# MethodProbesVisitor.java

    /*******************************************************************************
     * Copyright (c) 2009, 2013 Mountainminds GmbH & Co. KG and Contributors
     * All rights reserved. This program and the accompanying materials
     * are made available under the terms of the Eclipse Public License v1.0
     * which accompanies this distribution, and is available at
     * http://www.eclipse.org/legal/epl-v10.html
     *
     * Contributors:
     *    Marc R. Hoffmann - initial API and implementation
     *
     *******************************************************************************/
    package org.jacoco.core.internal.flow;

    import org.objectweb.asm.Label;
    import org.objectweb.asm.MethodVisitor;
    import org.objectweb.asm.Opcodes;

    /**
     * A {@link MethodVisitor} with additional methods to get probe insertion
     * information.
     */
    public abstract class MethodProbesVisitor extends MethodVisitor {

    	/**
    	 * New visitor instance without delegate visitor.
    	 */
    	public MethodProbesVisitor() {
    		this(null);
    	}

    	/**
    	 * New visitor instance that delegates to the given visitor.
    	 *
    	 * @param mv
    	 *            optional next visitor in chain
    	 */
    	public MethodProbesVisitor(final MethodVisitor mv) {
    		super(Opcodes.ASM4, mv);
    	}

    	/**
    	 * Visits an unconditional probe that should be inserted at the current
    	 * position.
    	 *
    	 * @param probeId
    	 *            id of the probe to insert
    	 */
    	public abstract void visitProbe(int probeId);

    	/**
    	 * Visits a jump instruction. A probe with the given id should be inserted
    	 * in a way that it is executed only when the jump to the given label is
    	 * executed.
    	 *
    	 * @param opcode
    	 *            the opcode of the type instruction to be visited. This opcode
    	 *            is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ,
    	 *            IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE,
    	 *            IF_ACMPEQ, IF_ACMPNE, GOTO, IFNULL or IFNONNULL.
    	 * @param label
    	 *            the operand of the instruction to be visited. This operand is
    	 *            a label that designates the instruction to which the jump
    	 *            instruction may jump.
    	 * @param probeId
    	 *            id of the probe
    	 * @see MethodVisitor#visitJumpInsn(int, Label)
    	 */
    	public abstract void visitJumpInsnWithProbe(int opcode, Label label,
    			int probeId);

    	/**
    	 * Visits a zero operand instruction with a probe. This event is used only
    	 * for instructions that terminate the method. Therefore the probe must be
    	 * inserted before the actual instruction.
    	 *
    	 * @param opcode
    	 *            the opcode of the instruction to be visited. This opcode is
    	 *            either IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN or
    	 *            ATHROW.
    	 * @param probeId
    	 *            id of the probe
    	 * @see MethodVisitor#visitInsn(int)
    	 */
    	public abstract void visitInsnWithProbe(int opcode, int probeId);

    	/**
    	 * Visits a TABLESWITCH instruction with optional probes for each target
    	 * label. Implementations can be optimized based on the fact that the same
    	 * target labels will always have the same probe id within a call to this
    	 * method. The probe id for each label can be obtained with
    	 * {@link LabelInfo#getProbeId(Label)}.
    	 *
    	 * @param min
    	 *            the minimum key value.
    	 * @param max
    	 *            the maximum key value.
    	 * @param dflt
    	 *            beginning of the default handler block.
    	 * @param labels
    	 *            beginnings of the handler blocks. <code>labels[i]</code> is
    	 *            the beginning of the handler block for the
    	 *            <code>min + i</code> key.
    	 * @see MethodVisitor#visitTableSwitchInsn(int, int, Label, Label[])
    	 */
    	public abstract void visitTableSwitchInsnWithProbes(int min, int max,
    			Label dflt, Label[] labels);

    	/**
    	 * Visits a LOOKUPSWITCH instruction with optional probes for each target
    	 * label. Implementations can be optimized based on the fact that the same
    	 * target labels will always have the same probe id within a call to this
    	 * method. The probe id for each label can be obtained with
    	 * {@link LabelInfo#getProbeId(Label)}.
    	 *
    	 * @param dflt
    	 *            beginning of the default handler block.
    	 * @param keys
    	 *            the values of the keys.
    	 * @param labels
    	 *            beginnings of the handler blocks. <code>labels[i]</code> is
    	 *            the beginning of the handler block for the
    	 *            <code>keys[i]</code> key.
    	 * @see MethodVisitor#visitLookupSwitchInsn(Label, int[], Label[])
    	 */
    	public abstract void visitLookupSwitchInsnWithProbes(Label dflt,
    			int[] keys, Label[] labels);

    }