ServerCache.java

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/*
 * This file is part of JXClient, the Fullscreen Java Crossfire Client.
 *
 * JXClient is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * JXClient 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with JXClient; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Copyright (C) 2005-2008 Yann Chachkoff
 * Copyright (C) 2006-2017,2019-2023 Andreas Kirschbaum
 * Copyright (C) 2010-2012,2014-2018,2020-2023 Nicolas Weeger
 */
 
package com.realtime.crossfire.jxclient.metaserver;
 
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.LineNumberReader;
import java.io.Reader;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
 
public class ServerCache {
 
    @NotNull
    public static final CharSequence DEFAULT_ENTRY_LOCALHOST = "0|localhost|0|--|Local server. Start server before you try to connect.|0|0|0|||";
 
    @NotNull
    private final Map<String, Info> entries = new HashMap<>();
 
    @Nullable
    private final Path file;
 
    public ServerCache(@Nullable final Path file) {
        this.file = file;
 
        load();
    }
 
    public void put(@NotNull final MetaserverEntry metaserverEntry) {
        entries.put(metaserverEntry.getKey(), new Info(metaserverEntry));
    }
 
    public void expire(final long timestamp) {
        final long now = System.currentTimeMillis();
        entries.values().removeIf(info -> now-info.getTimestamp() > timestamp);
    }
 
    @NotNull
    public Map<String, MetaserverEntry> getAll() {
        final Map<String, MetaserverEntry> result = new HashMap<>();
        for (Entry<String, Info> entry : entries.entrySet()) {
            result.put(entry.getKey(), entry.getValue().getMetaserverEntry());
        }
        return result;
    }
 
    private void load() {
        if (file == null) {
            return;
        }
 
        try {
            try (Reader isr = Files.newBufferedReader(file, StandardCharsets.UTF_8)) {
                try (LineNumberReader lnr = new LineNumberReader(isr)) {
                    while (true) {
                        final String line = lnr.readLine();
                        if (line == null) {
                            break;
                        }
 
                        final String[] tmp = line.split(" ", 2);
                        if (tmp.length != 2) {
                            System.err.println(file+":"+lnr.getLineNumber()+": syntax error");
                            continue;
                        }
 
                        final long timestamp;
                        try {
                            timestamp = Long.parseLong(tmp[0]);
                        } catch (final NumberFormatException ignored) {
                            System.err.println(file+":"+lnr.getLineNumber()+": syntax error");
                            continue;
                        }
                        if (!addEntry(tmp[1], timestamp)) {
                            System.err.println(file+":"+lnr.getLineNumber()+": syntax error");
                            //noinspection UnnecessaryContinue
                            continue;
                        }
                    }
                }
            }
        } catch (final NoSuchFileException ignored) {
            // add default entries if the cache files does not exist
            final long now = System.currentTimeMillis()-1;
            addEntry(DEFAULT_ENTRY_LOCALHOST, now);
            addEntry("0|crossfire.metalforge.net|0|--|Release Candidate 1.12.0<br>Eden Prairie, MN US<br><a href=\"http://www.metalforge.net\">http://www.metalforge.net</a>|0|0|0|Standard|Standard|Standard", now);
            addEntry("0|invidious2.meflin.net|0|--|<b>Invidious</b> - the next generation of Crossfire|0|0|0|Standard|Standard|Standard", now);
        } catch (final IOException ex) {
            System.err.println(file+": "+ex.getMessage());
        }
    }
 
    private boolean addEntry(@NotNull final CharSequence metaserverEntryLine, final long timestamp) {
        final MetaserverEntry metaserverEntry = MetaserverEntryParser.parseEntry(metaserverEntryLine);
        if (metaserverEntry == null) {
            return false;
        }
 
        entries.put(metaserverEntry.getKey(), new Info(metaserverEntry, timestamp));
        return true;
    }
 
    public void save() {
        if (file == null) {
            return;
        }
 
        try {
            saveInternal(file);
        } catch (final IOException ex) {
            System.err.println(file+": "+ex.getMessage());
        }
    }
 
    private void saveInternal(@NotNull final Path file) throws IOException {
        try (BufferedWriter bw = Files.newBufferedWriter(file, StandardCharsets.UTF_8)) {
            for (Info info : entries.values()) {
                bw.write(Long.toString(info.getTimestamp()));
                bw.write(' ');
                bw.write(MetaserverEntryParser.format(info.getMetaserverEntry()));
                bw.write('\n');
            }
        }
    }
 
}