Hello World

utils/rm/node_modules/geoip-lite/lib/fsWatcher.js

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+var fs = require('fs'),
+	path = require('path'),
+	FSWatcher = {};
+
+/**
+ * Takes a directory/file and watch for change. Upon change, call the
+ * callback.
+ *
+ * @param {String} name: name of this watcher
+ * @param {String} directory: path to the directory to watch
+ * @param {String} [filename]: (optional) specific filename to watch for,
+ *     watches for all files in the directory if unspecified
+ * @param {Integer} cooldownDelay: delay to wait before triggering the callback
+ * @param {Function} callback: function () : called when changes are detected
+**/
+function makeFsWatchFilter(name, directory, filename, cooldownDelay, callback) {
+	var cooldownId = null;
+
+	//Delete the cooldownId and callback the outer function
+	function timeoutCallback() {
+		cooldownId = null;
+		callback();
+	}
+
+	//This function is called when there is a change in the data directory
+	//It sets a timer to wait for the change to be completed
+	function onWatchEvent(event, changedFile) {
+		// check to make sure changedFile is not null
+		if (!changedFile) {
+			return;
+		}
+		
+		var filePath = path.join(directory, changedFile);
+
+		if (!filename || filename === changedFile) {
+			fs.exists(filePath, function onExists(exists) {
+				if (!exists) {
+					// if the changed file no longer exists, it was a deletion.
+					// we ignore deleted files
+					return;
+				}
+
+				//At this point, a new file system activity has been detected,
+				//We have to wait for file transfert to be finished before moving on.
+
+				//If a cooldownId already exists, we delete it
+				if (cooldownId !== null) {
+					clearTimeout(cooldownId);
+					cooldownId = null;
+				}
+
+				//Once the cooldownDelay has passed, the timeoutCallback function will be called
+				cooldownId = setTimeout(timeoutCallback, cooldownDelay);
+			});
+		}
+	}
+
+	//Manage the case where filename is missing (because it's optionnal)
+	if (typeof cooldownDelay === 'function') {
+		callback = cooldownDelay;
+		cooldownDelay = filename;
+		filename = null;
+	}
+
+	if (FSWatcher[name]) {
+		stopWatching(name);
+	}
+
+	FSWatcher[name] = fs.watch(directory, onWatchEvent);
+}
+
+/**
+ * Take a FSWatcher object and close it.
+ *
+ * @param {string} name: name of the watcher to close
+ *
+**/
+function stopWatching(name) {
+	FSWatcher[name].close();
+}
+
+module.exports.makeFsWatchFilter = makeFsWatchFilter;
+module.exports.stopWatching = stopWatching;