perf(res): XML decoding speed enhancement (PR #1293)

* chore: XML decoding speed improved for large APKs (finding class references)
* skip attach class node to xml for SimpleCodeWriter (used in jadx-cli)

Co-authored-by: Skylot <skylot@gmail.com>

jadx-core/src/main/java/jadx/core/dex/nodes/RootNode.java

@@ -334,6 +334,15 @@ public class RootNode {
 		return resolveClass(clsInfo);
 	}
 
+	/**
+	 * Searches for ClassNode by its full name (original or alias name)
+	 *
+	 * Warning: This method has a runtime of O(n) (n = number of classes).
+	 * If you need to call it more than once consider {@link #buildFullAliasClassCache()} instead
+	 *
+	 * @param fullName
+	 * @return
+	 */
 	@Nullable
 	public ClassNode searchClassByFullAlias(String fullName) {
 		for (ClassNode cls : classes) {
@@ -346,6 +355,24 @@ public class RootNode {
 		return null;
 	}
 
+	/**
+	 *
+	 * @return
+	 */
+	public Map<String, ClassNode> buildFullAliasClassCache() {
+		Map<String, ClassNode> classNameCache = new HashMap<>(classes.size());
+		for (ClassNode cls : classes) {
+			ClassInfo classInfo = cls.getClassInfo();
+			String fullName = classInfo.getFullName();
+			String alias = classInfo.getAliasFullName();
+			classNameCache.put(fullName, cls);
+			if (alias != null && !fullName.equals(alias)) {
+				classNameCache.put(alias, cls);
+			}
+		}
+		return classNameCache;
+	}
+
 	public List<ClassNode> searchClassByShortName(String shortName) {
 		List<ClassNode> list = new ArrayList<>();
 		for (ClassNode cls : classes) {

jadx-core/src/main/java/jadx/core/xmlgen/BinaryXMLParser.java

@@ -56,6 +56,8 @@ public class BinaryXMLParser extends CommonBinaryParser {
 	private final RootNode rootNode;
 	private String appPackageName;
 
+	private Map<String, ClassNode> classNameCache;
+
 	public BinaryXMLParser(RootNode rootNode) {
 		this.rootNode = rootNode;
 		try {
@@ -78,7 +80,9 @@ public class BinaryXMLParser extends CommonBinaryParser {
 		firstElement = true;
 		decode();
 		nsMap = null;
-		return writer.finish();
+		ICodeInfo codeInfo = writer.finish();
+		this.classNameCache = null; // reset class name cache
+		return codeInfo;
 	}
 
 	private boolean isBinaryXml() throws IOException {
@@ -467,6 +471,9 @@ public class BinaryXMLParser extends CommonBinaryParser {
 	}
 
 	private void attachClassNode(ICodeWriter writer, String attrName, String clsName) {
+		if (!writer.isMetadataSupported()) {
+			return;
+		}
 		if (clsName == null || !attrName.equals("name")) {
 			return;
 		}
@@ -476,7 +483,10 @@ public class BinaryXMLParser extends CommonBinaryParser {
 		} else {
 			clsFullName = clsName;
 		}
-		ClassNode classNode = rootNode.searchClassByFullAlias(clsFullName);
+		if (classNameCache == null) {
+			classNameCache = rootNode.buildFullAliasClassCache();
+		}
+		ClassNode classNode = classNameCache.get(clsFullName);
 		if (classNode != null) {
 			writer.attachAnnotation(classNode);
 		}