basicinterpreter.java

jboss规则引擎

/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 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.drools.asm.tree.analysis;

import java.util.List;

import org.drools.asm.Opcodes;
import org.drools.asm.Type;
import org.drools.asm.tree.AbstractInsnNode;
import org.drools.asm.tree.FieldInsnNode;
import org.drools.asm.tree.IntInsnNode;
import org.drools.asm.tree.LdcInsnNode;
import org.drools.asm.tree.MethodInsnNode;
import org.drools.asm.tree.MultiANewArrayInsnNode;
import org.drools.asm.tree.TypeInsnNode;

/**
 * An {@link Interpreter} for {@link BasicValue} values.
 * 
 * @author Eric Bruneton
 * @author Bing Ran
 */
public class BasicInterpreter
    implements
    Opcodes,
    Interpreter {

    public Value newValue(final Type type) {
        if ( type == null ) {
            return BasicValue.UNINITIALIZED_VALUE;
        }
        switch ( type.getSort() ) {
            case Type.VOID :
                return null;
            case Type.BOOLEAN :
            case Type.CHAR :
            case Type.BYTE :
            case Type.SHORT :
            case Type.INT :
                return BasicValue.INT_VALUE;
            case Type.FLOAT :
                return BasicValue.FLOAT_VALUE;
            case Type.LONG :
                return BasicValue.LONG_VALUE;
            case Type.DOUBLE :
                return BasicValue.DOUBLE_VALUE;
            case Type.ARRAY :
            case Type.OBJECT :
                return BasicValue.REFERENCE_VALUE;
            default :
                throw new RuntimeException( "Internal error." );
        }
    }

    public Value newOperation(final AbstractInsnNode insn) {
        switch ( insn.getOpcode() ) {
            case ACONST_NULL :
                return newValue( Type.getType( "Lnull;" ) );
            case ICONST_M1 :
            case ICONST_0 :
            case ICONST_1 :
            case ICONST_2 :
            case ICONST_3 :
            case ICONST_4 :
            case ICONST_5 :
                return BasicValue.INT_VALUE;
            case LCONST_0 :
            case LCONST_1 :
                return BasicValue.LONG_VALUE;
            case FCONST_0 :
            case FCONST_1 :
            case FCONST_2 :
                return BasicValue.FLOAT_VALUE;
            case DCONST_0 :
            case DCONST_1 :
                return BasicValue.DOUBLE_VALUE;
            case BIPUSH :
            case SIPUSH :
                return BasicValue.INT_VALUE;
            case LDC :
                final Object cst = ((LdcInsnNode) insn).cst;
                if ( cst instanceof Integer ) {
                    return BasicValue.INT_VALUE;
                } else if ( cst instanceof Float ) {
                    return BasicValue.FLOAT_VALUE;
                } else if ( cst instanceof Long ) {
                    return BasicValue.LONG_VALUE;
                } else if ( cst instanceof Double ) {
                    return BasicValue.DOUBLE_VALUE;
                } else if ( cst instanceof Type ) {
                    return newValue( Type.getType( "Ljava/lang/Class;" ) );
                } else {
                    return newValue( Type.getType( cst.getClass() ) );
                }
            case JSR :
                return BasicValue.RETURNADDRESS_VALUE;
            case GETSTATIC :
                return newValue( Type.getType( ((FieldInsnNode) insn).desc ) );
            case NEW :
                return newValue( Type.getType( "L" + ((TypeInsnNode) insn).desc + ";" ) );
            default :
                throw new RuntimeException( "Internal error." );
        }
    }

    public Value copyOperation(final AbstractInsnNode insn,
                               final Value value) throws AnalyzerException {
        return value;
    }

    public Value unaryOperation(final AbstractInsnNode insn,
                                final Value value) throws AnalyzerException {
        switch ( insn.getOpcode() ) {
            case INEG :
            case IINC :
            case L2I :
            case F2I :
            case D2I :
            case I2B :
            case I2C :
            case I2S :
                return BasicValue.INT_VALUE;
            case FNEG :
            case I2F :
            case L2F :
            case D2F :
                return BasicValue.FLOAT_VALUE;
            case LNEG :
            case I2L :
            case F2L :
            case D2L :
                return BasicValue.LONG_VALUE;
            case DNEG :
            case I2D :
            case L2D :
            case F2D :
                return BasicValue.DOUBLE_VALUE;
            case IFEQ :
            case IFNE :
            case IFLT :
            case IFGE :
            case IFGT :
            case IFLE :
            case TABLESWITCH :
            case LOOKUPSWITCH :
            case IRETURN :
            case LRETURN :
            case FRETURN :
            case DRETURN :
            case ARETURN :
            case PUTSTATIC :
                return null;
            case GETFIELD :
                return newValue( Type.getType( ((FieldInsnNode) insn).desc ) );
            case NEWARRAY :
                switch ( ((IntInsnNode) insn).operand ) {
                    case T_BOOLEAN :
                        return newValue( Type.getType( "[Z" ) );
                    case T_CHAR :
                        return newValue( Type.getType( "[C" ) );
                    case T_BYTE :
                        return newValue( Type.getType( "[B" ) );
                    case T_SHORT :
                        return newValue( Type.getType( "[S" ) );
                    case T_INT :
                        return newValue( Type.getType( "[I" ) );
                    case T_FLOAT :
                        return newValue( Type.getType( "[F" ) );
                    case T_DOUBLE :
                        return newValue( Type.getType( "[D" ) );
                    case T_LONG :
                        return newValue( Type.getType( "[J" ) );
                    default :
                        throw new AnalyzerException( "Invalid array type" );
                }
            case ANEWARRAY :
                String desc = ((TypeInsnNode) insn).desc;
                if ( desc.charAt( 0 ) == '[' ) {
                    return newValue( Type.getType( "[" + desc ) );
                } else {
                    return newValue( Type.getType( "[L" + desc + ";" ) );
                }
            case ARRAYLENGTH :
                return BasicValue.INT_VALUE;
            case ATHROW :
                return null;
            case CHECKCAST :
                desc = ((TypeInsnNode) insn).desc;
                if ( desc.charAt( 0 ) == '[' ) {
                    return newValue( Type.getType( desc ) );
                } else {
                    return newValue( Type.getType( "L" + desc + ";" ) );
                }
            case INSTANCEOF :
                return BasicValue.INT_VALUE;
            case MONITORENTER :
            case MONITOREXIT :
            case IFNULL :
            case IFNONNULL :
                return null;
            default :
                throw new RuntimeException( "Internal error." );
        }
    }

    public Value binaryOperation(final AbstractInsnNode insn,
                                 final Value value1,
                                 final Value value2) throws AnalyzerException {
        switch ( insn.getOpcode() ) {
            case IALOAD :
            case BALOAD :
            case CALOAD :
            case SALOAD :
            case IADD :
            case ISUB :
            case IMUL :
            case IDIV :
            case IREM :
            case ISHL :
            case ISHR :
            case IUSHR :
            case IAND :
            case IOR :
            case IXOR :
                return BasicValue.INT_VALUE;
            case FALOAD :
            case FADD :
            case FSUB :
            case FMUL :
            case FDIV :
            case FREM :
                return BasicValue.FLOAT_VALUE;
            case LALOAD :
            case LADD :
            case LSUB :
            case LMUL :
            case LDIV :
            case LREM :
            case LSHL :
            case LSHR :
            case LUSHR :
            case LAND :
            case LOR :
            case LXOR :
                return BasicValue.LONG_VALUE;
            case DALOAD :
            case DADD :
            case DSUB :
            case DMUL :
            case DDIV :
            case DREM :
                return BasicValue.DOUBLE_VALUE;
            case AALOAD :
                final Type t = ((BasicValue) value1).getType();
                if ( t != null && t.getSort() == Type.ARRAY ) {
                    return newValue( t.getElementType() );
                } else {
                    return BasicValue.REFERENCE_VALUE;
                }
            case LCMP :
            case FCMPL :
            case FCMPG :
            case DCMPL :
            case DCMPG :
                return BasicValue.INT_VALUE;
            case IF_ICMPEQ :
            case IF_ICMPNE :
            case IF_ICMPLT :
            case IF_ICMPGE :
            case IF_ICMPGT :
            case IF_ICMPLE :
            case IF_ACMPEQ :
            case IF_ACMPNE :
            case PUTFIELD :
                return null;
            default :
                throw new RuntimeException( "Internal error." );
        }
    }

    public Value ternaryOperation(final AbstractInsnNode insn,
                                  final Value value1,
                                  final Value value2,
                                  final Value value3) throws AnalyzerException {
        return null;
    }

    public Value naryOperation(final AbstractInsnNode insn,
                               final List values) throws AnalyzerException {
        if ( insn.getOpcode() == Opcodes.MULTIANEWARRAY ) {
            return newValue( Type.getType( ((MultiANewArrayInsnNode) insn).desc ) );
        } else {
            return newValue( Type.getReturnType( ((MethodInsnNode) insn).desc ) );
        }
    }

    public Value merge(final Value v,
                       final Value w) {
        if ( !v.equals( w ) ) {
            return BasicValue.UNINITIALIZED_VALUE;
        }
        return v;
    }
}