/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm.tree.analysis;

import java.util.List;

import org.objectweb.asm.Type;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.FieldInsnNode;
import org.objectweb.asm.tree.InvokeDynamicInsnNode;
import org.objectweb.asm.tree.MethodInsnNode;

/**
 * An extended {@link BasicInterpreter} that checks that bytecode instructions
 * are correctly used.
 * 
 * @author Eric Bruneton
 * @author Bing Ran
 */
public class BasicVerifier extends BasicInterpreter {

  public BasicVerifier() {
    super(ASM6);
  }

  protected BasicVerifier(final int api) {
    super(api);
  }

  @Override
  public BasicValue copyOperation(final AbstractInsnNode insn, final BasicValue value) throws AnalyzerException {
    Value expected;
    switch (insn.getOpcode()) {
    case ILOAD:
    case ISTORE:
      expected = BasicValue.INT_VALUE;
      break;
    case FLOAD:
    case FSTORE:
      expected = BasicValue.FLOAT_VALUE;
      break;
    case LLOAD:
    case LSTORE:
      expected = BasicValue.LONG_VALUE;
      break;
    case DLOAD:
    case DSTORE:
      expected = BasicValue.DOUBLE_VALUE;
      break;
    case ALOAD:
      if (!value.isReference()) {
        throw new AnalyzerException(insn, null, "an object reference", value);
      }
      return value;
    case ASTORE:
      if (!value.isReference() && !BasicValue.RETURNADDRESS_VALUE.equals(value)) {
        throw new AnalyzerException(insn, null, "an object reference or a return address", value);
      }
      return value;
    default:
      return value;
    }
    if (!expected.equals(value)) {
      throw new AnalyzerException(insn, null, expected, value);
    }
    return value;
  }

  @Override
  public BasicValue unaryOperation(final AbstractInsnNode insn, final BasicValue value) throws AnalyzerException {
    BasicValue expected;
    switch (insn.getOpcode()) {
    case INEG:
    case IINC:
    case I2F:
    case I2L:
    case I2D:
    case I2B:
    case I2C:
    case I2S:
    case IFEQ:
    case IFNE:
    case IFLT:
    case IFGE:
    case IFGT:
    case IFLE:
    case TABLESWITCH:
    case LOOKUPSWITCH:
    case IRETURN:
    case NEWARRAY:
    case ANEWARRAY:
      expected = BasicValue.INT_VALUE;
      break;
    case FNEG:
    case F2I:
    case F2L:
    case F2D:
    case FRETURN:
      expected = BasicValue.FLOAT_VALUE;
      break;
    case LNEG:
    case L2I:
    case L2F:
    case L2D:
    case LRETURN:
      expected = BasicValue.LONG_VALUE;
      break;
    case DNEG:
    case D2I:
    case D2F:
    case D2L:
    case DRETURN:
      expected = BasicValue.DOUBLE_VALUE;
      break;
    case GETFIELD:
      expected = newValue(Type.getObjectType(((FieldInsnNode) insn).owner));
      break;
    case CHECKCAST:
      if (!value.isReference()) {
        throw new AnalyzerException(insn, null, "an object reference", value);
      }
      return super.unaryOperation(insn, value);
    case ARRAYLENGTH:
      if (!isArrayValue(value)) {
        throw new AnalyzerException(insn, null, "an array reference", value);
      }
      return super.unaryOperation(insn, value);
    case ARETURN:
    case ATHROW:
    case INSTANCEOF:
    case MONITORENTER:
    case MONITOREXIT:
    case IFNULL:
    case IFNONNULL:
      if (!value.isReference()) {
        throw new AnalyzerException(insn, null, "an object reference", value);
      }
      return super.unaryOperation(insn, value);
    case PUTSTATIC:
      expected = newValue(Type.getType(((FieldInsnNode) insn).desc));
      break;
    default:
      throw new Error("Internal error.");
    }
    if (!isSubTypeOf(value, expected)) {
      throw new AnalyzerException(insn, null, expected, value);
    }
    return super.unaryOperation(insn, value);
  }

  @Override
  public BasicValue binaryOperation(final AbstractInsnNode insn, final BasicValue value1, final BasicValue value2) throws AnalyzerException {
    BasicValue expected1;
    BasicValue expected2;
    switch (insn.getOpcode()) {
    case IALOAD:
      expected1 = newValue(Type.getType("[I"));
      expected2 = BasicValue.INT_VALUE;
      break;
    case BALOAD:
      if (isSubTypeOf(value1, newValue(Type.getType("[Z")))) {
        expected1 = newValue(Type.getType("[Z"));
      } else {
        expected1 = newValue(Type.getType("[B"));
      }
      expected2 = BasicValue.INT_VALUE;
      break;
    case CALOAD:
      expected1 = newValue(Type.getType("[C"));
      expected2 = BasicValue.INT_VALUE;
      break;
    case SALOAD:
      expected1 = newValue(Type.getType("[S"));
      expected2 = BasicValue.INT_VALUE;
      break;
    case LALOAD:
      expected1 = newValue(Type.getType("[J"));
      expected2 = BasicValue.INT_VALUE;
      break;
    case FALOAD:
      expected1 = newValue(Type.getType("[F"));
      expected2 = BasicValue.INT_VALUE;
      break;
    case DALOAD:
      expected1 = newValue(Type.getType("[D"));
      expected2 = BasicValue.INT_VALUE;
      break;
    case AALOAD:
      expected1 = newValue(Type.getType("[Ljava/lang/Object;"));
      expected2 = BasicValue.INT_VALUE;
      break;
    case IADD:
    case ISUB:
    case IMUL:
    case IDIV:
    case IREM:
    case ISHL:
    case ISHR:
    case IUSHR:
    case IAND:
    case IOR:
    case IXOR:
    case IF_ICMPEQ:
    case IF_ICMPNE:
    case IF_ICMPLT:
    case IF_ICMPGE:
    case IF_ICMPGT:
    case IF_ICMPLE:
      expected1 = BasicValue.INT_VALUE;
      expected2 = BasicValue.INT_VALUE;
      break;
    case FADD:
    case FSUB:
    case FMUL:
    case FDIV:
    case FREM:
    case FCMPL:
    case FCMPG:
      expected1 = BasicValue.FLOAT_VALUE;
      expected2 = BasicValue.FLOAT_VALUE;
      break;
    case LADD:
    case LSUB:
    case LMUL:
    case LDIV:
    case LREM:
    case LAND:
    case LOR:
    case LXOR:
    case LCMP:
      expected1 = BasicValue.LONG_VALUE;
      expected2 = BasicValue.LONG_VALUE;
      break;
    case LSHL:
    case LSHR:
    case LUSHR:
      expected1 = BasicValue.LONG_VALUE;
      expected2 = BasicValue.INT_VALUE;
      break;
    case DADD:
    case DSUB:
    case DMUL:
    case DDIV:
    case DREM:
    case DCMPL:
    case DCMPG:
      expected1 = BasicValue.DOUBLE_VALUE;
      expected2 = BasicValue.DOUBLE_VALUE;
      break;
    case IF_ACMPEQ:
    case IF_ACMPNE:
      expected1 = BasicValue.REFERENCE_VALUE;
      expected2 = BasicValue.REFERENCE_VALUE;
      break;
    case PUTFIELD:
      FieldInsnNode fin = (FieldInsnNode) insn;
      expected1 = newValue(Type.getObjectType(fin.owner));
      expected2 = newValue(Type.getType(fin.desc));
      break;
    default:
      throw new Error("Internal error.");
    }
    if (!isSubTypeOf(value1, expected1)) {
      throw new AnalyzerException(insn, "First argument", expected1, value1);
    } else if (!isSubTypeOf(value2, expected2)) {
      throw new AnalyzerException(insn, "Second argument", expected2, value2);
    }
    if (insn.getOpcode() == AALOAD) {
      return getElementValue(value1);
    } else {
      return super.binaryOperation(insn, value1, value2);
    }
  }

  @Override
  public BasicValue ternaryOperation(final AbstractInsnNode insn, final BasicValue value1, final BasicValue value2, final BasicValue value3)
      throws AnalyzerException {
    BasicValue expected1;
    BasicValue expected3;
    switch (insn.getOpcode()) {
    case IASTORE:
      expected1 = newValue(Type.getType("[I"));
      expected3 = BasicValue.INT_VALUE;
      break;
    case BASTORE:
      if (isSubTypeOf(value1, newValue(Type.getType("[Z")))) {
        expected1 = newValue(Type.getType("[Z"));
      } else {
        expected1 = newValue(Type.getType("[B"));
      }
      expected3 = BasicValue.INT_VALUE;
      break;
    case CASTORE:
      expected1 = newValue(Type.getType("[C"));
      expected3 = BasicValue.INT_VALUE;
      break;
    case SASTORE:
      expected1 = newValue(Type.getType("[S"));
      expected3 = BasicValue.INT_VALUE;
      break;
    case LASTORE:
      expected1 = newValue(Type.getType("[J"));
      expected3 = BasicValue.LONG_VALUE;
      break;
    case FASTORE:
      expected1 = newValue(Type.getType("[F"));
      expected3 = BasicValue.FLOAT_VALUE;
      break;
    case DASTORE:
      expected1 = newValue(Type.getType("[D"));
      expected3 = BasicValue.DOUBLE_VALUE;
      break;
    case AASTORE:
      expected1 = value1;
      expected3 = BasicValue.REFERENCE_VALUE;
      break;
    default:
      throw new Error("Internal error.");
    }
    if (!isSubTypeOf(value1, expected1)) {
      throw new AnalyzerException(insn, "First argument", "a " + expected1 + " array reference", value1);
    } else if (!BasicValue.INT_VALUE.equals(value2)) {
      throw new AnalyzerException(insn, "Second argument", BasicValue.INT_VALUE, value2);
    } else if (!isSubTypeOf(value3, expected3)) {
      throw new AnalyzerException(insn, "Third argument", expected3, value3);
    }
    return null;
  }

  @Override
  public BasicValue naryOperation(final AbstractInsnNode insn, final List<? extends BasicValue> values) throws AnalyzerException {
    int opcode = insn.getOpcode();
    if (opcode == MULTIANEWARRAY) {
      for (int i = 0; i < values.size(); ++i) {
        if (!BasicValue.INT_VALUE.equals(values.get(i))) {
          throw new AnalyzerException(insn, null, BasicValue.INT_VALUE, values.get(i));
        }
      }
    } else {
      int i = 0;
      int j = 0;
      if (opcode != INVOKESTATIC && opcode != INVOKEDYNAMIC) {
        Type owner = Type.getObjectType(((MethodInsnNode) insn).owner);
        if (!isSubTypeOf(values.get(i++), newValue(owner))) {
          throw new AnalyzerException(insn, "Method owner", newValue(owner), values.get(0));
        }
      }
      String desc = (opcode == INVOKEDYNAMIC) ? ((InvokeDynamicInsnNode) insn).desc : ((MethodInsnNode) insn).desc;
      Type[] args = Type.getArgumentTypes(desc);
      while (i < values.size()) {
        BasicValue expected = newValue(args[j++]);
        BasicValue encountered = values.get(i++);
        if (!isSubTypeOf(encountered, expected)) {
          throw new AnalyzerException(insn, "Argument " + j, expected, encountered);
        }
      }
    }
    return super.naryOperation(insn, values);
  }

  @Override
  public void returnOperation(final AbstractInsnNode insn, final BasicValue value, final BasicValue expected) throws AnalyzerException {
    if (!isSubTypeOf(value, expected)) {
      throw new AnalyzerException(insn, "Incompatible return type", expected, value);
    }
  }

  protected boolean isArrayValue(final BasicValue value) {
    return value.isReference();
  }

  protected BasicValue getElementValue(final BasicValue objectArrayValue) throws AnalyzerException {
    return BasicValue.REFERENCE_VALUE;
  }

  protected boolean isSubTypeOf(final BasicValue value, final BasicValue expected) {
    return value.equals(expected);
  }
}
