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

   1 /*
   2  * Copyright (c) 2015, 2017, 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
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  23  * questions.
  24  */
  25 package java.lang;
  26 
  27 import jdk.internal.misc.JavaLangInvokeAccess;
  28 import jdk.internal.misc.SharedSecrets;
  29 
  30 import static java.lang.StackWalker.Option.*;
  31 import java.lang.StackWalker.StackFrame;
  32 import java.lang.invoke.MethodType;
  33 
  34 class StackFrameInfo implements StackFrame {
  35     private final byte RETAIN_CLASS_REF = 0x01;
  36 
  37     private final static JavaLangInvokeAccess JLIA =
  38         SharedSecrets.getJavaLangInvokeAccess();
  39 
  40     private final byte flags;
  41     private final Object memberName;
  42     private final short bci;
  43     private volatile StackTraceElement ste;
  44 
  45     /*
  46      * Create StackFrameInfo for StackFrameTraverser and LiveStackFrameTraverser
  47      * to use
  48      */
  49     StackFrameInfo(StackWalker walker) {
  50         this.flags = walker.retainClassRef ? RETAIN_CLASS_REF : 0;
  51         this.bci = -1;
  52         this.memberName = JLIA.newMemberName();
  53     }
  54 
  55     // package-private called by StackStreamFactory to skip
  56     // the capability check
  57     Class<?> declaringClass() {
  58         return JLIA.getDeclaringClass(memberName);
  59     }
  60 
  61     // ----- implementation of StackFrame methods
  62 
  63     @Override
  64     public String getClassName() {
  65         return declaringClass().getName();
  66     }
  67 
  68     @Override
  69     public Class<?> getDeclaringClass() {
  70         ensureRetainClassRefEnabled();
  71         return declaringClass();
  72     }
  73 
  74     @Override
  75     public String getMethodName() {
  76         return JLIA.getName(memberName);
  77     }
  78 
  79     @Override
  80     public MethodType getMethodType() {
  81         ensureRetainClassRefEnabled();
  82         return JLIA.getMethodType(memberName);
  83     }
  84 
  85     @Override
  86     public String getDescriptor() {
  87         return JLIA.getMethodDescriptor(memberName);
  88     }
  89 
  90     @Override
  91     public int getByteCodeIndex() {
  92         // bci not available for native methods
  93         if (isNativeMethod())
  94             return -1;
  95 
  96         return bci;
  97     }
  98 
  99     @Override
 100     public String getFileName() {
 101         return toStackTraceElement().getFileName();
 102     }
 103 
 104     @Override
 105     public int getLineNumber() {
 106         // line number not available for native methods
 107         if (isNativeMethod())
 108             return -2;
 109 
 110         return toStackTraceElement().getLineNumber();
 111     }
 112 
 113 
 114     @Override
 115     public boolean isNativeMethod() {
 116         return JLIA.isNative(memberName);
 117     }
 118 
 119     @Override
 120     public String toString() {
 121         return toStackTraceElement().toString();
 122     }
 123 
 124     @Override
 125     public StackTraceElement toStackTraceElement() {
 126         StackTraceElement s = ste;
 127         if (s == null) {
 128             synchronized (this) {
 129                 s = ste;
 130                 if (s == null) {
 131                     ste = s = StackTraceElement.of(this);
 132                 }
 133             }
 134         }
 135         return s;
 136     }
 137 
 138     private void ensureRetainClassRefEnabled() {
 139         if ((flags & RETAIN_CLASS_REF) == 0) {
 140             throw new UnsupportedOperationException("No access to RETAIN_CLASS_REFERENCE");
 141         }
 142     }
 143 }
--- EOF ---