/**
 * Copyright (C) 2010-2017 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
 */
/**
 * 
 */
package org.evosuite.instrumentation;

import org.evosuite.assertion.CheapPurityAnalyzer;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * It collects bytecode instructions for further purity analysis in the 
 * <code>CheapPurityAnalyzer</code> class:
 * <ul>
 * 	<li>PUTSTATIC</li>
 * 	<li>PUTFIELD</li>
 * 	<li>INVOKESTATIC</li>
 * 	<li>INVOKESPECIAL</li>
 * 	<li>INVOKEINTERFACE</li>
 * 	<li>INVOKEVIRTUAL</li>
 * </ul>
 * This class only reads the existing bytecode.
 * 
 * @author Juan Galeotti
 */
public class PurityAnalysisMethodVisitor extends MethodVisitor {

	private boolean updatesField;
	private final CheapPurityAnalyzer purityAnalyzer;
	private final String classNameWithDots;
	private final String methodName;
	private final String descriptor;

	/**
	 * <p>Constructor for PutStaticMethodAdapter.</p>
	 *
	 * @param className a {@link java.lang.String} object.
	 * @param methodName a {@link java.lang.String} object.
	 * @param descriptor a {@link java.lang.String} object.
	 * @param mv a {@link org.objectweb.asm.MethodVisitor} object.
	 * @param purityAnalyzer a {@link CheapPurityAnalyzer} object.
	 */
	public PurityAnalysisMethodVisitor(String className, String methodName,
			String descriptor, MethodVisitor mv,
			CheapPurityAnalyzer purityAnalyzer) {
		super(Opcodes.ASM5, mv);
		this.updatesField = false;
		this.purityAnalyzer = purityAnalyzer;
		this.classNameWithDots = className.replace('/', '.');
		this.methodName = methodName;
		this.descriptor = descriptor;
	}

	/* (non-Javadoc)
	 * @see org.objectweb.asm.MethodAdapter#visitFieldInsn(int, java.lang.String, java.lang.String, java.lang.String)
	 */
	/** {@inheritDoc} */
	@Override
	public void visitFieldInsn(int opcode, String owner, String name,
			String desc) {
		if (opcode == Opcodes.PUTSTATIC || opcode == Opcodes.PUTFIELD) {
			updatesField = true;
		}
		super.visitFieldInsn(opcode, owner, name, desc);
	}

	public boolean updatesField() {
		return updatesField;
	}

	@Override
	public void visitMethodInsn(int opcode, String owner, String name,
			String desc, boolean itf) {

		String targetClassName = owner.replace('/', '.');
		if (targetClassName.equals(org.evosuite.runtime.Random.class.getCanonicalName()) || !BytecodeInstrumentation.checkIfEvoSuitePackage(targetClassName)) {
			//Only ignore EvoSuite callbacks
			if (opcode == Opcodes.INVOKESTATIC) {
				this.purityAnalyzer.addStaticCall(classNameWithDots,
						methodName, descriptor, targetClassName, name, desc);
			} else if (opcode == Opcodes.INVOKEVIRTUAL) {
				this.purityAnalyzer.addVirtualCall(classNameWithDots,
						methodName, descriptor, targetClassName, name, desc);

			} else if (opcode == Opcodes.INVOKEINTERFACE) {
				this.purityAnalyzer.addInterfaceCall(classNameWithDots,
						methodName, descriptor, targetClassName, name, desc);

			} else if (opcode == Opcodes.INVOKESPECIAL) {
				this.purityAnalyzer.addSpecialCall(classNameWithDots,
						methodName, descriptor, targetClassName, name, desc);
			}
		}
		super.visitMethodInsn(opcode, owner, name, desc, itf);
	}
}