Cache entity max tracking distance

lithium-mixin-config.md

@@ -254,6 +254,10 @@ Uses custom hashset/list combination for faster mob spawn checks
 (default: `true`)  
 Various entity optimizations  
 
+### `mixin.entity.cache_max_track_distance`
+(default: `true`)  
+Caches the max tracking distance of entities with their passengers  
+
 ### `mixin.entity.collisions`
 (default: `true`)  
 Various entity collision optimizations  

src/main/java/me/jellysquid/mods/lithium/common/entity/PassengerCachingEntity.java

@@ -0,0 +1,11 @@
+package me.jellysquid.mods.lithium.common.entity;
+
+public interface PassengerCachingEntity {
+
+    boolean lithium$isPassengerListDirty();
+
+    void lithium$setPassengerListDirty(boolean dirty);
+
+    void lithium$setPassengerListDirtyRecursive(boolean dirty);
+
+}

src/main/java/me/jellysquid/mods/lithium/mixin/entity/cache_max_track_distance/EntityMixin.java

@@ -0,0 +1,43 @@
+package me.jellysquid.mods.lithium.mixin.entity.cache_max_track_distance;
+
+import me.jellysquid.mods.lithium.common.entity.PassengerCachingEntity;
+import net.minecraft.entity.Entity;
+import org.jetbrains.annotations.Nullable;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(Entity.class)
+public abstract class EntityMixin implements PassengerCachingEntity {
+    @Shadow
+    private @Nullable Entity vehicle;
+    @Unique
+    private boolean isPassengerListDirty = true;
+
+    @Override
+    public boolean lithium$isPassengerListDirty() {
+        return this.isPassengerListDirty;
+    }
+
+    @Override
+    public void lithium$setPassengerListDirty(boolean dirty) {
+        this.isPassengerListDirty = dirty;
+    }
+
+    @Override
+    public void lithium$setPassengerListDirtyRecursive(boolean dirty) {
+        this.isPassengerListDirty = true;
+        if (this.vehicle != null) {
+            ((PassengerCachingEntity) this.vehicle).lithium$setPassengerListDirtyRecursive(dirty);
+        }
+    }
+
+    @Inject(method = {"addPassenger", "removePassenger"}, at = @At("TAIL"))
+    private void lithium$markPassengerListDirty(Entity passenger, CallbackInfo ci) {
+        lithium$setPassengerListDirtyRecursive(true);
+    }
+
+}

src/main/java/me/jellysquid/mods/lithium/mixin/entity/cache_max_track_distance/ServerChunkLoadingManager$EntityTrackerMixin.java

@@ -0,0 +1,38 @@
+package me.jellysquid.mods.lithium.mixin.entity.cache_max_track_distance;
+
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+import me.jellysquid.mods.lithium.common.entity.PassengerCachingEntity;
+import net.minecraft.entity.Entity;
+import net.minecraft.server.world.ServerChunkLoadingManager;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+
+@Mixin(ServerChunkLoadingManager.EntityTracker.class)
+public abstract class ServerChunkLoadingManager$EntityTrackerMixin {
+
+    @Shadow
+    @Final
+    public Entity entity;
+
+    @Unique
+    private int cachedMaxTrackingDistance;
+
+    @WrapOperation(method = "updateTrackedStatus(Lnet/minecraft/server/network/ServerPlayerEntity;)V",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/server/world/ServerChunkLoadingManager$EntityTracker;getMaxTrackDistance()I"
+            )
+    )
+    private int cacheMaxTrackDistance(ServerChunkLoadingManager.EntityTracker instance, Operation<Integer> original) {
+        if (((PassengerCachingEntity) this.entity).lithium$isPassengerListDirty()) {
+            this.cachedMaxTrackingDistance = original.call(instance);
+            ((PassengerCachingEntity) this.entity).lithium$setPassengerListDirty(false);
+        }
+        return this.cachedMaxTrackingDistance;
+    }
+
+}

src/main/java/me/jellysquid/mods/lithium/mixin/entity/cache_max_track_distance/package-info.java

@@ -0,0 +1,4 @@
+@MixinConfigOption(description = "Caches the max tracking distance of entities with their passengers")
+package me.jellysquid.mods.lithium.mixin.entity.cache_max_track_distance;
+
+import net.caffeinemc.gradle.MixinConfigOption;

src/main/resources/lithium.mixins.json

@@ -102,6 +102,8 @@
     "collections.goals.GoalSelectorMixin",
     "collections.mob_spawning.PoolMixin",
     "collections.mob_spawning.SpawnSettingsMixin",
+    "entity.cache_max_track_distance.EntityMixin",
+    "entity.cache_max_track_distance.ServerChunkLoadingManager$EntityTrackerMixin",
     "entity.collisions.fluid.EntityMixin",
     "entity.collisions.intersection.EntityViewMixin",
     "entity.collisions.intersection.WorldMixin",