/*
* Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.sun.max.tele.field;
import com.sun.max.tele.reference.*;
import com.sun.max.tele.util.*;
import com.sun.max.vm.actor.holder.*;
import com.sun.max.vm.actor.member.*;
import com.sun.max.vm.type.*;
/**
* An accessor for reading object instance reference fields from VM memory, specified by class and field name.
*/
public final class TeleInstanceReferenceFieldAccess extends TeleInstanceFieldAccess {
public TeleInstanceReferenceFieldAccess(Class holder, String name, Class<?> type) {
super(holder, name, Kind.REFERENCE);
TeleError.check(ClassActor.fromJava(type).isAssignableFrom(fieldActor().descriptor().resolve(fieldActor().holder().classLoader)), "field has wrong type: " + name + " in class: " + holder);
final Kind kind = fieldActor().descriptor().toKind();
TeleError.check(kind != Kind.WORD, "Word field used as Reference field: " + fieldActor());
}
public TeleInstanceReferenceFieldAccess(Class holder, Class<?> type, InjectedReferenceFieldActor injectedReferenceFieldActor) {
this(holder, injectedReferenceFieldActor.name.toString(), type);
}
/**
* Reads from the specified object in VM memory the reference held in the field encapsulated by this accessor,
* traversing a forwarder if necessary; returns {@link RemoteReference#zero()} if the field's value does not point
* at a live object.
*
* @return the value of the instance field in VM memory interpreted as a reference, unless it is a forwarder in
* which case the reference returned refers to the destination of the forwarder.
*/
public RemoteReference readRemoteReference(RemoteReference remoteRef) {
return remoteRef.readFieldAsRemoteReference(fieldActor());
}
public static RemoteReference readPath(RemoteReference reference, TeleInstanceReferenceFieldAccess... fields) {
RemoteReference r = reference;
for (TeleInstanceReferenceFieldAccess field : fields) {
if (r.isZero()) {
return r;
}
r = field.readRemoteReference(r);
}
return r;
}
}