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1 files changed, 477 insertions, 0 deletions

diff --git a/node_modules/enhanced-resolve/lib/CachedInputFileSystem.js b/node_modules/enhanced-resolve/lib/CachedInputFileSystem.js
new file mode 100644
index 0000000..74dbd98
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+++ b/node_modules/enhanced-resolve/lib/CachedInputFileSystem.js
@@ -0,0 +1,477 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const nextTick = require("process").nextTick;
+
+/** @typedef {import("./Resolver").FileSystem} FileSystem */
+/** @typedef {import("./Resolver").SyncFileSystem} SyncFileSystem */
+
+const dirname = path => {
+	let idx = path.length - 1;
+	while (idx >= 0) {
+		const c = path.charCodeAt(idx);
+		// slash or backslash
+		if (c === 47 || c === 92) break;
+		idx--;
+	}
+	if (idx < 0) return "";
+	return path.slice(0, idx);
+};
+
+const runCallbacks = (callbacks, err, result) => {
+	if (callbacks.length === 1) {
+		callbacks[0](err, result);
+		callbacks.length = 0;
+		return;
+	}
+	let error;
+	for (const callback of callbacks) {
+		try {
+			callback(err, result);
+		} catch (e) {
+			if (!error) error = e;
+		}
+	}
+	callbacks.length = 0;
+	if (error) throw error;
+};
+
+class OperationMergerBackend {
+	/**
+	 * @param {any} provider async method
+	 * @param {any} syncProvider sync method
+	 * @param {any} providerContext call context for the provider methods
+	 */
+	constructor(provider, syncProvider, providerContext) {
+		this._provider = provider;
+		this._syncProvider = syncProvider;
+		this._providerContext = providerContext;
+		this._activeAsyncOperations = new Map();
+
+		this.provide = this._provider
+			? (path, options, callback) => {
+					if (typeof options === "function") {
+						callback = options;
+						options = undefined;
+					}
+					if (options) {
+						return this._provider.call(
+							this._providerContext,
+							path,
+							options,
+							callback
+						);
+					}
+					if (typeof path !== "string") {
+						callback(new TypeError("path must be a string"));
+						return;
+					}
+					let callbacks = this._activeAsyncOperations.get(path);
+					if (callbacks) {
+						callbacks.push(callback);
+						return;
+					}
+					this._activeAsyncOperations.set(path, (callbacks = [callback]));
+					provider(path, (err, result) => {
+						this._activeAsyncOperations.delete(path);
+						runCallbacks(callbacks, err, result);
+					});
+			  }
+			: null;
+		this.provideSync = this._syncProvider
+			? (path, options) => {
+					return this._syncProvider.call(this._providerContext, path, options);
+			  }
+			: null;
+	}
+
+	purge() {}
+	purgeParent() {}
+}
+
+/*
+
+IDLE:
+	insert data: goto SYNC
+
+SYNC:
+	before provide: run ticks
+	event loop tick: goto ASYNC_ACTIVE
+
+ASYNC:
+	timeout: run tick, goto ASYNC_PASSIVE
+
+ASYNC_PASSIVE:
+	before provide: run ticks
+
+IDLE --[insert data]--> SYNC --[event loop tick]--> ASYNC_ACTIVE --[interval tick]-> ASYNC_PASSIVE
+                                                          ^                             |
+                                                          +---------[insert data]-------+
+*/
+
+const STORAGE_MODE_IDLE = 0;
+const STORAGE_MODE_SYNC = 1;
+const STORAGE_MODE_ASYNC = 2;
+
+class CacheBackend {
+	/**
+	 * @param {number} duration max cache duration of items
+	 * @param {any} provider async method
+	 * @param {any} syncProvider sync method
+	 * @param {any} providerContext call context for the provider methods
+	 */
+	constructor(duration, provider, syncProvider, providerContext) {
+		this._duration = duration;
+		this._provider = provider;
+		this._syncProvider = syncProvider;
+		this._providerContext = providerContext;
+		/** @type {Map<string, (function(Error, any): void)[]>} */
+		this._activeAsyncOperations = new Map();
+		/** @type {Map<string, { err: Error, result: any, level: Set<string> }>} */
+		this._data = new Map();
+		/** @type {Set<string>[]} */
+		this._levels = [];
+		for (let i = 0; i < 10; i++) this._levels.push(new Set());
+		for (let i = 5000; i < duration; i += 500) this._levels.push(new Set());
+		this._currentLevel = 0;
+		this._tickInterval = Math.floor(duration / this._levels.length);
+		/** @type {STORAGE_MODE_IDLE | STORAGE_MODE_SYNC | STORAGE_MODE_ASYNC} */
+		this._mode = STORAGE_MODE_IDLE;
+
+		/** @type {NodeJS.Timeout | undefined} */
+		this._timeout = undefined;
+		/** @type {number | undefined} */
+		this._nextDecay = undefined;
+
+		this.provide = provider ? this.provide.bind(this) : null;
+		this.provideSync = syncProvider ? this.provideSync.bind(this) : null;
+	}
+
+	provide(path, options, callback) {
+		if (typeof options === "function") {
+			callback = options;
+			options = undefined;
+		}
+		if (typeof path !== "string") {
+			callback(new TypeError("path must be a string"));
+			return;
+		}
+		if (options) {
+			return this._provider.call(
+				this._providerContext,
+				path,
+				options,
+				callback
+			);
+		}
+
+		// When in sync mode we can move to async mode
+		if (this._mode === STORAGE_MODE_SYNC) {
+			this._enterAsyncMode();
+		}
+
+		// Check in cache
+		let cacheEntry = this._data.get(path);
+		if (cacheEntry !== undefined) {
+			if (cacheEntry.err) return nextTick(callback, cacheEntry.err);
+			return nextTick(callback, null, cacheEntry.result);
+		}
+
+		// Check if there is already the same operation running
+		let callbacks = this._activeAsyncOperations.get(path);
+		if (callbacks !== undefined) {
+			callbacks.push(callback);
+			return;
+		}
+		this._activeAsyncOperations.set(path, (callbacks = [callback]));
+
+		// Run the operation
+		this._provider.call(this._providerContext, path, (err, result) => {
+			this._activeAsyncOperations.delete(path);
+			this._storeResult(path, err, result);
+
+			// Enter async mode if not yet done
+			this._enterAsyncMode();
+
+			runCallbacks(callbacks, err, result);
+		});
+	}
+
+	provideSync(path, options) {
+		if (typeof path !== "string") {
+			throw new TypeError("path must be a string");
+		}
+		if (options) {
+			return this._syncProvider.call(this._providerContext, path, options);
+		}
+
+		// In sync mode we may have to decay some cache items
+		if (this._mode === STORAGE_MODE_SYNC) {
+			this._runDecays();
+		}
+
+		// Check in cache
+		let cacheEntry = this._data.get(path);
+		if (cacheEntry !== undefined) {
+			if (cacheEntry.err) throw cacheEntry.err;
+			return cacheEntry.result;
+		}
+
+		// Get all active async operations
+		// This sync operation will also complete them
+		const callbacks = this._activeAsyncOperations.get(path);
+		this._activeAsyncOperations.delete(path);
+
+		// Run the operation
+		// When in idle mode, we will enter sync mode
+		let result;
+		try {
+			result = this._syncProvider.call(this._providerContext, path);
+		} catch (err) {
+			this._storeResult(path, err, undefined);
+			this._enterSyncModeWhenIdle();
+			if (callbacks) runCallbacks(callbacks, err, undefined);
+			throw err;
+		}
+		this._storeResult(path, undefined, result);
+		this._enterSyncModeWhenIdle();
+		if (callbacks) runCallbacks(callbacks, undefined, result);
+		return result;
+	}
+
+	purge(what) {
+		if (!what) {
+			if (this._mode !== STORAGE_MODE_IDLE) {
+				this._data.clear();
+				for (const level of this._levels) {
+					level.clear();
+				}
+				this._enterIdleMode();
+			}
+		} else if (typeof what === "string") {
+			for (let [key, data] of this._data) {
+				if (key.startsWith(what)) {
+					this._data.delete(key);
+					data.level.delete(key);
+				}
+			}
+			if (this._data.size === 0) {
+				this._enterIdleMode();
+			}
+		} else {
+			for (let [key, data] of this._data) {
+				for (const item of what) {
+					if (key.startsWith(item)) {
+						this._data.delete(key);
+						data.level.delete(key);
+						break;
+					}
+				}
+			}
+			if (this._data.size === 0) {
+				this._enterIdleMode();
+			}
+		}
+	}
+
+	purgeParent(what) {
+		if (!what) {
+			this.purge();
+		} else if (typeof what === "string") {
+			this.purge(dirname(what));
+		} else {
+			const set = new Set();
+			for (const item of what) {
+				set.add(dirname(item));
+			}
+			this.purge(set);
+		}
+	}
+
+	_storeResult(path, err, result) {
+		if (this._data.has(path)) return;
+		const level = this._levels[this._currentLevel];
+		this._data.set(path, { err, result, level });
+		level.add(path);
+	}
+
+	_decayLevel() {
+		const nextLevel = (this._currentLevel + 1) % this._levels.length;
+		const decay = this._levels[nextLevel];
+		this._currentLevel = nextLevel;
+		for (let item of decay) {
+			this._data.delete(item);
+		}
+		decay.clear();
+		if (this._data.size === 0) {
+			this._enterIdleMode();
+		} else {
+			// @ts-ignore _nextDecay is always a number in sync mode
+			this._nextDecay += this._tickInterval;
+		}
+	}
+
+	_runDecays() {
+		while (
+			/** @type {number} */ (this._nextDecay) <= Date.now() &&
+			this._mode !== STORAGE_MODE_IDLE
+		) {
+			this._decayLevel();
+		}
+	}
+
+	_enterAsyncMode() {
+		let timeout = 0;
+		switch (this._mode) {
+			case STORAGE_MODE_ASYNC:
+				return;
+			case STORAGE_MODE_IDLE:
+				this._nextDecay = Date.now() + this._tickInterval;
+				timeout = this._tickInterval;
+				break;
+			case STORAGE_MODE_SYNC:
+				this._runDecays();
+				// @ts-ignore _runDecays may change the mode
+				if (this._mode === STORAGE_MODE_IDLE) return;
+				timeout = Math.max(
+					0,
+					/** @type {number} */ (this._nextDecay) - Date.now()
+				);
+				break;
+		}
+		this._mode = STORAGE_MODE_ASYNC;
+		const ref = setTimeout(() => {
+			this._mode = STORAGE_MODE_SYNC;
+			this._runDecays();
+		}, timeout);
+		if (ref.unref) ref.unref();
+		this._timeout = ref;
+	}
+
+	_enterSyncModeWhenIdle() {
+		if (this._mode === STORAGE_MODE_IDLE) {
+			this._mode = STORAGE_MODE_SYNC;
+			this._nextDecay = Date.now() + this._tickInterval;
+		}
+	}
+
+	_enterIdleMode() {
+		this._mode = STORAGE_MODE_IDLE;
+		this._nextDecay = undefined;
+		if (this._timeout) clearTimeout(this._timeout);
+	}
+}
+
+const createBackend = (duration, provider, syncProvider, providerContext) => {
+	if (duration > 0) {
+		return new CacheBackend(duration, provider, syncProvider, providerContext);
+	}
+	return new OperationMergerBackend(provider, syncProvider, providerContext);
+};
+
+module.exports = class CachedInputFileSystem {
+	constructor(fileSystem, duration) {
+		this.fileSystem = fileSystem;
+
+		this._lstatBackend = createBackend(
+			duration,
+			this.fileSystem.lstat,
+			this.fileSystem.lstatSync,
+			this.fileSystem
+		);
+		const lstat = this._lstatBackend.provide;
+		this.lstat = /** @type {FileSystem["lstat"]} */ (lstat);
+		const lstatSync = this._lstatBackend.provideSync;
+		this.lstatSync = /** @type {SyncFileSystem["lstatSync"]} */ (lstatSync);
+
+		this._statBackend = createBackend(
+			duration,
+			this.fileSystem.stat,
+			this.fileSystem.statSync,
+			this.fileSystem
+		);
+		const stat = this._statBackend.provide;
+		this.stat = /** @type {FileSystem["stat"]} */ (stat);
+		const statSync = this._statBackend.provideSync;
+		this.statSync = /** @type {SyncFileSystem["statSync"]} */ (statSync);
+
+		this._readdirBackend = createBackend(
+			duration,
+			this.fileSystem.readdir,
+			this.fileSystem.readdirSync,
+			this.fileSystem
+		);
+		const readdir = this._readdirBackend.provide;
+		this.readdir = /** @type {FileSystem["readdir"]} */ (readdir);
+		const readdirSync = this._readdirBackend.provideSync;
+		this.readdirSync = /** @type {SyncFileSystem["readdirSync"]} */ (readdirSync);
+
+		this._readFileBackend = createBackend(
+			duration,
+			this.fileSystem.readFile,
+			this.fileSystem.readFileSync,
+			this.fileSystem
+		);
+		const readFile = this._readFileBackend.provide;
+		this.readFile = /** @type {FileSystem["readFile"]} */ (readFile);
+		const readFileSync = this._readFileBackend.provideSync;
+		this.readFileSync = /** @type {SyncFileSystem["readFileSync"]} */ (readFileSync);
+
+		this._readJsonBackend = createBackend(
+			duration,
+			this.fileSystem.readJson ||
+				(this.readFile &&
+					((path, callback) => {
+						// @ts-ignore
+						this.readFile(path, (err, buffer) => {
+							if (err) return callback(err);
+							if (!buffer || buffer.length === 0)
+								return callback(new Error("No file content"));
+							let data;
+							try {
+								data = JSON.parse(buffer.toString("utf-8"));
+							} catch (e) {
+								return callback(e);
+							}
+							callback(null, data);
+						});
+					})),
+			this.fileSystem.readJsonSync ||
+				(this.readFileSync &&
+					(path => {
+						const buffer = this.readFileSync(path);
+						const data = JSON.parse(buffer.toString("utf-8"));
+						return data;
+					})),
+			this.fileSystem
+		);
+		const readJson = this._readJsonBackend.provide;
+		this.readJson = /** @type {FileSystem["readJson"]} */ (readJson);
+		const readJsonSync = this._readJsonBackend.provideSync;
+		this.readJsonSync = /** @type {SyncFileSystem["readJsonSync"]} */ (readJsonSync);
+
+		this._readlinkBackend = createBackend(
+			duration,
+			this.fileSystem.readlink,
+			this.fileSystem.readlinkSync,
+			this.fileSystem
+		);
+		const readlink = this._readlinkBackend.provide;
+		this.readlink = /** @type {FileSystem["readlink"]} */ (readlink);
+		const readlinkSync = this._readlinkBackend.provideSync;
+		this.readlinkSync = /** @type {SyncFileSystem["readlinkSync"]} */ (readlinkSync);
+	}
+
+	purge(what) {
+		this._statBackend.purge(what);
+		this._lstatBackend.purge(what);
+		this._readdirBackend.purgeParent(what);
+		this._readFileBackend.purge(what);
+		this._readlinkBackend.purge(what);
+		this._readJsonBackend.purge(what);
+	}
+};