Implement Leash API. Adds BUKKIT-4459, BUKKIT-4583

By: T00thpick1 <t00thpick1dirko@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftWorld.java

@@ -4,7 +4,6 @@ import java.io.File;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Random;
 import java.util.Set;
@@ -994,6 +993,9 @@ public class CraftWorld implements World {
                 entity = new EntityPainting(world, (int) x, (int) y, (int) z, dir);
             } else if (ItemFrame.class.isAssignableFrom(clazz)) {
                 entity = new EntityItemFrame(world, (int) x, (int) y, (int) z, dir);
+            } else if (LeashHitch.class.isAssignableFrom(clazz)) {
+                entity = new EntityLeash(world, (int) x, (int) y, (int) z);
+                entity.p = true;
             }
 
             if (entity != null && !((EntityHanging) entity).survives()) {

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java

@@ -147,6 +147,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         } else if (entity instanceof EntityHanging) {
             if (entity instanceof EntityPainting) { return new CraftPainting(server, (EntityPainting) entity); }
             else if (entity instanceof EntityItemFrame) { return new CraftItemFrame(server, (EntityItemFrame) entity); }
+            else if (entity instanceof EntityLeash) { return new CraftLeash(server, (EntityLeash) entity); }
             else { return new CraftHanging(server, (EntityHanging) entity); }
         }
         else if (entity instanceof EntityTNTPrimed) { return new CraftTNTPrimed(server, (EntityTNTPrimed) entity); }

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftLeash.java

@@ -0,0 +1,27 @@
+package org.bukkit.craftbukkit.entity;
+
+import net.minecraft.server.EntityLeash;
+
+import org.bukkit.craftbukkit.CraftServer;
+import org.bukkit.entity.EntityType;
+import org.bukkit.entity.LeashHitch;
+
+public class CraftLeash extends CraftHanging implements LeashHitch {
+    public CraftLeash(CraftServer server, EntityLeash entity) {
+        super(server, entity);
+    }
+
+    @Override
+    public EntityLeash getHandle() {
+        return (EntityLeash) entity;
+    }
+
+    @Override
+    public String toString() {
+        return "CraftLeash";
+    }
+
+    public EntityType getType() {
+        return EntityType.LEASH_HITCH;
+    }
+}

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java

@@ -14,18 +14,17 @@ import net.minecraft.server.EntityEnderPearl;
 import net.minecraft.server.EntityInsentient;
 import net.minecraft.server.EntityLargeFireball;
 import net.minecraft.server.EntityLiving;
-import net.minecraft.server.EntitySmallFireball;
-import net.minecraft.server.EntitySnowball;
 import net.minecraft.server.EntityPlayer;
 import net.minecraft.server.EntityPotion;
+import net.minecraft.server.EntitySmallFireball;
+import net.minecraft.server.EntitySnowball;
+import net.minecraft.server.EntityWither;
 import net.minecraft.server.EntityWitherSkull;
 import net.minecraft.server.GenericAttributes;
 import net.minecraft.server.MobEffect;
 import net.minecraft.server.MobEffectList;
-import net.minecraft.server.Packet42RemoveMobEffect;
 
 import org.apache.commons.lang.Validate;
-
 import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.block.Block;
@@ -35,11 +34,11 @@ import org.bukkit.craftbukkit.inventory.CraftEntityEquipment;
 import org.bukkit.craftbukkit.inventory.CraftItemStack;
 import org.bukkit.entity.Arrow;
 import org.bukkit.entity.Egg;
+import org.bukkit.entity.EnderPearl;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.EntityType;
-import org.bukkit.entity.HumanEntity;
-import org.bukkit.entity.EnderPearl;
 import org.bukkit.entity.Fireball;
+import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.LivingEntity;
 import org.bukkit.entity.Player;
 import org.bukkit.entity.Projectile;
@@ -407,6 +406,46 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
         return getHandle() instanceof EntityInsentient && ((EntityInsentient) getHandle()).getCustomNameVisible();
     }
 
+    public boolean isLeashed() {
+        if (!(getHandle() instanceof EntityInsentient)) {
+            return false;
+        }
+        return ((EntityInsentient) getHandle()).bI() != null;
+    }
+
+    public Entity getLeashHolder() throws IllegalStateException {
+        if (!isLeashed()) {
+            throw new IllegalStateException("Entity not leashed");
+        }
+        return ((EntityInsentient) getHandle()).bI().getBukkitEntity();
+    }
+
+    private boolean unleash() {
+        if (!isLeashed()) {
+            return false;
+        }
+        ((EntityInsentient) getHandle()).a(true, false);
+        return true;
+    }
+
+    public boolean setLeashHolder(Entity holder) {
+        if ((getHandle() instanceof EntityWither) || !(getHandle() instanceof EntityInsentient)) {
+            return false;
+        }
+
+        if (holder == null) {
+            return unleash();
+        }
+
+        if (holder.isDead()) {
+            return false;
+        }
+
+        unleash();
+        ((EntityInsentient) getHandle()).b(((CraftEntity) holder).getHandle(), true);
+        return true;
+    }
+
     @Deprecated
     public int _INVALID_getLastDamage() {
         return NumberConversions.ceil(getLastDamage());

paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -30,8 +30,8 @@ import net.minecraft.server.World;
 import net.minecraft.server.WorldServer;
 
 import org.bukkit.Bukkit;
-import org.bukkit.Server;
 import org.bukkit.Material;
+import org.bukkit.Server;
 import org.bukkit.block.Block;
 import org.bukkit.block.BlockFace;
 import org.bukkit.block.BlockState;
@@ -44,10 +44,8 @@ import org.bukkit.craftbukkit.entity.CraftPlayer;
 import org.bukkit.craftbukkit.inventory.CraftInventoryCrafting;
 import org.bukkit.craftbukkit.inventory.CraftItemStack;
 import org.bukkit.craftbukkit.util.CraftDamageSource;
-import org.bukkit.entity.AnimalTamer;
 import org.bukkit.entity.Arrow;
 import org.bukkit.entity.Creeper;
-import org.bukkit.entity.EntityType;
 import org.bukkit.entity.Horse;
 import org.bukkit.entity.LightningStrike;
 import org.bukkit.entity.LivingEntity;
@@ -706,4 +704,16 @@ public class CraftEventFactory {
             player.playerConnection.sendPacket(new Packet103SetSlot(player.activeContainer.windowId, slot.g, itemInHand));
         }
     }
+
+    public static PlayerUnleashEntityEvent callPlayerUnleashEntityEvent(EntityInsentient entity, EntityHuman player) {
+        PlayerUnleashEntityEvent event = new PlayerUnleashEntityEvent(entity.getBukkitEntity(), (Player) player.getBukkitEntity());
+        entity.world.getServer().getPluginManager().callEvent(event);
+        return event;
+    }
+
+    public static PlayerLeashEntityEvent callPlayerLeashEntityEvent(EntityInsentient entity, Entity leashHolder, EntityHuman player) {
+        PlayerLeashEntityEvent event = new PlayerLeashEntityEvent(entity.getBukkitEntity(), leashHolder.getBukkitEntity(), (Player) player.getBukkitEntity());
+        entity.world.getServer().getPluginManager().callEvent(event);
+        return event;
+    }
 }