webpack/lib/Cache.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");

function Cache(options) {
	this.options = options = options || {};
	this.map = {};
}
var $ = Cache.prototype;
module.exports = Cache;

$.get = function(request, callback) {
	var self = this;
	var item = self.map[request];
	if(!item) return callback(new Error("No Entry"));
	var count = item.files.length;
	var invalid = false;
	item.files.forEach(function(file) {
		fs.stat(file.path, function(err, stat) {
			if(err) return invalidate(err.toString());
			if(!stat) return invalidate("Cannot read stat");
			if(stat.mtime.getTime() !== file.time)
				return invalidate("File " + file.path + " has changed");
			valid();
		});
	});
	if(item.files.length === 0) valid();
	function invalidate(msg) {
		if(invalid) return;
		invalid = true;
		callback(new Error(msg));
	}
	function valid() {
		if(invalid) return;
		count--;
		if(count <= 0)
			callback(null, item.value);
	}
}

$.create = function(request) {
	var self = this;
	var item = {
		files: []
	};
	var cacheEntry = {
		add: function(path) {
			item.files.push({
				path: path,
				// TODO do it asynchronly
				time: fs.statSync(path).mtime.getTime()
			});
		},
		clear: function() {
			item.files.length = 0;
		},
		save: function(value) {
			item.value = value;
			self.map[request] = item;
			cacheEntry.saved = true;
		}
	}
	return cacheEntry;
}