JavaPluginLoader.java

package org.bukkit.plugin.java;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.logging.Level;
import java.util.regex.Pattern;

import org.apache.commons.lang.Validate;
import org.bukkit.Bukkit;
import org.bukkit.Server;
import org.bukkit.configuration.serialization.ConfigurationSerializable;
import org.bukkit.configuration.serialization.ConfigurationSerialization;
import org.bukkit.event.Event;
import org.bukkit.event.EventException;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.server.PluginDisableEvent;
import org.bukkit.event.server.PluginEnableEvent;
import org.bukkit.plugin.EventExecutor;
import org.bukkit.plugin.InvalidDescriptionException;
import org.bukkit.plugin.InvalidPluginException;
import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.PluginDescriptionFile;
import org.bukkit.plugin.PluginLoader;
import org.bukkit.plugin.RegisteredListener;
import org.bukkit.plugin.TimedRegisteredListener;
import org.bukkit.plugin.UnknownDependencyException;
import org.yaml.snakeyaml.error.YAMLException;

import com.google.common.collect.ImmutableList;

/**
 * Represents a Java plugin loader, allowing plugins in the form of .jar
 */
public class JavaPluginLoader implements PluginLoader {
    private final Server server;
    protected final Pattern[] fileFilters = new Pattern[] { Pattern.compile("\\.jar$"), };
    protected final Map<String, Class<?>> classes = new HashMap<String, Class<?>>();
    protected final Map<String, PluginClassLoader> loaders = new LinkedHashMap<String, PluginClassLoader>();

    public JavaPluginLoader(Server instance) {
        server = instance;
    }

    public Plugin loadPlugin(File file) throws InvalidPluginException {
        Validate.notNull(file, "File cannot be null");

        if (!file.exists()) {
            throw new InvalidPluginException(new FileNotFoundException(file.getPath() + " does not exist"));
        }

        PluginDescriptionFile description;
        try {
            description = getPluginDescription(file);
        } catch (InvalidDescriptionException ex) {
            throw new InvalidPluginException(ex);
        }

        File dataFolder = new File(file.getParentFile(), description.getName());
        File oldDataFolder = getDataFolder(file);

        // Found old data folder
        if (dataFolder.equals(oldDataFolder)) {
            // They are equal -- nothing needs to be done!
        } else if (dataFolder.isDirectory() && oldDataFolder.isDirectory()) {
            server.getLogger().log(Level.INFO, String.format(
                "While loading %s (%s) found old-data folder: %s next to the new one: %s",
                description.getName(),
                file,
                oldDataFolder,
                dataFolder
            ));
        } else if (oldDataFolder.isDirectory() && !dataFolder.exists()) {
            if (!oldDataFolder.renameTo(dataFolder)) {
                throw new InvalidPluginException("Unable to rename old data folder: '" + oldDataFolder + "' to: '" + dataFolder + "'");
            }
            server.getLogger().log(Level.INFO, String.format(
                "While loading %s (%s) renamed data folder: '%s' to '%s'",
                description.getName(),
                file,
                oldDataFolder,
                dataFolder
            ));
        }

        if (dataFolder.exists() && !dataFolder.isDirectory()) {
            throw new InvalidPluginException(String.format(
                "Projected datafolder: '%s' for %s (%s) exists and is not a directory",
                dataFolder,
                description.getName(),
                file
            ));
        }

        List<String> depend = description.getDepend();
        if (depend == null) {
            depend = ImmutableList.<String>of();
        }

        for (String pluginName : depend) {
            if (loaders == null) {
                throw new UnknownDependencyException(pluginName);
            }
            PluginClassLoader current = loaders.get(pluginName);

            if (current == null) {
                throw new UnknownDependencyException(pluginName);
            }
        }

        PluginClassLoader loader = null;
        JavaPlugin result = null;

        try {
            URL[] urls = new URL[1];

            urls[0] = file.toURI().toURL();

            if (description.getClassLoaderOf() != null) {
                loader = loaders.get(description.getClassLoaderOf());
                loader.addURL(urls[0]);
            } else {
                loader = new PluginClassLoader(this, urls, getClass().getClassLoader(), server, description, dataFolder, file);
            }

            Class<?> jarClass = Class.forName(description.getMain(), true, loader);
            Class<? extends JavaPlugin> plugin = jarClass.asSubclass(JavaPlugin.class);

            Constructor<? extends JavaPlugin> constructor = plugin.getConstructor();

            result = constructor.newInstance();
        } catch (InvocationTargetException ex) {
            throw new InvalidPluginException(ex.getCause());
        } catch (Throwable ex) {
            throw new InvalidPluginException(ex);
        }

        loaders.put(description.getName(), loader);

        return result;
    }

    public Plugin loadPlugin(File file, boolean ignoreSoftDependencies) throws InvalidPluginException {
        return loadPlugin(file);
    }

    protected File getDataFolder(File file) {
        File dataFolder = null;

        String filename = file.getName();
        int index = file.getName().lastIndexOf(".");

        if (index != -1) {
            String name = filename.substring(0, index);

            dataFolder = new File(file.getParentFile(), name);
        } else {
            // This is if there is no extension, which should not happen
            // Using _ to prevent name collision

            dataFolder = new File(file.getParentFile(), filename + "_");
        }

        return dataFolder;
    }

    public PluginDescriptionFile getPluginDescription(File file) throws InvalidDescriptionException {
        Validate.notNull(file, "File cannot be null");

        JarFile jar = null;
        InputStream stream = null;

        try {
            jar = new JarFile(file);
            JarEntry entry = jar.getJarEntry("plugin.yml");

            if (entry == null) {
                throw new InvalidDescriptionException(new FileNotFoundException("Jar does not contain plugin.yml"));
            }

            stream = jar.getInputStream(entry);

            return new PluginDescriptionFile(stream);

        } catch (IOException ex) {
            throw new InvalidDescriptionException(ex);
        } catch (YAMLException ex) {
            throw new InvalidDescriptionException(ex);
        } finally {
            if (jar != null) {
                try {
                    jar.close();
                } catch (IOException e) {
                }
            }
            if (stream != null) {
                try {
                    stream.close();
                } catch (IOException e) {
                }
            }
        }
    }

    public Pattern[] getPluginFileFilters() {
        return fileFilters;
    }

    public Class<?> getClassByName(final String name) {
        Class<?> cachedClass = classes.get(name);

        if (cachedClass != null) {
            return cachedClass;
        } else {
            for (String current : loaders.keySet()) {
                PluginClassLoader loader = loaders.get(current);

                try {
                    cachedClass = loader.findClass(name, false);
                } catch (ClassNotFoundException cnfe) {}
                if (cachedClass != null) {
                    return cachedClass;
                }
            }
        }
        return null;
    }

    public void setClass(final String name, final Class<?> clazz) {
        if (!classes.containsKey(name)) {
            classes.put(name, clazz);

            if (ConfigurationSerializable.class.isAssignableFrom(clazz)) {
                Class<? extends ConfigurationSerializable> serializable = clazz.asSubclass(ConfigurationSerializable.class);
                ConfigurationSerialization.registerClass(serializable);
            }
        }
    }

    public void removeClass(String name) {
        Class<?> clazz = classes.remove(name);

        try {
            if ((clazz != null) && (ConfigurationSerializable.class.isAssignableFrom(clazz))) {
                Class<? extends ConfigurationSerializable> serializable = clazz.asSubclass(ConfigurationSerializable.class);
                ConfigurationSerialization.unregisterClass(serializable);
            }
        } catch (NullPointerException ex) {
            // Boggle!
            // (Native methods throwing NPEs is not fun when you can't stop it before-hand)
        }
    }

    public Map<Class<? extends Event>, Set<RegisteredListener>> createRegisteredListeners(Listener listener, final Plugin plugin) {
        boolean useTimings = server.getPluginManager().useTimings();
        Map<Class<? extends Event>, Set<RegisteredListener>> ret = new HashMap<Class<? extends Event>, Set<RegisteredListener>>();
        Method[] methods;
        try {
            methods = listener.getClass().getDeclaredMethods();
        } catch (NoClassDefFoundError e) {
            Bukkit.getServer().getLogger().severe("Plugin " + plugin.getDescription().getName() + " is attempting to register event " + e.getMessage() + ", which does not exist. Ignoring events registered in " + listener.getClass());
            return ret;
        }
        for (int i = 0; i < methods.length; i++) {
            final Method method = methods[i];
            final EventHandler eh = method.getAnnotation(EventHandler.class);
            if (eh == null) continue;
            final Class<?> checkClass = method.getParameterTypes()[0];
            if (!Event.class.isAssignableFrom(checkClass) || method.getParameterTypes().length != 1) {
                plugin.getServer().getLogger().severe("Wrong method arguments used for event type registered");
                continue;
            }
            final Class<? extends Event> eventClass = checkClass.asSubclass(Event.class);
            method.setAccessible(true);
            Set<RegisteredListener> eventSet = ret.get(eventClass);
            if (eventSet == null) {
                eventSet = new HashSet<RegisteredListener>();
                ret.put(eventClass, eventSet);
            }
            EventExecutor executor = new EventExecutor() {
                public void execute(Listener listener, Event event) throws EventException {
                    try {
                        if (!eventClass.isAssignableFrom(event.getClass())) {
                            return;
                        }
                        method.invoke(listener, event);
                    } catch (InvocationTargetException ex) {
                        throw new EventException(ex.getCause());
                    } catch (Throwable t) {
                        throw new EventException(t);
                    }
                }
            };
            if (useTimings) {
                eventSet.add(new TimedRegisteredListener(listener, executor, eh.priority(), plugin, eh.ignoreCancelled()));
            } else {
                eventSet.add(new RegisteredListener(listener, executor, eh.priority(), plugin, eh.ignoreCancelled()));
            }
        }
        return ret;
    }

    public void enablePlugin(final Plugin plugin) {
        if (!(plugin instanceof JavaPlugin)) {
            throw new IllegalArgumentException("Plugin is not associated with this PluginLoader");
        }

        if (!plugin.isEnabled()) {
            String message = String.format("Enabling %s", plugin.getDescription().getFullName());
            plugin.getLogger().info(message);

            JavaPlugin jPlugin = (JavaPlugin) plugin;

            String pluginName = jPlugin.getDescription().getName();

            if (!loaders.containsKey(pluginName)) {
                loaders.put(pluginName, (PluginClassLoader) jPlugin.getClassLoader());
            }

            try {
                jPlugin.setEnabled(true);
            } catch (Throwable ex) {
                server.getLogger().log(Level.SEVERE, "Error occurred while enabling " + plugin.getDescription().getFullName() + " (Is it up to date?)", ex);
            }

            // Perhaps abort here, rather than continue going, but as it stands,
            // an abort is not possible the way it's currently written
            server.getPluginManager().callEvent(new PluginEnableEvent(plugin));
        }
    }

    public void disablePlugin(Plugin plugin) {
        if (!(plugin instanceof JavaPlugin)) {
            throw new IllegalArgumentException("Plugin is not associated with this PluginLoader");
        }

        if (plugin.isEnabled()) {
            String message = String.format("Disabling %s", plugin.getDescription().getFullName());
            plugin.getLogger().info(message);

            server.getPluginManager().callEvent(new PluginDisableEvent(plugin));

            JavaPlugin jPlugin = (JavaPlugin) plugin;
            ClassLoader cloader = jPlugin.getClassLoader();

            try {
                jPlugin.setEnabled(false);
            } catch (Throwable ex) {
                server.getLogger().log(Level.SEVERE, "Error occurred while disabling " + plugin.getDescription().getFullName() + " (Is it up to date?)", ex);
            }

            loaders.remove(jPlugin.getDescription().getName());

            if (cloader instanceof PluginClassLoader) {
                PluginClassLoader loader = (PluginClassLoader) cloader;
                Set<String> names = loader.getClasses();

                for (String name : names) {
                    removeClass(name);
                }
            }
        }
    }
}