lvalue.java

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/*
 * @(#)LValue.java	1.24 02/09/05
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright (c) 1997-1999 by Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 * 
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */

package com.sun.tools.example.debug.expr;

import com.sun.jdi.*;
import java.util.*;

abstract class LValue {

    // The JDI Value object for this LValue.  Once we have this Value,
    // we have to remember it since after we return the LValue object
    // to the ExpressionParser, it might decide that it needs 
    // the 'toString' value for the LValue in which case it will
    // call getMassagedValue to get this toString value.  At that
    // point, we don't want to call JDI a 2nd time to get the Value
    // for the LValue.  This is especially wrong when the LValue
    // represents a member function.  We would end up calling it
    // a 2nd time.
    //
    // Unfortunately, there are several levels of calls to
    // get/set values in this file.  To minimize confusion,
    // jdiValue is set/tested at the lowest level - right
    // next to the actual calls to JDI methods to get/set the
    // value in the debuggee.  
    protected Value jdiValue;

    abstract Value getValue() throws InvocationException, 
                                     IncompatibleThreadStateException,
                                     InvalidTypeException,
                                     ClassNotLoadedException,
                                     ParseException;

    abstract void setValue0(Value value) 
                   throws ParseException, InvalidTypeException, 
                          ClassNotLoadedException;

    abstract void invokeWith(List arguments) throws ParseException;

    void setValue(Value value) throws ParseException {
        try {
            setValue0(value);
        } catch (InvalidTypeException exc) {
            throw new ParseException(
                "Attempt to set value of incorrect type" +
                exc);
        } catch (ClassNotLoadedException exc) {
            throw new ParseException(
                "Attempt to set value before " + exc.className() + " was loaded" +
                exc);
        }
    }        

    void setValue(LValue lval) throws ParseException {
        setValue(lval.interiorGetValue());
    }

    LValue memberLValue(ExpressionParser.GetFrame frameGetter, 
                        String fieldName) throws ParseException {
        try {
            return memberLValue(fieldName, frameGetter.get().thread());
        } catch (IncompatibleThreadStateException exc) {
            throw new ParseException("Thread not suspended");
        }
    }

    LValue memberLValue(String fieldName, ThreadReference thread) throws ParseException {
        
        Value val = interiorGetValue();
        if ((val instanceof ArrayReference) &&
            "length".equals(fieldName)){
            return new LValueArrayLength((ArrayReference)val);
        }
        return new LValueInstanceMember(val, fieldName, thread);
    }

    // Return the Value for this LValue that would be used to concatenate
    // to a String.  IE, if it is an Object, call toString in the debuggee.
    Value getMassagedValue(ExpressionParser.GetFrame frameGetter) throws ParseException {
        Value vv = interiorGetValue();

        // If vv is an ObjectReference, then we have to
        // do the implicit call to toString().
        if (vv instanceof ObjectReference &&
            !(vv instanceof StringReference) && 
            !(vv instanceof ArrayReference)) {
            StackFrame frame;
            try {
                frame = frameGetter.get();
            } catch (IncompatibleThreadStateException exc) {
                throw new ParseException("Thread not suspended");
            }

            ThreadReference thread = frame.thread();
            LValue toStringMember = memberLValue("toString", thread);
            toStringMember.invokeWith(new ArrayList());
            return toStringMember.interiorGetValue();
        }
        return vv;
    }

    Value interiorGetValue() throws ParseException {
        Value value;
        try {
            value = getValue();
        } catch (InvocationException e) {
            throw new ParseException("Unable to complete expression. Exception " +
                                     e.exception() + " thrown");
        } catch (IncompatibleThreadStateException itse) {
            throw new ParseException("Unable to complete expression. Thread " +
                                     "not suspended for method invoke");
        } catch (InvalidTypeException ite) {
            throw new ParseException("Unable to complete expression. Method " +
                                     "argument type mismatch");
        } catch (ClassNotLoadedException tnle) {
            throw new ParseException("Unable to complete expression. Method " +
                                     "argument type " + tnle.className() + 
                                     " not yet loaded");
        }
        return value;
    }

    LValue arrayElementLValue(LValue lval) throws ParseException {
        Value indexValue = lval.interiorGetValue();
        int index;
        if ( (indexValue instanceof IntegerValue) ||
             (indexValue instanceof ShortValue) ||
             (indexValue instanceof ByteValue) ||
             (indexValue instanceof CharValue) ) {
            index = ((PrimitiveValue)indexValue).intValue();
        } else {
            throw new ParseException("Array index must be a integer type");
        }
        return new LValueArrayElement(interiorGetValue(), index);
    }

    public String toString() {
        try {
            return interiorGetValue().toString();
        } catch (ParseException e) {
            return "<Parse Exception>";
        }
    }

    static final int STATIC = 0;
    static final int INSTANCE = 1;

    static Field fieldByName(ReferenceType refType, String name, int kind) {
        /*
         * TO DO: Note that this currently fails to find superclass
         * or implemented interface fields. This is due to a temporary
         * limititation of RefType.fieldByName. Once that method is 
         * fixed, superclass fields will be found.
         */
        Field field = refType.fieldByName(name);
        if (field != null) {
            boolean isStatic = field.isStatic();
            if (((kind == STATIC) && !isStatic) || 
                ((kind == INSTANCE) && isStatic)) {
                field = null;
            }
        }
/***
        System.err.println("fieldByName: " + refType.name() + " " +
                                             name + " " +
                                             kind + " " + 
                                             (field != null));
***/
        return field;
    }

    static List methodsByName(ReferenceType refType, String name, int kind) {
        List list = refType.methodsByName(name);
        Iterator iter = list.iterator();
        while (iter.hasNext()) {
            Method method = (Method)iter.next();
            boolean isStatic = method.isStatic();
            if (((kind == STATIC) && !isStatic) || 
                ((kind == INSTANCE) && isStatic)) {
                iter.remove();
            }
        }
        return list;
    }

    static List primitiveTypeNames = new ArrayList();
    static {
        primitiveTypeNames.add("boolean");
        primitiveTypeNames.add("byte");
        primitiveTypeNames.add("char");
        primitiveTypeNames.add("short");
        primitiveTypeNames.add("int");
        primitiveTypeNames.add("long");
        primitiveTypeNames.add("float");
        primitiveTypeNames.add("double");
    }


    static final int SAME = 0;
    static final int ASSIGNABLE = 1;
    static final int DIFFERENT = 2;
    /*
     * Return SAME, DIFFERENT or ASSIGNABLE.
     * SAME means each arg type is the same as type of the corr. arg.
     * ASSIGNABLE means that not all the pairs are the same, but
     * for those that aren't, at least the argType is assignable
     * from the type of the argument value.
     * DIFFERENT means that in at least one pair, the
     * argType is not assignable from the type of the argument value.
     * IE, one is an Apple and the other is an Orange.
     */
    static int argumentsMatch(List argTypes, List arguments) {
        if (argTypes.size() != arguments.size()) {
            return DIFFERENT;
        }

        Iterator typeIter = argTypes.iterator();
        Iterator valIter = arguments.iterator();
        int result = SAME;

        // If any pair aren't the same, change the
        // result to ASSIGNABLE.  If any pair aren't
        // assignable, return DIFFERENT
        while (typeIter.hasNext()) {
            Type argType = (Type)typeIter.next();
            Value value = (Value)valIter.next();
            if (value == null) {
                // Null values can be passed to any non-primitive argument
                if (primitiveTypeNames.contains(argType.name())) {
                    return DIFFERENT;
                }
                // Else, we will assume that a null value
                // exactly matches an object type.
            }
            if (!value.type().equals(argType)) {
                if (isAssignableTo(value.type(), argType)) {
                    result = ASSIGNABLE;
                } else {
                    return DIFFERENT;
                }
            }
        }
        return result;
    }


    // These is...AssignableTo methods are based on similar code in the JDI
    // implementations of ClassType, ArrayType, and InterfaceType

    static boolean isComponentAssignable(Type fromType, Type toType) {
        if (fromType instanceof PrimitiveType) {
            // Assignment of primitive arrays requires identical
            // component types.
            return fromType.equals(toType);
        }
        if (toType instanceof PrimitiveType) {
            return false;
        }
        // Assignment of object arrays requires availability
        // of widening conversion of component types
        return isAssignableTo(fromType, toType);
    }

    static boolean isArrayAssignableTo(ArrayType fromType, Type toType) {
        if (toType instanceof ArrayType) {
            try {
                Type toComponentType = ((ArrayType)toType).componentType();
                return isComponentAssignable(fromType.componentType(), toComponentType);
            } catch (ClassNotLoadedException e) {
                // One or both component types has not yet been 
                // loaded => can't assign
                return false;
            }
        }
        if (toType instanceof InterfaceType) {
            // Only valid InterfaceType assignee is Cloneable
            return toType.name().equals("java.lang.Cloneable");
        } 
        // Only valid ClassType assignee is Object
        return toType.name().equals("java.lang.Object");
    }

    static boolean isAssignableTo(Type fromType, Type toType) {
        if (fromType.equals(toType)) {
            return true;
        }

        // If one is boolean, so must be the other.
        if (fromType instanceof BooleanType) {
            if (toType instanceof BooleanType) {
                return true;
            }
            return false;
        }
        if (toType instanceof BooleanType) {
            return false;
        }

        // Other primitive types are intermixable only with each other.
        if (fromType instanceof PrimitiveType) {
            if (toType instanceof PrimitiveType) {
                return true;
            }
            return false;
        } 
        if (toType instanceof PrimitiveType) {
            return false;
        }

        // neither one is primitive.
        if (fromType instanceof ArrayType) {
            return isArrayAssignableTo((ArrayType)fromType, toType);
        }
        List interfaces;
        if (fromType instanceof ClassType) {
            ClassType superclazz = ((ClassType)fromType).superclass();
            if ((superclazz != null) && isAssignableTo(superclazz, toType)) {
                return true;
            }