/*

 * Copyright (c) 2016, 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

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package jdk.jfr.internal;

import static jdk.jfr.internal.LogLevel.INFO;

import static jdk.jfr.internal.LogLevel.TRACE;

import static jdk.jfr.internal.LogLevel.WARN;

import static jdk.jfr.internal.LogTag.JFR;

import static jdk.jfr.internal.LogTag.JFR_SYSTEM;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.time.Duration;

import java.time.Instant;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.Timer;

import java.util.TimerTask;

import java.util.concurrent.CopyOnWriteArrayList;

import jdk.jfr.EventType;

import jdk.jfr.FlightRecorder;

import jdk.jfr.FlightRecorderListener;

import jdk.jfr.Recording;

import jdk.jfr.RecordingState;

import jdk.jfr.events.ActiveRecordingEvent;

import jdk.jfr.events.ActiveSettingEvent;

import jdk.jfr.internal.SecuritySupport.SecureRecorderListener;

import jdk.jfr.internal.instrument.JDKEvents;

public final class PlatformRecorder {

    private final List<PlatformRecording> recordings = new ArrayList<>();

    private final static List<SecureRecorderListener> changeListeners = new ArrayList<>();

    private final Repository repository;

    private final Timer timer;

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

    private final EventType activeRecordingEvent;

    private final EventType activeSettingEvent;

    private final Thread shutdownHook;

    private long recordingCounter = 0;

    private RepositoryChunk currentChunk;

    public PlatformRecorder() throws Exception {

        repository = Repository.getRepository();

        Logger.log(JFR_SYSTEM, INFO, "Initialized disk repository");

        repository.ensureRepository();

        jvm.createNativeJFR();

        Logger.log(JFR_SYSTEM, INFO, "Created native");

        JDKEvents.initialize();

        Logger.log(JFR_SYSTEM, INFO, "Registered JDK events");

        JDKEvents.addInstrumentation();

        startDiskMonitor();

        activeRecordingEvent = EventType.getEventType(ActiveRecordingEvent.class);

        activeSettingEvent = EventType.getEventType(ActiveSettingEvent.class);

        shutdownHook = SecuritySupport.createThreadWitNoPermissions("JFR: Shutdown Hook", new ShutdownHook(this));

        SecuritySupport.setUncaughtExceptionHandler(shutdownHook, new ShutdownHook.ExceptionHandler());

        SecuritySupport.registerShutdownHook(shutdownHook);

        timer = createTimer();

    }

    private static Timer createTimer() {

        try {

            List<Timer> result = new CopyOnWriteArrayList<>();

            Thread t = SecuritySupport.createThreadWitNoPermissions("Permissionless thread", ()-> {

                result.add(new Timer("JFR Recording Scheduler", true));

            });

            jvm.exclude(t);

            t.start();

            t.join();

            return result.get(0);

        } catch (InterruptedException e) {

            throw new IllegalStateException("Not able to create timer task. " + e.getMessage(), e);

        }

    }

    public synchronized PlatformRecording newRecording(Map<String, String> settings) {

        return newRecording(settings, ++recordingCounter);

    }

    // To be used internally when doing dumps.

    // Caller must have recorder lock and close recording before releasing lock

    public PlatformRecording newTemporaryRecording() {

        if(!Thread.holdsLock(this)) {

            throw new InternalError("Caller must have recorder lock");

        }

        return newRecording(new HashMap<>(), 0);

    }

    private synchronized PlatformRecording newRecording(Map<String, String> settings, long id) {

        PlatformRecording recording = new PlatformRecording(this, id);

        if (!settings.isEmpty()) {

            recording.setSettings(settings);

        }

        recordings.add(recording);

        return recording;

    }

    synchronized void finish(PlatformRecording recording) {

        if (recording.getState() == RecordingState.RUNNING) {

            recording.stop("Recording closed");

        }

        recordings.remove(recording);

    }

    public synchronized List<PlatformRecording> getRecordings() {

        return Collections.unmodifiableList(new ArrayList<PlatformRecording>(recordings));

    }

    public synchronized static void addListener(FlightRecorderListener changeListener) {

        AccessControlContext context = AccessController.getContext();

        SecureRecorderListener sl = new SecureRecorderListener(context, changeListener);

        boolean runInitialized;

        synchronized (PlatformRecorder.class) {

            runInitialized = FlightRecorder.isInitialized();

            changeListeners.add(sl);

        }

        if (runInitialized) {

            sl.recorderInitialized(FlightRecorder.getFlightRecorder());

        }

    }

    public synchronized static boolean removeListener(FlightRecorderListener changeListener) {

        for (SecureRecorderListener s : new ArrayList<>(changeListeners)) {

            if (s.getChangeListener() == changeListener) {

                changeListeners.remove(s);

                return true;

            }

        }

        return false;

    }

    static synchronized List<FlightRecorderListener> getListeners() {

        return new ArrayList<>(changeListeners);

    }

    Timer getTimer() {

        return timer;

    }

    public static void notifyRecorderInitialized(FlightRecorder recorder) {

        Logger.log(JFR_SYSTEM, TRACE, "Notifying listeners that Flight Recorder is initialized");

        for (FlightRecorderListener r : getListeners()) {

            r.recorderInitialized(recorder);

        }

    }

    // called by shutdown hook

    synchronized void destroy() {

        try {

            timer.cancel();

        } catch (Exception ex) {

            Logger.log(JFR_SYSTEM, WARN, "Shutdown hook could not cancel timer");

        }

        for (PlatformRecording p : getRecordings()) {

            if (p.getState() == RecordingState.RUNNING) {

                try {

                    p.stop("Shutdown");

                } catch (Exception ex) {

                    Logger.log(JFR, WARN, "Recording " + p.getName() + ":" + p.getId() + " could not be stopped");

                }

            }

        }

        JDKEvents.remove();

        if (jvm.hasNativeJFR()) {

            if (jvm.isRecording()) {

            }

            jvm.destroyNativeJFR();

        }

        repository.clear();

    }

    synchronized long start(PlatformRecording recording) {

        // State can only be NEW or DELAYED because of previous checks

        Instant now = Instant.now();

        recording.setStartTime(now);

        recording.updateTimer();

        Duration duration = recording.getDuration();

        if (duration != null) {

            recording.setStopTime(now.plus(duration));

        }

        boolean toDisk = recording.isToDisk();

        boolean beginPhysical = true;

        long streamInterval = recording.getStreamIntervalMillis();

        for (PlatformRecording s : getRecordings()) {

            if (s.getState() == RecordingState.RUNNING) {

                beginPhysical = false;

                if (s.isToDisk()) {

                    toDisk = true;

                }

                streamInterval = Math.min(streamInterval, s.getStreamIntervalMillis());

            }

        }

        long startNanos = -1;

        if (beginPhysical) {

            RepositoryChunk newChunk = null;

            if (toDisk) {

                newChunk = repository.newChunk(now);

                MetadataRepository.getInstance().setOutput(newChunk.getUnfishedFile().toString());

            } else {

                MetadataRepository.getInstance().setOutput(null);

            }

            currentChunk = newChunk;

            startNanos = jvm.getChunkStartNanos();

            recording.setState(RecordingState.RUNNING);

            updateSettings();

            writeMetaEvents();

        } else {

            RepositoryChunk newChunk = null;

            if (toDisk) {

                newChunk = repository.newChunk(now);

                RequestEngine.doChunkEnd();

                MetadataRepository.getInstance().setOutput(newChunk.getUnfishedFile().toString());

                startNanos = jvm.getChunkStartNanos();

            }

            recording.setState(RecordingState.RUNNING);

            updateSettings();

            writeMetaEvents();

            if (currentChunk != null) {

                finishChunk(currentChunk, now, recording);

            }

            currentChunk = newChunk;

        }

        if (toDisk) {

            RequestEngine.setFlushInterval(streamInterval);

        }

        RequestEngine.doChunkBegin();

        return startNanos;

    }

    synchronized void stop(PlatformRecording recording) {

        RecordingState state = recording.getState();

        if (Utils.isAfter(state, RecordingState.RUNNING)) {

            throw new IllegalStateException("Can't stop an already stopped recording.");

        }

        if (Utils.isBefore(state, RecordingState.RUNNING)) {

            throw new IllegalStateException("Recording must be started before it can be stopped.");

        }

        Instant now = Instant.now();

        boolean toDisk = false;

        boolean endPhysical = true;

        long streamInterval = Long.MAX_VALUE;

        for (PlatformRecording s : getRecordings()) {

            RecordingState rs = s.getState();

            if (s != recording && RecordingState.RUNNING == rs) {

                endPhysical = false;

                if (s.isToDisk()) {

                    toDisk = true;

                }

                streamInterval = Math.min(streamInterval, s.getStreamIntervalMillis());

            }

        }

        OldObjectSample.emit(recording);

        if (endPhysical) {

            RequestEngine.doChunkEnd();

            if (recording.isToDisk()) {

                if (currentChunk != null) {

                    MetadataRepository.getInstance().setOutput(null);

                    finishChunk(currentChunk, now, null);

                    currentChunk = null;

                }

            } else {

                // last memory

                dumpMemoryToDestination(recording);

            }

            disableEvents();

        } else {

            RepositoryChunk newChunk = null;

            RequestEngine.doChunkEnd();

            updateSettingsButIgnoreRecording(recording);

            if (toDisk) {

                newChunk = repository.newChunk(now);

                MetadataRepository.getInstance().setOutput(newChunk.getUnfishedFile().toString());

            } else {

                MetadataRepository.getInstance().setOutput(null);

            }

            writeMetaEvents();

            if (currentChunk != null) {

                finishChunk(currentChunk, now, null);

            }

            currentChunk = newChunk;

            RequestEngine.doChunkBegin();

        }

        if (toDisk) {

            RequestEngine.setFlushInterval(streamInterval);

        } else {

            RequestEngine.setFlushInterval(Long.MAX_VALUE);

        }

        recording.setState(RecordingState.STOPPED);

    }

    private void dumpMemoryToDestination(PlatformRecording recording)  {

        WriteableUserPath dest = recording.getDestination();

        if (dest != null) {

            MetadataRepository.getInstance().setOutput(dest.getRealPathText());

            recording.clearDestination();

        }

    }

    private void disableEvents() {

        MetadataRepository.getInstance().disableEvents();

    }

    void updateSettings() {

        updateSettingsButIgnoreRecording(null);

    }

    void updateSettingsButIgnoreRecording(PlatformRecording ignoreMe) {

        List<PlatformRecording> recordings = getRunningRecordings();

        List<Map<String, String>> list = new ArrayList<>(recordings.size());

        for (PlatformRecording r : recordings) {

            if (r != ignoreMe) {

                list.add(r.getSettings());

            }

        }

        MetadataRepository.getInstance().setSettings(list);

    }

    synchronized void rotateDisk() {

        Instant now = Instant.now();

        RepositoryChunk newChunk = repository.newChunk(now);

        RequestEngine.doChunkEnd();

        MetadataRepository.getInstance().setOutput(newChunk.getUnfishedFile().toString());

        writeMetaEvents();

        if (currentChunk != null) {

            finishChunk(currentChunk, now, null);

        }

        currentChunk = newChunk;

        RequestEngine.doChunkBegin();

    }

    private List<PlatformRecording> getRunningRecordings() {

        List<PlatformRecording> runningRecordings = new ArrayList<>();

        for (PlatformRecording recording : getRecordings()) {

            if (recording.getState() == RecordingState.RUNNING) {

                runningRecordings.add(recording);

            }

        }

        return runningRecordings;

    }

    private List<RepositoryChunk> makeChunkList(Instant startTime, Instant endTime) {

        Set<RepositoryChunk> chunkSet = new HashSet<>();

        for (PlatformRecording r : getRecordings()) {

            chunkSet.addAll(r.getChunks());

        }

        if (chunkSet.size() > 0) {

            List<RepositoryChunk> chunks = new ArrayList<>(chunkSet.size());

            for (RepositoryChunk rc : chunkSet) {

                if (rc.inInterval(startTime, endTime)) {

                    chunks.add(rc);

                }

            }

            // n*log(n), should be able to do n*log(k) with a priority queue,

            // where k = number of recordings, n = number of chunks

            Collections.sort(chunks, RepositoryChunk.END_TIME_COMPARATOR);

            return chunks;

        }

        return Collections.emptyList();

    }

    private void startDiskMonitor() {

        Thread t = SecuritySupport.createThreadWitNoPermissions("JFR Periodic Tasks", () -> periodicTask());

        SecuritySupport.setDaemonThread(t, true);

        t.start();

    }

    private void finishChunk(RepositoryChunk chunk, Instant time, PlatformRecording ignoreMe) {

        chunk.finish(time);

        for (PlatformRecording r : getRecordings()) {

            if (r != ignoreMe && r.getState() == RecordingState.RUNNING) {

                r.appendChunk(chunk);

            }

        }

        FilePurger.purge();

    }

    private void writeMetaEvents() {

        if (activeRecordingEvent.isEnabled()) {

            ActiveRecordingEvent event = ActiveRecordingEvent.EVENT.get();

            for (PlatformRecording r : getRecordings()) {

                if (r.getState() == RecordingState.RUNNING && r.shouldWriteMetadataEvent()) {

                    event.id = r.getId();

                    event.name = r.getName();

                    WriteableUserPath p = r.getDestination();

                    event.destination = p == null ? null : p.getRealPathText();

                    Duration d = r.getDuration();

                    event.recordingDuration = d == null ? Long.MAX_VALUE : d.toMillis();

                    Duration age = r.getMaxAge();

                    event.maxAge = age == null ? Long.MAX_VALUE : age.toMillis();

                    Long size = r.getMaxSize();

                    event.maxSize = size == null ? Long.MAX_VALUE : size;

                    Instant start = r.getStartTime();

                    event.recordingStart = start == null ? Long.MAX_VALUE : start.toEpochMilli();

                    Duration fi = r.getFlushInterval();

                    event.flushInterval = fi == null ? Long.MAX_VALUE : fi.toMillis();

                    event.commit();

                }

            }

        }

        if (activeSettingEvent.isEnabled()) {

            for (EventControl ec : MetadataRepository.getInstance().getEventControls()) {

                ec.writeActiveSettingEvent();

            }

        }

    }

    private void periodicTask() {

        if (!jvm.hasNativeJFR()) {

            return;

        }

        while (true) {

            synchronized (this) {

                if (jvm.shouldRotateDisk()) {

                    rotateDisk();

                }

            }

            long minDelta = RequestEngine.doPeriodic();

            long wait = Math.min(minDelta, Options.getWaitInterval());

            takeNap(wait);

        }

    }

    private void takeNap(long duration) {

        try {

            synchronized (JVM.FILE_DELTA_CHANGE) {

                JVM.FILE_DELTA_CHANGE.wait(duration < 10 ? 10 : duration);

            }

        } catch (InterruptedException e) {

            // Ignore

        }

    }

    synchronized Recording newCopy(PlatformRecording r, boolean stop) {

        Recording newRec = new Recording();

        PlatformRecording copy = PrivateAccess.getInstance().getPlatformRecording(newRec);

        copy.setSettings(r.getSettings());

        copy.setMaxAge(r.getMaxAge());

        copy.setMaxSize(r.getMaxSize());

        copy.setDumpOnExit(r.getDumpOnExit());

        copy.setName("Clone of " + r.getName());

        copy.setToDisk(r.isToDisk());

        copy.setInternalDuration(r.getDuration());

        copy.setStartTime(r.getStartTime());

        copy.setStopTime(r.getStopTime());

        if (r.getState() == RecordingState.NEW) {

            return newRec;

        }

        if (r.getState() == RecordingState.DELAYED) {

            copy.scheduleStart(r.getStartTime());

            return newRec;

        }

        copy.setState(r.getState());

        // recording has started, copy chunks

        for (RepositoryChunk c : r.getChunks()) {

            copy.add(c);

        }

        if (r.getState() == RecordingState.RUNNING) {

            if (stop) {

                copy.stop("Stopped when cloning recording '" + r.getName() + "'");

            } else {

                if (r.getStopTime() != null) {

                    TimerTask stopTask = copy.createStopTask();

                    copy.setStopTask(copy.createStopTask());