feat: allow to load directories

jadx-core/src/main/java/jadx/api/JadxArgsValidator.java

@@ -85,9 +85,6 @@ public class JadxArgsValidator {
 		if (!file.exists()) {
 			throw new JadxArgsValidateException("File not found " + file.getAbsolutePath());
 		}
-		if (file.isDirectory()) {
-			throw new JadxArgsValidateException("Expected file but found directory instead: " + file.getAbsolutePath());
-		}
 	}
 
 	private static void checkDir(File dir, String desc) {

jadx-core/src/main/java/jadx/api/JadxDecompiler.java

@@ -40,6 +40,7 @@ import jadx.core.dex.visitors.SaveCode;
 import jadx.core.export.ExportGradleProject;
 import jadx.core.utils.Utils;
 import jadx.core.utils.exceptions.JadxRuntimeException;
+import jadx.core.utils.files.FileUtils;
 import jadx.core.xmlgen.BinaryXMLParser;
 import jadx.core.xmlgen.ProtoXMLParser;
 import jadx.core.xmlgen.ResContainer;
@@ -113,8 +114,9 @@ public final class JadxDecompiler implements Closeable {
 	private void loadInputFiles() {
 		loadedInputs.clear();
 		List<Path> inputPaths = Utils.collectionMap(args.getInputFiles(), File::toPath);
+		List<Path> inputFiles = FileUtils.expandDirs(inputPaths);
 		for (JadxInputPlugin inputPlugin : pluginManager.getInputPlugins()) {
-			ILoadResult loadResult = inputPlugin.loadFiles(inputPaths);
+			ILoadResult loadResult = inputPlugin.loadFiles(inputFiles);
 			if (loadResult != null && !loadResult.isEmpty()) {
 				loadedInputs.add(loadResult);
 			}

jadx-core/src/main/java/jadx/api/ResourcesLoader.java

@@ -136,7 +136,7 @@ public final class ResourcesLoader {
 	}
 
 	private void loadFile(List<ResourceFile> list, File file) {
-		if (file == null) {
+		if (file == null || file.isDirectory()) {
 			return;
 		}
 		if (FileUtils.isZipFile(file)) {

jadx-core/src/main/java/jadx/core/utils/files/FileUtils.java

@@ -8,6 +8,7 @@ import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.file.FileVisitOption;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -41,6 +42,26 @@ public class FileUtils {
 	private FileUtils() {
 	}
 
+	public static List<Path> expandDirs(List<Path> paths) {
+		List<Path> files = new ArrayList<>(paths.size());
+		for (Path path : paths) {
+			if (Files.isDirectory(path)) {
+				expandDir(path, files);
+			} else {
+				files.add(path);
+			}
+		}
+		return files;
+	}
+
+	private static void expandDir(Path dir, List<Path> files) {
+		try (Stream<Path> walk = Files.walk(dir, FileVisitOption.FOLLOW_LINKS)) {
+			walk.filter(Files::isRegularFile).forEach(files::add);
+		} catch (Exception e) {
+			LOG.error("Failed to list files in directory: {}", dir, e);
+		}
+	}
+
 	public static void addFileToJar(JarOutputStream jar, File source, String entryName) throws IOException {
 		try (BufferedInputStream in = new BufferedInputStream(new FileInputStream(source))) {
 			JarEntry entry = new JarEntry(entryName);