Rename

Signed-off-by: Samisafool <thenerdiestguy@gmail.com>

libraries/launcher/org/prismlauncher/EntryPoint.java

@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 icelimetea, <fr3shtea@outlook.com>
+ *
+ *  This program 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, version 3.
+ *
+ *  This program 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.
+ *
+ *  Linking this library statically or dynamically with other modules is
+ *  making a combined work based on this library. Thus, the terms and
+ *  conditions of the GNU General Public License cover the whole
+ *  combination.
+ *
+ *  As a special exception, the copyright holders of this library give
+ *  you permission to link this library with independent modules to
+ *  produce an executable, regardless of the license terms of these
+ *  independent modules, and to copy and distribute the resulting
+ *  executable under terms of your choice, provided that you also meet,
+ *  for each linked independent module, the terms and conditions of the
+ *  license of that module. An independent module is a module which is
+ *  not derived from or based on this library. If you modify this
+ *  library, you may extend this exception to your version of the
+ *  library, but you are not obliged to do so. If you do not wish to do
+ *  so, delete this exception statement from your version.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
+package org.prismlauncher;
+
+import org.prismlauncher.exception.ParseException;
+import org.prismlauncher.utils.Parameters;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public final class EntryPoint {
+
+    private static final Logger LOGGER = Logger.getLogger("EntryPoint");
+
+    private final Parameters params = new Parameters();
+
+    public static void main(String[] args) {
+        EntryPoint listener = new EntryPoint();
+
+        int retCode = listener.listen();
+
+        if (retCode != 0) {
+            LOGGER.info("Exiting with " + retCode);
+
+            System.exit(retCode);
+        }
+    }
+
+    private Action parseLine(String inData) throws ParseException {
+        String[] tokens = inData.split("\\s+", 2);
+
+        if (tokens.length == 0)
+            throw new ParseException("Unexpected empty string!");
+
+        switch (tokens[0]) {
+            case "launch": {
+                return Action.Launch;
+            }
+
+            case "abort": {
+                return Action.Abort;
+            }
+
+            default: {
+                if (tokens.length != 2)
+                    throw new ParseException("Error while parsing:" + inData);
+
+                params.add(tokens[0], tokens[1]);
+
+                return Action.Proceed;
+            }
+        }
+    }
+
+    public int listen() {
+        Action action = Action.Proceed;
+
+        try (BufferedReader reader = new BufferedReader(new InputStreamReader(
+                System.in,
+                StandardCharsets.UTF_8
+        ))) {
+            String line;
+
+            while (action == Action.Proceed) {
+                if ((line = reader.readLine()) != null) {
+                    action = parseLine(line);
+                } else {
+                    action = Action.Abort;
+                }
+            }
+        } catch (IOException | ParseException e) {
+            LOGGER.log(Level.SEVERE, "Launcher ABORT due to exception:", e);
+
+            return 1;
+        }
+
+        // Main loop
+        if (action == Action.Abort) {
+            LOGGER.info("Launch aborted by the launcher.");
+
+            return 1;
+        }
+
+        try {
+            Launcher launcher =
+                    LauncherFactory
+                            .getInstance()
+                            .createLauncher(params);
+
+            launcher.launch();
+
+            return 0;
+        } catch (IllegalArgumentException e) {
+            LOGGER.log(Level.SEVERE, "Wrong argument.", e);
+
+            return 1;
+        } catch (Exception e) {
+            LOGGER.log(Level.SEVERE, "Exception caught from launcher.", e);
+
+            return 1;
+        }
+    }
+
+    private enum Action {
+        Proceed,
+        Launch,
+        Abort
+    }
+
+}

libraries/launcher/org/prismlauncher/Launcher.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2012-2021 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.prismlauncher;
+
+public interface Launcher {
+
+    void launch() throws Exception;
+
+}

libraries/launcher/org/prismlauncher/LauncherFactory.java

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 icelimetea, <fr3shtea@outlook.com>
+ *
+ *  This program 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, version 3.
+ *
+ *  This program 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.
+ *
+ *  Linking this library statically or dynamically with other modules is
+ *  making a combined work based on this library. Thus, the terms and
+ *  conditions of the GNU General Public License cover the whole
+ *  combination.
+ *
+ *  As a special exception, the copyright holders of this library give
+ *  you permission to link this library with independent modules to
+ *  produce an executable, regardless of the license terms of these
+ *  independent modules, and to copy and distribute the resulting
+ *  executable under terms of your choice, provided that you also meet,
+ *  for each linked independent module, the terms and conditions of the
+ *  license of that module. An independent module is a module which is
+ *  not derived from or based on this library. If you modify this
+ *  library, you may extend this exception to your version of the
+ *  library, but you are not obliged to do so. If you do not wish to do
+ *  so, delete this exception statement from your version.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package org.prismlauncher;
+
+import org.prismlauncher.impl.OneSixLauncher;
+import org.prismlauncher.utils.Parameters;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public final class LauncherFactory {
+
+    private static final LauncherFactory INSTANCE = new LauncherFactory();
+
+    private final Map<String, LauncherProvider> launcherRegistry = new HashMap<>();
+
+    private LauncherFactory() {
+        launcherRegistry.put("onesix", new LauncherProvider() {
+            @Override
+            public Launcher provide(Parameters parameters) {
+                return new OneSixLauncher(parameters);
+            }
+        });
+    }
+
+    public Launcher createLauncher(Parameters parameters) {
+        String name = parameters.first("launcher");
+
+        LauncherProvider launcherProvider = launcherRegistry.get(name);
+
+        if (launcherProvider == null)
+            throw new IllegalArgumentException("Invalid launcher type: " + name);
+
+        return launcherProvider.provide(parameters);
+    }
+
+    public static LauncherFactory getInstance() {
+        return INSTANCE;
+    }
+
+    public interface LauncherProvider {
+
+        Launcher provide(Parameters parameters);
+
+    }
+
+}

libraries/launcher/org/prismlauncher/applet/LegacyFrame.java

@@ -0,0 +1,163 @@
+/*
+ * Copyright 2012-2021 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.prismlauncher.applet;
+
+import net.minecraft.Launcher;
+
+import javax.imageio.ImageIO;
+import java.applet.Applet;
+import java.awt.*;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public final class LegacyFrame extends Frame {
+
+    private static final Logger LOGGER = Logger.getLogger("LegacyFrame");
+
+    private final Launcher appletWrap;
+
+    public LegacyFrame(String title, Applet mcApplet) {
+        super(title);
+
+        appletWrap = new Launcher(mcApplet);
+
+        mcApplet.setStub(appletWrap);
+
+        try {
+            setIconImage(ImageIO.read(new File("icon.png")));
+        } catch (IOException e) {
+            LOGGER.log(Level.WARNING, "Unable to read Minecraft icon!", e);
+        }
+
+        addWindowListener(new ForceExitHandler());
+    }
+
+    public void start (
+        String user,
+        String session,
+        int winSizeW,
+        int winSizeH,
+        boolean maximize,
+        String serverAddress,
+        String serverPort,
+        boolean isDemo
+    ) {
+        // Implements support for launching in to multiplayer on classic servers using a mpticket
+        // file generated by an external program and stored in the instance's root folder.
+
+        Path mpticketFile =
+                Paths.get(System.getProperty("user.dir"), "..", "mpticket");
+
+        Path mpticketFileCorrupt =
+                Paths.get(System.getProperty("user.dir"), "..", "mpticket.corrupt");
+
+        if (Files.exists(mpticketFile)) {
+            try {
+                List<String> lines = Files.readAllLines(mpticketFile, StandardCharsets.UTF_8);
+
+                if (lines.size() < 3) {
+                    Files.move(
+                            mpticketFile,
+                            mpticketFileCorrupt,
+                            StandardCopyOption.REPLACE_EXISTING
+                    );
+
+                    LOGGER.warning("Mpticket file is corrupted!");
+                } else {
+                    // Assumes parameters are valid and in the correct order
+                    appletWrap.setParameter("server", lines.get(0));
+                    appletWrap.setParameter("port", lines.get(1));
+                    appletWrap.setParameter("mppass", lines.get(2));
+                }
+            } catch (IOException e) {
+                LOGGER.log(Level.WARNING, "Unable to read mpticket file!", e);
+            }
+        }
+
+        if (serverAddress != null) {
+            appletWrap.setParameter("server", serverAddress);
+            appletWrap.setParameter("port", serverPort);
+        }
+
+        appletWrap.setParameter("username", user);
+        appletWrap.setParameter("sessionid", session);
+        appletWrap.setParameter("stand-alone", "true"); // Show the quit button.
+        appletWrap.setParameter("haspaid", "true"); // Some old versions need this for world saves to work.
+        appletWrap.setParameter("demo", isDemo ? "true" : "false");
+        appletWrap.setParameter("fullscreen", "false");
+
+        add(appletWrap);
+
+        appletWrap.setPreferredSize(new Dimension(winSizeW, winSizeH));
+
+        pack();
+
+        setLocationRelativeTo(null);
+        setResizable(true);
+
+        if (maximize)
+            this.setExtendedState(MAXIMIZED_BOTH);
+
+        validate();
+
+        appletWrap.init();
+        appletWrap.start();
+
+        setVisible(true);
+    }
+
+    private final class ForceExitHandler extends WindowAdapter {
+
+        @Override
+        public void windowClosing(WindowEvent e) {
+            new Thread(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        Thread.sleep(30000L);
+                    } catch (InterruptedException localInterruptedException) {
+                        localInterruptedException.printStackTrace();
+                    }
+
+                    LOGGER.info("Forcing exit!");
+
+                    System.exit(0);
+                }
+            }).start();
+
+            if (appletWrap != null) {
+                appletWrap.stop();
+                appletWrap.destroy();
+            }
+
+            // old minecraft versions can hang without this >_<
+            System.exit(0);
+        }
+
+    }
+
+}

libraries/launcher/org/prismlauncher/exception/ParameterNotFoundException.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2012-2021 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.prismlauncher.exception;
+
+public final class ParameterNotFoundException extends IllegalArgumentException {
+
+    public ParameterNotFoundException(String key) {
+        super("Unknown parameter name: " + key);
+    }
+
+}

libraries/launcher/org/prismlauncher/exception/ParseException.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2012-2021 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.prismlauncher.exception;
+
+public final class ParseException extends IllegalArgumentException {
+
+    public ParseException(String message) {
+        super(message);
+    }
+
+}

libraries/launcher/org/prismlauncher/impl/OneSixLauncher.java

@@ -0,0 +1,190 @@
+/* Copyright 2012-2021 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.prismlauncher.impl;
+
+import org.prismlauncher.Launcher;
+import org.prismlauncher.applet.LegacyFrame;
+import org.prismlauncher.utils.Parameters;
+import org.prismlauncher.utils.Utils;
+
+import java.applet.Applet;
+import java.io.File;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.ArrayList;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public final class OneSixLauncher implements Launcher {
+
+    private static final int DEFAULT_WINDOW_WIDTH = 854;
+    private static final int DEFAULT_WINDOW_HEIGHT = 480;
+
+    private static final Logger LOGGER = Logger.getLogger("OneSixLauncher");
+
+    // parameters, separated from ParamBucket
+    private final List<String> mcParams;
+    private final List<String> traits;
+    private final String appletClass;
+    private final String mainClass;
+    private final String userName, sessionId;
+    private final String windowTitle;
+
+    // secondary parameters
+    private final int winSizeW;
+    private final int winSizeH;
+    private final boolean maximize;
+    private final String cwd;
+
+    private final String serverAddress;
+    private final String serverPort;
+
+    private final ClassLoader classLoader;
+
+    public OneSixLauncher(Parameters params) {
+        classLoader = ClassLoader.getSystemClassLoader();
+
+        mcParams = params.allSafe("param", new ArrayList<String>());
+        mainClass = params.firstSafe("mainClass", "net.minecraft.client.Minecraft");
+        appletClass = params.firstSafe("appletClass", "net.minecraft.client.MinecraftApplet");
+        traits = params.allSafe("traits", new ArrayList<String>());
+
+        userName = params.first("userName");
+        sessionId = params.first("sessionId");
+        windowTitle = params.firstSafe("windowTitle", "Minecraft");
+
+        serverAddress = params.firstSafe("serverAddress", null);
+        serverPort = params.firstSafe("serverPort", null);
+
+        cwd = System.getProperty("user.dir");
+
+        String windowParams = params.firstSafe("windowParams", null);
+
+        if (windowParams != null) {
+            String[] dimStrings = windowParams.split("x");
+
+            if (windowParams.equalsIgnoreCase("max")) {
+                maximize = true;
+
+                winSizeW = DEFAULT_WINDOW_WIDTH;
+                winSizeH = DEFAULT_WINDOW_HEIGHT;
+            } else if (dimStrings.length == 2) {
+                maximize = false;
+
+                winSizeW = Integer.parseInt(dimStrings[0]);
+                winSizeH = Integer.parseInt(dimStrings[1]);
+            } else {
+                throw new IllegalArgumentException("Unexpected window size parameter value: " + windowParams);
+            }
+        } else {
+            maximize = false;
+
+            winSizeW = DEFAULT_WINDOW_WIDTH;
+            winSizeH = DEFAULT_WINDOW_HEIGHT;
+        }
+    }
+
+    private void invokeMain(Class<?> mainClass) throws Exception {
+        Method method = mainClass.getMethod("main", String[].class);
+
+        method.invoke(null, (Object) mcParams.toArray(new String[0]));
+    }
+
+    private void legacyLaunch() throws Exception {
+        // Get the Minecraft Class and set the base folder
+        Class<?> minecraftClass = classLoader.loadClass(mainClass);
+
+        Field baseDirField = Utils.getMinecraftBaseDirField(minecraftClass);
+
+        if (baseDirField == null) {
+            LOGGER.warning("Could not find Minecraft path field.");
+        } else {
+            baseDirField.setAccessible(true);
+
+            baseDirField.set(null, new File(cwd));
+        }
+
+        System.setProperty("minecraft.applet.TargetDirectory", cwd);
+
+        if (!traits.contains("noapplet")) {
+            LOGGER.info("Launching with applet wrapper...");
+
+            try {
+                Class<?> mcAppletClass = classLoader.loadClass(appletClass);
+
+                Applet mcApplet = (Applet) mcAppletClass.getConstructor().newInstance();
+
+                LegacyFrame mcWindow = new LegacyFrame(windowTitle, mcApplet);
+
+                mcWindow.start(
+                        userName,
+                        sessionId,
+                        winSizeW,
+                        winSizeH,
+                        maximize,
+                        serverAddress,
+                        serverPort,
+                        mcParams.contains("--demo")
+                );
+
+                return;
+            } catch (Exception e) {
+                LOGGER.log(Level.SEVERE, "Applet wrapper failed: ", e);
+
+                LOGGER.warning("Falling back to using main class.");
+            }
+        }
+
+        invokeMain(minecraftClass);
+    }
+
+    private void launchWithMainClass() throws Exception {
+        // window size, title and state, onesix
+
+        // FIXME: there is no good way to maximize the minecraft window in onesix.
+        // the following often breaks linux screen setups
+        // mcparams.add("--fullscreen");
+
+        if (!maximize) {
+            mcParams.add("--width");
+            mcParams.add(Integer.toString(winSizeW));
+            mcParams.add("--height");
+            mcParams.add(Integer.toString(winSizeH));
+        }
+
+        if (serverAddress != null) {
+            mcParams.add("--server");
+            mcParams.add(serverAddress);
+            mcParams.add("--port");
+            mcParams.add(serverPort);
+        }
+
+        invokeMain(classLoader.loadClass(mainClass));
+    }
+
+    @Override
+    public void launch() throws Exception {
+        if (traits.contains("legacyLaunch") || traits.contains("alphaLaunch")) {
+            // legacy launch uses the applet wrapper
+            legacyLaunch();
+        } else {
+            // normal launch just calls main()
+            launchWithMainClass();
+        }
+    }
+
+}

libraries/launcher/org/prismlauncher/utils/Parameters.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2012-2021 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.prismlauncher.utils;
+
+import org.prismlauncher.exception.ParameterNotFoundException;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public final class Parameters {
+
+    private final Map<String, List<String>> paramsMap = new HashMap<>();
+
+    public void add(String key, String value) {
+        List<String> params = paramsMap.get(key);
+
+        if (params == null) {
+            params = new ArrayList<>();
+
+            paramsMap.put(key, params);
+        }
+
+        params.add(value);
+    }
+
+    public List<String> all(String key) throws ParameterNotFoundException {
+        List<String> params = paramsMap.get(key);
+
+        if (params == null)
+            throw new ParameterNotFoundException(key);
+
+        return params;
+    }
+
+    public List<String> allSafe(String key, List<String> def) {
+        List<String> params = paramsMap.get(key);
+
+        if (params == null || params.isEmpty())
+            return def;
+
+        return params;
+    }
+
+    public String first(String key) throws ParameterNotFoundException {
+        List<String> list = all(key);
+
+        if (list.isEmpty())
+            throw new ParameterNotFoundException(key);
+
+        return list.get(0);
+    }
+
+    public String firstSafe(String key, String def) {
+        List<String> params = paramsMap.get(key);
+
+        if (params == null || params.isEmpty())
+            return def;
+
+        return params.get(0);
+    }
+
+}

libraries/launcher/org/prismlauncher/utils/Utils.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2012-2021 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.prismlauncher.utils;
+
+import java.io.File;
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+
+public final class Utils {
+
+    private Utils() {}
+
+    /**
+     * Finds a field that looks like a Minecraft base folder in a supplied class
+     *
+     * @param clazz the class to scan
+     */
+    public static Field getMinecraftBaseDirField(Class<?> clazz) {
+        for (Field f : clazz.getDeclaredFields()) {
+            // Has to be File
+            if (f.getType() != File.class)
+                continue;
+
+            // And Private Static.
+            if (!Modifier.isStatic(f.getModifiers()) || !Modifier.isPrivate(f.getModifiers()))
+                continue;
+
+            return f;
+        }
+
+        return null;
+    }
+
+}
+