PaperMC/nms-patches/DispenseBehaviorFireball.patch

--- ../work/decompile-bb26c12b/net/minecraft/server/DispenseBehaviorFireball.java	2014-11-27 08:59:46.637422129 +1100
+++ src/main/java/net/minecraft/server/DispenseBehaviorFireball.java	2014-11-27 08:42:10.172850872 +1100
@@ -2,6 +2,11 @@
 
 import java.util.Random;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.block.BlockDispenseEvent;
+// CraftBukkit end
+
 final class DispenseBehaviorFireball extends DispenseBehaviorItem {
 
     DispenseBehaviorFireball() {}
@@ -18,8 +23,38 @@
         double d4 = random.nextGaussian() * 0.05D + (double) enumdirection.getAdjacentY();
         double d5 = random.nextGaussian() * 0.05D + (double) enumdirection.getAdjacentZ();
 
-        world.addEntity(new EntitySmallFireball(world, d0, d1, d2, d3, d4, d5));
-        itemstack.a(1);
+        // CraftBukkit start
+        ItemStack itemstack1 = itemstack.a(1);
+        org.bukkit.block.Block block = world.getWorld().getBlockAt(isourceblock.getBlockPosition().getX(), isourceblock.getBlockPosition().getY(), isourceblock.getBlockPosition().getZ());
+        CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
+
+        BlockDispenseEvent event = new BlockDispenseEvent(block, craftItem.clone(), new org.bukkit.util.Vector(d3, d4, d5));
+        if (!BlockDispenser.eventFired) {
+            world.getServer().getPluginManager().callEvent(event);
+        }
+
+        if (event.isCancelled()) {
+            itemstack.count++;
+            return itemstack;
+        }
+
+        if (!event.getItem().equals(craftItem)) {
+            itemstack.count++;
+            // Chain to handler for new item
+            ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
+            IDispenseBehavior idispensebehavior = (IDispenseBehavior) BlockDispenser.M.get(eventStack.getItem());
+            if (idispensebehavior != IDispenseBehavior.a && idispensebehavior != this) {
+                idispensebehavior.a(isourceblock, eventStack);
+                return itemstack;
+            }
+        }
+
+        EntitySmallFireball entitysmallfireball = new EntitySmallFireball(world, d0, d1, d2, event.getVelocity().getX(), event.getVelocity().getY(), event.getVelocity().getZ());
+        entitysmallfireball.projectileSource = new org.bukkit.craftbukkit.projectiles.CraftBlockProjectileSource((TileEntityDispenser) isourceblock.getTileEntity());
+
+        world.addEntity(entitysmallfireball);
+        // itemstack.a(1); // Handled during event processing
+        // CraftBukkit end
         return itemstack;
     }