1 /*
   2  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package jdk.nashorn.internal.runtime;
  26 
  27 import java.io.NotSerializableException;
  28 import java.io.ObjectInputStream;
  29 import java.io.ObjectOutputStream;
  30 import jdk.nashorn.internal.codegen.types.Type;
  31 
  32 /**
  33  * This exception is thrown from an optimistic operation, e.g. an integer add,
  34  * that was to optimistic for what really took place. Typically things like
  35  * trying to get an array element that we want to be an int, and it was a double,
  36  * and an int add that actually overflows and needs a double for the representation
  37  */
  38 
  39 @SuppressWarnings("serial")
  40 public final class UnwarrantedOptimismException extends RuntimeException {
  41     /** Denotes an invalid program point */
  42     public static final int INVALID_PROGRAM_POINT = -1;
  43 
  44     /** The value for the first ordinary program point */
  45     public static final int FIRST_PROGRAM_POINT = 1;
  46 
  47     private Object returnValue;
  48     private final int    programPoint;
  49     private final Type   returnType;
  50 
  51     /**
  52      * Constructor without explicit return type. The return type is determined statically from the class of
  53      * the return value, and only canonical internal number representations are recognized. Use
  54      * {@link #createNarrowest} if you want to handle float and long values as numbers instead of objects.
  55      *
  56      * @param returnValue actual return value from the too narrow operation
  57      * @param programPoint program point where unwarranted optimism was detected
  58      */
  59     public UnwarrantedOptimismException(final Object returnValue, final int programPoint) {
  60         this(returnValue, programPoint, getReturnType(returnValue));
  61     }
  62 
  63     /**
  64      * Check if a program point is valid.
  65      * @param programPoint the program point
  66      * @return true if valid
  67      */
  68     public static boolean isValid(final int programPoint) {
  69         assert programPoint >= INVALID_PROGRAM_POINT;
  70         return programPoint != INVALID_PROGRAM_POINT;
  71     }
  72 
  73     private static Type getReturnType(final Object v) {
  74         if (v instanceof Double) {
  75             return Type.NUMBER;
  76         }
  77         assert !(v instanceof Integer) : v + " is an int"; // Can't have an unwarranted optimism exception with int
  78         return Type.OBJECT;
  79     }
  80 
  81     /**
  82      * Constructor with explicit return value type.
  83      * @param returnValue actual return value from the too narrow operation
  84      * @param programPoint program point where unwarranted optimism was detected
  85      * @param returnType type of the returned value. Used to disambiguate the return type. E.g. an {@code ObjectArrayData}
  86      * might return a {@link Double} for a particular element getter, but still throw this exception even if the call
  87      * site can accept a double, since the array's type is actually {@code Type#OBJECT}. In this case, it must
  88      * explicitly use this constructor to indicate its values are to be considered {@code Type#OBJECT} and not
  89      * {@code Type#NUMBER}.
  90      */
  91     public UnwarrantedOptimismException(final Object returnValue, final int programPoint, final Type returnType) {
  92         super("", null, false, Context.DEBUG);
  93         assert returnType != Type.OBJECT || returnValue == null || !Type.typeFor(returnValue.getClass()).isNumeric();
  94         assert returnType != Type.INT;
  95         this.returnValue  = returnValue;
  96         this.programPoint = programPoint;
  97         this.returnType   = returnType;
  98     }
  99 
 100     /**
 101      * Create an {@code UnwarrantedOptimismException} with the given return value and program point, narrowing
 102      * the type to {@code number} if the value is a float or a long that can be represented as double.
 103      *
 104      * @param returnValue the return value
 105      * @param programPoint the program point
 106      * @return the exception
 107      */
 108     public static UnwarrantedOptimismException createNarrowest(final Object returnValue, final int programPoint) {
 109         if (returnValue instanceof Float
 110                 || (returnValue instanceof Long && JSType.isRepresentableAsDouble((Long) returnValue))) {
 111             return new UnwarrantedOptimismException(((Number) returnValue).doubleValue(), programPoint, Type.NUMBER);
 112         }
 113         return new UnwarrantedOptimismException(returnValue, programPoint);
 114     }
 115 
 116     /**
 117      * Get the return value. This is a destructive readout, after the method is invoked the return value is null'd out.
 118      * @return return value
 119      */
 120     public Object getReturnValueDestructive() {
 121         final Object retval = returnValue;
 122         returnValue = null;
 123         return retval;
 124     }
 125 
 126     Object getReturnValueNonDestructive() {
 127         return returnValue;
 128     }
 129 
 130     /**
 131      * Get the return type
 132      * @return return type
 133      */
 134     public Type getReturnType() {
 135         return returnType;
 136     }
 137 
 138     /**
 139      * Does this exception refer to an invalid program point? This might be OK if
 140      * we throw it, e.g. from a parameter guard
 141      * @return true if invalid program point specified
 142      */
 143     public boolean hasInvalidProgramPoint() {
 144         return programPoint == INVALID_PROGRAM_POINT;
 145     }
 146 
 147     /**
 148      * Get the program point
 149      * @return the program point
 150      */
 151     public int getProgramPoint() {
 152         return programPoint;
 153     }
 154 
 155     /**
 156      * Check if we ended up with a primitive return value (even though it may be
 157      * too wide for what we tried to do, e.g. double instead of int)
 158      * @return true if return value is primitive
 159      */
 160     public boolean hasPrimitiveReturnValue() {
 161         return returnValue instanceof Number || returnValue instanceof Boolean;
 162     }
 163 
 164     @Override
 165     public String getMessage() {
 166         return "UNWARRANTED OPTIMISM: [returnValue=" +
 167             returnValue +
 168             " (class=" +
 169             (returnValue == null ? "null" : returnValue.getClass().getSimpleName()) +
 170             (hasInvalidProgramPoint() ?
 171                 " <invalid program point>" :
 172                 (" @ program point #" + programPoint)) +
 173             ")]";
 174     }
 175 
 176 
 177     private void writeObject(final ObjectOutputStream out) throws NotSerializableException {
 178         throw new NotSerializableException(getClass().getName());
 179     }
 180 
 181     private void readObject(final ObjectInputStream in) throws NotSerializableException {
 182         throw new NotSerializableException(getClass().getName());
 183     }
 184 }