TimeUnitTickedTriggerMod

ActionTime.java

package com.joedobo27.tuttm;

import com.wurmonline.server.behaviours.Action;

import java.util.WeakHashMap;

@SuppressWarnings("unused")
public class ActionTime {

    private int lastWholeUnitTime;
    private final int incrementTriggerMilliseconds;

    private static WeakHashMap<Action, ActionTime> performers = new WeakHashMap<>();

    private ActionTime(Action action, int incrementTriggerMilliseconds){
        this.incrementTriggerMilliseconds = incrementTriggerMilliseconds;
        performers.put(action, this);
    }

    public static ActionTime getActionTime(Action action, int incrementTriggerMilliseconds) {
        if (!performers.containsKey(action))
            return new ActionTime(action, incrementTriggerMilliseconds);
        return performers.get(action);
    }

    public boolean unitTimeJustTicked(float counterSeconds){
        final int SECONDS_TO_MILLISECONDS = 100;
        int unitTime = (int)(Math.floor((counterSeconds * SECONDS_TO_MILLISECONDS) / (this.incrementTriggerMilliseconds)));
        if (unitTime != this.lastWholeUnitTime){
            synchronized (this) {
                this.lastWholeUnitTime = unitTime;
            }
            return true;
        }
        return false;
    }
}

TimeUnitTickedTriggerMod.java

package com.joedobo27.tuttm;

import javassist.*;
import javassist.bytecode.*;
import javassist.expr.ExprEditor;
import javassist.expr.MethodCall;
import org.gotti.wurmunlimited.modloader.classhooks.HookManager;
import org.gotti.wurmunlimited.modloader.interfaces.Initable;
import org.gotti.wurmunlimited.modloader.interfaces.WurmServerMod;

import java.nio.ByteBuffer;
import java.util.Objects;
import java.util.logging.Logger;
import java.util.stream.IntStream;

public class TimeUnitTickedTriggerMod implements WurmServerMod, Initable {

    private static final Logger logger = Logger.getLogger(TimeUnitTickedTriggerMod.class.getName());

    @Override
    public void init() {
        modifyItemBehaviourAction();
    }

    private void modifyItemBehaviourAction(){
        /*
          5226: aload_1
          5227: invokevirtual #676                // Method com/wurmonline/server/behaviours/Action.justTickedSecond:()Z
          5230: ifeq          5246
          5233: aload_3
          5234: aload_2
          5235: iload         9
          5237: i2s
          5238: aload_1
          5239: invokevirtual #677                // Method com/wurmonline/server/behaviours/Action.getPower:()F
          5242: invokevirtual #678                // Method com/wurmonline/server/items/Item.repair:(Lcom/wurmonline/server/creatures/Creature;SF)D
         */
        try {
            ClassPool classPool = HookManager.getInstance().getClassPool();
            CtClass ctClassItemBehaviour = classPool.get("com.wurmonline.server.behaviours.ItemBehaviour");
            ctClassItemBehaviour.getClassFile().compact();
            Bytecode find = new Bytecode(ctClassItemBehaviour.getClassFile().getConstPool());
            find.addAload(1);
            find.addInvokevirtual("com/wurmonline/server/behaviours/Action", "justTickedSecond", "()Z");
            codeBranching(find, Opcode.IFEQ, 16);
            find.addAload(3);
            find.addAload(2);
            find.addIload(9);
            find.addOpcode(Opcode.I2S);
            find.addAload(1);
            find.addInvokevirtual("com/wurmonline/server/behaviours/Action", "getPower", "()F");
            find.addInvokevirtual("com/wurmonline/server/items/Item", "repair", "(Lcom/wurmonline/server/creatures/Creature;SF)D");

            CtMethod ctMethodAction = ctClassItemBehaviour.getMethod("action",
                    Descriptor.ofMethod(CtPrimitiveType.booleanType, new CtClass[]{
                            classPool.get("com.wurmonline.server.behaviours.Action"),
                            classPool.get("com.wurmonline.server.creatures.Creature"),
                            classPool.get("com.wurmonline.server.items.Item"),
                            CtPrimitiveType.shortType, CtPrimitiveType.floatType
                    }));

            int tableLineNumber = byteArrayToLineNumber(find.get(), ctMethodAction, 19);
            ctMethodAction.instrument(new ExprEditor() {
                @Override public void edit(MethodCall methodCall) throws CannotCompileException {
                    if (Objects.equals("justTickedSecond", methodCall.getMethodName()) &&
                            methodCall.getLineNumber() == tableLineNumber) {
                        methodCall.replace("{" +
                                "com.joedobo27.tuttm.ActionTime actionTime = " +
                                "com.joedobo27.tuttm.ActionTime#getActionTime(act, 100);" +
                                "if (actionTime.unitTimeJustTicked(counter))" +
                                "   $_ = true;" +
                                "else" +
                                "   $_ = false;" +
                                "}");
                    }
                }
            });
        }catch (NotFoundException | BadBytecode | CannotCompileException e){
            logger.warning(e.getMessage());
        }

    }

    @SuppressWarnings("SameParameterValue")
    private int byteArrayToLineNumber(byte[] bytesSeek, CtMethod ctMethod, int byteArraySize)
            throws BadBytecode, RuntimeException {

        // Using bytesSeek iterate through the ctMethod's bytecode looking for a matching byte array sized to byteArraySize
        int bytecodeIndex = -1;
        CodeIterator codeIterator = ctMethod.getMethodInfo().getCodeAttribute().iterator();
        codeIterator.begin();
        long find = byteArrayToLong(bytesSeek);
        while (codeIterator.hasNext() && codeIterator.lookAhead() + byteArraySize < codeIterator.getCodeLength()) {
            int index = codeIterator.next();
            byte[] bytesFound = new byte[byteArraySize];
            for(int i=0;i<byteArraySize;i++){
                bytesFound[i] = (byte)codeIterator.byteAt(index + i);
            }
            long found = byteArrayToLong(bytesFound);
            if (found == find) {
                bytecodeIndex = index;
            }
        }
        if (bytecodeIndex == -1)
            throw new RuntimeException("no bytecode match found.");
        // Get the line number table entry for the bytecodeIndex.
        LineNumberAttribute lineNumberAttribute = (LineNumberAttribute) ctMethod.getMethodInfo().getCodeAttribute()
                .getAttribute(LineNumberAttribute.tag);
        int lineNumber = lineNumberAttribute.toLineNumber(bytecodeIndex);
        int lineNumberTableOrdinal =  IntStream.range(0, lineNumberAttribute.tableLength())
                .filter(value -> Objects.equals(lineNumberAttribute.lineNumber(value), lineNumber))
                .findFirst()
                .orElseThrow(RuntimeException::new);
        return lineNumberAttribute.lineNumber(lineNumberTableOrdinal);
    }

    private static long byteArrayToLong(byte[] bytesOriginal) {
        if (bytesOriginal.length < 8) {
            byte[] bytesLongPadded = new byte[8];
            System.arraycopy(bytesOriginal, 0, bytesLongPadded, 8 - bytesOriginal.length,
                    bytesOriginal.length);
            return ByteBuffer.wrap(bytesLongPadded).getLong();
        }
        else
            return ByteBuffer.wrap(bytesOriginal).getLong();
    }

    @SuppressWarnings("SameParameterValue")
    private static void codeBranching(Bytecode bytecode, int opcode, int branchCount){
        bytecode.addOpcode(opcode);
        bytecode.add((branchCount >>> 8) & 0xFF, branchCount & 0xFF);
    }
}