rev 51958 : 8211122: Reduce the number of internal classes made accessible to jdk.unsupported
Reviewed-by: alanb, dfuchs, kvn

   1 /*
   2  * Copyright (c) 2015, 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.  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.
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  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
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  24  */
  25 package java.lang;
  26 
  27 import jdk.internal.access.JavaLangInvokeAccess;
  28 import jdk.internal.access.SharedSecrets;
  29 

  30 import java.lang.StackWalker.StackFrame;
  31 import java.lang.invoke.MethodType;
  32 
  33 class StackFrameInfo implements StackFrame {
  34     private final byte RETAIN_CLASS_REF = 0x01;
  35 
  36     private final static JavaLangInvokeAccess JLIA =
  37         SharedSecrets.getJavaLangInvokeAccess();
  38 
  39     private final byte flags;
  40     private final Object memberName;
  41     private final short bci;
  42     private volatile StackTraceElement ste;
  43 
  44     /*
  45      * Create StackFrameInfo for StackFrameTraverser and LiveStackFrameTraverser
  46      * to use
  47      */
  48     StackFrameInfo(StackWalker walker) {
  49         this.flags = walker.retainClassRef ? RETAIN_CLASS_REF : 0;
  50         this.bci = -1;
  51         this.memberName = JLIA.newMemberName();
  52     }
  53 
  54     // package-private called by StackStreamFactory to skip
  55     // the capability check
  56     Class<?> declaringClass() {
  57         return JLIA.getDeclaringClass(memberName);
  58     }
  59 
  60     // ----- implementation of StackFrame methods
  61 
  62     @Override
  63     public String getClassName() {
  64         return declaringClass().getName();
  65     }
  66 
  67     @Override
  68     public Class<?> getDeclaringClass() {
  69         ensureRetainClassRefEnabled();
  70         return declaringClass();
  71     }
  72 
  73     @Override
  74     public String getMethodName() {
  75         return JLIA.getName(memberName);
  76     }
  77 
  78     @Override
  79     public MethodType getMethodType() {
  80         ensureRetainClassRefEnabled();
  81         return JLIA.getMethodType(memberName);
  82     }
  83 
  84     @Override
  85     public String getDescriptor() {
  86         return JLIA.getMethodDescriptor(memberName);
  87     }
  88 
  89     @Override
  90     public int getByteCodeIndex() {
  91         // bci not available for native methods
  92         if (isNativeMethod())
  93             return -1;
  94 
  95         return bci;
  96     }
  97 
  98     @Override
  99     public String getFileName() {
 100         return toStackTraceElement().getFileName();
 101     }
 102 
 103     @Override
 104     public int getLineNumber() {
 105         // line number not available for native methods
 106         if (isNativeMethod())
 107             return -2;
 108 
 109         return toStackTraceElement().getLineNumber();
 110     }
 111 
 112 
 113     @Override
 114     public boolean isNativeMethod() {
 115         return JLIA.isNative(memberName);
 116     }
 117 
 118     @Override
 119     public String toString() {
 120         return toStackTraceElement().toString();
 121     }
 122 
 123     @Override
 124     public StackTraceElement toStackTraceElement() {
 125         StackTraceElement s = ste;
 126         if (s == null) {
 127             synchronized (this) {
 128                 s = ste;
 129                 if (s == null) {
 130                     ste = s = StackTraceElement.of(this);
 131                 }
 132             }
 133         }
 134         return s;
 135     }
 136 
 137     private void ensureRetainClassRefEnabled() {
 138         if ((flags & RETAIN_CLASS_REF) == 0) {
 139             throw new UnsupportedOperationException("No access to RETAIN_CLASS_REFERENCE");
 140         }
 141     }
 142 }
--- EOF ---