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.
  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
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  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 import java.lang.reflect.Method;
  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 Object memberName;
  42     private short bci;
  43     private ContinuationScope contScope;
  44 
  45     private volatile StackTraceElement ste;
  46 
  47     /*
  48      * Create StackFrameInfo for StackFrameTraverser and LiveStackFrameTraverser
  49      * to use
  50      */
  51     StackFrameInfo(StackWalker walker) {
  52         this.flags = walker.retainClassRef ? RETAIN_CLASS_REF : 0;
  53         this.bci = -1;
  54         this.memberName = JLIA.newMemberName();
  55     }
  56 
  57     // package-private called by StackStreamFactory to skip
  58     // the capability check
  59     Class<?> declaringClass() {
  60         return JLIA.getDeclaringClass(memberName);
  61     }
  62 
  63     void setMemberName(Method method) {
  64         this.memberName = JLIA.newMemberName(method);
  65     }
  66 
  67     void setBCI(short bci) {
  68         this.bci = bci;
  69     }
  70 
  71     void setContinuationScope(ContinuationScope contScope) {
  72         this.contScope = contScope;
  73     }
  74     
  75     protected void clear() {
  76     }
  77 
  78     // ----- implementation of StackFrame methods
  79 
  80     @Override
  81     public String getClassName() {
  82         return declaringClass().getName();
  83     }
  84 
  85     @Override
  86     public Class<?> getDeclaringClass() {
  87         ensureRetainClassRefEnabled();
  88         return declaringClass();
  89     }
  90 
  91     @Override
  92     public String getMethodName() {
  93         return JLIA.getName(memberName);
  94     }
  95 
  96     @Override
  97     public MethodType getMethodType() {
  98         ensureRetainClassRefEnabled();
  99         return JLIA.getMethodType(memberName);
 100     }
 101 
 102     @Override
 103     public String getDescriptor() {
 104         return JLIA.getMethodDescriptor(memberName);
 105     }
 106 
 107     @Override
 108     public int getByteCodeIndex() {
 109         // bci not available for native methods
 110         if (isNativeMethod())
 111             return -1;
 112 
 113         return bci;
 114     }
 115 
 116     @Override
 117     public String getFileName() {
 118         return toStackTraceElement().getFileName();
 119     }
 120 
 121     @Override
 122     public int getLineNumber() {
 123         // line number not available for native methods
 124         if (isNativeMethod())
 125             return -2;
 126 
 127         return toStackTraceElement().getLineNumber();
 128     }
 129 
 130 
 131     @Override
 132     public boolean isNativeMethod() {
 133         return JLIA.isNative(memberName);
 134     }
 135 
 136     @Override
 137     public java.lang.String getContinuationScopeName() {
 138         return contScope.getName();
 139     }
 140 
 141     @Override
 142     public String toString() {
 143         return toStackTraceElement().toString();
 144     }
 145 
 146     @Override
 147     public StackTraceElement toStackTraceElement() {
 148         StackTraceElement s = ste;
 149         if (s == null) {
 150             synchronized (this) {
 151                 s = ste;
 152                 if (s == null) {
 153                     ste = s = StackTraceElement.of(this);
 154                 }
 155             }
 156         }
 157         return s;
 158     }
 159 
 160     private void ensureRetainClassRefEnabled() {
 161         if ((flags & RETAIN_CLASS_REF) == 0) {
 162             throw new UnsupportedOperationException("No access to RETAIN_CLASS_REFERENCE");
 163         }
 164     }
 165 }