feat(cli): improve single file mode (#1344)(#1384)

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

@@ -32,23 +32,19 @@ public class JadxCLI {
 	public static int execute(String[] args) {
 		JadxCLIArgs jadxArgs = new JadxCLIArgs();
 		if (jadxArgs.processArgs(args)) {
-			return processAndSave(jadxArgs.toJadxArgs());
+			return processAndSave(jadxArgs);
 		}
 		return 0;
 	}
 
-	private static int processAndSave(JadxArgs jadxArgs) {
+	private static int processAndSave(JadxCLIArgs cliArgs) {
+		JadxArgs jadxArgs = cliArgs.toJadxArgs();
 		jadxArgs.setCodeCache(new NoOpCodeCache());
 		jadxArgs.setCodeWriterProvider(SimpleCodeWriter::new);
 		try (JadxDecompiler jadx = new JadxDecompiler(jadxArgs)) {
 			jadx.load();
-			if (LogHelper.getLogLevel() == LogHelper.LogLevelEnum.QUIET) {
-				jadx.save();
-			} else {
-				jadx.save(500, (done, total) -> {
-					int progress = (int) (done * 100.0 / total);
-					System.out.printf("INFO  - progress: %d of %d (%d%%)\r", done, total, progress);
-				});
+			if (!SingleClassMode.process(jadx, cliArgs)) {
+				save(jadx);
 			}
 			int errorsCount = jadx.getErrorsCount();
 			if (errorsCount != 0) {
@@ -60,4 +56,15 @@ public class JadxCLI {
 		}
 		return 0;
 	}
+
+	private static void save(JadxDecompiler jadx) {
+		if (LogHelper.getLogLevel() == LogHelper.LogLevelEnum.QUIET) {
+			jadx.save();
+		} else {
+			jadx.save(500, (done, total) -> {
+				int progress = (int) (done * 100.0 / total);
+				System.out.printf("INFO  - progress: %d of %d (%d%%)\r", done, total, progress);
+			});
+		}
+	}
 }

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

@@ -40,9 +40,12 @@ public class JadxCLIArgs {
 	@Parameter(names = { "-s", "--no-src" }, description = "do not decompile source code")
 	protected boolean skipSources = false;
 
-	@Parameter(names = { "--single-class" }, description = "decompile a single class")
+	@Parameter(names = { "--single-class" }, description = "decompile a single class, can raw name or an alias")
 	protected String singleClass = null;
 
+	@Parameter(names = { "--single-class-output" }, description = "file or dir for write if decompile a single class")
+	protected String singleClassOutput = null;
+
 	@Parameter(names = { "--output-format" }, description = "can be 'java' or 'json'")
 	protected String outputFormat = "java";
 
@@ -227,9 +230,6 @@ public class JadxCLIArgs {
 		args.setOutputFormat(JadxArgs.OutputFormatEnum.valueOf(outputFormat.toUpperCase()));
 		args.setThreadsCount(threadsCount);
 		args.setSkipSources(skipSources);
-		if (singleClass != null) {
-			args.setClassFilter(className -> singleClass.equals(className));
-		}
 		args.setSkipResources(skipResources);
 		args.setFallbackMode(fallbackMode);
 		args.setShowInconsistentCode(showInconsistentCode);
@@ -279,6 +279,14 @@ public class JadxCLIArgs {
 		return outDirRes;
 	}
 
+	public String getSingleClass() {
+		return singleClass;
+	}
+
+	public String getSingleClassOutput() {
+		return singleClassOutput;
+	}
+
 	public boolean isSkipResources() {
 		return skipResources;
 	}

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

@@ -58,6 +58,7 @@ public class LogHelper {
 			// show progress for all levels except quiet
 			setLevelForClass(JadxCLI.class, Level.INFO);
 			setLevelForClass(JadxDecompiler.class, Level.INFO);
+			setLevelForClass(SingleClassMode.class, Level.INFO);
 		}
 	}
 

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

@@ -0,0 +1,87 @@
+package jadx.cli;
+
+import java.io.File;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import jadx.api.ICodeInfo;
+import jadx.api.JadxDecompiler;
+import jadx.core.dex.attributes.AFlag;
+import jadx.core.dex.nodes.ClassNode;
+import jadx.core.dex.visitors.SaveCode;
+import jadx.core.utils.exceptions.JadxRuntimeException;
+import jadx.core.utils.files.FileUtils;
+
+public class SingleClassMode {
+	private static final Logger LOG = LoggerFactory.getLogger(SingleClassMode.class);
+
+	public static boolean process(JadxDecompiler jadx, JadxCLIArgs cliArgs) {
+		String singleClass = cliArgs.getSingleClass();
+		String singleClassOutput = cliArgs.getSingleClassOutput();
+		if (singleClass == null && singleClassOutput == null) {
+			return false;
+		}
+		ClassNode clsForProcess;
+		if (singleClass != null) {
+			clsForProcess = jadx.getRoot().resolveClass(singleClass);
+			if (clsForProcess == null) {
+				clsForProcess = jadx.getRoot().getClasses().stream()
+						.filter(cls -> cls.getClassInfo().getAliasFullName().equals(singleClass))
+						.findFirst().orElse(null);
+			}
+			if (clsForProcess == null) {
+				throw new JadxRuntimeException("Input class not found: " + singleClass);
+			}
+			if (clsForProcess.contains(AFlag.DONT_GENERATE)) {
+				throw new JadxRuntimeException("Input class can't be saved by currect jadx settings (marked as DONT_GENERATE)");
+			}
+			if (clsForProcess.isInner()) {
+				clsForProcess = clsForProcess.getTopParentClass();
+				LOG.warn("Input class is inner, parent class will be saved: {}", clsForProcess.getFullName());
+			}
+		} else {
+			// singleClassOutput is set
+			// expect only one class to be loaded
+			List<ClassNode> classes = jadx.getRoot().getClasses().stream()
+					.filter(c -> !c.isInner() && !c.contains(AFlag.DONT_GENERATE))
+					.collect(Collectors.toList());
+			int size = classes.size();
+			if (size == 1) {
+				clsForProcess = classes.get(0);
+			} else {
+				throw new JadxRuntimeException("Found " + size + " classes, single class output can't be used");
+			}
+		}
+		ICodeInfo codeInfo;
+		try {
+			codeInfo = clsForProcess.decompile();
+		} catch (Exception e) {
+			throw new JadxRuntimeException("Class decompilation failed", e);
+		}
+		String fileExt = SaveCode.getFileExtension(jadx.getRoot());
+		File out;
+		if (singleClassOutput == null) {
+			out = new File(jadx.getArgs().getOutDirSrc(), clsForProcess.getClassInfo().getAliasFullPath() + fileExt);
+		} else {
+			if (singleClassOutput.endsWith(fileExt)) {
+				// treat as file name
+				out = new File(singleClassOutput);
+			} else {
+				// treat as directory
+				out = new File(singleClassOutput, clsForProcess.getShortName() + fileExt);
+			}
+		}
+		File resultOut = FileUtils.prepareFile(out);
+		if (clsForProcess.getClassInfo().hasAlias()) {
+			LOG.info("Saving class '{}' (alias: '{}') to file '{}'",
+					clsForProcess.getClassInfo().getFullName(), clsForProcess.getFullName(), resultOut.getAbsolutePath());
+		} else {
+			LOG.info("Saving class '{}' to file '{}'", clsForProcess.getFullName(), resultOut.getAbsolutePath());
+		}
+		SaveCode.save(codeInfo.getCodeStr(), resultOut);
+		return true;
+	}
+}

jadx-core/src/main/java/jadx/core/dex/visitors/SaveCode.java

@@ -11,6 +11,7 @@ import jadx.api.JadxArgs;
 import jadx.api.plugins.utils.ZipSecurity;
 import jadx.core.dex.attributes.AFlag;
 import jadx.core.dex.nodes.ClassNode;
+import jadx.core.dex.nodes.RootNode;
 import jadx.core.utils.exceptions.JadxRuntimeException;
 import jadx.core.utils.files.FileUtils;
 
@@ -37,7 +38,7 @@ public class SaveCode {
 		if (cls.root().getArgs().isSkipFilesSave()) {
 			return;
 		}
-		String fileName = cls.getClassInfo().getAliasFullPath() + getFileExtension(cls);
+		String fileName = cls.getClassInfo().getAliasFullPath() + getFileExtension(cls.root());
 		save(codeStr, dir, fileName);
 	}
 
@@ -61,8 +62,8 @@ public class SaveCode {
 		}
 	}
 
-	private static String getFileExtension(ClassNode cls) {
-		JadxArgs.OutputFormatEnum outputFormat = cls.root().getArgs().getOutputFormat();
+	public static String getFileExtension(RootNode root) {
+		JadxArgs.OutputFormatEnum outputFormat = root.getArgs().getOutputFormat();
 		switch (outputFormat) {
 			case JAVA:
 				return ".java";