Paper/Spigot-Server-Patches/0186-PreCreatureSpawnEvent.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 14 Jan 2018 17:01:31 -0500
Subject: [PATCH] PreCreatureSpawnEvent

Adds an event to fire before an Entity is created, so that plugins that need to cancel
CreatureSpawnEvent can do so from this event instead.

Cancelling CreatureSpawnEvent rapidly causes a lot of garbage collection and CPU waste
as it's done after the Entity object has been fully created.

Mob Limiting plugins and blanket "ban this type of monster" plugins should use this event
instead and save a lot of server resources.

See: https://github.com/PaperMC/Paper/issues/917

diff --git a/src/main/java/net/minecraft/server/EntityTypes.java b/src/main/java/net/minecraft/server/EntityTypes.java
index b1fe488e41a2c9f77df091e1d14ed5c87a4358c8..14f47d100c3f44a8263c9b907e9ca74944676687 100644
--- a/src/main/java/net/minecraft/server/EntityTypes.java
+++ b/src/main/java/net/minecraft/server/EntityTypes.java
@@ -187,6 +187,20 @@ public class EntityTypes<T extends Entity> {
 
     @Nullable
     public T spawnCreature(WorldServer worldserver, @Nullable NBTTagCompound nbttagcompound, @Nullable IChatBaseComponent ichatbasecomponent, @Nullable EntityHuman entityhuman, BlockPosition blockposition, EnumMobSpawn enummobspawn, boolean flag, boolean flag1, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason spawnReason) {
+        // Paper start - Call PreCreatureSpawnEvent
+        org.bukkit.entity.EntityType type = org.bukkit.entity.EntityType.fromName(EntityTypes.getName(this).getKey());
+        if (type != null) {
+            com.destroystokyo.paper.event.entity.PreCreatureSpawnEvent event;
+            event = new com.destroystokyo.paper.event.entity.PreCreatureSpawnEvent(
+                MCUtil.toLocation(worldserver, blockposition),
+                type,
+                spawnReason
+            );
+            if (!event.callEvent()) {
+                return null;
+            }
+        }
+        // Paper end
         T t0 = this.createCreature(worldserver, nbttagcompound, ichatbasecomponent, entityhuman, blockposition, enummobspawn, flag, flag1);
 
         if (t0 != null) {
diff --git a/src/main/java/net/minecraft/server/EntityVillager.java b/src/main/java/net/minecraft/server/EntityVillager.java
index 732323ee1de01929c73bc5f98444c0f68f908a67..b6ad33b3bfc1a71d3e4495c803cba12ee3c2a971 100644
--- a/src/main/java/net/minecraft/server/EntityVillager.java
+++ b/src/main/java/net/minecraft/server/EntityVillager.java
@@ -868,6 +868,21 @@ public class EntityVillager extends EntityVillagerAbstract implements Reputation
             BlockPosition blockposition1 = this.a(blockposition, d0, d1);
 
             if (blockposition1 != null) {
+                // Paper start - Call PreCreatureSpawnEvent
+                com.destroystokyo.paper.event.entity.PreCreatureSpawnEvent event;
+                event = new com.destroystokyo.paper.event.entity.PreCreatureSpawnEvent(
+                    MCUtil.toLocation(world, blockposition1),
+                    org.bukkit.entity.EntityType.IRON_GOLEM,
+                    org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.VILLAGE_DEFENSE
+                );
+                if (!event.callEvent()) {
+                    if (event.shouldAbortSpawn()) {
+                        SensorGolemLastSeen.b(this); // Set Golem Last Seen to stop it from spawning another one
+                        return null;
+                    }
+                    break;
+                }
+                // Paper end
                 EntityIronGolem entityirongolem = (EntityIronGolem) EntityTypes.IRON_GOLEM.createCreature(worldserver, (NBTTagCompound) null, (IChatBaseComponent) null, (EntityHuman) null, blockposition1, EnumMobSpawn.MOB_SUMMONED, false, false);
 
                 if (entityirongolem != null) {
diff --git a/src/main/java/net/minecraft/server/MobSpawnerAbstract.java b/src/main/java/net/minecraft/server/MobSpawnerAbstract.java
index 34ab03fce7ab5c7702234590ffc9ca7fec72a86a..2827026ba4bdd857f231028393726d6c95610072 100644
--- a/src/main/java/net/minecraft/server/MobSpawnerAbstract.java
+++ b/src/main/java/net/minecraft/server/MobSpawnerAbstract.java
@@ -108,6 +108,27 @@ public abstract class MobSpawnerAbstract {
                         WorldServer worldserver = (WorldServer) world;
 
                         if (EntityPositionTypes.a((EntityTypes) optional.get(), worldserver, EnumMobSpawn.SPAWNER, new BlockPosition(d3, d4, d5), world.getRandom())) {
+                            // Paper start
+                            EntityTypes<?> entityType = optional.get();
+                            String key = EntityTypes.getName(entityType).getKey();
+
+                            org.bukkit.entity.EntityType type = org.bukkit.entity.EntityType.fromName(key);
+                            if (type != null) {
+                                com.destroystokyo.paper.event.entity.PreCreatureSpawnEvent event;
+                                event = new com.destroystokyo.paper.event.entity.PreCreatureSpawnEvent(
+                                    MCUtil.toLocation(world, d3, d4, d5),
+                                    type,
+                                    org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.SPAWNER
+                                );
+                                if (!event.callEvent()) {
+                                    flag = true;
+                                    if (event.shouldAbortSpawn()) {
+                                        break;
+                                    }
+                                    continue;
+                                }
+                            }
+                            // Paper end
                             Entity entity = EntityTypes.a(nbttagcompound, world, (entity1) -> {
                                 entity1.setPositionRotation(d3, d4, d5, entity1.yaw, entity1.pitch);
                                 return entity1;
diff --git a/src/main/java/net/minecraft/server/SensorGolemLastSeen.java b/src/main/java/net/minecraft/server/SensorGolemLastSeen.java
index 008932fafece5a62541b94444d56ab717c4d103f..f8727f7b3f146ae023c64ace4919d150c31a1ac3 100644
--- a/src/main/java/net/minecraft/server/SensorGolemLastSeen.java
+++ b/src/main/java/net/minecraft/server/SensorGolemLastSeen.java
@@ -29,7 +29,7 @@ public class SensorGolemLastSeen extends Sensor<EntityLiving> {
         Optional<List<EntityLiving>> optional = entityliving.getBehaviorController().getMemory(MemoryModuleType.MOBS);
 
         if (optional.isPresent()) {
-            boolean flag = ((List) optional.get()).stream().anyMatch((entityliving1) -> {
+            boolean flag = optional.get().stream().anyMatch((entityliving1) -> { // Paper - decompile fixes
                 return entityliving1.getEntityType().equals(EntityTypes.IRON_GOLEM);
             });
 
@@ -40,6 +40,7 @@ public class SensorGolemLastSeen extends Sensor<EntityLiving> {
         }
     }
 
+    public static void setDetectedRecently(EntityLiving entityLiving) { b(entityLiving); } // Paper - OBFHELPER
     public static void b(EntityLiving entityliving) {
         entityliving.getBehaviorController().a(MemoryModuleType.GOLEM_DETECTED_RECENTLY, true, 600L);
     }
diff --git a/src/main/java/net/minecraft/server/SpawnerCreature.java b/src/main/java/net/minecraft/server/SpawnerCreature.java
index 137ee1b453b80e96c1a8fa3271f6350f9294cafb..0ecdfd45073235b7b01e84f4490f17088c4ee675 100644
--- a/src/main/java/net/minecraft/server/SpawnerCreature.java
+++ b/src/main/java/net/minecraft/server/SpawnerCreature.java
@@ -184,9 +184,16 @@ public final class SpawnerCreature {
                                         j1 = biomesettingsmobs_c.d + worldserver.random.nextInt(1 + biomesettingsmobs_c.e - biomesettingsmobs_c.d);
                                     }
 
-                                    if (a(worldserver, enumcreaturetype, structuremanager, chunkgenerator, biomesettingsmobs_c, blockposition_mutableblockposition, d2) && spawnercreature_c.test(biomesettingsmobs_c.c, blockposition_mutableblockposition, ichunkaccess)) {
+                                    // Paper start
+                                    Boolean doSpawning = a(worldserver, enumcreaturetype, structuremanager, chunkgenerator, biomesettingsmobs_c, blockposition_mutableblockposition, d2);
+                                    if (doSpawning == null) {
+                                        return;
+                                    }
+                                    if (doSpawning && spawnercreature_c.test(biomesettingsmobs_c.c, blockposition_mutableblockposition, ichunkaccess)) {
+                                        // Paper end
                                         EntityInsentient entityinsentient = a(worldserver, biomesettingsmobs_c.c);
 
+
                                         if (entityinsentient == null) {
                                             return;
                                         }
@@ -239,8 +246,24 @@ public final class SpawnerCreature {
         }
     }
 
-    private static boolean a(WorldServer worldserver, EnumCreatureType enumcreaturetype, StructureManager structuremanager, ChunkGenerator chunkgenerator, BiomeSettingsMobs.c biomesettingsmobs_c, BlockPosition.MutableBlockPosition blockposition_mutableblockposition, double d0) {
+    private static Boolean a(WorldServer worldserver, EnumCreatureType enumcreaturetype, StructureManager structuremanager, ChunkGenerator chunkgenerator, BiomeSettingsMobs.c biomesettingsmobs_c, BlockPosition.MutableBlockPosition blockposition_mutableblockposition, double d0) { // Paper
         EntityTypes<?> entitytypes = biomesettingsmobs_c.c;
+        // Paper start
+        com.destroystokyo.paper.event.entity.PreCreatureSpawnEvent event;
+        org.bukkit.entity.EntityType type = org.bukkit.entity.EntityType.fromName(EntityTypes.getName(entitytypes).getKey());
+        if (type != null) {
+            event = new com.destroystokyo.paper.event.entity.PreCreatureSpawnEvent(
+                MCUtil.toLocation(worldserver, blockposition_mutableblockposition),
+                type, SpawnReason.NATURAL
+            );
+            if (!event.callEvent()) {
+                if (event.shouldAbortSpawn()) {
+                    return null;
+                }
+                return false;
+            }
+        }
+        // Paper end
 
         if (entitytypes.e() == EnumCreatureType.MISC) {
             return false;