Merge pull request #209 from jaguilar/dev

Add NetscriptJS evaluation

index.html

@@ -861,5 +861,5 @@
         <div class="loaderlabel">Loading Bitburner...</div>
     </div>
 </body>
-    <script src="dist/bundle.js"></script>
+    <script src="dist/engine.bundle.js"></script>
 </html>

package.json

@@ -32,6 +32,7 @@
     "supports-color": "^4.2.1",
     "tapable": "^0.2.7",
     "uglifyjs-webpack-plugin": "^0.4.6",
+    "uuid": "^3.2.1",
     "w3c-blob": "0.0.1",
     "watchpack": "^1.4.0",
     "webpack-sources": "^1.0.1",
@@ -42,6 +43,8 @@
     "beautify-lint": "^1.0.3",
     "benchmark": "^2.1.1",
     "bundle-loader": "~0.5.0",
+    "chai": "^4.1.2",
+    "chai-as-promised": "^7.1.1",
     "codacy-coverage": "^2.0.1",
     "codecov.io": "^0.1.2",
     "coffee-loader": "~0.7.1",
@@ -79,6 +82,7 @@
     "webpack": "^4.1.1",
     "webpack-cli": "^2.0.12",
     "webpack-dev-middleware": "^1.9.0",
+    "webpack-dev-server": "^3.1.4",
     "worker-loader": "^0.8.0"
   },
   "engines": {
@@ -107,6 +111,7 @@
     "nsp": "nsp check --output summary",
     "pretest": "npm run lint-files",
     "publish-patch": "npm run lint && npm run beautify-lint && mocha && npm version patch && git push && git push --tags && npm publish",
+    "start:dev": "webpack-dev-server",
     "test": "mocha test/*.test.js --max-old-space-size=4096 --harmony --check-leaks",
     "travis:benchmark": "npm run benchmark",
     "travis:lint": "npm run lint-files && npm run nsp",

src/NetscriptJSEvaluator.js

@@ -0,0 +1,102 @@
+import {registerEnv, unregisterEnv, makeEnvHeader} from "./NetscriptJSPreamble.js";
+import {makeRuntimeRejectMsg} from "./NetscriptEvaluator.js";
+
+// Makes a blob that contains the code of a given script.
+export function makeScriptBlob(code) {
+    return new Blob([code], {type: "text/javascript"});
+}
+
+// Begin executing a user JS script, and return a promise that resolves
+// or rejects when the script finishes.
+// - script is a script to execute (see Script.js). We depend only on .filename and .code.
+// scripts is an array of other scripts on the server.
+// env is the global environment that should be visible to all the scripts
+// (i.e. hack, grow, etc.).
+// When the promise returned by this resolves, we'll have finished
+// running the main function of the script.
+export async function executeJSScript(script, scripts = [], env = {}) {
+    const envUuid = registerEnv(env);
+    const envHeader = makeEnvHeader(envUuid);
+    const urlStack = _getScriptUrls(script, scripts, envHeader, []);
+
+    // The URL at the top is the one we want to import. It will
+    // recursively import all the other modules in the urlStack.
+    //
+    // Webpack likes to turn the import into a require, which sort of
+    // but not really behaves like import. Particularly, it cannot
+    // load fully dynamic content. So we hide the import from webpack
+    // by placing it inside an eval call.
+    try {
+        // TODO: putting await in a non-async function yields unhelpful
+        // "SyntaxError: unexpected reserved word" with no line number information.
+        const loadedModule  = await eval('import(urlStack[urlStack.length - 1])');
+        if (!loadedModule.main) {
+            throw makeRuntimeRejectMsg(script.filename +
+                                       " did not have a main function, cannot run it.");
+        }
+        return await loadedModule.main();
+    } finally {
+        // Revoke the generated URLs and unregister the environment.
+        for (const url in urlStack) URL.revokeObjectURL(url);
+        unregisterEnv(envUuid);
+    };
+}
+
+// Gets a stack of blob urls, the top/right-most element being
+// the blob url for the named script on the named server.
+//
+// - script -- the script for whom we are getting a URL.
+// - scripts -- all the scripts available on this server
+// - envHeader -- the preamble that goes at the start of every NSJS script.
+// - seen -- The modules above this one -- to prevent mutual dependency.
+//
+// TODO We don't make any effort to cache a given module when it is imported at
+// different parts of the tree. That hasn't presented any problem with during
+// testing, but it might be an idea for the future. Would require a topo-sort
+// then url-izing from leaf-most to root-most.
+function _getScriptUrls(script, scripts, envHeader, seen) {
+    // Inspired by: https://stackoverflow.com/a/43834063/91401
+    const urlStack = [];
+    seen.push(script);
+    try {
+        // Replace every import statement with an import to a blob url containing
+        // the corresponding script. E.g.
+        //
+        // import {foo} from "bar.js";
+        //
+        // becomes
+        //
+        // import {foo} from "blob://<uuid>"
+        //
+        // Where the blob URL contains the script content.
+        const transformedCode = script.code.replace(/((?:from|import)\s+(?:'|"))([^'"]+)('|";)/g,
+            (unmodified, prefix, filename, suffix) => {
+                const isAllowedImport = scripts.some(s => s.filename == filename);
+                if (!isAllowedImport) return unmodified;
+
+                // Find the corresponding script.
+                const [importedScript] = scripts.filter(s => s.filename == filename);
+
+                // Try to get a URL for the requested script and its dependencies.
+                const urls = _getScriptUrls(importedScript, scripts, envHeader, seen);
+
+                // The top url in the stack is the replacement import file for this script.
+                urlStack.push(...urls);
+                return [prefix, urls[urls.length - 1], suffix].join('');
+            });
+
+        // Inject the NSJS preamble at the top of the code.
+        const transformedCodeWithHeader = [envHeader, transformedCode].join("\n");
+
+        // If we successfully transformed the code, create a blob url for it and
+        // push that URL onto the top of the stack.
+        urlStack.push(URL.createObjectURL(makeScriptBlob(transformedCodeWithHeader)));
+        return urlStack;
+    } catch (err) {
+        // If there is an error, we need to clean up the URLs.
+        for (const url in urlStack) URL.revokeObjectURL(url);
+        throw err;
+    } finally {
+        seen.pop();
+    }
+}

src/NetscriptJSPreamble.js

@@ -0,0 +1,42 @@
+// A utility function that adds a preamble to each Netscript JS
+// script. This preamble will set all the global functions and
+// variables appropriately for the module.
+//
+// One caveat is that we don't allow the variables in the preable
+// to change. Unlike in normal Javascript, this would not change
+// properties of self. It would instead just change the variable
+// within the given module -- not good! Users should not really
+// need to do this anyway.
+
+import uuidv4 from "uuid/v4";
+import {sprintf} from "sprintf-js";
+
+window.__NSJS__environments = {};
+
+// Returns the UUID for the env.
+export function registerEnv(env) {
+    const uuid = uuidv4();
+    window.__NSJS__environments[uuid] = env;
+    return uuid;
+}
+
+export function unregisterEnv(uuid) {
+    delete window.__NSJS__environments[uuid];
+}
+
+export function makeEnvHeader(uuid) {
+    if (!(uuid in window.__NSJS__environments)) throw new Error("uuid is not in the environment" + uuid);
+
+    const env = window.__NSJS__environments[uuid];
+    var envLines = [];
+    for (const prop in env) {
+        envLines.push("const ", prop, " = ", "__NSJS_ENV[\"", prop, "\"];\n");
+    }
+
+    return sprintf(`
+        'use strict';
+        const __NSJS_ENV = window.__NSJS__environments['%s'];
+        // The global variable assignments (hack, weaken, etc.).
+        %s
+    `, uuid, envLines.join(""));
+}

tests/NetscriptJSTest.js

@@ -0,0 +1,49 @@
+import {executeJSScript} from "../src/NetscriptJSEvaluator.js";
+
+const chai = require("chai");
+const chaiAsPromised = require("chai-as-promised");
+chai.should();
+chai.use(chaiAsPromised);
+
+console.info('asdf');
+
+describe('NSJS ScriptStore', function() {
+    it('should run an imported function', async function() {
+        const s = { filename: "", code: "export function main() { return 2; }" };
+        chai.expect(await executeJSScript(s)).to.equal(2);
+    });
+
+    it('should handle recursive imports', async function() {
+        const s1 = { filename: "s1.js", code: "export function iAmRecursiveImport(x) { return x + 2; }" };
+        const s2 = { filename: "", code: `
+            import {iAmRecursiveImport} from \"s1.js\";
+            export function main() { return iAmRecursiveImport(3);
+        }`};
+        chai.expect(await executeJSScript(s2, [s1, s2])).to.equal(5);
+    });
+
+    it (`should correctly reference the passed global env`, async function() {
+        var [x, y] = [0, 0];
+        var env = {
+            updateX: function(value) { x = value; },
+            updateY: function(value) { y = value; },
+        };
+        const s1 = {filename: "s1.js", code: "export function importedFn(x) { updateX(x); }"};
+        const s2 = {filename: "s2.js", code: `
+            import {importedFn} from "s1.js";
+            export function main() { updateY(7); importedFn(3); }
+        `}
+        await executeJSScript(s2, [s1, s2], env);
+        chai.expect(y).to.equal(7);
+        chai.expect(x).to.equal(3);
+    });
+
+    it (`should throw on circular dep`, async function() {
+        const s1 = {filename: "s1.js", code: "import \"s2.js\""};
+        const s2 = {filename: "s2.js", code: `
+            import * as s1 from "s1.js";
+            export function main() {}
+        `}
+        executeJSScript(s2, [s1, s2]).should.eventually.throw();
+    });
+});

tests/index.html

@@ -0,0 +1,20 @@
+<html>
+    <!-- From https://medium.com/dailyjs/running-mocha-tests-as-native-es6-modules-in-a-browser-882373f2ecb0 -->
+    <head>
+        <meta charset="utf-8">
+        <title>Mocha Tests</title>
+        <link href="https://unpkg.com/mocha@4.0.1/mocha.css" rel="stylesheet" />
+    </head>
+    <body>
+        <div id="mocha"></div>
+
+        <script src="https://unpkg.com/mocha@4.0.1/mocha.js"></script>
+
+        <script>mocha.setup('bdd')</script>
+        <script type="module" src="../dist/tests.bundle.js"></script>
+        <script type="module">
+            mocha.checkLeaks();
+            mocha.run();
+        </script>
+    </body>
+</html>

tests/index.js

@@ -0,0 +1,3 @@
+//require("babel-core/register");
+//require("babel-polyfill");
+module.exports = require("./NetscriptJSTest.js");

webpack.config.js

@@ -15,11 +15,14 @@ module.exports = {
       }),
     ],
     target: "web",
-    entry: "./src/engine.js",
+    entry: {
+        engine: "./src/engine.js",
+        tests: "./tests/index.js",
+    },
     devtool: "nosources-source-map",
     output: {
         path: path.resolve(__dirname, "dist"),
-        filename: "bundle.js",
+        filename: "[name].bundle.js",
         devtoolModuleFilenameTemplate: "[id]"
     },
     module: {
@@ -44,5 +47,8 @@ module.exports = {
         namedChunks: false,
         minimize: false,
         portableRecords: true
+    },
+    devServer: {
+        publicPath: "/dist",
     }
 };