package.lib.DirectoryWatcher.js Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of watchpack Show documentation
Wrapper library for directory and file watching.
The newest version!
/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
"use strict";

const EventEmitter = require("events").EventEmitter;
const fs = require("graceful-fs");
const path = require("path");

const watchEventSource = require("./watchEventSource");

const EXISTANCE_ONLY_TIME_ENTRY = Object.freeze({});

let FS_ACCURACY = 2000;

const IS_OSX = require("os").platform() === "darwin";
const WATCHPACK_POLLING = process.env.WATCHPACK_POLLING;
const FORCE_POLLING =
	`${+WATCHPACK_POLLING}` === WATCHPACK_POLLING
		? +WATCHPACK_POLLING
		: !!WATCHPACK_POLLING && WATCHPACK_POLLING !== "false";

function withoutCase(str) {
	return str.toLowerCase();
}

function needCalls(times, callback) {
	return function() {
		if (--times === 0) {
			return callback();
		}
	};
}

class Watcher extends EventEmitter {
	constructor(directoryWatcher, filePath, startTime) {
		super();
		this.directoryWatcher = directoryWatcher;
		this.path = filePath;
		this.startTime = startTime && +startTime;
	}

	checkStartTime(mtime, initial) {
		const startTime = this.startTime;
		if (typeof startTime !== "number") return !initial;
		return startTime <= mtime;
	}

	close() {
		this.emit("closed");
	}
}

class DirectoryWatcher extends EventEmitter {
	constructor(watcherManager, directoryPath, options) {
		super();
		if (FORCE_POLLING) {
			options.poll = FORCE_POLLING;
		}
		this.watcherManager = watcherManager;
		this.options = options;
		this.path = directoryPath;
		// safeTime is the point in time after which reading is safe to be unchanged
		// timestamp is a value that should be compared with another timestamp (mtime)
		/** @type {Map} */
		this.filesWithoutCase = new Map();
		this.directories = new Map();
		this.lastWatchEvent = 0;
		this.initialScan = true;
		this.ignored = options.ignored || (() => false);
		this.nestedWatching = false;
		this.polledWatching =
			typeof options.poll === "number"
				? options.poll
				: options.poll
				? 5007
				: false;
		this.timeout = undefined;
		this.initialScanRemoved = new Set();
		this.initialScanFinished = undefined;
		/** @type {Map>} */
		this.watchers = new Map();
		this.parentWatcher = null;
		this.refs = 0;
		this._activeEvents = new Map();
		this.closed = false;
		this.scanning = false;
		this.scanAgain = false;
		this.scanAgainInitial = false;

		this.createWatcher();
		this.doScan(true);
	}

	createWatcher() {
		try {
			if (this.polledWatching) {
				this.watcher = {
					close: () => {
						if (this.timeout) {
							clearTimeout(this.timeout);
							this.timeout = undefined;
						}
					}
				};
			} else {
				if (IS_OSX) {
					this.watchInParentDirectory();
				}
				this.watcher = watchEventSource.watch(this.path);
				this.watcher.on("change", this.onWatchEvent.bind(this));
				this.watcher.on("error", this.onWatcherError.bind(this));
			}
		} catch (err) {
			this.onWatcherError(err);
		}
	}

	forEachWatcher(path, fn) {
		const watchers = this.watchers.get(withoutCase(path));
		if (watchers !== undefined) {
			for (const w of watchers) {
				fn(w);
			}
		}
	}

	setMissing(itemPath, initial, type) {
		if (this.initialScan) {
			this.initialScanRemoved.add(itemPath);
		}

		const oldDirectory = this.directories.get(itemPath);
		if (oldDirectory) {
			if (this.nestedWatching) oldDirectory.close();
			this.directories.delete(itemPath);

			this.forEachWatcher(itemPath, w => w.emit("remove", type));
			if (!initial) {
				this.forEachWatcher(this.path, w =>
					w.emit("change", itemPath, null, type, initial)
				);
			}
		}

		const oldFile = this.files.get(itemPath);
		if (oldFile) {
			this.files.delete(itemPath);
			const key = withoutCase(itemPath);
			const count = this.filesWithoutCase.get(key) - 1;
			if (count <= 0) {
				this.filesWithoutCase.delete(key);
				this.forEachWatcher(itemPath, w => w.emit("remove", type));
			} else {
				this.filesWithoutCase.set(key, count);
			}

			if (!initial) {
				this.forEachWatcher(this.path, w =>
					w.emit("change", itemPath, null, type, initial)
				);
			}
		}
	}

	setFileTime(filePath, mtime, initial, ignoreWhenEqual, type) {
		const now = Date.now();

		if (this.ignored(filePath)) return;

		const old = this.files.get(filePath);

		let safeTime, accuracy;
		if (initial) {
			safeTime = Math.min(now, mtime) + FS_ACCURACY;
			accuracy = FS_ACCURACY;
		} else {
			safeTime = now;
			accuracy = 0;

			if (old && old.timestamp === mtime && mtime + FS_ACCURACY < now) {
				// We are sure that mtime is untouched
				// This can be caused by some file attribute change
				// e. g. when access time has been changed
				// but the file content is untouched
				return;
			}
		}

		if (ignoreWhenEqual && old && old.timestamp === mtime) return;

		this.files.set(filePath, {
			safeTime,
			accuracy,
			timestamp: mtime
		});

		if (!old) {
			const key = withoutCase(filePath);
			const count = this.filesWithoutCase.get(key);
			this.filesWithoutCase.set(key, (count || 0) + 1);
			if (count !== undefined) {
				// There is already a file with case-insensitive-equal name
				// On a case-insensitive filesystem we may miss the renaming
				// when only casing is changed.
				// To be sure that our information is correct
				// we trigger a rescan here
				this.doScan(false);
			}

			this.forEachWatcher(filePath, w => {
				if (!initial || w.checkStartTime(safeTime, initial)) {
					w.emit("change", mtime, type);
				}
			});
		} else if (!initial) {
			this.forEachWatcher(filePath, w => w.emit("change", mtime, type));
		}
		this.forEachWatcher(this.path, w => {
			if (!initial || w.checkStartTime(safeTime, initial)) {
				w.emit("change", filePath, safeTime, type, initial);
			}
		});
	}

	setDirectory(directoryPath, birthtime, initial, type) {
		if (this.ignored(directoryPath)) return;
		if (directoryPath === this.path) {
			if (!initial) {
				this.forEachWatcher(this.path, w =>
					w.emit("change", directoryPath, birthtime, type, initial)
				);
			}
		} else {
			const old = this.directories.get(directoryPath);
			if (!old) {
				const now = Date.now();

				if (this.nestedWatching) {
					this.createNestedWatcher(directoryPath);
				} else {
					this.directories.set(directoryPath, true);
				}

				let safeTime;
				if (initial) {
					safeTime = Math.min(now, birthtime) + FS_ACCURACY;
				} else {
					safeTime = now;
				}

				this.forEachWatcher(directoryPath, w => {
					if (!initial || w.checkStartTime(safeTime, false)) {
						w.emit("change", birthtime, type);
					}
				});
				this.forEachWatcher(this.path, w => {
					if (!initial || w.checkStartTime(safeTime, initial)) {
						w.emit("change", directoryPath, safeTime, type, initial);
					}
				});
			}
		}
	}

	createNestedWatcher(directoryPath) {
		const watcher = this.watcherManager.watchDirectory(directoryPath, 1);
		watcher.on("change", (filePath, mtime, type, initial) => {
			this.forEachWatcher(this.path, w => {
				if (!initial || w.checkStartTime(mtime, initial)) {
					w.emit("change", filePath, mtime, type, initial);
				}
			});
		});
		this.directories.set(directoryPath, watcher);
	}

	setNestedWatching(flag) {
		if (this.nestedWatching !== !!flag) {
			this.nestedWatching = !!flag;
			if (this.nestedWatching) {
				for (const directory of this.directories.keys()) {
					this.createNestedWatcher(directory);
				}
			} else {
				for (const [directory, watcher] of this.directories) {
					watcher.close();
					this.directories.set(directory, true);
				}
			}
		}
	}

	watch(filePath, startTime) {
		const key = withoutCase(filePath);
		let watchers = this.watchers.get(key);
		if (watchers === undefined) {
			watchers = new Set();
			this.watchers.set(key, watchers);
		}
		this.refs++;
		const watcher = new Watcher(this, filePath, startTime);
		watcher.on("closed", () => {
			if (--this.refs <= 0) {
				this.close();
				return;
			}
			watchers.delete(watcher);
			if (watchers.size === 0) {
				this.watchers.delete(key);
				if (this.path === filePath) this.setNestedWatching(false);
			}
		});
		watchers.add(watcher);
		let safeTime;
		if (filePath === this.path) {
			this.setNestedWatching(true);
			safeTime = this.lastWatchEvent;
			for (const entry of this.files.values()) {
				fixupEntryAccuracy(entry);
				safeTime = Math.max(safeTime, entry.safeTime);
			}
		} else {
			const entry = this.files.get(filePath);
			if (entry) {
				fixupEntryAccuracy(entry);
				safeTime = entry.safeTime;
			} else {
				safeTime = 0;
			}
		}
		if (safeTime) {
			if (safeTime >= startTime) {
				process.nextTick(() => {
					if (this.closed) return;
					if (filePath === this.path) {
						watcher.emit(
							"change",
							filePath,
							safeTime,
							"watch (outdated on attach)",
							true
						);
					} else {
						watcher.emit(
							"change",
							safeTime,
							"watch (outdated on attach)",
							true
						);
					}
				});
			}
		} else if (this.initialScan) {
			if (this.initialScanRemoved.has(filePath)) {
				process.nextTick(() => {
					if (this.closed) return;
					watcher.emit("remove");
				});
			}
		} else if (
			filePath !== this.path &&
			!this.directories.has(filePath) &&
			watcher.checkStartTime(this.initialScanFinished, false)
		) {
			process.nextTick(() => {
				if (this.closed) return;
				watcher.emit("initial-missing", "watch (missing on attach)");
			});
		}
		return watcher;
	}

	onWatchEvent(eventType, filename) {
		if (this.closed) return;
		if (!filename) {
			// In some cases no filename is provided
			// This seem to happen on windows
			// So some event happened but we don't know which file is affected
			// We have to do a full scan of the directory
			this.doScan(false);
			return;
		}

		const filePath = path.join(this.path, filename);
		if (this.ignored(filePath)) return;

		if (this._activeEvents.get(filename) === undefined) {
			this._activeEvents.set(filename, false);
			const checkStats = () => {
				if (this.closed) return;
				this._activeEvents.set(filename, false);
				fs.lstat(filePath, (err, stats) => {
					if (this.closed) return;
					if (this._activeEvents.get(filename) === true) {
						process.nextTick(checkStats);
						return;
					}
					this._activeEvents.delete(filename);
					// ENOENT happens when the file/directory doesn't exist
					// EPERM happens when the containing directory doesn't exist
					if (err) {
						if (
							err.code !== "ENOENT" &&
							err.code !== "EPERM" &&
							err.code !== "EBUSY"
						) {
							this.onStatsError(err);
						} else {
							if (filename === path.basename(this.path)) {
								// This may indicate that the directory itself was removed
								if (!fs.existsSync(this.path)) {
									this.onDirectoryRemoved("stat failed");
								}
							}
						}
					}
					this.lastWatchEvent = Date.now();
					if (!stats) {
						this.setMissing(filePath, false, eventType);
					} else if (stats.isDirectory()) {
						this.setDirectory(
							filePath,
							+stats.birthtime || 1,
							false,
							eventType
						);
					} else if (stats.isFile() || stats.isSymbolicLink()) {
						if (stats.mtime) {
							ensureFsAccuracy(stats.mtime);
						}
						this.setFileTime(
							filePath,
							+stats.mtime || +stats.ctime || 1,
							false,
							false,
							eventType
						);
					}
				});
			};
			process.nextTick(checkStats);
		} else {
			this._activeEvents.set(filename, true);
		}
	}

	onWatcherError(err) {
		if (this.closed) return;
		if (err) {
			if (err.code !== "EPERM" && err.code !== "ENOENT") {
				console.error("Watchpack Error (watcher): " + err);
			}
			this.onDirectoryRemoved("watch error");
		}
	}

	onStatsError(err) {
		if (err) {
			console.error("Watchpack Error (stats): " + err);
		}
	}

	onScanError(err) {
		if (err) {
			console.error("Watchpack Error (initial scan): " + err);
		}
		this.onScanFinished();
	}

	onScanFinished() {
		if (this.polledWatching) {
			this.timeout = setTimeout(() => {
				if (this.closed) return;
				this.doScan(false);
			}, this.polledWatching);
		}
	}

	onDirectoryRemoved(reason) {
		if (this.watcher) {
			this.watcher.close();
			this.watcher = null;
		}
		this.watchInParentDirectory();
		const type = `directory-removed (${reason})`;
		for (const directory of this.directories.keys()) {
			this.setMissing(directory, null, type);
		}
		for (const file of this.files.keys()) {
			this.setMissing(file, null, type);
		}
	}

	watchInParentDirectory() {
		if (!this.parentWatcher) {
			const parentDir = path.dirname(this.path);
			// avoid watching in the root directory
			// removing directories in the root directory is not supported
			if (path.dirname(parentDir) === parentDir) return;

			this.parentWatcher = this.watcherManager.watchFile(this.path, 1);
			this.parentWatcher.on("change", (mtime, type) => {
				if (this.closed) return;

				// On non-osx platforms we don't need this watcher to detect
				// directory removal, as an EPERM error indicates that
				if ((!IS_OSX || this.polledWatching) && this.parentWatcher) {
					this.parentWatcher.close();
					this.parentWatcher = null;
				}
				// Try to create the watcher when parent directory is found
				if (!this.watcher) {
					this.createWatcher();
					this.doScan(false);

					// directory was created so we emit an event
					this.forEachWatcher(this.path, w =>
						w.emit("change", this.path, mtime, type, false)
					);
				}
			});
			this.parentWatcher.on("remove", () => {
				this.onDirectoryRemoved("parent directory removed");
			});
		}
	}

	doScan(initial) {
		if (this.scanning) {
			if (this.scanAgain) {
				if (!initial) this.scanAgainInitial = false;
			} else {
				this.scanAgain = true;
				this.scanAgainInitial = initial;
			}
			return;
		}
		this.scanning = true;
		if (this.timeout) {
			clearTimeout(this.timeout);
			this.timeout = undefined;
		}
		process.nextTick(() => {
			if (this.closed) return;
			fs.readdir(this.path, (err, items) => {
				if (this.closed) return;
				if (err) {
					if (err.code === "ENOENT" || err.code === "EPERM") {
						this.onDirectoryRemoved("scan readdir failed");
					} else {
						this.onScanError(err);
					}
					this.initialScan = false;
					this.initialScanFinished = Date.now();
					if (initial) {
						for (const watchers of this.watchers.values()) {
							for (const watcher of watchers) {
								if (watcher.checkStartTime(this.initialScanFinished, false)) {
									watcher.emit(
										"initial-missing",
										"scan (parent directory missing in initial scan)"
									);
								}
							}
						}
					}
					if (this.scanAgain) {
						this.scanAgain = false;
						this.doScan(this.scanAgainInitial);
					} else {
						this.scanning = false;
					}
					return;
				}
				const itemPaths = new Set(
					items.map(item => path.join(this.path, item.normalize("NFC")))
				);
				for (const file of this.files.keys()) {
					if (!itemPaths.has(file)) {
						this.setMissing(file, initial, "scan (missing)");
					}
				}
				for (const directory of this.directories.keys()) {
					if (!itemPaths.has(directory)) {
						this.setMissing(directory, initial, "scan (missing)");
					}
				}
				if (this.scanAgain) {
					// Early repeat of scan
					this.scanAgain = false;
					this.doScan(initial);
					return;
				}
				const itemFinished = needCalls(itemPaths.size + 1, () => {
					if (this.closed) return;
					this.initialScan = false;
					this.initialScanRemoved = null;
					this.initialScanFinished = Date.now();
					if (initial) {
						const missingWatchers = new Map(this.watchers);
						missingWatchers.delete(withoutCase(this.path));
						for (const item of itemPaths) {
							missingWatchers.delete(withoutCase(item));
						}
						for (const watchers of missingWatchers.values()) {
							for (const watcher of watchers) {
								if (watcher.checkStartTime(this.initialScanFinished, false)) {
									watcher.emit(
										"initial-missing",
										"scan (missing in initial scan)"
									);
								}
							}
						}
					}
					if (this.scanAgain) {
						this.scanAgain = false;
						this.doScan(this.scanAgainInitial);
					} else {
						this.scanning = false;
						this.onScanFinished();
					}
				});
				for (const itemPath of itemPaths) {
					fs.lstat(itemPath, (err2, stats) => {
						if (this.closed) return;
						if (err2) {
							if (
								err2.code === "ENOENT" ||
								err2.code === "EPERM" ||
								err2.code === "EACCES" ||
								err2.code === "EBUSY"
							) {
								this.setMissing(itemPath, initial, "scan (" + err2.code + ")");
							} else {
								this.onScanError(err2);
							}
							itemFinished();
							return;
						}
						if (stats.isFile() || stats.isSymbolicLink()) {
							if (stats.mtime) {
								ensureFsAccuracy(stats.mtime);
							}
							this.setFileTime(
								itemPath,
								+stats.mtime || +stats.ctime || 1,
								initial,
								true,
								"scan (file)"
							);
						} else if (stats.isDirectory()) {
							if (!initial || !this.directories.has(itemPath))
								this.setDirectory(
									itemPath,
									+stats.birthtime || 1,
									initial,
									"scan (dir)"
								);
						}
						itemFinished();
					});
				}
				itemFinished();
			});
		});
	}

	getTimes() {
		const obj = Object.create(null);
		let safeTime = this.lastWatchEvent;
		for (const [file, entry] of this.files) {
			fixupEntryAccuracy(entry);
			safeTime = Math.max(safeTime, entry.safeTime);
			obj[file] = Math.max(entry.safeTime, entry.timestamp);
		}
		if (this.nestedWatching) {
			for (const w of this.directories.values()) {
				const times = w.directoryWatcher.getTimes();
				for (const file of Object.keys(times)) {
					const time = times[file];
					safeTime = Math.max(safeTime, time);
					obj[file] = time;
				}
			}
			obj[this.path] = safeTime;
		}
		if (!this.initialScan) {
			for (const watchers of this.watchers.values()) {
				for (const watcher of watchers) {
					const path = watcher.path;
					if (!Object.prototype.hasOwnProperty.call(obj, path)) {
						obj[path] = null;
					}
				}
			}
		}
		return obj;
	}

	collectTimeInfoEntries(fileTimestamps, directoryTimestamps) {
		let safeTime = this.lastWatchEvent;
		for (const [file, entry] of this.files) {
			fixupEntryAccuracy(entry);
			safeTime = Math.max(safeTime, entry.safeTime);
			fileTimestamps.set(file, entry);
		}
		if (this.nestedWatching) {
			for (const w of this.directories.values()) {
				safeTime = Math.max(
					safeTime,
					w.directoryWatcher.collectTimeInfoEntries(
						fileTimestamps,
						directoryTimestamps
					)
				);
			}
			fileTimestamps.set(this.path, EXISTANCE_ONLY_TIME_ENTRY);
			directoryTimestamps.set(this.path, {
				safeTime
			});
		} else {
			for (const dir of this.directories.keys()) {
				// No additional info about this directory
				// but maybe another DirectoryWatcher has info
				fileTimestamps.set(dir, EXISTANCE_ONLY_TIME_ENTRY);
				if (!directoryTimestamps.has(dir))
					directoryTimestamps.set(dir, EXISTANCE_ONLY_TIME_ENTRY);
			}
			fileTimestamps.set(this.path, EXISTANCE_ONLY_TIME_ENTRY);
			directoryTimestamps.set(this.path, EXISTANCE_ONLY_TIME_ENTRY);
		}
		if (!this.initialScan) {
			for (const watchers of this.watchers.values()) {
				for (const watcher of watchers) {
					const path = watcher.path;
					if (!fileTimestamps.has(path)) {
						fileTimestamps.set(path, null);
					}
				}
			}
		}
		return safeTime;
	}

	close() {
		this.closed = true;
		this.initialScan = false;
		if (this.watcher) {
			this.watcher.close();
			this.watcher = null;
		}
		if (this.nestedWatching) {
			for (const w of this.directories.values()) {
				w.close();
			}
			this.directories.clear();
		}
		if (this.parentWatcher) {
			this.parentWatcher.close();
			this.parentWatcher = null;
		}
		this.emit("closed");
	}
}

module.exports = DirectoryWatcher;
module.exports.EXISTANCE_ONLY_TIME_ENTRY = EXISTANCE_ONLY_TIME_ENTRY;

function fixupEntryAccuracy(entry) {
	if (entry.accuracy > FS_ACCURACY) {
		entry.safeTime = entry.safeTime - entry.accuracy + FS_ACCURACY;
		entry.accuracy = FS_ACCURACY;
	}
}

function ensureFsAccuracy(mtime) {
	if (!mtime) return;
	if (FS_ACCURACY > 1 && mtime % 1 !== 0) FS_ACCURACY = 1;
	else if (FS_ACCURACY > 10 && mtime % 10 !== 0) FS_ACCURACY = 10;
	else if (FS_ACCURACY > 100 && mtime % 100 !== 0) FS_ACCURACY = 100;
	else if (FS_ACCURACY > 1000 && mtime % 1000 !== 0) FS_ACCURACY = 1000;
}