[feature] Jadx plugin extraction of method code

[Devilx86]

Describe your idea

Hello,
I am working on a Jadx plugin and I require extraction of method code alone. Similar to the ((JavaClass) node).getCode() a ((JavaMethod) node).getCode() or addition of a ((JavaMethod) node).getDefEndPos() would be helpful. Please let me know if there are any alternatives that I am not aware of which I could use.

Thanks

[skylot]

I require extraction of method code alone

Sure. I will add this method.
As a workaround for now, you can use this code:

private String cutMethodCode(MethodNode mth, ICodeInfo codeInfo) {
	int startPos = getCommentStartPos(codeInfo, mth.getDefPosition());
	int stopPos = getMethodEnd(mth, codeInfo);
	return codeInfo.getCodeStr().substring(startPos, stopPos);
}

protected int getCommentStartPos(ICodeInfo codeInfo, int pos) {
	String emptyLine = "\n\n";
	int emptyLinePos = codeInfo.getCodeStr().lastIndexOf(emptyLine, pos);
	return emptyLinePos == -1 ? pos : emptyLinePos + emptyLine.length();
}

private int getMethodEnd(MethodNode mth, ICodeInfo codeInfo) {
	// 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 ? end : codeInfo.getCodeStr().length();
}

[Devilx86]

Thank you! @skylot

[skylot]

Done. Added getCodeStr() method for MethodNode and JavaMethod classes. Check jadx snapshot version.

Although, it will not work for plugins running in jadx-cli because code metadata not added. It is possible to fix this by saving start/end method pos during codegen into new attribute, but for now I don't want to do this, because such case might be very rare. @Devilx86 if this affects you, let me know, and I will add this (maybe I will find a better approach).

[Devilx86]

Thanks very much @skylot, this works for my usecase. Another issue I noticed is that the ((JavaClass) node).getCode() method returns an empty string for inner classes. I was able to get around this with a modified version of the code you have shared above

public static String getClassCode(ClassNode cls, ICodeInfo codeInfo) {
        int startPos = getCommentStartPos(codeInfo, cls.getDefPosition());
	int stopPos = getEndFrom(cls.getDefPosition(), codeInfo) + 1;
	return codeInfo.getCodeStr().substring(startPos, stopPos);
}

private static int getEndFrom(int startPosition, ICodeInfo codeInfo) {
	// skip nested nodes DEF/END until first unpaired END annotation (end of this method)
	Integer end = codeInfo.getCodeMetadata().searchDown(startPosition + 1, new BiFunction<>() {
	.....
}