Fix infinite loop in mc.scheduledTasks (fixes #86)

src/main/java/com/replaymod/core/ReplayMod.java

@@ -26,6 +26,9 @@ import net.minecraftforge.fml.common.ModContainer;
 import net.minecraftforge.fml.common.event.FMLInitializationEvent;
 import net.minecraftforge.fml.common.event.FMLPostInitializationEvent;
 import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
+import net.minecraftforge.fml.common.eventhandler.EventBus;
+import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
+import net.minecraftforge.fml.common.gameevent.TickEvent;
 import org.apache.commons.io.FileUtils;
 
 import java.io.File;
@@ -306,11 +309,38 @@ public class ReplayMod {
         });
     }
 
+    /**
+     * Set when the currently running code has been scheduled by runLater.
+     * If this is the case, subsequent calls to runLater have to be delayed until all scheduled tasks have been
+     * processed, otherwise a livelock may occur.
+     */
+    private boolean inRunLater = false;
+
     public void runLater(Runnable runnable) {
+        if (mc.isCallingFromMinecraftThread() && inRunLater) {
+            EventBus bus = FMLCommonHandler.instance().bus();
+            bus.register(new Object() {
+                @SubscribeEvent
+                public void onRenderTick(TickEvent.RenderTickEvent event) {
+                    if (event.phase == TickEvent.Phase.START) {
+                        runLater(runnable);
+                        bus.unregister(this);
+                    }
+                }
+            });
+            return;
+        }
         @SuppressWarnings("unchecked")
         Queue<ListenableFutureTask> tasks = mc.scheduledTasks;
         synchronized (mc.scheduledTasks) {
-            tasks.add(ListenableFutureTask.create(runnable, null));
+            tasks.add(ListenableFutureTask.create(() -> {
+                inRunLater = true;
+                try {
+                    runnable.run();
+                } finally {
+                    inRunLater = false;
+                }
+            }, null));
         }
     }
 

src/main/java/com/replaymod/replay/ReplaySender.java

@@ -2,7 +2,7 @@ package com.replaymod.replay;
 
 import com.google.common.base.Preconditions;
 import com.google.common.io.Files;
-import com.google.common.util.concurrent.ListenableFutureTask;
+import com.replaymod.core.ReplayMod;
 import com.replaymod.core.utils.Restrictions;
 import com.replaymod.replay.camera.CameraEntity;
 import com.replaymod.replaystudio.replay.ReplayFile;
@@ -30,7 +30,6 @@ import java.io.*;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.Callable;
 
 /**
  * Sends replay packets to netty channels.
@@ -440,22 +439,19 @@ public class ReplaySender extends ChannelInboundHandlerAdapter {
                 }
             }
 
-            new Callable<Void>() {
+            new Runnable() {
                 @Override
                 @SuppressWarnings("unchecked")
-                public Void call() {
+                public void run() {
                     if (mc.theWorld == null || !mc.isCallingFromMinecraftThread()) {
-                        synchronized(mc.scheduledTasks) {
+                        ReplayMod.instance.runLater(this);
-                            mc.scheduledTasks.add(ListenableFutureTask.create(this));
+                        return;
-                        }
-                        return null;
                     }
 
                     CameraEntity cent = replayHandler.getCameraEntity();
                     cent.setCameraPosition(ppl.func_148932_c(), ppl.func_148928_d(), ppl.func_148933_e());
-                    return null;
                 }
-            }.call();
+            }.run();
         }
 
         if(p instanceof S2BPacketChangeGameState) {