1 /*
   2  * Copyright (c) 2012, 2018, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 package sun.jvm.hotspot.classfile;
  26 
  27 import java.io.PrintStream;
  28 import sun.jvm.hotspot.debugger.*;
  29 import sun.jvm.hotspot.memory.*;
  30 import sun.jvm.hotspot.runtime.*;
  31 import sun.jvm.hotspot.oops.*;
  32 import sun.jvm.hotspot.types.*;
  33 
  34 public class ClassLoaderData extends VMObject {
  35   static {
  36     VM.registerVMInitializedObserver(new java.util.Observer() {
  37         public void update(java.util.Observable o, Object data) {
  38           initialize(VM.getVM().getTypeDataBase());
  39         }
  40       });
  41   }
  42 
  43   private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
  44     Type type      = db.lookupType("ClassLoaderData");
  45     classLoaderField = type.getAddressField("_class_loader");
  46     nextField = type.getAddressField("_next");
  47     klassesField = new MetadataField(type.getAddressField("_klasses"), 0);
  48     isUnsafeAnonymousField = new CIntField(type.getCIntegerField("_is_unsafe_anonymous"), 0);
  49     dictionaryField = type.getAddressField("_dictionary");
  50   }
  51 
  52   private static AddressField   classLoaderField;
  53   private static AddressField nextField;
  54   private static MetadataField  klassesField;
  55   private static CIntField isUnsafeAnonymousField;
  56   private static AddressField dictionaryField;
  57 
  58   public ClassLoaderData(Address addr) {
  59     super(addr);
  60   }
  61 
  62   public Dictionary dictionary() {
  63       Address tmp = dictionaryField.getValue();
  64       return (Dictionary) VMObjectFactory.newObject(Dictionary.class, tmp);
  65   }
  66 
  67   public static ClassLoaderData instantiateWrapperFor(Address addr) {
  68     if (addr == null) {
  69       return null;
  70     }
  71     return new ClassLoaderData(addr);
  72   }
  73 
  74   public Oop getClassLoader() {
  75     Address handle = classLoaderField.getValue(getAddress());
  76     if (handle != null) {
  77       // Load through the handle
  78       OopHandle refs = handle.getOopHandleAt(0);
  79       return (Instance)VM.getVM().getObjectHeap().newOop(refs);
  80     }
  81     return null;
  82   }
  83 
  84   public boolean getisUnsafeAnonymous() {
  85     return isUnsafeAnonymousField.getValue(this) != 0;
  86   }
  87 
  88   public ClassLoaderData next() {
  89     return instantiateWrapperFor(nextField.getValue(getAddress()));
  90   }
  91 
  92   public Klass getKlasses()    { return (Klass)klassesField.getValue(this);  }
  93 
  94   /** Lookup an already loaded class. If not found null is returned. */
  95   public Klass find(String className) {
  96     for (Klass l = getKlasses(); l != null; l = l.getNextLinkKlass()) {
  97         if (l.getName().equals(className)) {
  98             return l;
  99         }
 100     }
 101     return null;
 102   }
 103 
 104   /** Iterate over all klasses - including object, primitive
 105       array klasses */
 106   public void classesDo(ClassLoaderDataGraph.ClassVisitor v) {
 107       for (Klass l = getKlasses(); l != null; l = l.getNextLinkKlass()) {
 108           v.visit(l);
 109       }
 110   }
 111 
 112   /** Iterate over all klasses in the dictionary, including initiating loader. */
 113   public void allEntriesDo(ClassLoaderDataGraph.ClassAndLoaderVisitor v) {
 114       for (Klass l = getKlasses(); l != null; l = l.getNextLinkKlass()) {
 115           dictionary().allEntriesDo(v, getClassLoader());
 116       }
 117   }
 118 }