bitburner-src/src/NetscriptJSEvaluator.ts
2021-10-27 14:29:13 -04:00

145 lines
5.9 KiB
TypeScript

import { makeRuntimeRejectMsg } from "./NetscriptEvaluator";
import { ScriptUrl } from "./Script/ScriptUrl";
import { WorkerScript } from "./Netscript/WorkerScript";
import { Script } from "./Script/Script";
// Makes a blob that contains the code of a given script.
function makeScriptBlob(code: string): Blob {
return new Blob([code], { type: "text/javascript" });
}
export function compile(script: Script, scripts: Script[]): void {
if (!shouldCompile(script, scripts)) return;
// 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.
script.markUpdated();
const uurls = _getScriptUrls(script, scripts, []);
if (script.url) URL.revokeObjectURL(script.url); // remove the old reference.
if (script.dependencies.length > 0) script.dependencies.forEach((dep) => URL.revokeObjectURL(dep.url));
script.url = uurls[uurls.length - 1].url;
script.module = new Promise((resolve) => resolve(eval("import(uurls[uurls.length - 1].url)")));
script.dependencies = uurls;
}
// 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(scripts: Script[] = [], workerScript: WorkerScript): Promise<void> {
const script = workerScript.getScript();
if (script === null) throw new Error("script is null");
compile(script, scripts);
const loadedModule = await script.module;
const ns = workerScript.env.vars;
// TODO: putting await in a non-async function yields unhelpful
// "SyntaxError: unexpected reserved word" with no line number information.
if (!loadedModule.main) {
throw makeRuntimeRejectMsg(
workerScript,
`${script.filename} cannot be run because it does not have a main function.`,
);
}
return loadedModule.main(ns);
}
/** Returns whether we should compile the script parameter.
*
* @param {Script} script
* @param {Script[]} scripts
*/
function shouldCompile(script: Script, scripts: Script[]): boolean {
if (script.module === "") return true;
return script.dependencies.some((dep) => {
const depScript = scripts.find((s) => s.filename == dep.filename);
// If the script is not present on the server, we should recompile, if only to get any necessary
// compilation errors.
if (!depScript) return true;
const depIsMoreRecent = depScript.moduleSequenceNumber > script.moduleSequenceNumber;
return depIsMoreRecent;
});
}
// 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
// - 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.
/**
* @param {Script} script
* @param {Script[]} scripts
* @param {Script[]} seen
* @returns {ScriptUrl[]} All of the compiled scripts, with the final one
* in the list containing the blob corresponding to
* the script parameter.
*/
// BUG: apparently seen is never consulted. Oops.
function _getScriptUrls(script: Script, scripts: Script[], seen: Script[]): ScriptUrl[] {
// Inspired by: https://stackoverflow.com/a/43834063/91401
/** @type {ScriptUrl[]} */
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.
let 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, seen);
// The top url in the stack is the replacement import file for this script.
urlStack.push(...urls);
return [prefix, urls[urls.length - 1].url, suffix].join("");
},
);
// We automatically define a print function() in the NetscriptJS module so that
// accidental calls to window.print() do not bring up the "print screen" dialog
transformedCode += `\n\nfunction print() {throw new Error("Invalid call to window.print(). Did you mean to use Netscript's print()?");}`;
// If we successfully transformed the code, create a blob url for it and
// push that URL onto the top of the stack.
urlStack.push(new ScriptUrl(script.filename, URL.createObjectURL(makeScriptBlob(transformedCode))));
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();
}
}