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

 *

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

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 * 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.jfr.internal.instrument;

import java.util.ArrayList;

import java.util.List;

import jdk.internal.module.Modules;

import jdk.jfr.Event;

import jdk.jfr.FlightRecorder;

import jdk.jfr.events.ActiveRecordingEvent;

import jdk.jfr.events.ActiveSettingEvent;

import jdk.jfr.events.ErrorThrownEvent;

import jdk.jfr.events.ExceptionStatisticsEvent;

import jdk.jfr.events.ExceptionThrownEvent;

import jdk.jfr.events.FileForceEvent;

import jdk.jfr.events.FileReadEvent;

import jdk.jfr.events.FileWriteEvent;

import jdk.jfr.events.SocketReadEvent;

import jdk.jfr.events.SocketWriteEvent;

import jdk.jfr.internal.JVM;

import jdk.jfr.internal.LogLevel;

import jdk.jfr.internal.LogTag;

import jdk.jfr.internal.Logger;

import jdk.jfr.internal.RequestEngine;

import jdk.jfr.internal.SecuritySupport;

import jdk.jfr.internal.Utils;

public final class JDKEvents {

    private static final Class<?>[] eventClasses = {

        FileForceEvent.class,

        FileReadEvent.class,

        FileWriteEvent.class,

        SocketReadEvent.class,

        SocketWriteEvent.class,

        ExceptionThrownEvent.class,

        ExceptionStatisticsEvent.class,

        ErrorThrownEvent.class,

        ActiveSettingEvent.class,

        ActiveRecordingEvent.class

    };

    // This is a list of the classes with instrumentation code that should be applied.

    private static final Class<?>[] instrumentationClasses = new Class<?>[] {

        FileInputStreamInstrumentor.class,

        FileOutputStreamInstrumentor.class,

        RandomAccessFileInstrumentor.class,

        FileChannelImplInstrumentor.class,

        SocketInputStreamInstrumentor.class,

        SocketOutputStreamInstrumentor.class,

        SocketChannelImplInstrumentor.class

    };

    private static final Class<?>[] targetClasses = new Class<?>[instrumentationClasses.length];

    private static final JVM jvm = JVM.getJVM();

    private static final Runnable emitExceptionStatistics = JDKEvents::emitExceptionStatistics;

    private static boolean initializationTriggered;

    @SuppressWarnings("unchecked")

    public synchronized static void initialize() {

        try {

            if (initializationTriggered == false) {

                Module jdkJfrModule = Event.class.getModule();

                Module javaBaseModule = Object.class.getModule();

                Modules.addReads(javaBaseModule, jdkJfrModule);

                Modules.addExports(jdkJfrModule, Utils.EVENTS_PACKAGE_NAME, javaBaseModule);

                Modules.addExports(jdkJfrModule, Utils.INSTRUMENT_PACKAGE_NAME, javaBaseModule);

                Modules.addExports(jdkJfrModule, Utils.HANDLERS_PACKAGE_NAME, javaBaseModule);

                for (Class<?> eventClass : eventClasses) {

                    SecuritySupport.registerEvent((Class<? extends Event>) eventClass);

                }

                initializationTriggered = true;

                FlightRecorder.addPeriodicEvent(ExceptionStatisticsEvent.class, emitExceptionStatistics);

            }

        } catch (Exception e) {

            Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not initialize JDK events. " + e.getMessage());

        }

    }

    public static void addInstrumentation() {

        try {

            List<Class<?>> list = new ArrayList<>();

            for (int i = 0; i < instrumentationClasses.length; i++) {

                JIInstrumentationTarget tgt = instrumentationClasses[i].getAnnotation(JIInstrumentationTarget.class);

                Class<?> clazz = Class.forName(tgt.value());

                targetClasses[i] = clazz;

                list.add(clazz);

            }

            list.add(java.lang.Throwable.class);

            list.add(java.lang.Error.class);

            Logger.log(LogTag.JFR_SYSTEM, LogLevel.INFO, "Retransformed JDK classes");

            jvm.retransformClasses(list.toArray(new Class<?>[list.size()]));

        } catch (Exception e) {

            Logger.log(LogTag.JFR_SYSTEM, LogLevel.WARN, "Could not add instrumentation for JDK events. " + e.getMessage());

        }

    }

    private static void emitExceptionStatistics() {

        ExceptionStatisticsEvent t = new ExceptionStatisticsEvent();

        t.throwables = ThrowableTracer.numThrowables();

        t.commit();

    }

    @SuppressWarnings("deprecation")

    public static byte[] retransformCallback(Class<?> klass, byte[] oldBytes) throws Throwable {

        if (java.lang.Throwable.class == klass) {

            Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, "Instrumenting java.lang.Throwable");

            return ConstructorTracerWriter.generateBytes(java.lang.Throwable.class, oldBytes);

        }

        if (java.lang.Error.class == klass) {

            Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, "Instrumenting java.lang.Error");

            return ConstructorTracerWriter.generateBytes(java.lang.Error.class, oldBytes);

        }

        for (int i = 0; i < targetClasses.length; i++) {

            if (targetClasses[i].equals(klass)) {

                Class<?> c = instrumentationClasses[i];

                Logger.log(LogTag.JFR_SYSTEM, LogLevel.TRACE, () -> "Processing instrumentation class: " + c);

                return new JIClassInstrumentation(instrumentationClasses[i], klass, oldBytes).getNewBytes();

            }

        }

        return oldBytes;

    }

    public static void remove() {

        RequestEngine.removeHook(JDKEvents::emitExceptionStatistics);

    }

}