.12-浅析webpack源码之NodeWatchFileSystem模块总览

const Watchpack = require("watchpack");class NodeWatchFileSystem { ???constructor(inputFileSystem) { ???????this.inputFileSystem = inputFileSystem; ???????this.watcherOptions = { ???????????aggregateTimeout: 0 ???????}; ???????this.watcher = new Watchpack(this.watcherOptions); ???} ???watch( ???????files, /*Array*/ ???????dirs, /*Array*/ ???????missing, /*Array*/ ???????startTime, /*number*/ ???????options, /*object*/ ???????callback, /*function*/ ???????callbackUndelayed /*function*/ ???) { ???????// params validate... ???????const oldWatcher = this.watcher; ???????// 生成Watchpack对象 ???????this.watcher = new Watchpack(options); ???????if (callbackUndelayed) ???????????this.watcher.once("change", callbackUndelayed); ???????this.watcher.once("aggregated", (changes, removals) => { /**/ }); ???????// 调用watch方法 ???????this.watcher.watch(files.concat(missing), dirs.concat(missing), startTime); ???????if (oldWatcher) { ???????????oldWatcher.close(); ???????} ???????return { ???????????close: () => { /**/ }, ???????????pause: () => { /**/ } ???????}; ???}}module.exports = NodeWatchFileSystem;

var watcherManager = require("./watcherManager");var EventEmitter = require("events").EventEmitter;Watchpack.prototype = Object.create(EventEmitter.prototype);class Watchpack { ???constructor(options) { ???????EventEmitter.call(this); ???????if (!options) options = {}; ???????if (!options.aggregateTimeout) options.aggregateTimeout = 200; ???????this.options = options; ???????this.watcherOptions = { ???????????ignored: options.ignored, ???????????poll: options.poll ???????}; ???????this.fileWatchers = []; ???????this.dirWatchers = []; ???????this.mtimes = Object.create(null); ???????this.paused = false; ???????this.aggregatedChanges = []; ???????this.aggregatedRemovals = []; ???????this.aggregateTimeout = 0; ???????this._onTimeout = this._onTimeout.bind(this); ???} ???watch(files, directories, startTime) { ???????this.paused = false; ???????var oldFileWatchers = this.fileWatchers; ???????var oldDirWatchers = this.dirWatchers; ???????this.fileWatchers = files.map(function(file) { ???????????return this._fileWatcher(file, watcherManager.watchFile(file, this.watcherOptions, startTime)); ???????}, this); ???????this.dirWatchers = directories.map(function(dir) { ???????????return this._dirWatcher(dir, watcherManager.watchDirectory(dir, this.watcherOptions, startTime)); ???????}, this); ???????oldFileWatchers.forEach(function(w) { ???????????w.close(); ???????}, this); ???????oldDirWatchers.forEach(function(w) { ???????????w.close(); ???????}, this); ???}; ???pause() { /**/ }; ???getTimes() { /**/ }; ???_fileWatcher(file, watcher) { /**/ }; ???_dirWatcher(item, watcher) { /**/ }; ???_onChange(item, mtime, file) { /**/ }; ???_onRemove(item, file) { /**/ }; ???_onTimeout() { /**/ }; ???close() { /**/ };}module.exports = Watchpack;function addWatchersToArray(watchers, array) { /**/ }

var path = require("path");class WatcherManager { ???constructor() { ???????this.directoryWatchers = {}; ???}; ???// 工厂函数 ???getDirectoryWatcher(directory, options) { ???????// 引入模块 ???????var DirectoryWatcher = require("./DirectoryWatcher"); ???????options = options || {}; ???????var key = directory + " " + JSON.stringify(options); ???????if (!this.directoryWatchers[key]) { ???????????this.directoryWatchers[key] = new DirectoryWatcher(directory, options); ???????????// 文件监视结束则从容器删除 ???????????this.directoryWatchers[key].on("closed", function() { ???????????????delete this.directoryWatchers[key]; ???????????}.bind(this)); ???????} ???????return this.directoryWatchers[key]; ???}; ???// 监视文件 ???watchFile(p, options, startTime) { ???????var directory = path.dirname(p); ???????return this.getDirectoryWatcher(directory, options).watch(p, startTime); ???}; ???// 监视目录 ???watchDirectory(directory, options, startTime) { ???????return this.getDirectoryWatcher(directory, options).watch(directory, startTime); ???};}module.exports = new WatcherManager();

var EventEmitter = require("events").EventEmitter;var async = require("async");var chokidar = require("chokidar");var fs = require("graceful-fs");class Watcher { ???constructor(directoryWatcher, filePath, startTime) { ???????EventEmitter.call(this); ???????this.directoryWatcher = directoryWatcher; ???????this.path = filePath; ???????this.startTime = startTime && +startTime; ???????this.data = 0; ???}; ???checkStartTime(mtime, initial) { /**/ }; ???close() { /**/ };}function DirectoryWatcher(directoryPath, options) { ???EventEmitter.call(this); ???this.options = options; ???this.path = directoryPath; ???this.files = Object.create(null); ???this.directories = Object.create(null); ???this.watcher = chokidar.watch(directoryPath, { ???????ignoreInitial: true, ???????persistent: true, ???????followSymlinks: false, ???????depth: 0, ???????atomic: false, ???????alwaysStat: true, ???????ignorePermissionErrors: true, ???????ignored: options.ignored, ???????usePolling: options.poll ? true : undefined, ???????interval: typeof options.poll === "number" ? options.poll : undefined, ???????disableGlobbing: true ???}); ???this.watcher.on("add", this.onFileAdded.bind(this)); ???this.watcher.on("addDir", this.onDirectoryAdded.bind(this)); ???this.watcher.on("change", this.onChange.bind(this)); ???this.watcher.on("unlink", this.onFileUnlinked.bind(this)); ???this.watcher.on("unlinkDir", this.onDirectoryUnlinked.bind(this)); ???this.watcher.on("error", this.onWatcherError.bind(this)); ???// ...}DirectoryWatcher.prototype.watch = function watch(filePath, startTime) { ???this.watchers[withoutCase(filePath)] = this.watchers[withoutCase(filePath)] || []; ???this.refs++; ???var watcher = new Watcher(this, filePath, startTime); ???watcher.on("closed", function() { /**/ }.bind(this)); ???// ... ???return watcher;};// ...module.exports = DirectoryWatcher;