index.js

'use strict';

var version = '0.0.0';

var lodash = require('lodash');

var LoopStopManager = require('./loop-stop/manager');
var LoopStopInjector = require('./loop-stop/injector');
var jailEnvironment = require('./environment');

module.exports = JSJail();

function JSJail() {

    // Pre initialization of necessary parameters in jail environment.
    jailEnvironment.add({LoopStopManager: LoopStopManager});

    var t = {};

    t.version = version;

    t.make = make;

    return t;

    /**
     * Returns an object which represents the jail (separate environment to JS execution).
     *
     * @public
     */
    function make(code) {

        try {

            var jailInitializationCode = LoopStopInjector.inject(code);

            jailInitializationCode = tryToCoverWindow(jailInitializationCode);

            // Preparation for function call.
            var parameters = jailEnvironment.getNames();
            // Add code as the last parameter of function for an apply call.
            parameters.push(jailInitializationCode);

            var f = Function.apply(null, parameters);

            return new f(jailEnvironment.getValues());

        } catch (err) {

            // TODO Will make some handling in the near future
            console.error("While we were trying to make a jail some problem caused:", err);

        }

    }

    /**
     * Makes stubs of variables for avoid the changing of outside environment which has these variables too.
     *
     * TODO need to take this function into a separate module.
     *
     * @private
     * @param {String} code The source code.
     */
    function tryToCoverWindow(code) {

        if (typeof window === "object") {

            var variables = Object.getOwnPropertyNames(window);

            if (!window.hasOwnProperty('window')) {

                variables.push('window');

            }

            var stubDeclarations = '';
            variables.forEach(function(name) {

                // If the name really can be the name of variable.
                if (lodash.isString(name)) {

                    var stub = 'var ' + name + '; \n';

                    stubDeclarations = stubDeclarations + stub;

                }

            });

            code = stubDeclarations + code;

        }

        return code;

    }

}