			processor: this._readContextTimestampAndHash.bind(this)
		});
		/** @type {AsyncQueue<string, string, string | null>} */
		this.managedItemQueue = new AsyncQueue({
			name: "managed item info",
			parallelism: 10,
			processor: this._getManagedItemInfo.bind(this)
		});
		/** @type {AsyncQueue<string, string, Set<string>>} */
		this.managedItemDirectoryQueue = new AsyncQueue({
			name: "managed item directory info",
			parallelism: 10,
			processor: this._getManagedItemDirectoryInfo.bind(this)
		});
		this.managedPaths = Array.from(managedPaths);
		this.managedPathsWithSlash = /** @type {string[]} */ (
			this.managedPaths.filter(p => typeof p === "string")
		).map(p => join(fs, p, "_").slice(0, -1));

this.managedPathsRegExps = /** @type {RegExp[]} */ (
			this.managedPaths.filter(p => typeof p !== "string")
		);
		this.immutablePaths = Array.from(immutablePaths);
		this.immutablePathsWithSlash = /** @type {string[]} */ (
			this.immutablePaths.filter(p => typeof p === "string")
		).map(p => join(fs, p, "_").slice(0, -1));
		this.immutablePathsRegExps = /** @type {RegExp[]} */ (
			this.immutablePaths.filter(p => typeof p !== "string")
		);

this._cachedDeprecatedFileTimestamps = undefined;
		this._cachedDeprecatedContextTimestamps = undefined;

this._warnAboutExperimentalEsmTracking = false;

this._statCreatedSnapshots = 0;
		this._statTestedSnapshotsCached = 0;
		this._statTestedSnapshotsNotCached = 0;
		this._statTestedChildrenCached = 0;
		this._statTestedChildrenNotCached = 0;
		this._statTestedEntries = 0;
	}

logStatistics() {
		const logWhenMessage = (header, message) => {
			if (message) {
				this.logger.log(`${header}: ${message}`);
			}
		};
		this.logger.log(`${this._statCreatedSnapshots} new snapshots created`);
		this.logger.log(
			`${
				this._statTestedSnapshotsNotCached &&
				Math.round(
					(this._statTestedSnapshotsNotCached * 100) /
						(this._statTestedSnapshotsCached +
							this._statTestedSnapshotsNotCached)
				)
			}% root snapshot uncached (${this._statTestedSnapshotsNotCached} / ${
				this._statTestedSnapshotsCached + this._statTestedSnapshotsNotCached
			})`
		);
		this.logger.log(
			`${
				this._statTestedChildrenNotCached &&
				Math.round(
					(this._statTestedChildrenNotCached * 100) /
						(this._statTestedChildrenCached + this._statTestedChildrenNotCached)
				)
			}% children snapshot uncached (${this._statTestedChildrenNotCached} / ${
				this._statTestedChildrenCached + this._statTestedChildrenNotCached
			})`
		);
		this.logger.log(`${this._statTestedEntries} entries tested`);
		this.logger.log(
			`File info in cache: ${this._fileTimestamps.size} timestamps ${this._fileHashes.size} hashes ${this._fileTshs.size} timestamp hash combinations`
		);
		logWhenMessage(
			`File timestamp snapshot optimization`,
			this._fileTimestampsOptimization.getStatisticMessage()
		);
		logWhenMessage(
			`File hash snapshot optimization`,
			this._fileHashesOptimization.getStatisticMessage()
		);
		logWhenMessage(
			`File timestamp hash combination snapshot optimization`,
			this._fileTshsOptimization.getStatisticMessage()
		);
		this.logger.log(
			`Directory info in cache: ${this._contextTimestamps.size} timestamps ${this._contextHashes.size} hashes ${this._contextTshs.size} timestamp hash combinations`
		);
		logWhenMessage(
			`Directory timestamp snapshot optimization`,
			this._contextTimestampsOptimization.getStatisticMessage()
		);
		logWhenMessage(
			`Directory hash snapshot optimization`,
			this._contextHashesOptimization.getStatisticMessage()
		);
		logWhenMessage(
			`Directory timestamp hash combination snapshot optimization`,
			this._contextTshsOptimization.getStatisticMessage()
		);
		logWhenMessage(
			`Missing items snapshot optimization`,
			this._missingExistenceOptimization.getStatisticMessage()
		);
		this.logger.log(
			`Managed items info in cache: ${this._managedItems.size} items`
		);
		logWhenMessage(
			`Managed items snapshot optimization`,
			this._managedItemInfoOptimization.getStatisticMessage()
		);
		logWhenMessage(
			`Managed files snapshot optimization`,
			this._managedFilesOptimization.getStatisticMessage()
		);
		logWhenMessage(
			`Managed contexts snapshot optimization`,
			this._managedContextsOptimization.getStatisticMessage()
		);
		logWhenMessage(
			`Managed missing snapshot optimization`,
			this._managedMissingOptimization.getStatisticMessage()
		);
	}

_log(path, reason, ...args) {
		const key = path + reason;
		if (this._loggedPaths.has(key)) return;
		this._loggedPaths.add(key);
		this.logger.debug(`${path} invalidated because ${reason}`, ...args);
		if (--this._remainingLogs === 0) {
			this.logger.debug(
				"Logging limit has been reached and no further logging will be emitted by FileSystemInfo"
			);
		}
	}

clear() {
		this._remainingLogs = this.logger ? 40 : 0;
		if (this._loggedPaths !== undefined) this._loggedPaths.clear();

this._snapshotCache = new WeakMap();
		this._fileTimestampsOptimization.clear();
		this._fileHashesOptimization.clear();
		this._fileTshsOptimization.clear();
		this._contextTimestampsOptimization.clear();
		this._contextHashesOptimization.clear();
		this._contextTshsOptimization.clear();
		this._missingExistenceOptimization.clear();
		this._managedItemInfoOptimization.clear();
		this._managedFilesOptimization.clear();
		this._managedContextsOptimization.clear();
		this._managedMissingOptimization.clear();
		this._fileTimestamps.clear();
		this._fileHashes.clear();
		this._fileTshs.clear();
		this._contextTimestamps.clear();
		this._contextHashes.clear();
		this._contextTshs.clear();
		this._managedItems.clear();
		this._managedItems.clear();

this._cachedDeprecatedFileTimestamps = undefined;
		this._cachedDeprecatedContextTimestamps = undefined;

/**
	 * @param {ReadonlyMap<string, FileSystemInfoEntry | "ignore" | null>} map timestamps
	 * @param {boolean=} immutable if 'map' is immutable and FileSystemInfo can keep referencing it
	 * @returns {void}
	 */
	addFileTimestamps(map, immutable) {
		this._fileTimestamps.addAll(map, immutable);
		this._cachedDeprecatedFileTimestamps = undefined;
	}

/**
	 * @param {ReadonlyMap<string, FileSystemInfoEntry | "ignore" | null>} map timestamps
	 * @param {boolean=} immutable if 'map' is immutable and FileSystemInfo can keep referencing it
	 * @returns {void}
	 */
	addContextTimestamps(map, immutable) {
		this._contextTimestamps.addAll(map, immutable);
		this._cachedDeprecatedContextTimestamps = undefined;
	}

/**
	 * @param {string} path file path
	 * @param {function(WebpackError=, (FileSystemInfoEntry | "ignore" | null)=): void} callback callback function
	 * @returns {void}
	 */
	getFileTimestamp(path, callback) {
		const cache = this._fileTimestamps.get(path);
		if (cache !== undefined) return callback(null, cache);
		this.fileTimestampQueue.add(path, callback);
	}

/**
	 * @param {string} path context path
	 * @param {function(WebpackError=, (ResolvedContextFileSystemInfoEntry | "ignore" | null)=): void} callback callback function
	 * @returns {void}
	 */
	getContextTimestamp(path, callback) {
		const cache = this._contextTimestamps.get(path);
		if (cache !== undefined) {
			if (cache === "ignore") return callback(null, "ignore");
			const resolved = getResolvedTimestamp(cache);
			if (resolved !== undefined) return callback(null, resolved);
			return this._resolveContextTimestamp(cache, callback);
		}
		this.contextTimestampQueue.add(path, (err, entry) => {
			if (err) return callback(err);
			const resolved = getResolvedTimestamp(entry);
			if (resolved !== undefined) return callback(null, resolved);
			this._resolveContextTimestamp(entry, callback);
		});
	}

/**
	 * @param {string} path context path
	 * @param {function(WebpackError=, (ContextFileSystemInfoEntry | "ignore" | null)=): void} callback callback function
	 * @returns {void}
	 */
	_getUnresolvedContextTimestamp(path, callback) {
		const cache = this._contextTimestamps.get(path);
		if (cache !== undefined) return callback(null, cache);
		this.contextTimestampQueue.add(path, callback);
	}

/**
	 * @param {string} path file path
	 * @param {function(WebpackError=, string=): void} callback callback function
	 * @returns {void}
	 */
	getFileHash(path, callback) {
		const cache = this._fileHashes.get(path);
		if (cache !== undefined) return callback(null, cache);
		this.fileHashQueue.add(path, callback);
	}

/**
	 * @param {string} path context path
	 * @param {function(WebpackError=, string=): void} callback callback function
	 * @returns {void}
	 */
	getContextHash(path, callback) {
		const cache = this._contextHashes.get(path);
		if (cache !== undefined) {
			const resolved = getResolvedHash(cache);
			if (resolved !== undefined) return callback(null, resolved);
			return this._resolveContextHash(cache, callback);
		}
		this.contextHashQueue.add(path, (err, entry) => {
			if (err) return callback(err);
			const resolved = getResolvedHash(entry);
			if (resolved !== undefined) return callback(null, resolved);
			this._resolveContextHash(entry, callback);
		});
	}

/**
	 * @param {string} path context path
	 * @param {function(WebpackError=, ContextHash=): void} callback callback function
	 * @returns {void}
	 */
	_getUnresolvedContextHash(path, callback) {
		const cache = this._contextHashes.get(path);
		if (cache !== undefined) return callback(null, cache);
		this.contextHashQueue.add(path, callback);
	}

/**
	 * @param {string} path context path
	 * @param {function(WebpackError=, ResolvedContextTimestampAndHash=): void} callback callback function
	 * @returns {void}
	 */
	getContextTsh(path, callback) {
		const cache = this._contextTshs.get(path);
		if (cache !== undefined) {
			const resolved = getResolvedTimestamp(cache);
			if (resolved !== undefined) return callback(null, resolved);
			return this._resolveContextTsh(cache, callback);
		}
		this.contextTshQueue.add(path, (err, entry) => {
			if (err) return callback(err);
			const resolved = getResolvedTimestamp(entry);
			if (resolved !== undefined) return callback(null, resolved);
			this._resolveContextTsh(entry, callback);
		});
	}

/**
	 * @param {string} path context path
	 * @param {function(WebpackError=, ContextTimestampAndHash=): void} callback callback function
	 * @returns {void}
	 */
	_getUnresolvedContextTsh(path, callback) {
		const cache = this._contextTshs.get(path);
		if (cache !== undefined) return callback(null, cache);
		this.contextTshQueue.add(path, callback);
	}

_createBuildDependenciesResolvers() {
		const resolveContext = createResolver({
			resolveToContext: true,
			exportsFields: [],
			fileSystem: this.fs
		});
		const resolveCjs = createResolver({
			extensions: [".js", ".json", ".node"],
			conditionNames: ["require", "node"],
			exportsFields: ["exports"],
			fileSystem: this.fs
		});
		const resolveCjsAsChild = createResolver({
			extensions: [".js", ".json", ".node"],
			conditionNames: ["require", "node"],
			exportsFields: [],
			fileSystem: this.fs
		});
		const resolveEsm = createResolver({
			extensions: [".js", ".json", ".node"],
			fullySpecified: true,
			conditionNames: ["import", "node"],
			exportsFields: ["exports"],
			fileSystem: this.fs
		});
		return { resolveContext, resolveEsm, resolveCjs, resolveCjsAsChild };
	}

/**
	 * @param {string} context context directory
	 * @param {Iterable<string>} deps dependencies
	 * @param {function(Error=, ResolveBuildDependenciesResult=): void} callback callback function
	 * @returns {void}
	 */
	resolveBuildDependencies(context, deps, callback) {
		const { resolveContext, resolveEsm, resolveCjs, resolveCjsAsChild } =
			this._createBuildDependenciesResolvers();

/** @type {Set<string>} */
		const files = new Set();
		/** @type {Set<string>} */
		const fileSymlinks = new Set();
		/** @type {Set<string>} */
		const directories = new Set();
		/** @type {Set<string>} */
		const directorySymlinks = new Set();
		/** @type {Set<string>} */
		const missing = new Set();
		/** @type {Set<string>} */
		const resolveFiles = new Set();
		/** @type {Set<string>} */
		const resolveDirectories = new Set();
		/** @type {Set<string>} */
		const resolveMissing = new Set();
		/** @type {Map<string, string | false>} */
		const resolveResults = new Map();
		const invalidResolveResults = new Set();
		const resolverContext = {
			fileDependencies: resolveFiles,
			contextDependencies: resolveDirectories,
			missingDependencies: resolveMissing
		};
		const expectedToString = expected => {
			return expected ? ` (expected ${expected})` : "";
		};
		const jobToString = job => {
			switch (job.type) {
				case RBDT_RESOLVE_CJS:
					return `resolve commonjs ${job.path}${expectedToString(
						job.expected
					)}`;
				case RBDT_RESOLVE_ESM:
					return `resolve esm ${job.path}${expectedToString(job.expected)}`;
				case RBDT_RESOLVE_DIRECTORY:
					return `resolve directory ${job.path}`;
				case RBDT_RESOLVE_CJS_FILE:
					return `resolve commonjs file ${job.path}${expectedToString(
						job.expected
					)}`;
				case RBDT_RESOLVE_ESM_FILE:
					return `resolve esm file ${job.path}${expectedToString(
						job.expected
					)}`;
				case RBDT_DIRECTORY:
					return `directory ${job.path}`;
				case RBDT_FILE:
					return `file ${job.path}`;
				case RBDT_DIRECTORY_DEPENDENCIES:
					return `directory dependencies ${job.path}`;
				case RBDT_FILE_DEPENDENCIES:
					return `file dependencies ${job.path}`;
			}
			return `unknown ${job.type} ${job.path}`;
		};
		const pathToString = job => {
			let result = ` at ${jobToString(job)}`;
			job = job.issuer;
			while (job !== undefined) {
				result += `\n at ${jobToString(job)}`;
				job = job.issuer;
			}
			return result;
		};
		processAsyncTree(
			Array.from(deps, dep => ({
				type: RBDT_RESOLVE_CJS,
				context,
				path: dep,
				expected: undefined,
				issuer: undefined
			})),
			20,
			(job, push, callback) => {
				const { type, context, path, expected } = job;
				const resolveDirectory = path => {
					const key = `d\n${context}\n${path}`;
					if (resolveResults.has(key)) {
						return callback();
					}
					resolveResults.set(key, undefined);
					resolveContext(context, path, resolverContext, (err, _, result) => {
						if (err) {
							if (expected === false) {
								resolveResults.set(key, false);
								return callback();
							}
							invalidResolveResults.add(key);
							err.message += `\nwhile resolving '${path}' in ${context} to a directory`;
							return callback(err);
						}
						const resultPath = result.path;
						resolveResults.set(key, resultPath);
						push({
							type: RBDT_DIRECTORY,
							context: undefined,
							path: resultPath,
							expected: undefined,
							issuer: job
						});
						callback();
					});
				};
				const resolveFile = (path, symbol, resolve) => {
					const key = `${symbol}\n${context}\n${path}`;
					if (resolveResults.has(key)) {
						return callback();
					}
					resolveResults.set(key, undefined);
					resolve(context, path, resolverContext, (err, _, result) => {
						if (typeof expected === "string") {
							if (!err && result && result.path === expected) {
								resolveResults.set(key, result.path);
							} else {
								invalidResolveResults.add(key);
								this.logger.warn(
									`Resolving '${path}' in ${context} for build dependencies doesn't lead to expected result '${expected}', but to '${
										err || (result && result.path)
									}' instead. Resolving dependencies are ignored for this path.\n${pathToString(
										job
									)}`
								);
							}
						} else {
							if (err) {
								if (expected === false) {
									resolveResults.set(key, false);
									return callback();
								}
								invalidResolveResults.add(key);
								err.message += `\nwhile resolving '${path}' in ${context} as file\n${pathToString(
									job
								)}`;
								return callback(err);
							}
							const resultPath = result.path;
							resolveResults.set(key, resultPath);
							push({
								type: RBDT_FILE,
								context: undefined,
								path: resultPath,
								expected: undefined,
								issuer: job
							});
						}
						callback();
					});
				};
				switch (type) {
					case RBDT_RESOLVE_CJS: {
						const isDirectory = /[\\/]$/.test(path);
						if (isDirectory) {
							resolveDirectory(path.slice(0, path.length - 1));
						} else {
							resolveFile(path, "f", resolveCjs);
						}
						break;
					}
					case RBDT_RESOLVE_ESM: {
						const isDirectory = /[\\/]$/.test(path);
						if (isDirectory) {
							resolveDirectory(path.slice(0, path.length - 1));
						} else {
							resolveFile(path);
						}
						break;
					}
					case RBDT_RESOLVE_DIRECTORY: {
						resolveDirectory(path);
						break;
					}
					case RBDT_RESOLVE_CJS_FILE: {
						resolveFile(path, "f", resolveCjs);
						break;
					}
					case RBDT_RESOLVE_CJS_FILE_AS_CHILD: {
						resolveFile(path, "c", resolveCjsAsChild);
						break;
					}
					case RBDT_RESOLVE_ESM_FILE: {
						resolveFile(path, "e", resolveEsm);
						break;
					}
					case RBDT_FILE: {
						if (files.has(path)) {
							callback();
							break;
						}
						files.add(path);
						this.fs.realpath(path, (err, _realPath) => {
							if (err) return callback(err);
							const realPath = /** @type {string} */ (_realPath);
							if (realPath !== path) {
								fileSymlinks.add(path);
								resolveFiles.add(path);
								if (files.has(realPath)) return callback();
								files.add(realPath);
							}
							push({
								type: RBDT_FILE_DEPENDENCIES,
								context: undefined,
								path: realPath,
								expected: undefined,
								issuer: job
							});
							callback();
						});
						break;
					}
					case RBDT_DIRECTORY: {
						if (directories.has(path)) {
							callback();
							break;
						}
						directories.add(path);
						this.fs.realpath(path, (err, _realPath) => {
							if (err) return callback(err);
							const realPath = /** @type {string} */ (_realPath);
							if (realPath !== path) {
								directorySymlinks.add(path);
								resolveFiles.add(path);
								if (directories.has(realPath)) return callback();
								directories.add(realPath);
							}
							push({
								type: RBDT_DIRECTORY_DEPENDENCIES,
								context: undefined,
								path: realPath,
								expected: undefined,
								issuer: job
							});
							callback();
						});
						break;
					}
					case RBDT_FILE_DEPENDENCIES: {
						// Check for known files without dependencies
						if (/\.json5?$|\.yarn-integrity$|yarn\.lock$|\.ya?ml/.test(path)) {
							process.nextTick(callback);
							break;
						}
						// Check commonjs cache for the module
						/** @type {NodeModule} */
						const module = require.cache[path];
						if (module && Array.isArray(module.children)) {
							children: for (const child of module.children) {
								let childPath = child.filename;
								if (childPath) {
									push({
										type: RBDT_FILE,
										context: undefined,
										path: childPath,
										expected: undefined,
										issuer: job
									});
									const context = dirname(this.fs, path);
									for (const modulePath of module.paths) {
										if (childPath.startsWith(modulePath)) {
											let subPath = childPath.slice(modulePath.length + 1);
											const packageMatch = /^(@[^\\/]+[\\/])[^\\/]+/.exec(
												subPath
											);
											if (packageMatch) {
												push({
													type: RBDT_FILE,
													context: undefined,
													path:
														modulePath +
														childPath[modulePath.length] +
														packageMatch[0] +
														childPath[modulePath.length] +
														"package.json",
													expected: false,
													issuer: job
												});
											}
											let request = subPath.replace(/\\/g, "/");
											if (request.endsWith(".js"))
												request = request.slice(0, -3);
											push({
												type: RBDT_RESOLVE_CJS_FILE_AS_CHILD,
												context,
												path: request,
												expected: child.filename,
												issuer: job
											});
											continue children;
										}
									}
									let request = relative(this.fs, context, childPath);
									if (request.endsWith(".js")) request = request.slice(0, -3);
									request = request.replace(/\\/g, "/");
									if (!request.startsWith("../")) request = `./${request}`;
									push({
										type: RBDT_RESOLVE_CJS_FILE,
										context,
										path: request,
										expected: child.filename,
										issuer: job
									});
								}
							}
						} else if (supportsEsm && /\.m?js$/.test(path)) {
							if (!this._warnAboutExperimentalEsmTracking) {
								this.logger.log(
									"Node.js doesn't offer a (nice) way to introspect the ESM dependency graph yet.\n" +
										"Until a full solution is available webpack uses an experimental ESM tracking based on parsing.\n" +
										"As best effort webpack parses the ESM files to guess dependencies. But this can lead to expensive and incorrect tracking."
								);
								this._warnAboutExperimentalEsmTracking = true;
							}
							const lexer = require("es-module-lexer");
							lexer.init.then(() => {
								this.fs.readFile(path, (err, content) => {
									if (err) return callback(err);
									try {
										const context = dirname(this.fs, path);
										const source = content.toString();
										const [imports] = lexer.parse(source);
										for (const imp of imports) {
											try {
												let dependency;
												if (imp.d === -1) {
													// import ... from "..."
													dependency = JSON.parse(
														source.substring(imp.s - 1, imp.e + 1)
													);
												} else if (imp.d > -1) {
													// import()
													let expr = source.substring(imp.s, imp.e).trim();
													if (expr[0] === "'")
														expr = `"${expr
															.slice(1, -1)
															.replace(/"/g, '\\"')}"`;
													dependency = JSON.parse(expr);
												} else {
													// e.g. import.meta
													continue;
												}
												push({
													type: RBDT_RESOLVE_ESM_FILE,
													context,
													path: dependency,
													expected: undefined,
													issuer: job
												});
											} catch (e) {
												this.logger.warn(
													`Parsing of ${path} for build dependencies failed at 'import(${source.substring(
														imp.s,
														imp.e
													)})'.\n` +
														"Build dependencies behind this expression are ignored and might cause incorrect cache invalidation."
												);
												this.logger.debug(pathToString(job));
												this.logger.debug(e.stack);
											}
										}
									} catch (e) {
										this.logger.warn(
											`Parsing of ${path} for build dependencies failed and all dependencies of this file are ignored, which might cause incorrect cache invalidation..`
										);
										this.logger.debug(pathToString(job));
										this.logger.debug(e.stack);
									}
									process.nextTick(callback);
								});
							}, callback);
							break;
						} else {
							this.logger.log(
								`Assuming ${path} has no dependencies as we were unable to assign it to any module system.`
							);
							this.logger.debug(pathToString(job));
						}
						process.nextTick(callback);
						break;
					}
					case RBDT_DIRECTORY_DEPENDENCIES: {
						const match =
							/(^.+[\\/]node_modules[\\/](?:@[^\\/]+[\\/])?[^\\/]+)/.exec(path);
						const packagePath = match ? match[1] : path;
						const packageJson = join(this.fs, packagePath, "package.json");
						this.fs.readFile(packageJson, (err, content) => {
							if (err) {
								if (err.code === "ENOENT") {
									resolveMissing.add(packageJson);
									const parent = dirname(this.fs, packagePath);
									if (parent !== packagePath) {
										push({
											type: RBDT_DIRECTORY_DEPENDENCIES,
											context: undefined,
											path: parent,
											expected: undefined,
											issuer: job
										});
									}
									callback();
									return;
								}
								return callback(err);
							}
							resolveFiles.add(packageJson);
							let packageData;
							try {
								packageData = JSON.parse(content.toString("utf-8"));
							} catch (e) {
								return callback(e);
							}
							const depsObject = packageData.dependencies;
							const optionalDepsObject = packageData.optionalDependencies;
							const allDeps = new Set();
							const optionalDeps = new Set();
							if (typeof depsObject === "object" && depsObject) {
								for (const dep of Object.keys(depsObject)) {
									allDeps.add(dep);
								}
							}
							if (
								typeof optionalDepsObject === "object" &&
								optionalDepsObject
							) {
								for (const dep of Object.keys(optionalDepsObject)) {
									allDeps.add(dep);
									optionalDeps.add(dep);
								}
							}
							for (const dep of allDeps) {
								push({
									type: RBDT_RESOLVE_DIRECTORY,
									context: packagePath,
									path: dep,
									expected: !optionalDeps.has(dep),
									issuer: job
								});
							}
							callback();
						});
						break;
					}
				}
			},
			err => {
				if (err) return callback(err);
				for (const l of fileSymlinks) files.delete(l);
				for (const l of directorySymlinks) directories.delete(l);
				for (const k of invalidResolveResults) resolveResults.delete(k);
				callback(null, {
					files,
					directories,
					missing,
					resolveResults,
					resolveDependencies: {
						files: resolveFiles,
						directories: resolveDirectories,
						missing: resolveMissing
					}
				});
			}
		);
	}

/**
	 * @param {Map<string, string | false>} resolveResults results from resolving
	 * @param {function(Error=, boolean=): void} callback callback with true when resolveResults resolve the same way
	 * @returns {void}
	 */
	checkResolveResultsValid(resolveResults, callback) {
		const { resolveCjs, resolveCjsAsChild, resolveEsm, resolveContext } =
			this._createBuildDependenciesResolvers();
		asyncLib.eachLimit(
			resolveResults,
			20,
			([key, expectedResult], callback) => {
				const [type, context, path] = key.split("\n");
				switch (type) {
					case "d":
						resolveContext(context, path, {}, (err, _, result) => {
							if (expectedResult === false)
								return callback(err ? undefined : INVALID);
							if (err) return callback(err);
							const resultPath = result.path;
							if (resultPath !== expectedResult) return callback(INVALID);
							callback();
						});
						break;
					case "f":
						resolveCjs(context, path, {}, (err, _, result) => {
							if (expectedResult === false)
								return callback(err ? undefined : INVALID);
							if (err) return callback(err);
							const resultPath = result.path;
							if (resultPath !== expectedResult) return callback(INVALID);
							callback();
						});
						break;
					case "c":
						resolveCjsAsChild(context, path, {}, (err, _, result) => {
							if (expectedResult === false)
								return callback(err ? undefined : INVALID);
							if (err) return callback(err);
							const resultPath = result.path;
							if (resultPath !== expectedResult) return callback(INVALID);
							callback();
						});
						break;
					case "e":
						resolveEsm(context, path, {}, (err, _, result) => {
							if (expectedResult === false)
								return callback(err ? undefined : INVALID);
							if (err) return callback(err);
							const resultPath = result.path;
							if (resultPath !== expectedResult) return callback(INVALID);
							callback();
						});
						break;
					default:
						callback(new Error("Unexpected type in resolve result key"));
						break;
				}
			},
			/**
			 * @param {Error | typeof INVALID=} err error or invalid flag
			 * @returns {void}
			 */
			err => {
				if (err === INVALID) {
					return callback(null, false);
				}
				if (err) {
					return callback(err);
				}
				return callback(null, true);
			}
		);
	}

/**
	 *
	 * @param {number} startTime when processing the files has started
	 * @param {Iterable<string>} files all files
	 * @param {Iterable<string>} directories all directories
	 * @param {Iterable<string>} missing all missing files or directories
	 * @param {Object} options options object (for future extensions)
	 * @param {boolean=} options.hash should use hash to snapshot
	 * @param {boolean=} options.timestamp should use timestamp to snapshot
	 * @param {function(WebpackError=, Snapshot=): void} callback callback function
	 * @returns {void}
	 */
	createSnapshot(startTime, files, directories, missing, options, callback) {
		/** @type {Map<string, FileSystemInfoEntry | null>} */
		const fileTimestamps = new Map();
		/** @type {Map<string, string | null>} */
		const fileHashes = new Map();
		/** @type {Map<string, TimestampAndHash | string | null>} */
		const fileTshs = new Map();
		/** @type {Map<string, FileSystemInfoEntry | null>} */
		const contextTimestamps = new Map();
		/** @type {Map<string, string | null>} */
		const contextHashes = new Map();
		/** @type {Map<string, ResolvedContextTimestampAndHash | null>} */
		const contextTshs = new Map();
		/** @type {Map<string, boolean>} */
		const missingExistence = new Map();
		/** @type {Map<string, string>} */
		const managedItemInfo = new Map();
		/** @type {Set<string>} */
		const managedFiles = new Set();
		/** @type {Set<string>} */
		const managedContexts = new Set();
		/** @type {Set<string>} */
		const managedMissing = new Set();
		/** @type {Set<Snapshot>} */
		const children = new Set();

const snapshot = new Snapshot();
		if (startTime) snapshot.setStartTime(startTime);

/** @type {Set<string>} */
		const managedItems = new Set();

/** 1 = timestamp, 2 = hash, 3 = timestamp + hash */
		const mode = options && options.hash ? (options.timestamp ? 3 : 2) : 1;

callback(null, snapshot);
			}
		};
		const jobError = () => {
			if (jobs > 0) {
				// large negative number instead of NaN or something else to keep jobs to stay a SMI (v8)
				jobs = -100000000;
				callback(null, null);
			}
		};
		const checkManaged = (path, managedSet) => {
			for (const immutablePath of this.immutablePathsRegExps) {
				if (immutablePath.test(path)) {
					managedSet.add(path);
					return true;
				}
			}
			for (const immutablePath of this.immutablePathsWithSlash) {
				if (path.startsWith(immutablePath)) {
					managedSet.add(path);
					return true;
				}
			}
			for (const managedPath of this.managedPathsRegExps) {
				const match = managedPath.exec(path);
				if (match) {
					const managedItem = getManagedItem(match[1], path);
					if (managedItem) {
						managedItems.add(managedItem);
						managedSet.add(path);
						return true;
					}
				}
			}
			for (const managedPath of this.managedPathsWithSlash) {
				if (path.startsWith(managedPath)) {
					const managedItem = getManagedItem(managedPath, path);
					if (managedItem) {
						managedItems.add(managedItem);
						managedSet.add(path);
						return true;
					}
				}
			}
			return false;
		};
		const captureNonManaged = (items, managedSet) => {
			const capturedItems = new Set();
			for (const path of items) {
				if (!checkManaged(path, managedSet)) capturedItems.add(path);
			}
			return capturedItems;
		};
		if (files) {
			const capturedFiles = captureNonManaged(files, managedFiles);
			switch (mode) {
				case 3:
					this._fileTshsOptimization.optimize(snapshot, capturedFiles);
					for (const path of capturedFiles) {
						const cache = this._fileTshs.get(path);
						if (cache !== undefined) {
							fileTshs.set(path, cache);
						} else {
							jobs++;
							this._getFileTimestampAndHash(path, (err, entry) => {
								if (err) {
									if (this.logger) {
										this.logger.debug(
											`Error snapshotting file timestamp hash combination of ${path}: ${err.stack}`
										);
									}
									jobError();
								} else {
									fileTshs.set(path, entry);
									jobDone();
								}
							});
						}
					}
					break;
				case 2:
					this._fileHashesOptimization.optimize(snapshot, capturedFiles);
					for (const path of capturedFiles) {
						const cache = this._fileHashes.get(path);
						if (cache !== undefined) {
							fileHashes.set(path, cache);
						} else {
							jobs++;
							this.fileHashQueue.add(path, (err, entry) => {
								if (err) {
									if (this.logger) {
										this.logger.debug(
											`Error snapshotting file hash of ${path}: ${err.stack}`
										);
									}
									jobError();
								} else {
									fileHashes.set(path, entry);
									jobDone();
								}
							});
						}
					}
					break;
				case 1:
					this._fileTimestampsOptimization.optimize(snapshot, capturedFiles);
					for (const path of capturedFiles) {
						const cache = this._fileTimestamps.get(path);
						if (cache !== undefined) {
							if (cache !== "ignore") {
								fileTimestamps.set(path, cache);
							}
						} else {
							jobs++;
							this.fileTimestampQueue.add(path, (err, entry) => {
								if (err) {
									if (this.logger) {
										this.logger.debug(
											`Error snapshotting file timestamp of ${path}: ${err.stack}`
										);
									}
									jobError();
								} else {
									fileTimestamps.set(path, entry);
									jobDone();
								}
							});
						}
					}
					break;
			}
		}
		if (directories) {
			const capturedDirectories = captureNonManaged(
				directories,
				managedContexts
			);
			switch (mode) {
				case 3:
					this._contextTshsOptimization.optimize(snapshot, capturedDirectories);
					for (const path of capturedDirectories) {
						const cache = this._contextTshs.get(path);
						/** @type {ResolvedContextTimestampAndHash} */
						let resolved;
						if (
							cache !== undefined &&
							(resolved = getResolvedTimestamp(cache)) !== undefined
						) {
							contextTshs.set(path, resolved);
						} else {
							jobs++;
							/**
							 * @param {Error=} err error
							 * @param {ResolvedContextTimestampAndHash=} entry entry
							 * @returns {void}
							 */
							const callback = (err, entry) => {
								if (err) {
									if (this.logger) {
										this.logger.debug(
											`Error snapshotting context timestamp hash combination of ${path}: ${err.stack}`
										);
									}
									jobError();
								} else {
									contextTshs.set(path, entry);
									jobDone();
								}
							};
							if (cache !== undefined) {
								this._resolveContextTsh(cache, callback);
							} else {
								this.getContextTsh(path, callback);
							}
						}
					}
					break;
				case 2:
					this._contextHashesOptimization.optimize(
						snapshot,
						capturedDirectories
					);
					for (const path of capturedDirectories) {
						const cache = this._contextHashes.get(path);
						let resolved;
						if (
							cache !== undefined &&
							(resolved = getResolvedHash(cache)) !== undefined
						) {
							contextHashes.set(path, resolved);
						} else {
							jobs++;
							const callback = (err, entry) => {
								if (err) {
									if (this.logger) {
										this.logger.debug(
											`Error snapshotting context hash of ${path}: ${err.stack}`
										);
									}
									jobError();
								} else {
									contextHashes.set(path, entry);
									jobDone();
								}
							};
							if (cache !== undefined) {
								this._resolveContextHash(cache, callback);
							} else {
								this.getContextHash(path, callback);
							}
						}
					}
					break;
				case 1:
					this._contextTimestampsOptimization.optimize(
						snapshot,
						capturedDirectories
					);
					for (const path of capturedDirectories) {
						const cache = this._contextTimestamps.get(path);
						if (cache === "ignore") continue;
						let resolved;
						if (
							cache !== undefined &&
							(resolved = getResolvedTimestamp(cache)) !== undefined
						) {
							contextTimestamps.set(path, resolved);
						} else {
							jobs++;
							/**
							 * @param {Error=} err error
							 * @param {ResolvedContextFileSystemInfoEntry=} entry entry
							 * @returns {void}
							 */
							const callback = (err, entry) => {
								if (err) {
									if (this.logger) {
										this.logger.debug(
											`Error snapshotting context timestamp of ${path}: ${err.stack}`
										);
									}
									jobError();
								} else {
									contextTimestamps.set(path, entry);
									jobDone();
								}
							};
							if (cache !== undefined) {
								this._resolveContextTimestamp(cache, callback);
							} else {
								this.getContextTimestamp(path, callback);
							}
						}
					}
					break;
			}
		}
		if (missing) {
			const capturedMissing = captureNonManaged(missing, managedMissing);
			this._missingExistenceOptimization.optimize(snapshot, capturedMissing);
			for (const path of capturedMissing) {
				const cache = this._fileTimestamps.get(path);
				if (cache !== undefined) {
					if (cache !== "ignore") {
						missingExistence.set(path, Boolean(cache));
					}
				} else {
					jobs++;
					this.fileTimestampQueue.add(path, (err, entry) => {
						if (err) {
							if (this.logger) {
								this.logger.debug(
									`Error snapshotting missing timestamp of ${path}: ${err.stack}`
								);
							}
							jobError();
						} else {
							missingExistence.set(path, Boolean(entry));
							jobDone();
						}
					});
				}
			}
		}
		this._managedItemInfoOptimization.optimize(snapshot, managedItems);
		for (const path of managedItems) {
			const cache = this._managedItems.get(path);
			if (cache !== undefined) {
				managedItemInfo.set(path, cache);
			} else {
				jobs++;
				this.managedItemQueue.add(path, (err, entry) => {
					if (err) {
						if (this.logger) {
							this.logger.debug(
								`Error snapshotting managed item ${path}: ${err.stack}`
							);
						}
						jobError();
					} else {
						managedItemInfo.set(path, entry);
						jobDone();
					}
				});
			}
		}
		jobDone();
	}

/**
	 * @param {Snapshot} snapshot1 a snapshot
	 * @param {Snapshot} snapshot2 a snapshot
	 * @returns {Snapshot} merged snapshot
	 */
	mergeSnapshots(snapshot1, snapshot2) {
		const snapshot = new Snapshot();
		if (snapshot1.hasStartTime() && snapshot2.hasStartTime())
			snapshot.setStartTime(Math.min(snapshot1.startTime, snapshot2.startTime));
		else if (snapshot2.hasStartTime()) snapshot.startTime = snapshot2.startTime;
		else if (snapshot1.hasStartTime()) snapshot.startTime = snapshot1.startTime;
		if (snapshot1.hasFileTimestamps() || snapshot2.hasFileTimestamps()) {
			snapshot.setFileTimestamps(
				mergeMaps(snapshot1.fileTimestamps, snapshot2.fileTimestamps)
			);
		}
		if (snapshot1.hasFileHashes() || snapshot2.hasFileHashes()) {
			snapshot.setFileHashes(
				mergeMaps(snapshot1.fileHashes, snapshot2.fileHashes)
			);
		}
		if (snapshot1.hasFileTshs() || snapshot2.hasFileTshs()) {
			snapshot.setFileTshs(mergeMaps(snapshot1.fileTshs, snapshot2.fileTshs));
		}
		if (snapshot1.hasContextTimestamps() || snapshot2.hasContextTimestamps()) {
			snapshot.setContextTimestamps(
				mergeMaps(snapshot1.contextTimestamps, snapshot2.contextTimestamps)
			);
		}
		if (snapshot1.hasContextHashes() || snapshot2.hasContextHashes()) {
			snapshot.setContextHashes(
				mergeMaps(snapshot1.contextHashes, snapshot2.contextHashes)
			);
		}
		if (snapshot1.hasContextTshs() || snapshot2.hasContextTshs()) {
			snapshot.setContextTshs(
				mergeMaps(snapshot1.contextTshs, snapshot2.contextTshs)
			);
		}
		if (snapshot1.hasMissingExistence() || snapshot2.hasMissingExistence()) {
			snapshot.setMissingExistence(
				mergeMaps(snapshot1.missingExistence, snapshot2.missingExistence)
			);
		}
		if (snapshot1.hasManagedItemInfo() || snapshot2.hasManagedItemInfo()) {
			snapshot.setManagedItemInfo(
				mergeMaps(snapshot1.managedItemInfo, snapshot2.managedItemInfo)
			);
		}
		if (snapshot1.hasManagedFiles() || snapshot2.hasManagedFiles()) {
			snapshot.setManagedFiles(
				mergeSets(snapshot1.managedFiles, snapshot2.managedFiles)
			);
		}
		if (snapshot1.hasManagedContexts() || snapshot2.hasManagedContexts()) {
			snapshot.setManagedContexts(
				mergeSets(snapshot1.managedContexts, snapshot2.managedContexts)
			);
		}
		if (snapshot1.hasManagedMissing() || snapshot2.hasManagedMissing()) {
			snapshot.setManagedMissing(
				mergeSets(snapshot1.managedMissing, snapshot2.managedMissing)
			);
		}
		if (snapshot1.hasChildren() || snapshot2.hasChildren()) {
			snapshot.setChildren(mergeSets(snapshot1.children, snapshot2.children));
		}
		if (
			this._snapshotCache.get(snapshot1) === true &&
			this._snapshotCache.get(snapshot2) === true
		) {
			this._snapshotCache.set(snapshot, true);
		}
		return snapshot;
	}

/**
	 * @param {Snapshot} snapshot the snapshot made
	 * @param {function(WebpackError=, boolean=): void} callback callback function
	 * @returns {void}
	 */
	checkSnapshotValid(snapshot, callback) {
		const cachedResult = this._snapshotCache.get(snapshot);
		if (cachedResult !== undefined) {
			this._statTestedSnapshotsCached++;
			if (typeof cachedResult === "boolean") {
				callback(null, cachedResult);
			} else {
				cachedResult.push(callback);
			}
			return;
		}
		this._statTestedSnapshotsNotCached++;
		this._checkSnapshotValidNoCache(snapshot, callback);
	}

/**
	 * @param {Snapshot} snapshot the snapshot made
	 * @param {function(WebpackError=, boolean=): void} callback callback function
	 * @returns {void}
	 */
	_checkSnapshotValidNoCache(snapshot, callback) {
		/** @type {number | undefined} */
		let startTime = undefined;
		if (snapshot.hasStartTime()) {
			startTime = snapshot.startTime;
		}
		let jobs = 1;
		const jobDone = () => {
			if (--jobs === 0) {
				this._snapshotCache.set(snapshot, true);
				callback(null, true);
			}
		};
		const invalid = () => {
			if (jobs > 0) {
				// large negative number instead of NaN or something else to keep jobs to stay a SMI (v8)
				jobs = -100000000;
				this._snapshotCache.set(snapshot, false);
				callback(null, false);
			}
		};
		const invalidWithError = (path, err) => {
			if (this._remainingLogs > 0) {
				this._log(path, `error occurred: %s`, err);
			}
			invalid();
		};
		/**
		 * @param {string} path file path
		 * @param {string} current current hash
		 * @param {string} snap snapshot hash
		 * @returns {boolean} true, if ok
		 */
		const checkHash = (path, current, snap) => {
			if (current !== snap) {
				// If hash differ it's invalid
				if (this._remainingLogs > 0) {
					this._log(path, `hashes differ (%s != %s)`, current, snap);
				}
				return false;
			}
			return true;
		};
		/**
		 * @param {string} path file path
		 * @param {boolean} current current entry
		 * @param {boolean} snap entry from snapshot
		 * @returns {boolean} true, if ok
		 */
		const checkExistence = (path, current, snap) => {
			if (!current !== !snap) {
				// If existence of item differs
				// it's invalid
				if (this._remainingLogs > 0) {
					this._log(
						path,
						current ? "it didn't exist before" : "it does no longer exist"
					);
				}
				return false;
			}
			return true;
		};
		/**
		 * @param {string} path file path
		 * @param {FileSystemInfoEntry} current current entry
		 * @param {FileSystemInfoEntry} snap entry from snapshot
		 * @param {boolean} log log reason
		 * @returns {boolean} true, if ok
		 */
		const checkFile = (path, current, snap, log = true) => {
			if (current === snap) return true;
			if (!checkExistence(path, Boolean(current), Boolean(snap))) return false;
			if (current) {
				// For existing items only
				if (typeof startTime === "number" && current.safeTime > startTime) {
					// If a change happened after starting reading the item
					// this may no longer be valid
					if (log && this._remainingLogs > 0) {
						this._log(
							path,
							`it may have changed (%d) after the start time of the snapshot (%d)`,
							current.safeTime,
							startTime
						);
					}
					return false;
				}
				if (
					snap.timestamp !== undefined &&
					current.timestamp !== snap.timestamp
				) {
					// If we have a timestamp (it was a file or symlink) and it differs from current timestamp
					// it's invalid
					if (log && this._remainingLogs > 0) {
						this._log(
							path,
							`timestamps differ (%d != %d)`,
							current.timestamp,
							snap.timestamp
						);
					}
					return false;
				}
			}
			return true;
		};
		/**
		 * @param {string} path file path
		 * @param {ResolvedContextFileSystemInfoEntry} current current entry
		 * @param {ResolvedContextFileSystemInfoEntry} snap entry from snapshot
		 * @param {boolean} log log reason
		 * @returns {boolean} true, if ok
		 */
		const checkContext = (path, current, snap, log = true) => {
			if (current === snap) return true;
			if (!checkExistence(path, Boolean(current), Boolean(snap))) return false;
			if (current) {
				// For existing items only
				if (typeof startTime === "number" && current.safeTime > startTime) {
					// If a change happened after starting reading the item
					// this may no longer be valid
					if (log && this._remainingLogs > 0) {
						this._log(
							path,
							`it may have changed (%d) after the start time of the snapshot (%d)`,
							current.safeTime,
							startTime
						);
					}
					return false;
				}
				if (
					snap.timestampHash !== undefined &&
					current.timestampHash !== snap.timestampHash
				) {
					// If we have a timestampHash (it was a directory) and it differs from current timestampHash
					// it's invalid
					if (log && this._remainingLogs > 0) {
						this._log(
							path,
							`timestamps hashes differ (%s != %s)`,
							current.timestampHash,
							snap.timestampHash
						);
					}
					return false;
				}
			}
			return true;
		};
		if (snapshot.hasChildren()) {
			const childCallback = (err, result) => {
				if (err || !result) return invalid();
				else jobDone();
			};
			for (const child of snapshot.children) {
				const cache = this._snapshotCache.get(child);
				if (cache !== undefined) {
					this._statTestedChildrenCached++;
					/* istanbul ignore else */
					if (typeof cache === "boolean") {
						if (cache === false) {
							invalid();
							return;
						}
					} else {
						jobs++;
						cache.push(childCallback);
					}
				} else {
					this._statTestedChildrenNotCached++;
					jobs++;
					this._checkSnapshotValidNoCache(child, childCallback);
				}
			}
		}
		if (snapshot.hasFileTimestamps()) {
			const { fileTimestamps } = snapshot;
			this._statTestedEntries += fileTimestamps.size;
			for (const [path, ts] of fileTimestamps) {
				const cache = this._fileTimestamps.get(path);
				if (cache !== undefined) {
					if (cache !== "ignore" && !checkFile(path, cache, ts)) {
						invalid();
						return;
					}
				} else {
					jobs++;
					this.fileTimestampQueue.add(path, (err, entry) => {
						if (err) return invalidWithError(path, err);
						if (!checkFile(path, entry, ts)) {
							invalid();
						} else {
							jobDone();
						}
					});
				}
			}
		}
		const processFileHashSnapshot = (path, hash) => {
			const cache = this._fileHashes.get(path);
			if (cache !== undefined) {
				if (cache !== "ignore" && !checkHash(path, cache, hash)) {
					invalid();
					return;
				}
			} else {
				jobs++;
				this.fileHashQueue.add(path, (err, entry) => {
					if (err) return invalidWithError(path, err);
					if (!checkHash(path, entry, hash)) {
						invalid();
					} else {
						jobDone();
					}
				});
			}
		};
		if (snapshot.hasFileHashes()) {
			const { fileHashes } = snapshot;
			this._statTestedEntries += fileHashes.size;
			for (const [path, hash] of fileHashes) {
				processFileHashSnapshot(path, hash);
			}
		}
		if (snapshot.hasFileTshs()) {
			const { fileTshs } = snapshot;
			this._statTestedEntries += fileTshs.size;
			for (const [path, tsh] of fileTshs) {
				if (typeof tsh === "string") {
					processFileHashSnapshot(path, tsh);
				} else {
					const cache = this._fileTimestamps.get(path);
					if (cache !== undefined) {
						if (cache === "ignore" || !checkFile(path, cache, tsh, false)) {
							processFileHashSnapshot(path, tsh && tsh.hash);
						}
					} else {
						jobs++;
						this.fileTimestampQueue.add(path, (err, entry) => {
							if (err) return invalidWithError(path, err);
							if (!checkFile(path, entry, tsh, false)) {
								processFileHashSnapshot(path, tsh && tsh.hash);
							}
							jobDone();
						});
					}
				}
			}
		}
		if (snapshot.hasContextTimestamps()) {
			const { contextTimestamps } = snapshot;
			this._statTestedEntries += contextTimestamps.size;
			for (const [path, ts] of contextTimestamps) {
				const cache = this._contextTimestamps.get(path);
				if (cache === "ignore") continue;
				let resolved;
				if (
					cache !== undefined &&
					(resolved = getResolvedTimestamp(cache)) !== undefined
				) {
					if (!checkContext(path, resolved, ts)) {
						invalid();
						return;
					}
				} else {
					jobs++;
					/**
					 * @param {Error=} err error
					 * @param {ResolvedContextFileSystemInfoEntry=} entry entry
					 * @returns {void}
					 */
					const callback = (err, entry) => {
						if (err) return invalidWithError(path, err);
						if (!checkContext(path, entry, ts)) {
							invalid();
						} else {
							jobDone();
						}
					};
					if (cache !== undefined) {
						this._resolveContextTimestamp(cache, callback);
					} else {
						this.getContextTimestamp(path, callback);
					}
				}
			}
		}
		const processContextHashSnapshot = (path, hash) => {
			const cache = this._contextHashes.get(path);
			let resolved;
			if (
				cache !== undefined &&
				(resolved = getResolvedHash(cache)) !== undefined
			) {
				if (!checkHash(path, resolved, hash)) {
					invalid();
					return;
				}
			} else {
				jobs++;
				const callback = (err, entry) => {
					if (err) return invalidWithError(path, err);
					if (!checkHash(path, entry, hash)) {
						invalid();
					} else {
						jobDone();
					}
				};
				if (cache !== undefined) {
					this._resolveContextHash(cache, callback);
				} else {
					this.getContextHash(path, callback);
				}
			}
		};
		if (snapshot.hasContextHashes()) {
			const { contextHashes } = snapshot;
			this._statTestedEntries += contextHashes.size;
			for (const [path, hash] of contextHashes) {
				processContextHashSnapshot(path, hash);
			}
		}
		if (snapshot.hasContextTshs()) {
			const { contextTshs } = snapshot;
			this._statTestedEntries += contextTshs.size;
			for (const [path, tsh] of contextTshs) {
				if (typeof tsh === "string") {
					processContextHashSnapshot(path, tsh);
				} else {
					const cache = this._contextTimestamps.get(path);
					if (cache === "ignore") continue;
					let resolved;
					if (
						cache !== undefined &&
						(resolved = getResolvedTimestamp(cache)) !== undefined
					) {
						if (!checkContext(path, resolved, tsh, false)) {
							processContextHashSnapshot(path, tsh && tsh.hash);
						}
					} else {
						jobs++;
						/**
						 * @param {Error=} err error
						 * @param {ResolvedContextFileSystemInfoEntry=} entry entry
						 * @returns {void}
						 */
						const callback = (err, entry) => {
							if (err) return invalidWithError(path, err);
							if (!checkContext(path, entry, tsh, false)) {
								processContextHashSnapshot(path, tsh && tsh.hash);
							}
							jobDone();
						};
						if (cache !== undefined) {
							this._resolveContextTimestamp(cache, callback);
						} else {
							this.getContextTimestamp(path, callback);
						}
					}
				}
			}
		}
		if (snapshot.hasMissingExistence()) {
			const { missingExistence } = snapshot;
			this._statTestedEntries += missingExistence.size;
			for (const [path, existence] of missingExistence) {
				const cache = this._fileTimestamps.get(path);
				if (cache !== undefined) {
					if (
						cache !== "ignore" &&
						!checkExistence(path, Boolean(cache), Boolean(existence))
					) {
						invalid();
						return;
					}
				} else {
					jobs++;
					this.fileTimestampQueue.add(path, (err, entry) => {
						if (err) return invalidWithError(path, err);
						if (!checkExistence(path, Boolean(entry), Boolean(existence))) {
							invalid();
						} else {
							jobDone();
						}
					});
				}
			}
		}
		if (snapshot.hasManagedItemInfo()) {
			const { managedItemInfo } = snapshot;
			this._statTestedEntries += managedItemInfo.size;
			for (const [path, info] of managedItemInfo) {
				const cache = this._managedItems.get(path);
				if (cache !== undefined) {
					if (!checkHash(path, cache, info)) {
						invalid();
						return;
					}
				} else {
					jobs++;
					this.managedItemQueue.add(path, (err, entry) => {
						if (err) return invalidWithError(path, err);
						if (!checkHash(path, entry, info)) {
							invalid();
						} else {
							jobDone();
						}
					});
				}
			}
		}
		jobDone();

// if there was an async action
		// try to join multiple concurrent request for this snapshot
		if (jobs > 0) {
			const callbacks = [callback];
			callback = (err, result) => {
				for (const callback of callbacks) callback(err, result);
			};
			this._snapshotCache.set(snapshot, callbacks);
		}
	}

_readFileTimestamp(path, callback) {
		this.fs.stat(path, (err, stat) => {
			if (err) {
				if (err.code === "ENOENT") {
					this._fileTimestamps.set(path, null);
					this._cachedDeprecatedFileTimestamps = undefined;
					return callback(null, null);
				}
				return callback(err);
			}

let ts;
			if (stat.isDirectory()) {
				ts = {
					safeTime: 0,
					timestamp: undefined
				};
			} else {
				const mtime = +stat.mtime;

if (mtime) applyMtime(mtime);

ts = {
					safeTime: mtime ? mtime + FS_ACCURACY : Infinity,
					timestamp: mtime
				};
			}

this._fileTimestamps.set(path, ts);
			this._cachedDeprecatedFileTimestamps = undefined;

callback(null, ts);
		});
	}

_readFileHash(path, callback) {
		this.fs.readFile(path, (err, content) => {
			if (err) {
				if (err.code === "EISDIR") {
					this._fileHashes.set(path, "directory");
					return callback(null, "directory");
				}
				if (err.code === "ENOENT") {
					this._fileHashes.set(path, null);
					return callback(null, null);
				}
				if (err.code === "ERR_FS_FILE_TOO_LARGE") {
					this.logger.warn(`Ignoring ${path} for hashing as it's very large`);
					this._fileHashes.set(path, "too large");
					return callback(null, "too large");
				}
				return callback(err);
			}

const hash = createHash(this._hashFunction);

hash.update(content);

const digest = /** @type {string} */ (hash.digest("hex"));

this._fileHashes.set(path, digest);

callback(null, digest);
		});
	}

_getFileTimestampAndHash(path, callback) {
		const continueWithHash = hash => {
			const cache = this._fileTimestamps.get(path);
			if (cache !== undefined) {
				if (cache !== "ignore") {
					const result = {
						...cache,
						hash
					};
					this._fileTshs.set(path, result);
					return callback(null, result);
				} else {
					this._fileTshs.set(path, hash);
					return callback(null, hash);
				}
			} else {
				this.fileTimestampQueue.add(path, (err, entry) => {
					if (err) {
						return callback(err);
					}
					const result = {
						...entry,
						hash
					};
					this._fileTshs.set(path, result);
					return callback(null, result);
				});
			}
		};

/**
	 * @template T
	 * @template ItemType
	 * @param {Object} options options
	 * @param {string} options.path path
	 * @param {function(string): ItemType} options.fromImmutablePath called when context item is an immutable path
	 * @param {function(string): ItemType} options.fromManagedItem called when context item is a managed path
	 * @param {function(string, string, function(Error=, ItemType=): void): void} options.fromSymlink called when context item is a symlink
	 * @param {function(string, IStats, function(Error=, ItemType=): void): void} options.fromFile called when context item is a file
	 * @param {function(string, IStats, function(Error=, ItemType=): void): void} options.fromDirectory called when context item is a directory
	 * @param {function(string[], ItemType[]): T} options.reduce called from all context items
	 * @param {function(Error=, (T)=): void} callback callback
	 */
	_readContext(
		{
			path,
			fromImmutablePath,
			fromManagedItem,
			fromSymlink,
			fromFile,
			fromDirectory,
			reduce
		},
		callback
	) {
		this.fs.readdir(path, (err, _files) => {
			if (err) {
				if (err.code === "ENOENT") {
					return callback(null, null);
				}
				return callback(err);
			}
			const files = /** @type {string[]} */ (_files)
				.map(file => file.normalize("NFC"))
				.filter(file => !/^\./.test(file))
				.sort();
			asyncLib.map(
				files,
				(file, callback) => {
					const child = join(this.fs, path, file);
					for (const immutablePath of this.immutablePathsRegExps) {
						if (immutablePath.test(path)) {
							// ignore any immutable path for timestamping
							return callback(null, fromImmutablePath(path));
						}
					}
					for (const immutablePath of this.immutablePathsWithSlash) {
						if (path.startsWith(immutablePath)) {
							// ignore any immutable path for timestamping
							return callback(null, fromImmutablePath(path));
						}
					}
					for (const managedPath of this.managedPathsRegExps) {
						const match = managedPath.exec(path);
						if (match) {
							const managedItem = getManagedItem(match[1], path);
							if (managedItem) {
								// construct timestampHash from managed info
								return this.managedItemQueue.add(managedItem, (err, info) => {
									if (err) return callback(err);
									return callback(null, fromManagedItem(info));
								});
							}
						}
					}
					for (const managedPath of this.managedPathsWithSlash) {
						if (path.startsWith(managedPath)) {
							const managedItem = getManagedItem(managedPath, child);
							if (managedItem) {
								// construct timestampHash from managed info
								return this.managedItemQueue.add(managedItem, (err, info) => {
									if (err) return callback(err);
									return callback(null, fromManagedItem(info));
								});
							}
						}
					}

lstatReadlinkAbsolute(this.fs, child, (err, stat) => {
						if (err) return callback(err);

if (typeof stat === "string") {
							return fromSymlink(child, stat, callback);
						}

if (stat.isFile()) {
							return fromFile(child, stat, callback);
						}
						if (stat.isDirectory()) {
							return fromDirectory(child, stat, callback);
						}
						callback(null, null);
					});
				},
				(err, results) => {
					if (err) return callback(err);
					const result = reduce(files, results);
					callback(null, result);
				}
			);
		});
	}

_readContextTimestamp(path, callback) {
		this._readContext(
			{
				path,
				fromImmutablePath: () => null,
				fromManagedItem: info => ({
					safeTime: 0,
					timestampHash: info
				}),
				fromSymlink: (file, target, callback) => {
					callback(null, {
						timestampHash: target,
						symlinks: new Set([target])
					});
				},
				fromFile: (file, stat, callback) => {
					// Prefer the cached value over our new stat to report consistent results
					const cache = this._fileTimestamps.get(file);
					if (cache !== undefined)
						return callback(null, cache === "ignore" ? null : cache);

const mtime = +stat.mtime;

if (mtime) applyMtime(mtime);

const ts = {
						safeTime: mtime ? mtime + FS_ACCURACY : Infinity,
						timestamp: mtime
					};

this._fileTimestamps.set(file, ts);
					this._cachedDeprecatedFileTimestamps = undefined;
					callback(null, ts);
				},
				fromDirectory: (directory, stat, callback) => {
					this.contextTimestampQueue.increaseParallelism();
					this._getUnresolvedContextTimestamp(directory, (err, tsEntry) => {
						this.contextTimestampQueue.decreaseParallelism();
						callback(err, tsEntry);
					});
				},
				reduce: (files, tsEntries) => {
					let symlinks = undefined;

const hash = createHash(this._hashFunction);

for (const file of files) hash.update(file);
					let safeTime = 0;
					for (const entry of tsEntries) {
						if (!entry) {
							hash.update("n");
							continue;
						}
						if (entry.timestamp) {
							hash.update("f");
							hash.update(`${entry.timestamp}`);
						} else if (entry.timestampHash) {
							hash.update("d");
							hash.update(`${entry.timestampHash}`);
						}
						if (entry.symlinks !== undefined) {
							if (symlinks === undefined) symlinks = new Set();
							addAll(entry.symlinks, symlinks);
						}
						if (entry.safeTime) {
							safeTime = Math.max(safeTime, entry.safeTime);
						}
					}

const digest = /** @type {string} */ (hash.digest("hex"));

const result = {
						safeTime,
						timestampHash: digest
					};
					if (symlinks) result.symlinks = symlinks;
					return result;
				}
			},
			(err, result) => {
				if (err) return callback(err);
				this._contextTimestamps.set(path, result);
				this._cachedDeprecatedContextTimestamps = undefined;

callback(null, result);
			}
		);
	}

/**
	 * @param {ContextFileSystemInfoEntry} entry entry
	 * @param {function(Error=, ResolvedContextFileSystemInfoEntry=): void} callback callback
	 * @returns {void}
	 */
	_resolveContextTimestamp(entry, callback) {
		const hashes = [];
		let safeTime = 0;
		processAsyncTree(
			entry.symlinks,
			10,
			(target, push, callback) => {
				this._getUnresolvedContextTimestamp(target, (err, entry) => {
					if (err) return callback(err);
					if (entry && entry !== "ignore") {
						hashes.push(entry.timestampHash);
						if (entry.safeTime) {
							safeTime = Math.max(safeTime, entry.safeTime);
						}
						if (entry.symlinks !== undefined) {
							for (const target of entry.symlinks) push(target);
						}
					}
					callback();
				});
			},
			err => {
				if (err) return callback(err);
				const hash = createHash(this._hashFunction);
				hash.update(entry.timestampHash);
				if (entry.safeTime) {
					safeTime = Math.max(safeTime, entry.safeTime);
				}
				hashes.sort();
				for (const h of hashes) {
					hash.update(h);
				}
				callback(
					null,
					(entry.resolved = {
						safeTime,
						timestampHash: /** @type {string} */ (hash.digest("hex"))
					})
				);
			}
		);
	}

_readContextHash(path, callback) {
		this._readContext(
			{
				path,
				fromImmutablePath: () => "",
				fromManagedItem: info => info || "",
				fromSymlink: (file, target, callback) => {
					callback(null, {
						hash: target,
						symlinks: new Set([target])
					});
				},
				fromFile: (file, stat, callback) =>
					this.getFileHash(file, (err, hash) => {
						callback(err, hash || "");
					}),
				fromDirectory: (directory, stat, callback) => {
					this.contextHashQueue.increaseParallelism();
					this._getUnresolvedContextHash(directory, (err, hash) => {
						this.contextHashQueue.decreaseParallelism();
						callback(err, hash || "");
					});
				},
				/**
				 * @param {string[]} files files
				 * @param {(string | ContextHash)[]} fileHashes hashes
				 * @returns {ContextHash} reduced hash
				 */
				reduce: (files, fileHashes) => {
					let symlinks = undefined;
					const hash = createHash(this._hashFunction);

for (const file of files) hash.update(file);
					for (const entry of fileHashes) {
						if (typeof entry === "string") {
							hash.update(entry);
						} else {
							hash.update(entry.hash);
							if (entry.symlinks) {
								if (symlinks === undefined) symlinks = new Set();
								addAll(entry.symlinks, symlinks);
							}
						}
					}

/**
	 * @param {ContextHash} entry context hash
	 * @param {function(Error=, string=): void} callback callback
	 * @returns {void}
	 */
	_resolveContextHash(entry, callback) {
		const hashes = [];
		processAsyncTree(
			entry.symlinks,
			10,
			(target, push, callback) => {
				this._getUnresolvedContextHash(target, (err, hash) => {
					if (err) return callback(err);
					if (hash) {
						hashes.push(hash.hash);
						if (hash.symlinks !== undefined) {
							for (const target of hash.symlinks) push(target);
						}
					}
					callback();
				});
			},
			err => {
				if (err) return callback(err);
				const hash = createHash(this._hashFunction);
				hash.update(entry.hash);
				hashes.sort();
				for (const h of hashes) {
					hash.update(h);
				}
				callback(
					null,
					(entry.resolved = /** @type {string} */ (hash.digest("hex")))
				);
			}
		);
	}

_readContextTimestampAndHash(path, callback) {
		const finalize = (timestamp, hash) => {
			const result =
				timestamp === "ignore"
					? hash
					: {
							...timestamp,
							...hash
					  };
			this._contextTshs.set(path, result);
			callback(null, result);
		};
		const cachedHash = this._contextHashes.get(path);
		const cachedTimestamp = this._contextTimestamps.get(path);
		if (cachedHash !== undefined) {
			if (cachedTimestamp !== undefined) {
				finalize(cachedTimestamp, cachedHash);
			} else {
				this.contextTimestampQueue.add(path, (err, entry) => {
					if (err) return callback(err);
					finalize(entry, cachedHash);
				});
			}
		} else {
			if (cachedTimestamp !== undefined) {
				this.contextHashQueue.add(path, (err, entry) => {
					if (err) return callback(err);
					finalize(cachedTimestamp, entry);
				});
			} else {
				this._readContext(
					{
						path,
						fromImmutablePath: () => null,
						fromManagedItem: info => ({
							safeTime: 0,
							timestampHash: info,
							hash: info || ""
						}),
						fromSymlink: (fle, target, callback) => {
							callback(null, {
								timestampHash: target,
								hash: target,
								symlinks: new Set([target])
							});
						},
						fromFile: (file, stat, callback) => {
							this._getFileTimestampAndHash(file, callback);
						},
						fromDirectory: (directory, stat, callback) => {
							this.contextTshQueue.increaseParallelism();
							this.contextTshQueue.add(directory, (err, result) => {
								this.contextTshQueue.decreaseParallelism();
								callback(err, result);
							});
						},
						/**
						 * @param {string[]} files files
						 * @param {(Partial<TimestampAndHash> & Partial<ContextTimestampAndHash> | string | null)[]} results results
						 * @returns {ContextTimestampAndHash} tsh
						 */
						reduce: (files, results) => {
							let symlinks = undefined;

const tsHash = createHash(this._hashFunction);
							const hash = createHash(this._hashFunction);

for (const file of files) {
								tsHash.update(file);
								hash.update(file);
							}
							let safeTime = 0;
							for (const entry of results) {
								if (!entry) {
									tsHash.update("n");
									continue;
								}
								if (typeof entry === "string") {
									tsHash.update("n");
									hash.update(entry);
									continue;
								}
								if (entry.timestamp) {
									tsHash.update("f");
									tsHash.update(`${entry.timestamp}`);
								} else if (entry.timestampHash) {
									tsHash.update("d");
									tsHash.update(`${entry.timestampHash}`);
								}
								if (entry.symlinks !== undefined) {
									if (symlinks === undefined) symlinks = new Set();
									addAll(entry.symlinks, symlinks);
								}
								if (entry.safeTime) {
									safeTime = Math.max(safeTime, entry.safeTime);
								}
								hash.update(entry.hash);
							}

/**
	 * @param {ContextTimestampAndHash} entry entry
	 * @param {function(Error=, ResolvedContextTimestampAndHash=): void} callback callback
	 * @returns {void}
	 */
	_resolveContextTsh(entry, callback) {
		const hashes = [];
		const tsHashes = [];
		let safeTime = 0;
		processAsyncTree(
			entry.symlinks,
			10,
			(target, push, callback) => {
				this._getUnresolvedContextTsh(target, (err, entry) => {
					if (err) return callback(err);
					if (entry) {
						hashes.push(entry.hash);
						if (entry.timestampHash) tsHashes.push(entry.timestampHash);
						if (entry.safeTime) {
							safeTime = Math.max(safeTime, entry.safeTime);
						}
						if (entry.symlinks !== undefined) {
							for (const target of entry.symlinks) push(target);
						}
					}
					callback();
				});
			},
			err => {
				if (err) return callback(err);
				const hash = createHash(this._hashFunction);
				const tsHash = createHash(this._hashFunction);
				hash.update(entry.hash);
				if (entry.timestampHash) tsHash.update(entry.timestampHash);
				if (entry.safeTime) {
					safeTime = Math.max(safeTime, entry.safeTime);
				}
				hashes.sort();
				for (const h of hashes) {
					hash.update(h);
				}
				tsHashes.sort();
				for (const h of tsHashes) {
					tsHash.update(h);
				}
				callback(
					null,
					(entry.resolved = {
						safeTime,
						timestampHash: /** @type {string} */ (tsHash.digest("hex")),
						hash: /** @type {string} */ (hash.digest("hex"))
					})
				);
			}
		);
	}

_getManagedItemDirectoryInfo(path, callback) {
		this.fs.readdir(path, (err, elements) => {
			if (err) {
				if (err.code === "ENOENT" || err.code === "ENOTDIR") {
					return callback(null, EMPTY_SET);
				}
				return callback(err);
			}
			const set = new Set(
				/** @type {string[]} */ (elements).map(element =>
					join(this.fs, path, element)
				)
			);
			callback(null, set);
		});
	}

_getManagedItemInfo(path, callback) {
		const dir = dirname(this.fs, path);
		this.managedItemDirectoryQueue.add(dir, (err, elements) => {
			if (err) {
				return callback(err);
			}
			if (!elements.has(path)) {
				// file or directory doesn't exist
				this._managedItems.set(path, "missing");
				return callback(null, "missing");
			}
			// something exists
			// it may be a file or directory
			if (
				path.endsWith("node_modules") &&
				(path.endsWith("/node_modules") || path.endsWith("\\node_modules"))
			) {
				// we are only interested in existence of this special directory
				this._managedItems.set(path, "exists");
				return callback(null, "exists");
			}

// we assume it's a directory, as files shouldn't occur in managed paths
			const packageJsonPath = join(this.fs, path, "package.json");
			this.fs.readFile(packageJsonPath, (err, content) => {
				if (err) {
					if (err.code === "ENOENT" || err.code === "ENOTDIR") {
						// no package.json or path is not a directory
						this.fs.readdir(path, (err, elements) => {
							if (
								!err &&
								elements.length === 1 &&
								elements[0] === "node_modules"
							) {
								// This is only a grouping folder e. g. used by yarn
								// we are only interested in existence of this special directory
								this._managedItems.set(path, "nested");
								return callback(null, "nested");
							}
							const problem = `Managed item ${path} isn't a directory or doesn't contain a package.json`;
							this.logger.warn(problem);
							return callback(new Error(problem));
						});
						return;
					}
					return callback(err);
				}
				let data;
				try {
					data = JSON.parse(content.toString("utf-8"));
				} catch (e) {
					return callback(e);
				}
				const info = `${data.name || ""}@${data.version || ""}`;
				this._managedItems.set(path, info);
				callback(null, info);
			});
		});
	}

getDeprecatedFileTimestamps() {
		if (this._cachedDeprecatedFileTimestamps !== undefined)
			return this._cachedDeprecatedFileTimestamps;
		const map = new Map();
		for (const [path, info] of this._fileTimestamps) {
			if (info) map.set(path, typeof info === "object" ? info.safeTime : null);
		}
		return (this._cachedDeprecatedFileTimestamps = map);
	}

getDeprecatedContextTimestamps() {
		if (this._cachedDeprecatedContextTimestamps !== undefined)
			return this._cachedDeprecatedContextTimestamps;
		const map = new Map();
		for (const [path, info] of this._contextTimestamps) {
			if (info) map.set(path, typeof info === "object" ? info.safeTime : null);
		}
		return (this._cachedDeprecatedContextTimestamps = map);
	}
}

module.exports = FileSystemInfo;
module.exports.Snapshot = Snapshot;

cmd: