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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

 * 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.jfr.internal;

import java.lang.annotation.Annotation;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Set;

import jdk.internal.module.Modules;

import jdk.jfr.AnnotationElement;

import jdk.jfr.Enabled;

import jdk.jfr.Event;

import jdk.jfr.Name;

import jdk.jfr.Period;

import jdk.jfr.SettingControl;

import jdk.jfr.SettingDefinition;

import jdk.jfr.StackTrace;

import jdk.jfr.Threshold;

import jdk.jfr.events.ActiveSettingEvent;

import jdk.jfr.internal.EventInstrumentation.SettingInfo;

import jdk.jfr.internal.settings.CutoffSetting;

import jdk.jfr.internal.settings.EnabledSetting;

import jdk.jfr.internal.settings.PeriodSetting;

import jdk.jfr.internal.settings.StackTraceSetting;

import jdk.jfr.internal.settings.ThresholdSetting;

// This class can't have a hard reference from PlatformEventType, since it

// holds SettingControl instances that need to be released

// when a class is unloaded (to avoid memory leaks).

public final class EventControl {

    static final String FIELD_SETTING_PREFIX = "setting";

    private static final Type TYPE_ENABLED = TypeLibrary.createType(EnabledSetting.class);

    private static final Type TYPE_THRESHOLD = TypeLibrary.createType(ThresholdSetting.class);

    private static final Type TYPE_STACK_TRACE = TypeLibrary.createType(StackTraceSetting.class);

    private static final Type TYPE_PERIOD = TypeLibrary.createType(PeriodSetting.class);

    private static final Type TYPE_CUTOFF = TypeLibrary.createType(CutoffSetting.class);

    private final List<SettingInfo> settingInfos = new ArrayList<>();

    private final Map<String, Control> eventControls = new HashMap<>(5);

    private final PlatformEventType type;

    private final String idName;

    EventControl(PlatformEventType eventType) {

        eventControls.put(Enabled.NAME, defineEnabled(eventType));

        if (eventType.hasDuration()) {

            eventControls.put(Threshold.NAME, defineThreshold(eventType));

        }

        if (eventType.hasStackTrace()) {

            eventControls.put(StackTrace.NAME, defineStackTrace(eventType));

        }

        if (eventType.hasPeriod()) {

            eventControls.put(Period.NAME, definePeriod(eventType));

        }

        if (eventType.hasCutoff()) {

            eventControls.put(Cutoff.NAME, defineCutoff(eventType));

        }

        ArrayList<AnnotationElement> aes = new ArrayList<>(eventType.getAnnotationElements());

        remove(eventType, aes, Threshold.class);

        remove(eventType, aes, Period.class);

        remove(eventType, aes, Enabled.class);

        remove(eventType, aes, StackTrace.class);

        remove(eventType, aes, Cutoff.class);

        aes.trimToSize();

        eventType.setAnnotations(aes);

        this.type = eventType;

        this.idName = String.valueOf(eventType.getId());

    }

    static void remove(PlatformEventType type, List<AnnotationElement> aes, Class<? extends java.lang.annotation.Annotation> clazz) {

        long id = Type.getTypeId(clazz);

        for (AnnotationElement a : type.getAnnotationElements()) {

            if (a.getTypeId() == id && a.getTypeName().equals(clazz.getName())) {

                aes.remove(a);

            }

        }

    }

    EventControl(PlatformEventType es, Class<? extends Event> eventClass) {

        this(es);

        defineSettings(eventClass);

    }

    @SuppressWarnings("unchecked")

    private void defineSettings(Class<?> eventClass) {

        // Iterate up the class hierarchy and let

        // subclasses shadow base classes.

        boolean allowPrivateMethod = true;

        while (eventClass != null) {

            for (Method m : eventClass.getDeclaredMethods()) {

                boolean isPrivate = Modifier.isPrivate(m.getModifiers());

                if (m.getReturnType() == Boolean.TYPE && m.getParameterCount() == 1 && (!isPrivate || allowPrivateMethod)) {

                    SettingDefinition se = m.getDeclaredAnnotation(SettingDefinition.class);

                    if (se != null) {

                        Class<?> settingClass = m.getParameters()[0].getType();

                        if (!Modifier.isAbstract(settingClass.getModifiers()) && SettingControl.class.isAssignableFrom(settingClass)) {

                            String name = m.getName();

                            Name n = m.getAnnotation(Name.class);

                            if (n != null) {

                                name = n.value();

                            }

                            if (!eventControls.containsKey(name)) {

                                defineSetting((Class<? extends SettingControl>) settingClass, m, type, name);

                            }

                        }

                    }

                }

            }

            eventClass = eventClass.getSuperclass();

            allowPrivateMethod = false;

        }

    }

    private void defineSetting(Class<? extends SettingControl> settingsClass, Method method, PlatformEventType eventType, String settingName) {

        try {

            Module settingModule = settingsClass.getModule();

            Modules.addReads(settingModule, EventControl.class.getModule());

            int index = settingInfos.size();

            SettingInfo si = new SettingInfo(FIELD_SETTING_PREFIX + index, index);

            si.settingControl = instantiateSettingControl(settingsClass);

            Control c = si.settingControl;

            c.setDefault();

            String defaultValue = c.getValueSafe();

            if (defaultValue != null) {

                Type settingType = TypeLibrary.createType(settingsClass);

                ArrayList<AnnotationElement> aes = new ArrayList<>();

                for (Annotation a : method.getDeclaredAnnotations()) {

                    AnnotationElement ae = TypeLibrary.createAnnotation(a);

                    if (ae != null) {

                        aes.add(ae);

                    }

                }

                aes.trimToSize();

                eventControls.put(settingName, si.settingControl);

                eventType.add(PrivateAccess.getInstance().newSettingDescriptor(settingType, settingName, defaultValue, aes));

                settingInfos.add(si);

            }

        } catch (InstantiationException e) {

            // Programming error by user, fail fast

            throw new InstantiationError("Could not instantiate setting " + settingsClass.getName() + " for event " + eventType.getLogName() + ". " + e.getMessage());

        } catch (IllegalAccessException e) {

            // Programming error by user, fail fast

            throw new IllegalAccessError("Could not access setting " + settingsClass.getName() + " for event " + eventType.getLogName() + ". " + e.getMessage());

        }

    }

    private SettingControl instantiateSettingControl(Class<? extends SettingControl> settingControlClass) throws IllegalAccessException, InstantiationException {

        SecuritySupport.makeVisibleToJFR(settingControlClass);

        final Constructor<?> cc;

        try {

            cc = settingControlClass.getDeclaredConstructors()[0];

        } catch (Exception e) {

            throw (Error) new InternalError("Could not get constructor for " + settingControlClass.getName()).initCause(e);

        }

        SecuritySupport.setAccessible(cc);

        try {

            return (SettingControl) cc.newInstance();

        } catch (IllegalArgumentException | InvocationTargetException e) {

            throw (Error) new InternalError("Could not instantiate setting for class " + settingControlClass.getName());

        }

    }

    private static Control defineEnabled(PlatformEventType type) {

        Enabled enabled = type.getAnnotation(Enabled.class);

        // Java events are enabled by default,

        // JVM events are not, maybe they should be? Would lower learning curve

        // there too.

        String def = type.isJVM() ? "false" : "true";

        if (enabled != null) {

            def = Boolean.toString(enabled.value());

        }

        type.add(PrivateAccess.getInstance().newSettingDescriptor(TYPE_ENABLED, Enabled.NAME, def, Collections.emptyList()));

        return new EnabledSetting(type, def);

    }

    private static Control defineThreshold(PlatformEventType type) {

        Threshold threshold = type.getAnnotation(Threshold.class);

        String def = "0 ns";

        if (threshold != null) {

            def = threshold.value();

        }

        type.add(PrivateAccess.getInstance().newSettingDescriptor(TYPE_THRESHOLD, Threshold.NAME, def, Collections.emptyList()));

        return new ThresholdSetting(type, def);

    }

    private static Control defineStackTrace(PlatformEventType type) {

        StackTrace stackTrace = type.getAnnotation(StackTrace.class);

        String def = "true";

        if (stackTrace != null) {

            def = Boolean.toString(stackTrace.value());

        }

        type.add(PrivateAccess.getInstance().newSettingDescriptor(TYPE_STACK_TRACE, StackTrace.NAME, def, Collections.emptyList()));

        return new StackTraceSetting(type, def);

    }

    private static Control defineCutoff(PlatformEventType type) {

        Cutoff cutoff = type.getAnnotation(Cutoff.class);

        String def = Cutoff.INIFITY;

        if (cutoff != null) {

            def = cutoff.value();

        }

        type.add(PrivateAccess.getInstance().newSettingDescriptor(TYPE_CUTOFF, Cutoff.NAME, def, Collections.emptyList()));

        return new CutoffSetting(type, def);

    }

    private static Control definePeriod(PlatformEventType type) {

        Period period = type.getAnnotation(Period.class);

        String def = "everyChunk";

        if (period != null) {

            def = period.value();

        }

        type.add(PrivateAccess.getInstance().newSettingDescriptor(TYPE_PERIOD, PeriodSetting.NAME, def, Collections.emptyList()));

        return new PeriodSetting(type, def);

    }

    void disable() {

        for (Control c : eventControls.values()) {

            if (c instanceof EnabledSetting) {

                c.setValueSafe("false");

                return;

            }

        }

    }

    void writeActiveSettingEvent() {

        if (!type.isRegistered()) {

            return;

        }

        for (Map.Entry<String, Control> entry : eventControls.entrySet()) {

            Control c = entry.getValue();

            if (Utils.isSettingVisible(c, type.hasEventHook())) {

                String value = c.getLastValue();

                if (value == null) {

                    value = c.getDefaultValue();

                }

                ActiveSettingEvent ase = new ActiveSettingEvent();

                ase.id = type.getId();

                ase.name = entry.getKey();

                ase.value = value;

                ase.commit();

            }

        }

    }

    public Set<Entry<String, Control>> getEntries() {

        return eventControls.entrySet();

    }

    public PlatformEventType getEventType() {

        return type;

    }

    public String getSettingsId() {

        return idName;

    }

    public List<SettingInfo> getSettingInfos() {

        return settingInfos;

    }

}