content: /*******************************************************************************
   * Copyright (c) 2009, 2019 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.jacoco.core.internal.instr.InstrSupport;
  import org.objectweb.asm.Label;
  import org.objectweb.asm.MethodVisitor;
  import org.objectweb.asm.tree.MethodNode;
  
  /**
   * 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(InstrSupport.ASM_API_VERSION, mv);
  	}
  
  	/**
  	 * Visits an unconditional probe that should be inserted at the current
  	 * position.
  	 * 
  	 * @param probeId
  	 *            id of the probe to insert
  	 */
  	@SuppressWarnings("unused")
  	public void visitProbe(final 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
  	 * @param frame
  	 *            stackmap frame status after the execution of the jump
  	 *            instruction. The instance is only valid with the call of this
  	 *            method.
  	 * @see MethodVisitor#visitJumpInsn(int, Label)
  	 */
  	@SuppressWarnings("unused")
  	public void visitJumpInsnWithProbe(final int opcode, final Label label,
  			final int probeId, final IFrame frame) {
  	}
  
  	/**
  	 * 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)
  	 */
  	@SuppressWarnings("unused")
  	public void visitInsnWithProbe(final int opcode, final 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.
  	 * @param frame
  	 *            stackmap frame status after the execution of the switch
  	 *            instruction. The instance is only valid with the call of this
  	 *            method.
  	 * @see MethodVisitor#visitTableSwitchInsn(int, int, Label, Label[])
  	 */
  	@SuppressWarnings("unused")
  	public void visitTableSwitchInsnWithProbes(final int min, final int max,
  			final Label dflt, final Label[] labels, final IFrame frame) {
  	}
  
  	/**
  	 * 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.
  	 * @param frame
  	 *            stackmap frame status after the execution of the switch
  	 *            instruction. The instance is only valid with the call of this
  	 *            method.
  	 * @see MethodVisitor#visitLookupSwitchInsn(Label, int[], Label[])
  	 */
  	@SuppressWarnings("unused")
  	public void visitLookupSwitchInsnWithProbes(final Label dflt,
  			final int[] keys, final Label[] labels, final IFrame frame) {
  	}
  
  	/**
  	 * This method can be overwritten to hook into the process of emitting the
  	 * instructions of this method as <code>visitX()</code> events.
  	 *
  	 * @param methodNode
  	 *            the content to emit
  	 * @param methodVisitor
  	 *            A visitor to emit the content to. Note that this is not
  	 *            necessarily this visitor instance but some wrapper which
  	 *            calculates the probes.
  	 */
  	public void accept(final MethodNode methodNode,
  			final MethodVisitor methodVisitor) {
  		methodNode.accept(methodVisitor);
  	}
  
  }
  