Refactor EntityDamageEvents. Adds BUKKIT-1944 & BUKKIT-3684

By: feildmaster <admin@feildmaster.com>

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

@@ -39,6 +39,7 @@ import org.bukkit.craftbukkit.entity.CraftLivingEntity;
 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;
@@ -64,6 +65,9 @@ import org.bukkit.event.server.ServerListPingEvent;
 import org.bukkit.inventory.InventoryView;
 
 public class CraftEventFactory {
+    public static final DamageSource MELTING = CraftDamageSource.copyOf(DamageSource.BURN);
+    public static final DamageSource POISON = CraftDamageSource.copyOf(DamageSource.MAGIC);
+
     // helper methods
     private static boolean canBuild(CraftWorld world, Player player, int x, int z) {
         WorldServer worldServer = world.getHandle();
@@ -379,6 +383,7 @@ public class CraftEventFactory {
     }
 
     public static EntityDamageEvent handleEntityDamageEvent(Entity entity, DamageSource source, int damage) {
+        if (source instanceof EntityDamageSource) {
             Entity damager = source.getEntity();
             DamageCause cause = DamageCause.ENTITY_ATTACK;
 
@@ -394,6 +399,42 @@ public class CraftEventFactory {
             }
 
             return callEntityDamageEvent(damager, entity, cause, damage);
+        } else if (source == DamageSource.OUT_OF_WORLD) {
+            EntityDamageEvent event = callEvent(new EntityDamageByBlockEvent(null, entity.getBukkitEntity(), DamageCause.VOID, damage));
+            if (!event.isCancelled()) {
+                event.getEntity().setLastDamageCause(event);
+            }
+            return event;
+        }
+
+        DamageCause cause = null;
+        if (source == DamageSource.FIRE) {
+            cause = DamageCause.FIRE;
+        } else if (source == DamageSource.STARVE) {
+            cause = DamageCause.STARVATION;
+        } else if (source == DamageSource.WITHER) {
+            cause = DamageCause.WITHER;
+        } else if (source == DamageSource.STUCK) {
+            cause = DamageCause.SUFFOCATION;
+        } else if (source == DamageSource.DROWN) {
+            cause = DamageCause.DROWNING;
+        } else if (source == DamageSource.BURN) {
+            cause = DamageCause.FIRE_TICK;
+        } else if (source == MELTING) {
+            cause = DamageCause.MELTING;
+        } else if (source == POISON) {
+            cause = DamageCause.POISON;
+        } else if (source == DamageSource.MAGIC) {
+            cause = DamageCause.MAGIC;
+        }
+
+        if (cause != null) {
+            return callEntityDamageEvent(null, entity, cause, damage);
+        }
+
+        // If an event was called earlier, we return null.
+        // EG: Cactus, Lava, EntityEnderPearl "fall", FallingSand
+        return null;
     }
 
     // Non-Living Entities such as EntityEnderCrystal need to call this
@@ -401,6 +442,7 @@ public class CraftEventFactory {
         if (!(source instanceof EntityDamageSource)) {
             return false;
         }
+        // We don't need to check for null, since EntityDamageSource will always return an event
         EntityDamageEvent event = handleEntityDamageEvent(entity, source, damage);
         return event.isCancelled() || event.getDamage() == 0;
     }

paper-server/src/main/java/org/bukkit/craftbukkit/util/CraftDamageSource.java

@@ -0,0 +1,31 @@
+package org.bukkit.craftbukkit.util;
+
+import net.minecraft.server.DamageSource;
+
+// Util class to create custom DamageSources.
+public final class CraftDamageSource extends DamageSource {
+    public static DamageSource copyOf(final DamageSource original) {
+        CraftDamageSource newSource = new CraftDamageSource(original.translationIndex);
+
+        // Check ignoresArmor
+        if (original.ignoresArmor()) {
+            newSource.j();
+        }
+
+        // Check magic
+        if (original.q()) {
+            newSource.r();
+        }
+
+        // Check fire
+        if (original.c()) {
+            newSource.l();
+        }
+
+        return newSource;
+    }
+
+    private CraftDamageSource(String identifier) {
+        super(identifier);
+    }
+}