core: decompile '.class' files

jadx-cli/src/main/java/jadx/cli/JadxCLIArgs.java

@@ -20,7 +20,7 @@ import com.beust.jcommander.ParameterException;
 
 public final class JadxCLIArgs implements IJadxArgs {
 
-	@Parameter(description = "<input file> (.dex, .apk or .jar)")
+	@Parameter(description = "<input file> (.dex, .apk, .jar or .class)")
 	protected List<String> files;
 
 	@Parameter(names = {"-d", "--output-dir"}, description = "output directory")

jadx-core/build.gradle

@@ -2,6 +2,7 @@ ext.jadxClasspath = 'clsp-data/android-4.3.jar'
 
 dependencies {
     compile files('lib/dx-1.8.jar')
+    compile 'org.ow2.asm:asm:5.0.3'
     runtime files(jadxClasspath)
 }
 

jadx-core/src/main/java/jadx/core/utils/AsmUtils.java

+package jadx.core.utils;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+
+import org.objectweb.asm.ClassReader;
+
+public class AsmUtils {
+
+	private AsmUtils() {
+	}
+
+	public static String getNameFromClassFile(File file) throws IOException {
+		FileInputStream in = new FileInputStream(file);
+		ClassReader classReader = new ClassReader(in);
+		return classReader.getClassName();
+	}
+
+}

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

+package jadx.core.utils.files;
+
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.jar.JarEntry;
+import java.util.jar.JarOutputStream;
+
+public class FileUtils {
+
+	private FileUtils() {
+	}
+
+	public static void addFileToJar(JarOutputStream jar, File source, String entryName) throws IOException {
+		BufferedInputStream in = null;
+		try {
+			JarEntry entry = new JarEntry(entryName);
+			entry.setTime(source.lastModified());
+			jar.putNextEntry(entry);
+			in = new BufferedInputStream(new FileInputStream(source));
+
+			byte[] buffer = new byte[8192];
+			while (true) {
+				int count = in.read(buffer);
+				if (count == -1) {
+					break;
+				}
+				jar.write(buffer, 0, count);
+			}
+			jar.closeEntry();
+		} finally {
+			if (in != null) {
+				in.close();
+			}
+		}
+	}
+}

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

 package jadx.core.utils.files;
 
+import jadx.core.utils.AsmUtils;
 import jadx.core.utils.exceptions.DecodeException;
 import jadx.core.utils.exceptions.JadxException;
-import jadx.core.utils.exceptions.JadxRuntimeException;
 
 import java.io.ByteArrayOutputStream;
 import java.io.File;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.jar.JarOutputStream;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
@@ -35,37 +37,44 @@ public class InputFile {
 		if (fileName.endsWith(".dex")) {
 			return new Dex(file);
 		}
+		if (fileName.endsWith(".class")) {
+			return loadFromClassFile(file);
+		}
 		if (fileName.endsWith(".apk")) {
-			byte[] data = openDexFromZip(file);
-			if (data == null) {
-				throw new JadxRuntimeException("File 'classes.dex' not found in file: " + file);
+			Dex dex = loadFromZip(file);
+			if (dex == null) {
+				throw new IOException("File 'classes.dex' not found in file: " + file);
 			}
-			return new Dex(data);
+			return dex;
 		}
 		if (fileName.endsWith(".jar")) {
 			// check if jar contains 'classes.dex'
-			byte[] data = openDexFromZip(file);
-			if (data != null) {
-				return new Dex(data);
-			}
-			try {
-				LOG.info("converting to dex: {} ...", fileName);
-				JavaToDex j2d = new JavaToDex();
-				byte[] ba = j2d.convert(file.getAbsolutePath());
-				if (ba.length == 0) {
-					throw new JadxException(j2d.isError() ? j2d.getDxErrors() : "Empty dx output");
-				} else if (j2d.isError()) {
-					LOG.warn("dx message: " + j2d.getDxErrors());
-				}
-				return new Dex(ba);
-			} catch (Throwable e) {
-				throw new DecodeException("java class to dex conversion error:\n " + e.getMessage(), e);
+			Dex dex = loadFromZip(file);
+			if (dex != null) {
+				return dex;
 			}
+			return loadFromJar(file);
 		}
 		throw new DecodeException("Unsupported input file format: " + file);
 	}
 
-	private byte[] openDexFromZip(File file) throws IOException {
+	private static Dex loadFromJar(File jarFile) throws DecodeException {
+		try {
+			LOG.info("converting to dex: {} ...", jarFile.getName());
+			JavaToDex j2d = new JavaToDex();
+			byte[] ba = j2d.convert(jarFile.getAbsolutePath());
+			if (ba.length == 0) {
+				throw new JadxException(j2d.isError() ? j2d.getDxErrors() : "Empty dx output");
+			} else if (j2d.isError()) {
+				LOG.warn("dx message: " + j2d.getDxErrors());
+			}
+			return new Dex(ba);
+		} catch (Throwable e) {
+			throw new DecodeException("java class to dex conversion error:\n " + e.getMessage(), e);
+		}
+	}
+
+	private static Dex loadFromZip(File file) throws IOException {
 		ZipFile zf = new ZipFile(file);
 		ZipEntry dex = zf.getEntry("classes.dex");
 		if (dex == null) {
@@ -87,7 +96,19 @@ public class InputFile {
 			}
 			zf.close();
 		}
-		return bytesOut.toByteArray();
+		return new Dex(bytesOut.toByteArray());
+	}
+
+	private static Dex loadFromClassFile(File file) throws IOException, DecodeException {
+		File outFile = File.createTempFile("jadx-tmp-", System.nanoTime() + ".jar");
+		outFile.deleteOnExit();
+		FileOutputStream out = new FileOutputStream(outFile);
+		JarOutputStream jo = new JarOutputStream(out);
+		String clsName = AsmUtils.getNameFromClassFile(file);
+		FileUtils.addFileToJar(jo, file, clsName + ".class");
+		jo.close();
+		out.close();
+		return loadFromJar(outFile);
 	}
 
 	public File getFile() {

jadx-core/src/test/java/jadx/api/InternalJadxTest.java

@@ -7,17 +7,15 @@ import jadx.core.dex.nodes.ClassNode;
 import jadx.core.dex.nodes.MethodNode;
 import jadx.core.dex.visitors.DepthTraversal;
 import jadx.core.dex.visitors.IDexTreeVisitor;
+import jadx.core.utils.files.FileUtils;
 
-import java.io.BufferedInputStream;
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.net.URISyntaxException;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.jar.JarEntry;
 import java.util.jar.JarOutputStream;
 
 import static org.hamcrest.CoreMatchers.containsString;
@@ -94,7 +92,7 @@ public abstract class InternalJadxTest extends TestUtils {
 		File temp = File.createTempFile("jadx-tmp-", System.nanoTime() + ".jar");
 		JarOutputStream jo = new JarOutputStream(new FileOutputStream(temp));
 		for (File file : list) {
-			add(file, path + "/" + file.getName(), jo);
+			FileUtils.addFileToJar(jo, file, path + "/" + file.getName());
 		}
 		jo.close();
 		if (deleteTmpJar) {
@@ -127,29 +125,6 @@ public abstract class InternalJadxTest extends TestUtils {
 		return list;
 	}
 
-	private void add(File source, String entryName, JarOutputStream target) throws IOException {
-		BufferedInputStream in = null;
-		try {
-			JarEntry entry = new JarEntry(entryName);
-			entry.setTime(source.lastModified());
-			target.putNextEntry(entry);
-			in = new BufferedInputStream(new FileInputStream(source));
-
-			byte[] buffer = new byte[1024];
-			while (true) {
-				int count = in.read(buffer);
-				if (count == -1) {
-					break;
-				}
-				target.write(buffer, 0, count);
-			}
-			target.closeEntry();
-		} finally {
-			if (in != null) {
-				in.close();
-			}
-		}
-	}
 
 	// Use only for debug purpose
 	@Deprecated