/*

 * Copyright (c) 2001, 2021, 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

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 */

package jdk.internal.reflect;

import sun.reflect.misc.ReflectUtil;

import java.lang.reflect.*;

import jdk.internal.misc.Unsafe;

/** Used only for the first few invocations of a Constructor;

    afterward, switches to bytecode-based implementation */

class NativeConstructorAccessorImpl extends ConstructorAccessorImpl {

    private static final Unsafe U = Unsafe.getUnsafe();

    private static final long GENERATED_OFFSET

        = U.objectFieldOffset(NativeConstructorAccessorImpl.class, "generated");

    private final Constructor<?> c;

    private DelegatingConstructorAccessorImpl parent;

    private int numInvocations;

    private volatile int generated;

    NativeConstructorAccessorImpl(Constructor<?> c) {

        this.c = c;

    }

    public Object newInstance(Object[] args)

        throws InstantiationException,

               IllegalArgumentException,

               InvocationTargetException

    {

        // We can't inflate a constructor belonging to a vm-anonymous class

        // because that kind of class can't be referred to by name, hence can't

        // be found from the generated bytecode.

        if (++numInvocations > ReflectionFactory.inflationThreshold()

                && !c.getDeclaringClass().isHidden()

                && generated == 0

                && U.compareAndSetInt(this, GENERATED_OFFSET, 0, 1)) {

            try {

                ConstructorAccessorImpl acc = (ConstructorAccessorImpl)

                    new MethodAccessorGenerator().

                        generateConstructor(c.getDeclaringClass(),

                                            c.getParameterTypes(),

                                            c.getExceptionTypes(),

                                            c.getModifiers());

                parent.setDelegate(acc);

            } catch (Throwable t) {

                // Throwable happens in generateConstructor, restore generated to 0

                generated = 0;

                throw t;

            }

        }

        return newInstance0(c, args);

    }

    void setParent(DelegatingConstructorAccessorImpl parent) {

        this.parent = parent;

    }

    private static native Object newInstance0(Constructor<?> c, Object[] args)

        throws InstantiationException,

               IllegalArgumentException,

               InvocationTargetException;

}