/*
 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */
package java.lang;

import jdk.internal.misc.JavaLangInvokeAccess;
import jdk.internal.misc.SharedSecrets;

import static java.lang.StackWalker.Option.*;
import java.lang.StackWalker.StackFrame;
import java.lang.invoke.MethodType;

class StackFrameInfo implements StackFrame {
 private final byte RETAIN_CLASS_REF = 0x01;

 private final static JavaLangInvokeAccess JLIA =
 SharedSecrets.getJavaLangInvokeAccess();

 private final byte flags;
 private final Object memberName;
 private final short bci;
 private volatile StackTraceElement ste;

 /*
 * Create StackFrameInfo for StackFrameTraverser and LiveStackFrameTraverser
 * to use
 */
 StackFrameInfo(StackWalker walker) {
 this.flags = walker.retainClassRef ? RETAIN_CLASS_REF : 0;
 this.bci = -1;
 this.memberName = JLIA.newMemberName();
 }

 // package-private called by StackStreamFactory to skip
 // the capability check
 Class<?> declaringClass() {
 return JLIA.getDeclaringClass(memberName);
 }

 // ----- implementation of StackFrame methods

 @Override
 public String getClassName() {
 return declaringClass().getName();
 }

 @Override
 public Class<?> getDeclaringClass() {
 ensureRetainClassRefEnabled();
 return declaringClass();
 }

 @Override
 public String getMethodName() {
 return JLIA.getName(memberName);
 }

 @Override
 public MethodType getMethodType() {
 ensureRetainClassRefEnabled();
 return JLIA.getMethodType(memberName);
 }

 @Override
 public String getDescriptor() {
 return JLIA.getMethodDescriptor(memberName);
 }

 @Override
 public int getByteCodeIndex() {
 // bci not available for native methods
 if (isNativeMethod())
 return -1;

 return bci;
 }

 @Override
 public String getFileName() {
 return toStackTraceElement().getFileName();
 }

 @Override
 public int getLineNumber() {
 // line number not available for native methods
 if (isNativeMethod())
 return -2;

 return toStackTraceElement().getLineNumber();
 }


 @Override
 public boolean isNativeMethod() {
 return JLIA.isNative(memberName);
 }

 @Override
 public String toString() {
 return toStackTraceElement().toString();
 }

 @Override
 public StackTraceElement toStackTraceElement() {
 StackTraceElement s = ste;
 if (s == null) {
 synchronized (this) {
 s = ste;
 if (s == null) {
 ste = s = StackTraceElement.of(this);
 }
 }
 }
 return s;
 }

 private void ensureRetainClassRefEnabled() {
 if ((flags & RETAIN_CLASS_REF) == 0) {
 throw new UnsupportedOperationException("No access to RETAIN_CLASS_REFERENCE");
 }
 }
}