Testing Bdew's title injector, might work better now that EnumExtend seems to be broken

src/main/java/mod/sin/wyvern/mastercraft/TitleInjector.java

@@ -0,0 +1,96 @@
+package mod.sin.wyvern.mastercraft;
+
+import javassist.ClassPool;
+import javassist.*;
+import javassist.bytecode.*;
+
+import java.io.IOException;
+
+public class TitleInjector {
+    private final CtClass titleCls;
+    private final ConstPool constPool;
+    private final CodeIterator codeIterator;
+    private int insertPos = -1;
+    private int lastOrd = -1;
+    private int arraySizePos = -1;
+
+
+    public TitleInjector(ClassPool classPool) throws NotFoundException, BadBytecode {
+        titleCls = classPool.getCtClass("com.wurmonline.server.players.Titles$Title");
+        CtConstructor initializer = titleCls.getClassInitializer();
+        CodeAttribute codeAttr = initializer.getMethodInfo().getCodeAttribute();
+        constPool = codeAttr.getConstPool();
+        codeIterator = codeAttr.iterator();
+
+        BytecodeTools b = new BytecodeTools(constPool);
+
+        // My code needs a bit more stack space than javac-generated one
+        codeAttr.setMaxStack(codeAttr.getMaxStack() + 3);
+
+        while (codeIterator.hasNext()) {
+            int pos = codeIterator.next();
+            int op = codeIterator.byteAt(pos);
+            if (op == Bytecode.AASTORE) {
+                insertPos = codeIterator.next();
+            } else if (op == Bytecode.ANEWARRAY) {
+                arraySizePos = pos - 2;
+            } else if (op == Bytecode.NEW) {
+                pos = codeIterator.next(); // dup
+                pos = codeIterator.next(); // ldc of ident
+                pos = codeIterator.next(); // here's the ordinal
+                lastOrd = BytecodeTools.getInteger(constPool, codeIterator, pos);
+            }
+        }
+
+        if (insertPos == -1) throw new RuntimeException("Failed to find AASTORE");
+        if (lastOrd == -1) throw new RuntimeException("Failed to find ordinals");
+        if (arraySizePos == -1) throw new RuntimeException("Failed to array size position");
+    }
+
+    public void saveDebug() throws IOException, CannotCompileException, NotFoundException {
+        titleCls.writeFile();
+    }
+
+
+    public void addTitle(String ident, int id, String name, String femaleName, int skillId, String type) throws BadBytecode, CannotCompileException {
+        int ordinal = ++lastOrd;
+        Bytecode code = new Bytecode(constPool);
+
+        // When starting the values array is on stack, dup it for later use
+        code.add(Bytecode.DUP);
+
+        // Put out ordinal, will be used by AASTORE
+        BytecodeTools.putInteger(constPool, code, ordinal);
+
+        // Make new instance, and dupe that too
+        code.addNew("com.wurmonline.server.players.Titles$Title");
+        code.add(Bytecode.DUP);
+
+        // Put constructor parameters into stack
+        code.addLdc(ident);
+        BytecodeTools.putInteger(constPool, code, ordinal);
+        BytecodeTools.putInteger(constPool, code, id);
+        code.addLdc(name);
+        code.addLdc(femaleName);
+        BytecodeTools.putInteger(constPool, code, skillId);
+        code.addGetstatic("com.wurmonline.server.players.Titles$TitleType", type, "Lcom/wurmonline/server/players/Titles$TitleType;");
+
+        // Call constructor, this will use one copy of our instance duped above, we need 2 more so dup it again
+        code.addInvokespecial("com.wurmonline.server.players.Titles$Title", "<init>", "(Ljava/lang/String;IILjava/lang/String;Ljava/lang/String;ILcom/wurmonline/server/players/Titles$TitleType;)V");
+        code.add(Bytecode.DUP);
+
+        // Put instance into static field - this will use the second copy of our instance
+        //code.addPutstatic("net.bdew.wurm.halloween.titles.TitlesExtended", ident, "Lcom/wurmonline/server/players/Titles$Title;");
+
+        // And finally stick it into values array, this will use the duped array, ordinal and the final copy of our instance
+        code.add(Bytecode.AASTORE);
+
+        // End of bytecode gen, insert it into the initializer
+        byte[] bytes = code.get();
+        codeIterator.insertAt(insertPos, bytes);
+        insertPos += bytes.length;
+
+        // And increase array size
+        codeIterator.write16bit(codeIterator.u16bitAt(arraySizePos) + 1, arraySizePos);
+    }
+}