From a5d69248dd82510c99d6179e22d98e0bdaa8a609 Mon Sep 17 00:00:00 2001
From: theit8514 <theit8514@users.noreply.github.com>
Date: Mon, 3 Jan 2022 10:20:46 -0500
Subject: [PATCH] Replace regex import with acorn AST parser
---
src/NetscriptJSEvaluator.ts | 70 +++++++++++++++++++++++++------------
1 file changed, 48 insertions(+), 22 deletions(-)
diff --git a/src/NetscriptJSEvaluator.ts b/src/NetscriptJSEvaluator.ts
index d4c7b6dbc..5fba53557 100644
--- a/src/NetscriptJSEvaluator.ts
+++ b/src/NetscriptJSEvaluator.ts
@@ -1,3 +1,10 @@
+/**
+ * Uses the acorn.js library to parse a script's code into an AST and
+ * recursively walk through that AST to replace import urls with blobs
+ */
+import * as walk from "acorn-walk";
+import { parse } from "acorn";
+
import { makeRuntimeRejectMsg } from "./NetscriptEvaluator";
import { ScriptUrl } from "./Script/ScriptUrl";
import { WorkerScript } from "./Netscript/WorkerScript";
@@ -125,32 +132,51 @@ function _getScriptUrls(script: Script, scripts: Script[], seen: Script[]): Scri
// 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) => areImportsEquals(s.filename, filename));
- if (!isAllowedImport) return unmodified;
- // Find the corresponding script.
- const [importedScript] = scripts.filter((s) => areImportsEquals(s.filename, filename));
+ // Parse the code into an ast tree
+ const ast: any = parse(script.code, { sourceType: "module", ecmaVersion: "latest", ranges: true });
- // Check to see if the urls for this script are stored in the cache by the hash value.
- let urls = ImportCache.get(importedScript.hash());
- // If we don't have it in the cache, then we need to generate the urls for it.
- if (!urls) {
- // Try to get a URL for the requested script and its dependencies.
- urls = _getScriptUrls(importedScript, scripts, seen);
- }
+ const importNodes: Array<any> = [];
+ // Walk the nodes of this tree and find any import declaration statements.
+ walk.simple(ast, {
+ ImportDeclaration(node: any) {
+ // Push this import onto the stack to replace
+ importNodes.push({
+ filename: node.source.value,
+ start: node.source.range[0] + 1,
+ end: node.source.range[1] - 1
+ });
+ }
+ });
+ // Sort the nodes from last start index to first. This replaces the last import with a blob first,
+ // preventing the ranges for other imports from being shifted.
+ importNodes.sort((a, b) => b.start - a.start);
+ let transformedCode = script.code;
+ // Loop through each node and replace the script name with a blob url.
+ for (const node of importNodes) {
+ const filename = node.filename.startsWith("./") ? node.filename.substring(2) : node.filename;
- // The top url in the stack is the replacement import file for this script.
- urlStack.push(...urls);
- const blob = urls[urls.length - 1].url;
- ImportCache.store(importedScript.hash(), urls);
+ // Find the corresponding script.
+ const matchingScripts = scripts.filter((s) => areImportsEquals(s.filename, filename));
+ if (matchingScripts.length === 0) continue;
- // Replace the blob inside the import statement.
- return [prefix, blob, suffix].join("");
- },
- );
+ const [importedScript] = matchingScripts;
+ // Check to see if the urls for this script are stored in the cache by the hash value.
+ let urls = ImportCache.get(importedScript.hash());
+ // If we don't have it in the cache, then we need to generate the urls for it.
+ if (!urls) {
+ // Try to get a URL for the requested script and its dependencies.
+ urls = _getScriptUrls(importedScript, scripts, seen);
+ }
+
+ // The top url in the stack is the replacement import file for this script.
+ urlStack.push(...urls);
+ const blob = urls[urls.length - 1].url;
+ ImportCache.store(importedScript.hash(), urls);
+
+ // Replace the blob inside the import statement.
+ transformedCode = transformedCode.substring(0, node.start) + blob + transformedCode.substring(node.end);
+ }
// 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