source: trip-planner-front/node_modules/watchpack/lib/watchpack.js@ 1ad8e64

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

const getWatcherManager = require("./getWatcherManager");
const LinkResolver = require("./LinkResolver");
const EventEmitter = require("events").EventEmitter;
const globToRegExp = require("glob-to-regexp");
const watchEventSource = require("./watchEventSource");

let EXISTANCE_ONLY_TIME_ENTRY; // lazy required

const EMPTY_ARRAY = [];
const EMPTY_OPTIONS = {};

function addWatchersToSet(watchers, set) {
        for (const w of watchers) {
                if (w !== true && !set.has(w.directoryWatcher)) {
                        set.add(w.directoryWatcher);
                        addWatchersToSet(w.directoryWatcher.directories.values(), set);
                }
        }
}

const stringToRegexp = ignored => {
        const source = globToRegExp(ignored, { globstar: true, extended: true })
                .source;
        const matchingStart = source.slice(0, source.length - 1) + "(?:$|\\/)";
        return matchingStart;
};

const ignoredToRegexp = ignored => {
        if (Array.isArray(ignored)) {
                return new RegExp(ignored.map(i => stringToRegexp(i)).join("|"));
        } else if (typeof ignored === "string") {
                return new RegExp(stringToRegexp(ignored));
        } else if (ignored instanceof RegExp) {
                return ignored;
        } else if (ignored) {
                throw new Error(`Invalid option for 'ignored': ${ignored}`);
        } else {
                return undefined;
        }
};

const normalizeOptions = options => {
        return {
                followSymlinks: !!options.followSymlinks,
                ignored: ignoredToRegexp(options.ignored),
                poll: options.poll
        };
};

const normalizeCache = new WeakMap();
const cachedNormalizeOptions = options => {
        const cacheEntry = normalizeCache.get(options);
        if (cacheEntry !== undefined) return cacheEntry;
        const normalized = normalizeOptions(options);
        normalizeCache.set(options, normalized);
        return normalized;
};

class Watchpack extends EventEmitter {
        constructor(options) {
                super();
                if (!options) options = EMPTY_OPTIONS;
                this.options = options;
                this.aggregateTimeout =
                        typeof options.aggregateTimeout === "number"
                                ? options.aggregateTimeout
                                : 200;
                this.watcherOptions = cachedNormalizeOptions(options);
                this.watcherManager = getWatcherManager(this.watcherOptions);
                this.fileWatchers = new Map();
                this.directoryWatchers = new Map();
                this.startTime = undefined;
                this.paused = false;
                this.aggregatedChanges = new Set();
                this.aggregatedRemovals = new Set();
                this.aggregateTimer = undefined;
                this._onTimeout = this._onTimeout.bind(this);
        }

        watch(arg1, arg2, arg3) {
                let files, directories, missing, startTime;
                if (!arg2) {
                        ({
                                files = EMPTY_ARRAY,
                                directories = EMPTY_ARRAY,
                                missing = EMPTY_ARRAY,
                                startTime
                        } = arg1);
                } else {
                        files = arg1;
                        directories = arg2;
                        missing = EMPTY_ARRAY;
                        startTime = arg3;
                }
                this.paused = false;
                const oldFileWatchers = this.fileWatchers;
                const oldDirectoryWatchers = this.directoryWatchers;
                const ignored = this.watcherOptions.ignored;
                const filter = ignored
                        ? path => !ignored.test(path.replace(/\\/g, "/"))
                        : () => true;
                const addToMap = (map, key, item) => {
                        const list = map.get(key);
                        if (list === undefined) {
                                map.set(key, [item]);
                        } else {
                                list.push(item);
                        }
                };
                const fileWatchersNeeded = new Map();
                const directoryWatchersNeeded = new Map();
                const missingFiles = new Set();
                if (this.watcherOptions.followSymlinks) {
                        const resolver = new LinkResolver();
                        for (const file of files) {
                                if (filter(file)) {
                                        for (const innerFile of resolver.resolve(file)) {
                                                if (file === innerFile || filter(innerFile)) {
                                                        addToMap(fileWatchersNeeded, innerFile, file);
                                                }
                                        }
                                }
                        }
                        for (const file of missing) {
                                if (filter(file)) {
                                        for (const innerFile of resolver.resolve(file)) {
                                                if (file === innerFile || filter(innerFile)) {
                                                        missingFiles.add(file);
                                                        addToMap(fileWatchersNeeded, innerFile, file);
                                                }
                                        }
                                }
                        }
                        for (const dir of directories) {
                                if (filter(dir)) {
                                        let first = true;
                                        for (const innerItem of resolver.resolve(dir)) {
                                                if (filter(innerItem)) {
                                                        addToMap(
                                                                first ? directoryWatchersNeeded : fileWatchersNeeded,
                                                                innerItem,
                                                                dir
                                                        );
                                                }
                                                first = false;
                                        }
                                }
                        }
                } else {
                        for (const file of files) {
                                if (filter(file)) {
                                        addToMap(fileWatchersNeeded, file, file);
                                }
                        }
                        for (const file of missing) {
                                if (filter(file)) {
                                        missingFiles.add(file);
                                        addToMap(fileWatchersNeeded, file, file);
                                }
                        }
                        for (const dir of directories) {
                                if (filter(dir)) {
                                        addToMap(directoryWatchersNeeded, dir, dir);
                                }
                        }
                }
                const newFileWatchers = new Map();
                const newDirectoryWatchers = new Map();
                const setupFileWatcher = (watcher, key, files) => {
                        watcher.on("initial-missing", type => {
                                for (const file of files) {
                                        if (!missingFiles.has(file)) this._onRemove(file, file, type);
                                }
                        });
                        watcher.on("change", (mtime, type) => {
                                for (const file of files) {
                                        this._onChange(file, mtime, file, type);
                                }
                        });
                        watcher.on("remove", type => {
                                for (const file of files) {
                                        this._onRemove(file, file, type);
                                }
                        });
                        newFileWatchers.set(key, watcher);
                };
                const setupDirectoryWatcher = (watcher, key, directories) => {
                        watcher.on("initial-missing", type => {
                                for (const item of directories) {
                                        this._onRemove(item, item, type);
                                }
                        });
                        watcher.on("change", (file, mtime, type) => {
                                for (const item of directories) {
                                        this._onChange(item, mtime, file, type);
                                }
                        });
                        watcher.on("remove", type => {
                                for (const item of directories) {
                                        this._onRemove(item, item, type);
                                }
                        });
                        newDirectoryWatchers.set(key, watcher);
                };
                // Close unneeded old watchers
                const fileWatchersToClose = [];
                const directoryWatchersToClose = [];
                for (const [key, w] of oldFileWatchers) {
                        if (!fileWatchersNeeded.has(key)) {
                                w.close();
                        } else {
                                fileWatchersToClose.push(w);
                        }
                }
                for (const [key, w] of oldDirectoryWatchers) {
                        if (!directoryWatchersNeeded.has(key)) {
                                w.close();
                        } else {
                                directoryWatchersToClose.push(w);
                        }
                }
                // Create new watchers and install handlers on these watchers
                watchEventSource.batch(() => {
                        for (const [key, files] of fileWatchersNeeded) {
                                const watcher = this.watcherManager.watchFile(key, startTime);
                                if (watcher) {
                                        setupFileWatcher(watcher, key, files);
                                }
                        }
                        for (const [key, directories] of directoryWatchersNeeded) {
                                const watcher = this.watcherManager.watchDirectory(key, startTime);
                                if (watcher) {
                                        setupDirectoryWatcher(watcher, key, directories);
                                }
                        }
                });
                // Close old watchers
                for (const w of fileWatchersToClose) w.close();
                for (const w of directoryWatchersToClose) w.close();
                // Store watchers
                this.fileWatchers = newFileWatchers;
                this.directoryWatchers = newDirectoryWatchers;
                this.startTime = startTime;
        }

        close() {
                this.paused = true;
                if (this.aggregateTimer) clearTimeout(this.aggregateTimer);
                for (const w of this.fileWatchers.values()) w.close();
                for (const w of this.directoryWatchers.values()) w.close();
                this.fileWatchers.clear();
                this.directoryWatchers.clear();
        }

        pause() {
                this.paused = true;
                if (this.aggregateTimer) clearTimeout(this.aggregateTimer);
        }

        getTimes() {
                const directoryWatchers = new Set();
                addWatchersToSet(this.fileWatchers.values(), directoryWatchers);
                addWatchersToSet(this.directoryWatchers.values(), directoryWatchers);
                const obj = Object.create(null);
                for (const w of directoryWatchers) {
                        const times = w.getTimes();
                        for (const file of Object.keys(times)) obj[file] = times[file];
                }
                return obj;
        }

        getTimeInfoEntries() {
                if (EXISTANCE_ONLY_TIME_ENTRY === undefined) {
                        EXISTANCE_ONLY_TIME_ENTRY = require("./DirectoryWatcher")
                                .EXISTANCE_ONLY_TIME_ENTRY;
                }
                const directoryWatchers = new Set();
                addWatchersToSet(this.fileWatchers.values(), directoryWatchers);
                addWatchersToSet(this.directoryWatchers.values(), directoryWatchers);
                const map = new Map();
                for (const w of directoryWatchers) {
                        const times = w.getTimeInfoEntries();
                        for (const [path, entry] of times) {
                                if (map.has(path)) {
                                        if (entry === EXISTANCE_ONLY_TIME_ENTRY) continue;
                                        const value = map.get(path);
                                        if (value === entry) continue;
                                        if (value !== EXISTANCE_ONLY_TIME_ENTRY) {
                                                map.set(path, Object.assign({}, value, entry));
                                                continue;
                                        }
                                }
                                map.set(path, entry);
                        }
                }
                return map;
        }

        getAggregated() {
                if (this.aggregateTimer) {
                        clearTimeout(this.aggregateTimer);
                        this.aggregateTimer = undefined;
                }
                const changes = this.aggregatedChanges;
                const removals = this.aggregatedRemovals;
                this.aggregatedChanges = new Set();
                this.aggregatedRemovals = new Set();
                return { changes, removals };
        }

        _onChange(item, mtime, file, type) {
                file = file || item;
                if (!this.paused) {
                        this.emit("change", file, mtime, type);
                        if (this.aggregateTimer) clearTimeout(this.aggregateTimer);
                        this.aggregateTimer = setTimeout(this._onTimeout, this.aggregateTimeout);
                }
                this.aggregatedRemovals.delete(item);
                this.aggregatedChanges.add(item);
        }

        _onRemove(item, file, type) {
                file = file || item;
                if (!this.paused) {
                        this.emit("remove", file, type);
                        if (this.aggregateTimer) clearTimeout(this.aggregateTimer);
                        this.aggregateTimer = setTimeout(this._onTimeout, this.aggregateTimeout);
                }
                this.aggregatedChanges.delete(item);
                this.aggregatedRemovals.add(item);
        }

        _onTimeout() {
                this.aggregateTimer = undefined;
                const changes = this.aggregatedChanges;
                const removals = this.aggregatedRemovals;
                this.aggregatedChanges = new Set();
                this.aggregatedRemovals = new Set();
                this.emit("aggregated", changes, removals);
        }
}

module.exports = Watchpack;