feat(api): allow to get method code (#2305)

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

@@ -2,7 +2,6 @@ package jadx.api;
 
 import java.util.Collections;
 import java.util.List;
-import java.util.Objects;
 import java.util.stream.Collectors;
 
 import org.jetbrains.annotations.ApiStatus;
@@ -79,15 +78,9 @@ public final class JavaMethod implements JavaNode {
 			return Collections.emptyList();
 		}
 		JadxDecompiler decompiler = getDeclaringClass().getRootDecompiler();
-		return ovrdAttr.getRelatedMthNodes().stream()
-				.map(m -> {
-					JavaMethod javaMth = decompiler.convertMethodNode(m);
-					if (javaMth == null) {
-						LOG.warn("Failed convert to java method: {}", m);
-					}
-					return javaMth;
-				})
-				.filter(Objects::nonNull)
+		return ovrdAttr.getRelatedMthNodes()
+				.stream()
+				.map(decompiler::convertMethodNode)
 				.collect(Collectors.toList());
 	}
 
@@ -104,6 +97,10 @@ public final class JavaMethod implements JavaNode {
 		return mth.getDefPosition();
 	}
 
+	public String getCodeStr() {
+		return mth.getCodeStr();
+	}
+
 	@Override
 	public void removeAlias() {
 		this.mth.getMethodInfo().removeAlias();

jadx-core/src/main/java/jadx/api/utils/CodeUtils.java

@@ -1,5 +1,13 @@
 package jadx.api.utils;
 
+import java.util.function.BiFunction;
+
+import jadx.api.ICodeInfo;
+import jadx.api.metadata.ICodeAnnotation;
+import jadx.api.metadata.ICodeNodeRef;
+import jadx.api.metadata.annotations.NodeDeclareRef;
+import jadx.core.dex.nodes.MethodNode;
+
 public class CodeUtils {
 
 	public static String getLineForPos(String code, int pos) {
@@ -47,4 +55,71 @@ public class CodeUtils {
 			line++;
 		}
 	}
+
+	/**
+	 * Cut method code (including comments and annotations) from class code.
+	 *
+	 * @return method code or empty string if metadata is not available
+	 */
+	public static String extractMethodCode(MethodNode mth, ICodeInfo codeInfo) {
+		int end = getMethodEnd(mth, codeInfo);
+		if (end == -1) {
+			return "";
+		}
+		int start = getMethodStart(mth, codeInfo);
+		if (end < start) {
+			return "";
+		}
+		return codeInfo.getCodeStr().substring(start, end);
+	}
+
+	/**
+	 * Search first empty line before method definition to include comments and annotations
+	 */
+	private static int getMethodStart(MethodNode mth, ICodeInfo codeInfo) {
+		int pos = mth.getDefPosition();
+		String newLineStr = mth.root().getArgs().getCodeNewLineStr();
+		String emptyLine = newLineStr + newLineStr;
+		int emptyLinePos = codeInfo.getCodeStr().lastIndexOf(emptyLine, pos);
+		return emptyLinePos == -1 ? pos : emptyLinePos + emptyLine.length();
+	}
+
+	/**
+	 * Search method end position in provided class code info.
+	 *
+	 * @return end pos or -1 if metadata not available
+	 */
+	public static int getMethodEnd(MethodNode mth, ICodeInfo codeInfo) {
+		if (!codeInfo.hasMetadata()) {
+			return -1;
+		}
+		// skip nested nodes DEF/END until first unpaired END annotation (end of this method)
+		Integer end = codeInfo.getCodeMetadata().searchDown(mth.getDefPosition() + 1, new BiFunction<>() {
+			int nested = 0;
+
+			@Override
+			public Integer apply(Integer pos, ICodeAnnotation ann) {
+				switch (ann.getAnnType()) {
+					case DECLARATION:
+						ICodeNodeRef node = ((NodeDeclareRef) ann).getNode();
+						switch (node.getAnnType()) {
+							case CLASS:
+							case METHOD:
+								nested++;
+								break;
+						}
+						break;
+
+					case END:
+						if (nested == 0) {
+							return pos;
+						}
+						nested--;
+						break;
+				}
+				return null;
+			}
+		});
+		return end == null ? -1 : end;
+	}
 }

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

@@ -5,6 +5,7 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
@@ -668,6 +669,13 @@ public class MethodNode extends NotificationAttrNode implements IMethodDetails,
 		return insnsCount;
 	}
 
+	/**
+	 * Returns method code with comments and annotations
+	 */
+	public String getCodeStr() {
+		return CodeUtils.extractMethodCode(this, getTopParentClass().getCode());
+	}
+
 	@Override
 	public boolean isVarArg() {
 		return accFlags.isVarArgs();
@@ -693,6 +701,7 @@ public class MethodNode extends NotificationAttrNode implements IMethodDetails,
 		return javaNode;
 	}
 
+	@ApiStatus.Internal
 	public void setJavaNode(JavaMethod javaNode) {
 		this.javaNode = javaNode;
 	}