From 93b7eb015309363a90db72c9b530d0c7b553f4c2 Mon Sep 17 00:00:00 2001
From: Merlin Beutlberger <m.beutlberger@sap.com>
Date: Tue, 16 Nov 2021 15:02:51 +0100
Subject: [PATCH] lbt/bundle/Builder: Resolve sourceMappingURL for locating
 input source maps

---
 lib/lbt/bundle/Builder.js | 56 ++++++++++++++++++++++++++-------------
 1 file changed, 37 insertions(+), 19 deletions(-)

diff --git a/lib/lbt/bundle/Builder.js b/lib/lbt/bundle/Builder.js
index bfe3cf135..754aed86a 100644
--- a/lib/lbt/bundle/Builder.js
+++ b/lib/lbt/bundle/Builder.js
@@ -18,7 +18,7 @@ const {SectionType} = require("./BundleDefinition");
 const BundleWriter = require("./BundleWriter");
 const log = require("@ui5/logger").getLogger("lbt:bundle:Builder");
 
-const sourcemapPattern = /\/\/# sourceMappingURL=data:application\/json;charset=utf-8;base64,(.+)/i;
+const sourceMapUrlPattern = /\/\/# sourceMappingURL=(.+)\s*$/;
 const xmlHtmlPrePattern = /<(?:\w+:)?pre\b/;
 
 const strReplacements = {
@@ -224,7 +224,7 @@ class BundleBuilder {
 			this.outW.writeln(`}`);
 		}
 		if (this.options.sourceMap) {
-			this.outW.writeln(`//# sourceMappingURL=${path.basename(resolvedModule.name)}.map`);
+			this.outW.writeln(`//# sourceMappingURL=${path.posix.basename(resolvedModule.name)}.map`);
 		}
 	}
 
@@ -367,7 +367,7 @@ class BundleBuilder {
 		}
 
 		map.sourceRoot = path.posix.relative(
-			path.dirname(this._bundleName), path.dirname(moduleName));
+			path.posix.dirname(this._bundleName), path.posix.dirname(moduleName));
 
 		this._sourceMap.sections.push({
 			offset: {
@@ -543,25 +543,43 @@ class BundleBuilder {
 
 	async retrieveSourceMapForModule(moduleName, moduleContent) {
 		let moduleSourceMap = null;
-		try {
-			const sourceMapResource = await this.pool.findResource(`${moduleName}.map`);
-			moduleSourceMap = (await sourceMapResource.buffer()).toString();
-		} catch (e) {
-			// No input source map
-			// TODO: Differentiate real errors from file not found
-		}
+		let newModuleContent = moduleContent;
+
+		const sourceMapUrlMatch = moduleContent.match(sourceMapUrlPattern);
+		if (sourceMapUrlMatch) {
+			const sourceMapUrl = sourceMapUrlMatch[1];
+
+			if (sourceMapUrl.startsWith("data:")) {
+				// Data-URL indicates an inline source map
+				const expectedTypeAndEncoding = "data:application/json;charset=utf-8;base64,";
+				if (sourceMapUrl.startsWith(expectedTypeAndEncoding)) {
+					const base64Content = sourceMapUrl.slice(expectedTypeAndEncoding.length);
+					moduleSourceMap = Buffer.from(base64Content, "base64").toString();
+				} else {
+					log.warn("TODO");
+				}
+			} else {
+				if (path.posix.isAbsolute(sourceMapUrl)) {
+					log.warn("Unexpected absolute source map path");
+				}
 
-		if (!moduleSourceMap) {
-			const inlineSourcemap = moduleContent.match(sourcemapPattern);
-			if (inlineSourcemap) {
-				moduleSourceMap = Buffer.from(inlineSourcemap[1], "base64").toString();
-			}
-		}
+				// TODO: Check for actual URL, which is not supported
 
-		// Strip sourceMappingURL from module code to be bundled
-		// It has no effect and might be cause for confusion
-		const newModuleContent = moduleContent.replace(/\/\/# sourceMappingURL=.*/, "");
+				const sourceMapPath = path.posix.join(path.posix.dirname(moduleName), sourceMapUrl);
 
+				try {
+					const sourceMapResource = await this.pool.findResource(sourceMapPath);
+					moduleSourceMap = (await sourceMapResource.buffer()).toString();
+				} catch (e) {
+					// No input source map
+					// TODO: Differentiate real errors from file not found
+				}
+			}
+
+			// Strip sourceMappingURL from module code to be bundled
+			// It has no effect and might be cause for confusion
+			newModuleContent = moduleContent.replace(sourceMapUrlPattern, "");
+		}
 		return {
 			moduleSourceMap,
 			moduleContent: newModuleContent