/*
 * Copyright (c) 2008, 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the Classpath exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package org.openjdk.btrace.instr;

import static org.objectweb.asm.Opcodes.ANEWARRAY;
import static org.objectweb.asm.Opcodes.NEWARRAY;

import org.objectweb.asm.MethodVisitor;

/**
 * This visitor helps in inserting code whenever an array is allocated. The code to insert on method
 * entry may be decided by derived class. By default, this class inserts code to print allocated
 * array objects.
 *
 * @author A. Sundararajan
 */
public class ArrayAllocInstrumentor extends MethodInstrumentor {
  public ArrayAllocInstrumentor(
      ClassLoader cl,
      MethodVisitor mv,
      MethodInstrumentorHelper mHelper,
      String parentClz,
      String superClz,
      int access,
      String name,
      String desc) {
    super(cl, mv, mHelper, parentClz, superClz, access, name, desc);
  }

  @Override
  public void visitIntInsn(int opcode, int operand) {
    String desc = null;
    if (opcode == NEWARRAY) {
      desc = InstrumentUtils.arrayDescriptorFor(operand);
      onBeforeArrayNew(getPlainType(desc), 1);
    }
    super.visitIntInsn(opcode, operand);
    if (opcode == NEWARRAY) {
      onAfterArrayNew(getPlainType(desc), 1);
    }
  }

  @Override
  public void visitTypeInsn(int opcode, String desc) {
    if (opcode == ANEWARRAY) {
      onBeforeArrayNew("L" + desc + ";", 1);
    }
    super.visitTypeInsn(opcode, desc);
    if (opcode == ANEWARRAY) {
      onAfterArrayNew("L" + desc + ";", 1);
    }
  }

  @Override
  public void visitMultiANewArrayInsn(String desc, int dims) {
    String type = getPlainType(desc);
    onBeforeArrayNew(type, dims);
    super.visitMultiANewArrayInsn(desc, dims);
    onAfterArrayNew(type, dims);
  }

  protected void onBeforeArrayNew(String desc, int dims) {
    asm.println("before allocating " + desc);
  }

  protected void onAfterArrayNew(String desc, int dims) {
    asm.dup().printObject();
  }

  private String getPlainType(String desc) {
    int index = desc.lastIndexOf('[') + 1;
    if (index > 0) {
      return desc.substring(index);
    }
    return desc;
  }
}
