Java Code Examples for org.apache.bcel.classfile.JavaClass#equals()

/** Returns true if {@code childClass} is a subclass of {@code parentClass}. */
static boolean isClassSubClassOf(JavaClass childClass, JavaClass parentClass) {
  for (JavaClass superClass : getClassHierarchy(childClass)) {
    if (superClass.equals(parentClass)) {
      return true;
    }
  }
  return false;
}
 

/**
 * This commutative operation returns the first common superclass (narrowest ReferenceType
 * referencing a class, not an interface).
 * If one of the types is a superclass of the other, the former is returned.
 * If "this" is Type.NULL, then t is returned.
 * If t is Type.NULL, then "this" is returned.
 * If "this" equals t ['this.equals(t)'] "this" is returned.
 * If "this" or t is an ArrayType, then Type.OBJECT is returned;
 * unless their dimensions match. Then an ArrayType of the same
 * number of dimensions is returned, with its basic type being the
 * first common super class of the basic types of "this" and t.
 * If "this" or t is a ReferenceType referencing an interface, then Type.OBJECT is returned.
 * If not all of the two classes' superclasses cannot be found, "null" is returned.
 * See the JVM specification edition 2, "�4.9.2 The Bytecode Verifier".
 *
 * @throws ClassNotFoundException on failure to find superclasses of this
 *  type, or the type passed as a parameter
 */
public ReferenceType getFirstCommonSuperclass( final ReferenceType t ) throws ClassNotFoundException {
    if (this.equals(Type.NULL)) {
        return t;
    }
    if (t.equals(Type.NULL)) {
        return this;
    }
    if (this.equals(t)) {
        return this;
        /*
         * TODO: Above sounds a little arbitrary. On the other hand, there is
         * no object referenced by Type.NULL so we can also say all the objects
         * referenced by Type.NULL were derived from java.lang.Object.
         * However, the Java Language's "instanceof" operator proves us wrong:
         * "null" is not referring to an instance of java.lang.Object :)
         */
    }
    /* This code is from a bug report by Konstantin Shagin <[email protected]> */
    if ((this instanceof ArrayType) && (t instanceof ArrayType)) {
        final ArrayType arrType1 = (ArrayType) this;
        final ArrayType arrType2 = (ArrayType) t;
        if ((arrType1.getDimensions() == arrType2.getDimensions())
                && arrType1.getBasicType() instanceof ObjectType
                && arrType2.getBasicType() instanceof ObjectType) {
            return new ArrayType(((ObjectType) arrType1.getBasicType())
                    .getFirstCommonSuperclass((ObjectType) arrType2.getBasicType()), arrType1
                    .getDimensions());
        }
    }
    if ((this instanceof ArrayType) || (t instanceof ArrayType)) {
        return Type.OBJECT;
        // TODO: Is there a proof of OBJECT being the direct ancestor of every ArrayType?
    }
    if (((this instanceof ObjectType) && ((ObjectType) this).referencesInterfaceExact())
            || ((t instanceof ObjectType) && ((ObjectType) t).referencesInterfaceExact())) {
        return Type.OBJECT;
        // TODO: The above line is correct comparing to the vmspec2. But one could
        // make class file verification a bit stronger here by using the notion of
        // superinterfaces or even castability or assignment compatibility.
    }
    // this and t are ObjectTypes, see above.
    final ObjectType thiz = (ObjectType) this;
    final ObjectType other = (ObjectType) t;
    final JavaClass[] thiz_sups = Repository.getSuperClasses(thiz.getClassName());
    final JavaClass[] other_sups = Repository.getSuperClasses(other.getClassName());
    if ((thiz_sups == null) || (other_sups == null)) {
        return null;
    }
    // Waaahh...
    final JavaClass[] this_sups = new JavaClass[thiz_sups.length + 1];
    final JavaClass[] t_sups = new JavaClass[other_sups.length + 1];
    System.arraycopy(thiz_sups, 0, this_sups, 1, thiz_sups.length);
    System.arraycopy(other_sups, 0, t_sups, 1, other_sups.length);
    this_sups[0] = Repository.lookupClass(thiz.getClassName());
    t_sups[0] = Repository.lookupClass(other.getClassName());
    for (final JavaClass t_sup : t_sups) {
        for (final JavaClass this_sup : this_sups) {
            if (this_sup.equals(t_sup)) {
                return ObjectType.getInstance(this_sup.getClassName());
            }
        }
    }
    // Huh? Did you ask for Type.OBJECT's superclass??
    return null;
}
 

/**
 * This commutative operation returns the first common superclass (narrowest ReferenceType
 * referencing a class, not an interface).
 * If one of the types is a superclass of the other, the former is returned.
 * If "this" is Type.NULL, then t is returned.
 * If t is Type.NULL, then "this" is returned.
 * If "this" equals t ['this.equals(t)'] "this" is returned.
 * If "this" or t is an ArrayType, then Type.OBJECT is returned.
 * If "this" or t is a ReferenceType referencing an interface, then Type.OBJECT is returned.
 * If not all of the two classes' superclasses cannot be found, "null" is returned.
 * See the JVM specification edition 2, "�4.9.2 The Bytecode Verifier".
 *
 * @deprecated use getFirstCommonSuperclass(ReferenceType t) which has
 *             slightly changed semantics.
 * @throws ClassNotFoundException on failure to find superclasses of this
 *  type, or the type passed as a parameter
 */
@Deprecated
public ReferenceType firstCommonSuperclass( final ReferenceType t ) throws ClassNotFoundException {
    if (this.equals(Type.NULL)) {
        return t;
    }
    if (t.equals(Type.NULL)) {
        return this;
    }
    if (this.equals(t)) {
        return this;
        /*
         * TODO: Above sounds a little arbitrary. On the other hand, there is
         * no object referenced by Type.NULL so we can also say all the objects
         * referenced by Type.NULL were derived from java.lang.Object.
         * However, the Java Language's "instanceof" operator proves us wrong:
         * "null" is not referring to an instance of java.lang.Object :)
         */
    }
    if ((this instanceof ArrayType) || (t instanceof ArrayType)) {
        return Type.OBJECT;
        // TODO: Is there a proof of OBJECT being the direct ancestor of every ArrayType?
    }
    if (((this instanceof ObjectType) && ((ObjectType) this).referencesInterface())
            || ((t instanceof ObjectType) && ((ObjectType) t).referencesInterface())) {
        return Type.OBJECT;
        // TODO: The above line is correct comparing to the vmspec2. But one could
        // make class file verification a bit stronger here by using the notion of
        // superinterfaces or even castability or assignment compatibility.
    }
    // this and t are ObjectTypes, see above.
    final ObjectType thiz = (ObjectType) this;
    final ObjectType other = (ObjectType) t;
    final JavaClass[] thiz_sups = Repository.getSuperClasses(thiz.getClassName());
    final JavaClass[] other_sups = Repository.getSuperClasses(other.getClassName());
    if ((thiz_sups == null) || (other_sups == null)) {
        return null;
    }
    // Waaahh...
    final JavaClass[] this_sups = new JavaClass[thiz_sups.length + 1];
    final JavaClass[] t_sups = new JavaClass[other_sups.length + 1];
    System.arraycopy(thiz_sups, 0, this_sups, 1, thiz_sups.length);
    System.arraycopy(other_sups, 0, t_sups, 1, other_sups.length);
    this_sups[0] = Repository.lookupClass(thiz.getClassName());
    t_sups[0] = Repository.lookupClass(other.getClassName());
    for (final JavaClass t_sup : t_sups) {
        for (final JavaClass this_sup : this_sups) {
            if (this_sup.equals(t_sup)) {
                return ObjectType.getInstance(this_sup.getClassName());
            }
        }
    }
    // Huh? Did you ask for Type.OBJECT's superclass??
    return null;
}
 

/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitINVOKESPECIAL(final INVOKESPECIAL o) {
    try {
    // INVOKESPECIAL is a LoadClass; the Class where the referenced method is declared in,
    // is therefore resolved/verified.
    // INVOKESPECIAL is an InvokeInstruction, the argument and return types are resolved/verified,
    // too. So are the allowed method names.
    final String classname = o.getClassName(constantPoolGen);
    final JavaClass jc = Repository.lookupClass(classname);
    final Method m = getMethodRecursive(jc, o);
    if (m == null) {
        constraintViolated(o, "Referenced method '"+o.getMethodName(constantPoolGen)+"' with expected signature '"+o.getSignature(constantPoolGen)
            +"' not found in class '"+jc.getClassName()+"'.");
    }

    JavaClass current = Repository.lookupClass(myOwner.getClassName());
    if (current.isSuper()) {

        if ((Repository.instanceOf( current, jc )) && (!current.equals(jc))) {

            if (! (o.getMethodName(constantPoolGen).equals(Const.CONSTRUCTOR_NAME) )) {
                // Special lookup procedure for ACC_SUPER classes.

                int supidx = -1;

                Method meth = null;
                while (supidx != 0) {
                    supidx = current.getSuperclassNameIndex();
                    current = Repository.lookupClass(current.getSuperclassName());

                    final Method[] meths = current.getMethods();
                    for (final Method meth2 : meths) {
                        if    ( (meth2.getName().equals(o.getMethodName(constantPoolGen))) &&
                             (Type.getReturnType(meth2.getSignature()).equals(o.getReturnType(constantPoolGen))) &&
                             (objarrayequals(Type.getArgumentTypes(meth2.getSignature()), o.getArgumentTypes(constantPoolGen))) ) {
                            meth = meth2;
                            break;
                        }
                    }
                    if (meth != null) {
                        break;
                    }
                }
                if (meth == null) {
                    constraintViolated(o, "ACC_SUPER special lookup procedure not successful: method '"+
                        o.getMethodName(constantPoolGen)+"' with proper signature not declared in superclass hierarchy.");
                }
            }
        }
    }

    } catch (final ClassNotFoundException e) {
    // FIXME: maybe not the best way to handle this
    throw new AssertionViolatedException("Missing class: " + e, e);
    }

}