[PoC] ResourcePool: Add option to prefer analyzing a resource's source content

Possible follow up of #551 to
improve dependency analysis.

JSModuleAnalyzer has trouble detecting some dependencies in minified
code if they have been "mangled". E.g. in case jQuery is not named
jQuery anymore.

This change solves that by trying to retrieve the debug ("source")
content of a resource to analyze that instead of the minified version.
However, integrating this on the ResourcePool level is not ideal and a
more general solution to this problem should be preferred.

Therefore this PR should only act as an illustration of the discussions
and thoughts. Currently it should not be merged.

Author: RandomByte

Diff for: lib/lbt/resources/ResourceCollector.js

@@ -108,8 +108,14 @@ class ResourceCollector {
 		}
 	}
 
-	async enrichWithDependencyInfo(resourceInfo) {
-		return this._pool.getModuleInfo(resourceInfo.name).then((moduleInfo) => {
+	async enrichWithDependencyInfo({resourceInfo, debugBundleFilter}) {
+		return this._pool.getModuleInfo(resourceInfo.name, {
+			// While analyzing non-debug resources, try to analyze the content of the corresponding
+			// debug resource instead
+			preferDebugResources: true,
+			// Provide the debugBundleFilter to prevent that debug bundles are "preferred"
+			debugBundleFilter
+		}).then((moduleInfo) => {
 			if ( moduleInfo.name ) {
 				resourceInfo.module = moduleInfo.name;
 			}
@@ -192,7 +198,10 @@ class ResourceCollector {
 				if ( (!info.isDebug || debugBundleFilter.matches(name)) ) {
 					// Only analyze non-debug files which are not special debug bundles (like sap-ui-core-dbg.js)
 					promises.push(
-						this.enrichWithDependencyInfo(info)
+						this.enrichWithDependencyInfo({
+							resourceInfo: info,
+							debugBundleFilter
+						})
 					);
 				} else {
 					nonBundledDebugResources.push(info);

Diff for: lib/lbt/resources/ResourcePool.js

@@ -15,6 +15,7 @@ const XMLTemplateAnalyzer = require("../analyzer/XMLTemplateAnalyzer");
 const LibraryFileAnalyzer = require("./LibraryFileAnalyzer");
 const ModuleInfo = require("./ModuleInfo");
 const ResourceFilterList = require("./ResourceFilterList");
+const ResourceInfoList = require("./ResourceInfoList");
 /*
 const Resource = require("./Resource");
  */
@@ -57,12 +58,15 @@ function scanFileOrDir(fileOrDir, name, pool) {
 }
 */
 
-async function determineDependencyInfo(resource, rawInfo, pool) {
+async function determineDependencyInfo(resource, dbgResource, rawInfo, pool) {
 	const info = new ModuleInfo(resource.name);
 	info.size = resource.fileSize;
 	if ( /\.js$/.test(resource.name) ) {
-		// console.log("analyzing %s", resource.file);
-		const code = await resource.buffer();
+		// console.log("analyzing %s", resource.name);
+
+		// Retrieve the content from the "debug resource".
+		// Note that in many cases "resource" and "dbgResource" are the same object
+		const code = await dbgResource.buffer();
 		info.size = code.length;
 		const promises = [];
 		let ast;
@@ -177,14 +181,30 @@ class ResourcePool {
 	 * Retrieves the module info
 	 *
 	 * @param {string} name module name
+	 * @param {object} options
+	 * @param {boolean} options.preferDebugResources
+	 * @param {ResourceFilterList} options.debugBundleFilter
 	 * @returns {Promise<ModuleInfo>}
 	 */
-	async getModuleInfo(name) {
+	async getModuleInfo(name, options) {
 		let info = this._dependencyInfos.get(name);
 		if ( info == null ) {
 			// console.log("analyzing ", name);
+			let dbgResource;
+			if (options && options.preferDebugResources) {
+				// If requested, try to retrieve the corresponding debug-resource (xyz-dbg.js) and pass it to
+				// determineDependencyInfo as well. Its dependency analysis will perform better with the
+				// not-minified content of a resource.
+				const dbgName = ResourceInfoList.getDebugName(name);
+				if (dbgName && (!options.debugBundleFilter || !options.debugBundleFilter.matches(dbgName))) {
+					dbgResource = this._resourcesByName.get(dbgName);
+				}
+			}
 			const resource = await this.findResource(name);
-			info = await determineDependencyInfo( resource, this._rawModuleInfos.get(name), this );
+			if (!dbgResource) {
+				dbgResource = resource;
+			}
+			info = await determineDependencyInfo(resource, dbgResource, this._rawModuleInfos.get(name), this);
 			// console.log("finished analyzing ", name);
 			this._dependencyInfos.set(name, info);
 		}