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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.io.IOException;

import java.io.RandomAccessFile;

import java.nio.channels.ReadableByteChannel;

import java.nio.file.Path;

import java.time.Instant;

import java.time.LocalDateTime;

import java.time.ZonedDateTime;

import java.util.Comparator;

import java.util.Objects;

import jdk.jfr.internal.SecuritySupport.SafePath;

final class RepositoryChunk {

    private static final int MAX_CHUNK_NAMES = 100;

    static final Comparator<RepositoryChunk> END_TIME_COMPARATOR = new Comparator<RepositoryChunk>() {

        @Override

        public int compare(RepositoryChunk c1, RepositoryChunk c2) {

            return c1.endTime.compareTo(c2.endTime);

        }

    };

    private final SafePath repositoryPath;

    private final SafePath unFinishedFile;

    private final SafePath file;

    private final Instant startTime;

    private final RandomAccessFile unFinishedRAF;

    private Instant endTime = null; // unfinished

    private int refCount = 0;

    private long size;

    RepositoryChunk(SafePath path, Instant startTime) throws Exception {

        ZonedDateTime z = ZonedDateTime.now();

        String fileName = Repository.REPO_DATE_FORMAT.format(

                LocalDateTime.ofInstant(startTime, z.getZone()));

        this.startTime = startTime;

        this.repositoryPath = path;

        this.file = findFileName(repositoryPath, fileName, ".jfr");

        this.unFinishedRAF = SecuritySupport.createRandomAccessFile(unFinishedFile);

    }

    private static SafePath findFileName(SafePath directory, String name, String extension) throws Exception {

        Path p = directory.toPath().resolve(name + extension);

        for (int i = 1; i < MAX_CHUNK_NAMES; i++) {

            SafePath s = new SafePath(p);

            if (!SecuritySupport.exists(s)) {

                return s;

            }

            String extendedName = String.format("%s_%02d%s", name, i, extension);

            p = directory.toPath().resolve(extendedName);

        }

        p = directory.toPath().resolve(name + "_" + System.currentTimeMillis() + extension);

        return SecuritySupport.toRealPath(new SafePath(p));

    }

    public SafePath getUnfishedFile() {

        return unFinishedFile;

    }

    void finish(Instant endTime) {

        try {

            finishWithException(endTime);

        } catch (IOException e) {

            Logger.log(LogTag.JFR, LogLevel.ERROR, "Could not finish chunk. " + e.getMessage());

        }

    }

    private void finishWithException(Instant endTime) throws IOException {

        unFinishedRAF.close();

        this.size = finish(unFinishedFile, file);

        this.endTime = endTime;

        Logger.log(LogTag.JFR_SYSTEM, LogLevel.DEBUG, () -> "Chunk finished: " + file);

    }

    private static long finish(SafePath unFinishedFile, SafePath file) throws IOException {

        Objects.requireNonNull(unFinishedFile);

        Objects.requireNonNull(file);

        return SecuritySupport.getFileSize(file);

    }

    public Instant getStartTime() {

        return startTime;

    }

    public Instant getEndTime() {

        return endTime;

    }

    private void delete(SafePath f) {

        try {

            SecuritySupport.delete(f);

            Logger.log(LogTag.JFR, LogLevel.DEBUG, () -> "Repository chunk " + f + " deleted");

        } catch (IOException e) {

            if (f != null) {

            }

        }

    }

    private void destroy() {

        if (!isFinished()) {

            finish(Instant.MIN);

        }

        if (file != null) {

            delete(file);

        }

        try {

            unFinishedRAF.close();

        } catch (IOException e) {

            Logger.log(LogTag.JFR, LogLevel.ERROR, () -> "Could not close random access file: " + unFinishedFile.toString() + ". File will not be deleted due to: " + e.getMessage());

        }

    }

    public synchronized void use() {

        ++refCount;

        Logger.log(LogTag.JFR_SYSTEM, LogLevel.DEBUG, () -> "Use chunk " + toString() + " ref count now " + refCount);

    }

    public synchronized void release() {

        --refCount;

        Logger.log(LogTag.JFR_SYSTEM, LogLevel.DEBUG, () -> "Release chunk " + toString() + " ref count now " + refCount);

        if (refCount == 0) {

            destroy();

        }

    }

    @Override

    @SuppressWarnings("deprecation")

    protected void finalize() {

        boolean destroy = false;

        synchronized (this) {

            if (refCount > 0) {

                destroy = true;

            }

        }

        if (destroy) {

            destroy();

        }

    }

    public long getSize() {

        return size;

    }

    public boolean isFinished() {

        return endTime != null;

    }

    @Override

    public String toString() {

        if (isFinished()) {

            return file.toString();

        }

        return unFinishedFile.toString();

    }

    ReadableByteChannel newChannel() throws IOException {

        if (!isFinished()) {

            throw new IOException("Chunk not finished");

        }

        return ((SecuritySupport.newFileChannelToRead(file)));

    }

    public boolean inInterval(Instant startTime, Instant endTime) {

        if (startTime != null && getEndTime().isBefore(startTime)) {

            return false;

        }

        if (endTime != null && getStartTime().isAfter(endTime)) {

            return false;

        }

        return true;

    }

    public SafePath getFile() {

        return file;

    }

}