Add event cancellation watcher

3 files changed, 137 insertions, 0 deletions

diff --git a/src/main/java/moe/nea/kowalski/KowalskiCommand.kt b/src/main/java/moe/nea/kowalski/KowalskiCommand.kt
new file mode 100644
index 0000000..b2a975a
--- /dev/null
+++ b/src/main/java/moe/nea/kowalski/KowalskiCommand.kt
@@ -0,0 +1,61 @@
+package moe.nea.kowalski
+
+import net.minecraft.client.Minecraft
+import net.minecraft.command.CommandBase
+import net.minecraft.command.ICommandSender
+import net.minecraft.util.BlockPos
+import net.minecraft.util.ChatComponentText
+
+object KowalskiCommand : CommandBase() {
+    override fun getCommandName(): String {
+        return "kowalski"
+    }
+
+    override fun canCommandSenderUseCommand(sender: ICommandSender?): Boolean {
+        return true
+    }
+
+    override fun getCommandUsage(sender: ICommandSender?): String {
+        return ""
+    }
+
+
+    override fun addTabCompletionOptions(
+        sender: ICommandSender?,
+        args: Array<out String>,
+        pos: BlockPos?
+    ): List<String> {
+        return when (args.size) {
+            1 -> getListOfStringsMatchingLastWord(args, "whocancels")
+            2 -> when (args[0]) {
+                "whocancels" -> getListOfStringsMatchingLastWord(args, "ClientChatReceivedEvent")
+                else -> emptyList()
+            }
+            else -> emptyList()
+        }
+    }
+
+    fun chat(text: String) {
+        Minecraft.getMinecraft().ingameGUI.chatGUI.printChatMessage(ChatComponentText("§e[§fKW§e]§r $text"))
+    }
+
+    override fun processCommand(sender: ICommandSender, args: Array<out String>) {
+        when (args.firstOrNull()) {
+            "whocancels" -> {
+                if (args.size != 2) {
+                    chat("§cPlease provide an event to listen to: §bwhocancels <eventname>")
+                    return
+                }
+                val eventName = args[1]
+                if (eventName in Kowalski.watchedEvents) {
+                    Kowalski.watchedEvents.remove(eventName)
+                    chat("§fRemoved §c$eventName §ffrom watched events")
+                } else {
+                    Kowalski.watchedEvents.add(eventName)
+                    chat("§fAdded §b$eventName §fto watched events")
+                }
+            }
+        }
+    }
+
+}
diff --git a/src/main/java/moe/nea/kowalski/init/EventClassTransformer.java b/src/main/java/moe/nea/kowalski/init/EventClassTransformer.java
new file mode 100644
index 0000000..a80a5b5
--- /dev/null
+++ b/src/main/java/moe/nea/kowalski/init/EventClassTransformer.java
@@ -0,0 +1,47 @@
+package moe.nea.kowalski.init;
+
+import net.minecraft.launchwrapper.IClassTransformer;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.*;
+
+import java.util.ListIterator;
+
+public class EventClassTransformer implements IClassTransformer {
+    @Override
+    public byte[] transform(String name, String transformedName, byte[] basicClass) {
+        if (!"net.minecraftforge.fml.common.eventhandler.Event".equals(name))
+            return basicClass;
+        ClassNode classNode = new ClassNode();
+        ClassReader classReader = new ClassReader(basicClass);
+        classReader.accept(classNode, 0);
+        for (MethodNode method : classNode.methods) {
+            if (method.name.equals("setCanceled")) {
+                transformCancelMethod(method);
+            }
+        }
+        ClassWriter writer = new ClassWriter(0);
+        classNode.accept(writer);
+        return writer.toByteArray();
+    }
+
+    private void transformCancelMethod(MethodNode method) {
+        ListIterator<AbstractInsnNode> iterator =
+                method.instructions.iterator();
+        while (iterator.hasNext()) {
+            AbstractInsnNode insn = iterator.next();
+            if (insn.getOpcode() != Opcodes.PUTFIELD) {
+                continue;
+            }
+            method.instructions.insert(insn, buildCallKowalski());
+        }
+    }
+
+    private InsnList buildCallKowalski() {
+        InsnList insnList = new InsnList();
+        insnList.add(new VarInsnNode(Opcodes.ALOAD, 0));
+        insnList.add(new MethodInsnNode(Opcodes.INVOKESTATIC, "moe/nea/kowalski/Kowalski", "eventIsBeingCancelled", "(Lnet/minecraftforge/fml/common/eventhandler/Event;)V", false));
+        return insnList;
+    }
+}
diff --git a/src/main/java/moe/nea/kowalski/init/KowalskiTweaker.java b/src/main/java/moe/nea/kowalski/init/KowalskiTweaker.java
new file mode 100644
index 0000000..4cb836c
--- /dev/null
+++ b/src/main/java/moe/nea/kowalski/init/KowalskiTweaker.java
@@ -0,0 +1,29 @@
+package moe.nea.kowalski.init;
+
+import net.minecraft.launchwrapper.ITweaker;
+import net.minecraft.launchwrapper.LaunchClassLoader;
+
+import java.io.File;
+import java.util.List;
+
+public class KowalskiTweaker implements ITweaker {
+    @Override
+    public void acceptOptions(List<String> args, File gameDir, File assetsDir, String profile) {
+
+    }
+
+    @Override
+    public void injectIntoClassLoader(LaunchClassLoader classLoader) {
+classLoader.registerTransformer("moe.nea.kowalski.init.EventClassTransformer");
+    }
+
+    @Override
+    public String getLaunchTarget() {
+        return null;
+    }
+
+    @Override
+    public String[] getLaunchArguments() {
+        return new String[0];
+    }
+}