refactor: Update API usage of sax-wasm

- Updating to the new recommended API of sax-wasm
- Reuse parseXML in xml transpiler

Author: matz3

src/linter/xmlTemplate/transpiler.ts

@@ -1,26 +1,21 @@
-import {SaxEventType, SAXParser, Tag as SaxTag} from "sax-wasm";
+import {SaxEventType, Tag as SaxTag} from "sax-wasm";
 import {ReadStream} from "node:fs";
-import fs from "node:fs/promises";
-import {finished} from "node:stream/promises";
 import {taskStart} from "../../utils/perf.js";
 import LinterContext, {TranspileResult} from "../LinterContext.js";
 import Parser from "./Parser.js";
 import {getLogger} from "@ui5/logger";
-import {createRequire} from "node:module";
 import {MESSAGE} from "../messages.js";
-import {loadApiExtract, ApiExtract} from "../../utils/ApiExtract.js";
+import {loadApiExtract} from "../../utils/ApiExtract.js";
 import ControllerByIdInfo from "./ControllerByIdInfo.js";
-const require = createRequire(import.meta.url);
+import {parseXML} from "../../utils/xmlParser.js";
 
 const log = getLogger("linter:xmlTemplate:transpiler");
 
-let saxWasmBuffer: Buffer;
-let apiExtract: ApiExtract;
+const apiExtract = await loadApiExtract();
 
 export default async function transpileXml(
 	resourcePath: string, contentStream: ReadStream, context: LinterContext, controllerByIdInfo: ControllerByIdInfo
 ): Promise<TranspileResult | undefined> {
-	await init();
 	try {
 		const taskEnd = taskStart("Transpile XML", resourcePath, true);
 		const res = await transpileXmlToJs(resourcePath, contentStream, context, controllerByIdInfo);
@@ -36,65 +31,20 @@ export default async function transpileXml(
 	}
 }
 
-let initializing: Promise<void>;
-async function init() {
-	// eslint-disable-next-line @typescript-eslint/no-misused-promises
-	if (initializing) {
-		return initializing;
-	}
-	// Get the path to the WebAssembly binary and load it
-	const saxPath = require.resolve("sax-wasm/lib/sax-wasm.wasm");
-	const taskEnd = taskStart("XML Transpiler initialization");
-
-	return initializing = Promise.all([
-		fs.readFile(saxPath),
-		loadApiExtract(),
-	]).then((results) => {
-		saxWasmBuffer = results[0];
-		apiExtract = results[1];
-		taskEnd();
-	});
-}
-
 async function transpileXmlToJs(
 	resourcePath: string, contentStream: ReadStream, context: LinterContext, controllerByIdInfo: ControllerByIdInfo
 ): Promise<TranspileResult> {
 	const parser = new Parser(resourcePath, apiExtract, context, controllerByIdInfo);
 
-	// Initialize parser
-	const saxParser = new SAXParser(SaxEventType.OpenTag | SaxEventType.CloseTag);
-
-	saxParser.eventHandler = (event, tag) => {
-		if (tag instanceof SaxTag) {
+	await parseXML(contentStream, (event, detail) => {
+		if (detail instanceof SaxTag) {
 			if (event === SaxEventType.OpenTag) {
-				parser.pushTag(tag.toJSON() as SaxTag);
+				parser.pushTag(detail.toJSON() as SaxTag);
 			} else if (event === SaxEventType.CloseTag) {
-				parser.popTag(tag.toJSON() as SaxTag);
-			}
-		}
-	};
-
-	// Instantiate and prepare the wasm for parsing
-	if (!await saxParser.prepareWasm(saxWasmBuffer)) {
-		throw new Error("Unknown error during WASM Initialization");
-	}
-
-	// stream from a file in the current directory
-	contentStream.on("data", (chunk: Uint8Array) => {
-		try {
-			saxParser.write(chunk);
-		} catch (err) {
-			if (err instanceof Error) {
-				// In case of an error, destroy the content stream to make the
-				// error bubble up to our callers
-				contentStream.destroy(err);
-			} else {
-				throw err;
+				parser.popTag(detail.toJSON() as SaxTag);
 			}
 		}
 	});
-	await finished(contentStream);
-	saxParser.end();
 
 	return parser.generate();
 }

src/utils/xmlParser.ts

@@ -3,6 +3,7 @@ import {Detail, Reader, SaxEventType, SAXParser, Tag, Text} from "sax-wasm";
 import {finished} from "node:stream/promises";
 import fs from "node:fs/promises";
 import {createRequire} from "node:module";
+import {Readable} from "node:stream";
 const require = createRequire(import.meta.url);
 
 export function isSaxParserToJSON(tag: unknown): tag is Tag {
@@ -38,27 +39,16 @@ export async function parseXML(
 	const saxWasmBuffer = await initSaxWasm();
 	const saxParser = new SAXParser(SaxEventType.CloseTag + SaxEventType.OpenTag);
 
-	saxParser.eventHandler = parseHandler;
-
 	// Instantiate and prepare the wasm for parsing
 	if (!await saxParser.prepareWasm(saxWasmBuffer)) {
 		throw new Error("Unknown error during WASM Initialization");
 	}
 
-	// stream from a file in the current directory
-	contentStream.on("data", (chunk: Uint8Array) => {
-		try {
-			saxParser.write(chunk);
-		} catch (err) {
-			if (err instanceof Error) {
-				// In case of an error, destroy the content stream to make the
-				// error bubble up to our callers
-				contentStream.destroy(err);
-			} else {
-				throw err;
-			}
-		}
-	});
+	const webContentStream = Readable.toWeb(contentStream);
+
+	for await (const [event, detail] of saxParser.parse(webContentStream.getReader())) {
+		parseHandler(event, detail);
+	}
+
 	await finished(contentStream);
-	saxParser.end();
 }