ipojo.plugin/src/main/java/org/apache/felix/ipojo/manipulation/ConstructorCodeAdapter.java

/* 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.felix.ipojo.manipulation;

import java.util.logging.Level;

import org.apache.felix.ipojo.plugin.IPojoPluginConfiguration;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodAdapter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;


/**
 * Constructor Adapter : add a component manager argument inside a constructor.
 * @author <a href="mailto:felix-dev@incubator.apache.org">Felix Project Team</a>
 */
public class ConstructorCodeAdapter extends MethodAdapter implements Opcodes {

    /** The owner class of the field.
     * m_owner : String
     */
    private String m_owner;
    
    private boolean m_superDetected;

    /** PropertyCodeAdapter constructor.
     * A new FiledCodeAdapter should be create for each method visit.
     * @param mv MethodVisitor
     * @param owner Name of the class
     */
    public ConstructorCodeAdapter(final MethodVisitor mv, final String owner) {
    	super(mv);
        m_owner = owner;
        m_superDetected = false;
    }


    /** Visit Method for Field instance (GETFIELD).
     * @see org.objectweb.asm.MethodVisitor#visitFieldInsn(int, String, String, String)
     * @param opcode : visited operation code
     * @param owner : owner of the field
     * @param name : name of the field
     * @param desc : decriptor of the field
     */
    public void visitFieldInsn(
            final int opcode,
            final String owner,
            final String name,
            final String desc) {
        if (owner.equals(m_owner)) {
            if (opcode == GETFIELD) {
            		IPojoPluginConfiguration.getLogger().log(Level.INFO, "Manipulate a GETFIELD on : " + name);
                    String gDesc = "()" + desc;
                    visitMethodInsn(INVOKEVIRTUAL, owner, "_get" + name, gDesc);
                    return;
            } else
            	if (opcode == PUTFIELD) {
            		// replaces PUTFIELD f by INVOKESPECIAL _setf
            		IPojoPluginConfiguration.getLogger().log(Level.INFO, "Manipulate a PUTFIELD on : " + name);
            		String sDesc = "(" + desc + ")V";
            		visitMethodInsn(INVOKESPECIAL, owner, "_set" + name, sDesc);
            		return;
            	}
        }
        super.visitFieldInsn(opcode, owner, name, desc);
    }
    
    public void visitMethodInsn(int opcode, String owner, String name, String desc) {
    	// A method call is detected, check if it is the super call :
    	if(!m_superDetected) {
    		m_superDetected = true; 
    		// The first invocation is the super call
    		// 1) Visit the super constructor :
    		mv.visitVarInsn(ALOAD, 0);
    		mv.visitMethodInsn(opcode, owner, name, desc); // Super constructor invocation
    		
    		// 2) Load the object and the component manager argument 
    		mv.visitVarInsn(ALOAD, 0);
    		//mv.visitVarInsn(ALOAD, Type.getArgumentTypes(m_constructorDesc).length);
    		mv.visitVarInsn(ALOAD, 1);  // CM is always the first argument
    		// 3) Initialize the field 
    		mv.visitMethodInsn(INVOKESPECIAL, m_owner, "_setComponentManager", "(Lorg/apache/felix/ipojo/ComponentManagerImpl;)V");
    		// insertion finished	
    	} 
    	else { mv.visitMethodInsn(opcode, owner, name, desc); }
    }
    
    public void visitVarInsn(int opcode, int var) {
    	if(!m_superDetected) { return;	} // Do nothing the ALOAD 0 will be injected by visitMethodInsn
    	else { 
    		if (var == 0) { mv.visitVarInsn(opcode, var); }  // ALOAD 0 (THIS)
    		else { mv.visitVarInsn(opcode, var+1); }	// All other variable count 
    		}
    }
    
    public void visitIincInsn(int var, int increment) {
    	if(var != 0) { mv.visitIincInsn(var+1, increment); }
    	else { mv.visitIincInsn(var, increment); } // Increment the current object ???
    }
    
    public void visitLocalVariable(String name, String desc, String signature, Label start, Label end, int index) {
    	if(index == 0) {
    		mv.visitLocalVariable(name, desc, signature, start, end, index);
    		mv.visitLocalVariable("_manager", "Lorg/apache/felix/ipojo/ComponentManagerImpl;", null, start, end, 1);
    		IPojoPluginConfiguration.getLogger().log(Level.INFO, "Local Variable : " + name + " index = " + index + " desc = " + desc);
    		IPojoPluginConfiguration.getLogger().log(Level.INFO, "Local Variable : " + "_manager" + " index = " + 1 + " desc = " + "Lorg/apache/felix/ipojo/ComponentManagerImpl;");
    	}
    	mv.visitLocalVariable(name, desc, signature, start, end, index+1);
    	IPojoPluginConfiguration.getLogger().log(Level.INFO, "Local Variable : " + name + " index = " + index + " desc = " + desc);
    }
    
    public void visitMaxs(int maxStack, int maxLocals) {
    	mv.visitMaxs(maxStack, maxLocals+1);
    }
}