1 files changed, 131 insertions, 0 deletions
diff --git a/patches/api/0079-PreCreatureSpawnEvent.patch b/patches/api/0079-PreCreatureSpawnEvent.patch
new file mode 100644
index 0000000000..60f65dc98d
--- /dev/null
+++ b/patches/api/0079-PreCreatureSpawnEvent.patch
@@ -0,0 +1,131 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <[email protected]>
+Date: Sun, 14 Jan 2018 16:59:43 -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/com/destroystokyo/paper/event/entity/PreCreatureSpawnEvent.java b/src/main/java/com/destroystokyo/paper/event/entity/PreCreatureSpawnEvent.java
+new file mode 100644
+index 0000000000000000000000000000000000000000..633ef4dcc701916f2dbfefbbebd5994f93ffc2a4
+--- /dev/null
++++ b/src/main/java/com/destroystokyo/paper/event/entity/PreCreatureSpawnEvent.java
+@@ -0,0 +1,109 @@
++package com.destroystokyo.paper.event.entity;
++
++import org.bukkit.Location;
++import org.bukkit.entity.EntityType;
++import org.bukkit.event.Cancellable;
++import org.bukkit.event.Event;
++import org.bukkit.event.HandlerList;
++import org.bukkit.event.entity.CreatureSpawnEvent;
++import org.jetbrains.annotations.ApiStatus;
++import org.jetbrains.annotations.NotNull;
++
++/**
++ * WARNING: This event only fires for a limited number of cases, and not for every case that {@link CreatureSpawnEvent} does.
++ * <p>
++ * You should still listen to {@link CreatureSpawnEvent} as a backup, and only use this event as an "enhancement".
++ * The intent of this event is to improve server performance, so it fires even if the spawning might fail later, for
++ * example when the entity would be unable to spawn due to limited space or lighting.
++ * <p>
++ * Currently: NATURAL and SPAWNER based reasons. <!-- Please submit a Pull Request for future additions. -->
++ * Also, Plugins that replace Entity Registrations with their own custom entities might not fire this event.
++ */
++public class PreCreatureSpawnEvent extends Event implements Cancellable {
++
++    private static final HandlerList HANDLER_LIST = new HandlerList();
++
++    @NotNull private final Location location;
++    @NotNull private final EntityType type;
++    @NotNull private final CreatureSpawnEvent.SpawnReason reason;
++    private boolean shouldAbortSpawn;
++
++    private boolean cancelled;
++
++    @ApiStatus.Internal
++    public PreCreatureSpawnEvent(@NotNull Location location, @NotNull EntityType type, @NotNull CreatureSpawnEvent.SpawnReason reason) {
++        this.location = location;
++        this.type = type;
++        this.reason = reason;
++    }
++
++    /**
++     * @return The location this creature is being spawned at
++     */
++    @NotNull
++    public Location getSpawnLocation() {
++        return this.location.clone();
++    }
++
++    /**
++     * @return The type of creature being spawned
++     */
++    @NotNull
++    public EntityType getType() {
++        return this.type;
++    }
++
++    /**
++     * @return Reason this creature is spawning (ie, NATURAL vs SPAWNER)
++     */
++    @NotNull
++    public CreatureSpawnEvent.SpawnReason getReason() {
++        return this.reason;
++    }
++
++    /**
++     * @return If the spawn process should be aborted vs trying more attempts
++     */
++    public boolean shouldAbortSpawn() {
++        return this.shouldAbortSpawn;
++    }
++
++    /**
++     * Set this if you are more blanket blocking all types of these spawns, and wish to abort the spawn process from
++     * trying more attempts after this cancellation.
++     *
++     * @param shouldAbortSpawn Set if the spawn process should be aborted vs trying more attempts
++     */
++    public void setShouldAbortSpawn(boolean shouldAbortSpawn) {
++        this.shouldAbortSpawn = shouldAbortSpawn;
++    }
++
++    /**
++     * @return If the spawn of this creature is cancelled or not
++     */
++    @Override
++    public boolean isCancelled() {
++        return this.cancelled;
++    }
++
++    /**
++     * Cancelling this event is more efficient than cancelling {@link CreatureSpawnEvent}
++     *
++     * @param cancel {@code true} if you wish to cancel this event, and abort the spawn of this creature
++     */
++    @Override
++    public void setCancelled(boolean cancel) {
++        this.cancelled = cancel;
++    }
++
++    @NotNull
++    @Override
++    public HandlerList getHandlers() {
++        return HANDLER_LIST;
++    }
++
++    @NotNull
++    public static HandlerList getHandlerList() {
++        return HANDLER_LIST;
++    }
++}