Merge pull request #2 from InitAuther97/master

Add Java17+ support

Author: ShirasawaSama

README.md

@@ -12,8 +12,7 @@ A Spigot mixin development framework.
 java -javaagent:PaperShelled.jar -jar server_core.jar
 ```
 
-Then you can put your plugins in the `PaperShelled/plugins` directory!
-
+4. Then you can put your plugins in the `PaperShelled/plugins` directory and enjoy it!
 ## For plugin developers
 
 See also: https://github.com/Apisium/PaperShelledPluginTemplate

build.gradle

@@ -43,6 +43,7 @@ jar {
         attributes 'Can-Retransform-Classes': 'true'
         attributes 'Agent-Class': 'cn.apisium.papershelled.PaperShelledAgent'
         attributes 'Premain-Class': 'cn.apisium.papershelled.PaperShelledAgent'
+        attributes 'Main-Class': 'cn.apisium.papershelled.launcher.Launcher'
     }
 }
 

src/main/java/cn/apisium/papershelled/PaperShelledAgent.java

@@ -2,6 +2,7 @@
 
 import cn.apisium.papershelled.services.MixinService;
 import com.google.common.io.ByteStreams;
+import org.checkerframework.checker.units.qual.C;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.*;
@@ -28,7 +29,7 @@
 import java.util.Objects;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
-import java.util.logging.*;
+import java.util.logging.Logger;
 
 public final class PaperShelledAgent {
     private static boolean initialized;
@@ -61,10 +62,12 @@ public String map(String name) {
 
     @Nullable
     public static InputStream getResourceAsStream(String name) { return ClassLoader.getSystemResourceAsStream(name); }
+
     @Nullable
     public static InputStream getClassAsStream(String name) {
         return getResourceAsStream(name.replace('.', '/') + ".class");
     }
+
     public static byte[] getClassAsByteArray(String name) throws IOException {
         try (InputStream is = getClassAsStream(name)) {
             if (is == null) throw new FileNotFoundException("Class not found: " + name);
@@ -76,9 +79,50 @@ private final static class Transformer implements ClassFileTransformer {
         @Override
         public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
                                 ProtectionDomain protectionDomain, byte[] data) {
-            if ("org/bukkit/craftbukkit/Main".equals(className)) {
+            if("io/papermc/paperclip/Paperclip".equals(className)) {
+                ClassReader cr = new ClassReader(data);
+                ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
+                cr.accept(new ClassVisitor(Opcodes.ASM9, cw) {
+                    @Override
+                    public MethodVisitor visitMethod(int access, String name, String descriptor, String signature, String[] exceptions) {
+                        MethodVisitor v = super.visitMethod(access, name, descriptor, signature, exceptions);
+                        return name.equals("main") ? new MethodVisitor(Opcodes.ASM9) {
+                            /**
+                             * What I want is as follows:
+                             * {@code
+                             *
+                             * public static void main(String[] args){
+                             *     cn.apisium.papershelled.launcher.Launcher.launch(args);
+                             * }
+                             *
+                             * }
+                             * And this is the ASM way to make it.
+                             */
+                            @Override
+                            public void visitCode() {
+                                super.visitCode();
+                                Label l0 = new Label();
+                                v.visitLabel(l0);
+                                v.visitLineNumber(0, l0);//Trick JVM
+                                v.visitVarInsn(Opcodes.ALOAD, 0);
+                                v.visitMethodInsn(Opcodes.INVOKESTATIC, "cn/apisium/papershelled/launcher/Launcher", "launch", "([Ljava/lang/String;)V", false);
+                                Label l1 = new Label();
+                                v.visitLabel(l1);
+                                v.visitLineNumber(0, l1);
+                                v.visitInsn(Opcodes.RETURN);
+                                Label l2 = new Label();
+                                v.visitLabel(l2);
+                                v.visitLocalVariable("args", "[Ljava/lang/String;", null, l0, l2, 0);
+                                v.visitMaxs(1, 1);
+                                v.visitEnd();
+                            }
+                        } : v;
+                    }
+                }, ClassReader.EXPAND_FRAMES);
+                return cw.toByteArray();
+            } else if ("org/bukkit/craftbukkit/Main".equals(className)) {
                 data = inject(data, "main", "cn/apisium/papershelled/PaperShelledAgent", "init");
-                URL url = Objects.requireNonNull(ClassLoader.getSystemResource("org/bukkit/craftbukkit/Main.class"));
+                URL url = Objects.requireNonNull(loader.getResource("org/bukkit/craftbukkit/Main.class"));
                 try {
                     serverJar = Paths.get(new URI(url.getFile().split("!", 2)[0]));
                 } catch (URISyntaxException e) {

src/main/java/cn/apisium/papershelled/launcher/Launcher.java

@@ -0,0 +1,44 @@
+package cn.apisium.papershelled.launcher;
+
+import cn.apisium.papershelled.PaperShelledAgent;
+
+import java.lang.reflect.Method;
+import java.net.URL;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.jar.JarFile;
+
+@SuppressWarnings("unused")
+public class Launcher {
+    public static void launch(String[] args) {
+        try {
+            Class<?> clipClz = Launcher.class.getClassLoader().loadClass("io.papermc.paperclip.Paperclip");
+            Method setupClasspath = clipClz.getDeclaredMethod("setupClasspath");
+            setupClasspath.setAccessible(true);
+            Arrays.stream((URL[]) setupClasspath.invoke(null)).map(u -> {
+                try {
+                    return new JarFile(Paths.get(u.toURI()).toFile());
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                }
+            }).forEach(PaperShelledAgent.getInstrumentation()::appendToSystemClassLoaderSearch);
+            Thread server = new Thread(() -> {
+                try {
+                    Method findMainClass = clipClz.getDeclaredMethod("findMainClass");
+                    findMainClass.setAccessible(true);
+                    String name = (String) findMainClass.invoke(null);
+                    Class<?> main = Class.forName(name);
+                    System.out.print("Launching ");
+                    System.out.println(name);
+                    main.getMethod("main", String[].class).invoke(null, (Object)args);
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                }
+            }, "Server Thread");
+            server.setContextClassLoader(Launcher.class.getClassLoader());
+            server.start();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+}