webpack/lib/performantStat.js

Packs CommonJs Modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loading of js, json, jade, coffee, css, ... out of the box and more with custom loaders.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
var fs = require("fs");

var MAX_DURATION = 2000;
var lastTime = new Date();
var cache = {};

module.exports = function(pathname, callback) {
	var currentTime = new Date();

	// clear all if old
	if(currentTime - lastTime > MAX_DURATION)
		cache = {};

	var cacheEntry = cache[pathname];

	if(cacheEntry) {
		if(cacheEntry.listeners)
			return cacheEntry.listeners.push(callback);
		else if(currentTime - cacheEntry.time <= MAX_DURATION)
			return callback(cacheEntry.err, cacheEntry.result);
	}

	var listeners = [callback];
	cache[pathname] = cacheEntry = {
		listeners: listeners
	};

	// do the request
	lastTime = currentTime;
	// console.log("request to " + pathname);
	fs.stat(pathname, function(err, result) {
		cacheEntry.time = currentTime;
		cacheEntry.err = err;
		cacheEntry.result = result;
		delete cacheEntry.listeners;
		listeners.forEach(function(listener) {
			listener(err, result);
		});
	});
}