Added transformer support for plugins

src/main/java/net/raphimc/viaproxy/plugins/PluginManager.java

@@ -17,15 +17,21 @@
  */
 package net.raphimc.viaproxy.plugins;
 
+import com.vdurmont.semver4j.Semver;
+import net.lenni0451.classtransform.TransformerManager;
+import net.lenni0451.classtransform.additionalclassprovider.GuavaClassPathProvider;
+import net.lenni0451.classtransform.utils.loader.InjectionClassLoader;
+import net.lenni0451.classtransform.utils.tree.IClassProvider;
 import net.lenni0451.lambdaevents.LambdaManager;
 import net.lenni0451.lambdaevents.generator.LambdaMetaFactoryGenerator;
+import net.raphimc.viaproxy.ViaProxy;
+import net.raphimc.viaproxy.util.URLClassProvider;
 import net.raphimc.viaproxy.util.logging.Logger;
 import org.yaml.snakeyaml.Yaml;
 
 import java.io.File;
 import java.io.InputStream;
 import java.net.URL;
-import java.net.URLClassLoader;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -37,6 +43,7 @@ public class PluginManager {
     public static final File PLUGINS_DIR = new File("plugins");
 
     private static final Yaml YAML = new Yaml();
+    private static final IClassProvider ROOT_CLASS_PROVIDER = new GuavaClassPathProvider();
     private static final List<ViaProxyPlugin> PLUGINS = new ArrayList<>();
 
     public static List<ViaProxyPlugin> getPlugins() {
@@ -64,7 +71,10 @@ public class PluginManager {
     }
 
     private static void loadAndScanJar(final File file) throws Throwable {
-        URLClassLoader loader = new URLClassLoader(new URL[]{file.toURI().toURL()}, PluginManager.class.getClassLoader());
+        URL url = file.toURI().toURL();
+        URLClassProvider classProvider = new URLClassProvider(ROOT_CLASS_PROVIDER, url);
+        TransformerManager transformerManager = new TransformerManager(classProvider);
+        InjectionClassLoader loader = new InjectionClassLoader(transformerManager, PluginManager.class.getClassLoader(), url);
         InputStream viaproxyYml = loader.getResourceAsStream("viaproxy.yml");
         if (viaproxyYml == null) throw new IllegalStateException("Plugin '" + file.getName() + "' does not have a viaproxy.yml");
         Map<String, Object> yaml = YAML.load(viaproxyYml);
@@ -72,6 +82,10 @@ public class PluginManager {
         if (!yaml.containsKey("author")) throw new IllegalStateException("Plugin '" + file.getName() + "' does not have a author attribute in the viaproxy.yml");
         if (!yaml.containsKey("version")) throw new IllegalStateException("Plugin '" + file.getName() + "' does not have a version attribute in the viaproxy.yml");
         if (!yaml.containsKey("main")) throw new IllegalStateException("Plugin '" + file.getName() + "' does not have a main attribute in the viaproxy.yml");
+        Semver minVersion = new Semver(yaml.getOrDefault("minVersion", "0.0.0").toString());
+        if (!ViaProxy.VERSION.equals("${version}") && minVersion.isLowerThan(new Semver(ViaProxy.VERSION))) {
+            throw new IllegalStateException("Plugin '" + file.getName() + "' requires a newer version of ViaProxy (v" + minVersion + ")");
+        }
 
         String main = (String) yaml.get("main");
 
@@ -83,6 +97,7 @@ public class PluginManager {
         ViaProxyPlugin plugin = (ViaProxyPlugin) instance;
         PLUGINS.add(plugin);
 
+        plugin.registerTransformers(transformerManager, classProvider);
         plugin.onEnable();
         Logger.LOGGER.info("Successfully loaded plugin '" + yaml.get("name") + "' by " + yaml.get("author") + " (v" + yaml.get("version") + ")");
     }

src/main/java/net/raphimc/viaproxy/plugins/ViaProxyPlugin.java

@@ -17,8 +17,14 @@
  */
 package net.raphimc.viaproxy.plugins;
 
+import net.lenni0451.classtransform.TransformerManager;
+import net.lenni0451.classtransform.utils.tree.IClassProvider;
+
 public abstract class ViaProxyPlugin {
 
     public abstract void onEnable();
 
+    public void registerTransformers(final TransformerManager transformerManager, final IClassProvider classProvider) {
+    }
+
 }

src/main/java/net/raphimc/viaproxy/util/URLClassProvider.java

@@ -0,0 +1,57 @@
+/*
+ * This file is part of ViaProxy - https://github.com/RaphiMC/ViaProxy
+ * Copyright (C) 2023 RK_01/RaphiMC and contributors
+ *
+ * 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, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package net.raphimc.viaproxy.util;
+
+import net.lenni0451.classtransform.utils.ASMUtils;
+import net.lenni0451.classtransform.utils.tree.IClassProvider;
+import org.apache.commons.io.IOUtils;
+
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Supplier;
+
+public class URLClassProvider implements IClassProvider {
+
+    private final IClassProvider parent;
+    private final List<URL> urls;
+
+    public URLClassProvider(final IClassProvider parent, final URL... urls) {
+        this.parent = parent;
+        this.urls = Arrays.asList(urls);
+    }
+
+    @Override
+    public byte[] getClass(String name) {
+        for (URL url : this.urls) {
+            try (InputStream is = new URL("jar:" + url + "!/" + ASMUtils.slash(name) + ".class").openStream()) {
+                IOUtils.toByteArray(is);
+            } catch (Throwable ignored) {
+            }
+        }
+        return this.parent.getClass(name);
+    }
+
+    @Override
+    public Map<String, Supplier<byte[]>> getAllClasses() {
+        return this.parent.getAllClasses();
+    }
+
+}