MethodParameterWriter.java

/*******************************************************************************
 * Copyright (c) 2015 Jeff Martin.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser General Public
 * License v3.0 which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/lgpl.html
 *
 * Contributors:
 * Jeff Martin - initial API and implementation
 ******************************************************************************/
package cuchaz.enigma.bytecode;

import java.util.ArrayList;
import java.util.List;

import javassist.CtBehavior;
import javassist.CtClass;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.LocalVariableAttribute;
import cuchaz.enigma.mapping.ArgumentEntry;
import cuchaz.enigma.mapping.BehaviorEntry;
import cuchaz.enigma.mapping.EntryFactory;
import cuchaz.enigma.mapping.Signature;
import cuchaz.enigma.mapping.Translator;

public class MethodParameterWriter
{
	
	private Translator m_translator;
	
	public MethodParameterWriter(Translator translator)
	{
		m_translator = translator;
	}
	
	public void writeMethodArguments(CtClass c)
	{
		
		// Procyon will read method arguments from the "MethodParameters"
		// attribute, so write those
		for(CtBehavior behavior : c.getDeclaredBehaviors())
		{
			
			// if there's a local variable table here, don't write a
			// MethodParameters attribute
			// let the local variable writer deal with it instead
			// procyon starts doing really weird things if we give it both
			// attributes
			CodeAttribute codeAttribute =
				behavior.getMethodInfo().getCodeAttribute();
			if(codeAttribute != null
				&& codeAttribute.getAttribute(LocalVariableAttribute.tag) != null)
				continue;
			
			BehaviorEntry behaviorEntry =
				EntryFactory.getBehaviorEntry(behavior);
			
			// get the number of arguments
			Signature signature = behaviorEntry.getSignature();
			if(signature == null)
				// static initializers have no signatures, or arguments
				continue;
			int numParams = signature.getArgumentTypes().size();
			if(numParams <= 0)
				continue;
			
			// get the list of argument names
			List<String> names = new ArrayList<String>(numParams);
			for(int i = 0; i < numParams; i++)
				names.add(m_translator.translate(new ArgumentEntry(
					behaviorEntry, i, "")));
			
			// save the mappings to the class
			MethodParametersAttribute.updateClass(behavior.getMethodInfo(),
				names);
		}
	}
}