/*

 * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.lang;

import jdk.internal.access.JavaLangInvokeAccess;

import jdk.internal.access.SharedSecrets;

import java.lang.StackWalker.StackFrame;

import java.lang.invoke.MethodType;

class StackFrameInfo implements StackFrame {

    private static final JavaLangInvokeAccess JLIA =

        SharedSecrets.getJavaLangInvokeAccess();

    private final boolean retainClassRef;

    private final Object memberName;    // MemberName initialized by VM

    private int bci;                    // initialized by VM to >= 0

    private volatile StackTraceElement ste;

    /*

     * Construct an empty StackFrameInfo object that will be filled by the VM

     * during stack walking.

     *

     * @see StackStreamFactory.AbstractStackWalker#callStackWalk

     * @see StackStreamFactory.AbstractStackWalker#fetchStackFrames

     */

    StackFrameInfo(StackWalker walker) {

        this.retainClassRef = walker.retainClassRef;

        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 (!retainClassRef) {

            throw new UnsupportedOperationException("No access to RETAIN_CLASS_REFERENCE");

        }

    }

}