Paper/nms-patches/Container.patch

--- a/net/minecraft/server/Container.java
+++ b/net/minecraft/server/Container.java
@@ -8,6 +8,17 @@
 import java.util.Set;
 import javax.annotation.Nullable;
 
+// CraftBukkit start
+import java.util.HashMap;
+import java.util.Map;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.Event.Result;
+import org.bukkit.event.inventory.InventoryDragEvent;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.InventoryView;
+// CraftBukkit end
+
 public abstract class Container {
 
     public List<ItemStack> b = Lists.newArrayList();
@@ -19,12 +30,24 @@
     protected List<ICrafting> listeners = Lists.newArrayList();
     private Set<EntityHuman> i = Sets.newHashSet();
 
+    // CraftBukkit start
+    public boolean checkReachable = true;
+    public abstract InventoryView getBukkitView();
+    public void transferTo(Container other, org.bukkit.craftbukkit.entity.CraftHumanEntity player) {
+        InventoryView source = this.getBukkitView(), destination = other.getBukkitView();
+        ((CraftInventory) source.getTopInventory()).getInventory().onClose(player);
+        ((CraftInventory) source.getBottomInventory()).getInventory().onClose(player);
+        ((CraftInventory) destination.getTopInventory()).getInventory().onOpen(player);
+        ((CraftInventory) destination.getBottomInventory()).getInventory().onOpen(player);
+    }
+    // CraftBukkit end
+
     public Container() {}
 
     protected Slot a(Slot slot) {
         slot.rawSlotIndex = this.c.size();
         this.c.add(slot);
-        this.b.add((Object) null);
+        this.b.add(null); // CraftBukkit - fix decompile error
         return slot;
     }
 
@@ -128,6 +151,7 @@
                     k = playerinventory.getCarried().count;
                     Iterator iterator = this.h.iterator();
 
+                    Map<Integer, ItemStack> draggedSlots = new HashMap<Integer, ItemStack>(); // CraftBukkit - Store slots from drag in map (raw slot id -> new stack)
                     while (iterator.hasNext()) {
                         Slot slot1 = (Slot) iterator.next();
 
@@ -145,16 +169,48 @@
                             }
 
                             k -= itemstack2.count - i1;
-                            slot1.set(itemstack2);
+                            // slot1.set(itemstack2);
+                            draggedSlots.put(slot1.rawSlotIndex, itemstack2); // CraftBukkit - Put in map instead of setting
                         }
                     }
 
-                    itemstack1.count = k;
-                    if (itemstack1.count <= 0) {
-                        itemstack1 = null;
+                    // CraftBukkit start - InventoryDragEvent
+                    InventoryView view = getBukkitView();
+                    org.bukkit.inventory.ItemStack newcursor = CraftItemStack.asCraftMirror(itemstack1);
+                    newcursor.setAmount(k);
+                    Map<Integer, org.bukkit.inventory.ItemStack> eventmap = new HashMap<Integer, org.bukkit.inventory.ItemStack>();
+                    for (Map.Entry<Integer, ItemStack> ditem : draggedSlots.entrySet()) {
+                        eventmap.put(ditem.getKey(), CraftItemStack.asBukkitCopy(ditem.getValue()));
+                    }
+
+                    // It's essential that we set the cursor to the new value here to prevent item duplication if a plugin closes the inventory.
+                    ItemStack oldCursor = playerinventory.getCarried();
+                    playerinventory.setCarried(CraftItemStack.asNMSCopy(newcursor));
+
+                    InventoryDragEvent event = new InventoryDragEvent(view, (newcursor.getType() != org.bukkit.Material.AIR ? newcursor : null), CraftItemStack.asBukkitCopy(oldCursor), this.dragType == 1, eventmap);
+                    entityhuman.world.getServer().getPluginManager().callEvent(event);
+
+                    // Whether or not a change was made to the inventory that requires an update.
+                    boolean needsUpdate = event.getResult() != Result.DEFAULT;
+
+                    if (event.getResult() != Result.DENY) {
+                        for (Map.Entry<Integer, ItemStack> dslot : draggedSlots.entrySet()) {
+                            view.setItem(dslot.getKey(), CraftItemStack.asBukkitCopy(dslot.getValue()));
+                        }
+                        // The only time the carried item will be set to null is if the inventory is closed by the server.
+                        // If the inventory is closed by the server, then the cursor items are dropped.  This is why we change the cursor early.
+                        if (playerinventory.getCarried() != null) {
+                            playerinventory.setCarried(CraftItemStack.asNMSCopy(event.getCursor()));
+                            needsUpdate = true;
+                        }
+                    } else {
+                        playerinventory.setCarried(oldCursor);
                     }
 
-                    playerinventory.setCarried(itemstack1);
+                    if (needsUpdate && entityhuman instanceof EntityPlayer) {
+                        ((EntityPlayer) entityhuman).updateInventory(this);
+                    }
+                    // CraftBukkit end
                 }
 
                 this.d();
@@ -177,8 +233,14 @@
                         }
 
                         if (j == 1) {
-                            entityhuman.drop(playerinventory.getCarried().cloneAndSubtract(1), true);
-                            if (playerinventory.getCarried().count == 0) {
+                            // CraftBukkit start - Store a reference, don't drop unless > 0
+                            ItemStack carried = playerinventory.getCarried();
+                            if (carried.count > 0) {
+                                entityhuman.drop(carried.cloneAndSubtract(1), true);
+                            }
+
+                            if (carried.count == 0) {
+                                // CraftBukkit end
                                 playerinventory.setCarried((ItemStack) null);
                             }
                         }
@@ -229,7 +291,11 @@
                                 slot2.set(itemstack3.cloneAndSubtract(j1));
                                 if (itemstack3.count == 0) {
                                     playerinventory.setCarried((ItemStack) null);
+                                // CraftBukkit start - Update client cursor if we didn't empty it
+                                } else if (entityhuman instanceof EntityPlayer) {
+                                    ((EntityPlayer) entityhuman).playerConnection.sendPacket(new PacketPlayOutSetSlot(-1, -1, entityhuman.inventory.getCarried()));
                                 }
+                                // CraftBukkit end
                             }
                         } else if (slot2.isAllowed(entityhuman)) {
                             if (itemstack3 == null) {
@@ -259,7 +325,11 @@
                                     itemstack3.cloneAndSubtract(j1);
                                     if (itemstack3.count == 0) {
                                         playerinventory.setCarried((ItemStack) null);
+                                    // CraftBukkit start - Update client cursor if we didn't empty it
+                                    } else if (entityhuman instanceof EntityPlayer) {
+                                        ((EntityPlayer) entityhuman).playerConnection.sendPacket(new PacketPlayOutSetSlot(-1, -1, entityhuman.inventory.getCarried()));
                                     }
+                                    // CraftBukkit end
 
                                     itemstack1.count += j1;
                                 } else if (itemstack3.count <= slot2.getMaxStackSize(itemstack3)) {
@@ -268,7 +338,10 @@
                                 }
                             } else if (itemstack1.getItem() == itemstack3.getItem() && itemstack3.getMaxStackSize() > 1 && (!itemstack1.usesData() || itemstack1.getData() == itemstack3.getData()) && ItemStack.equals(itemstack1, itemstack3)) {
                                 j1 = itemstack1.count;
-                                if (j1 > 0 && j1 + itemstack3.count <= itemstack3.getMaxStackSize()) {
+                                // CraftBukkit start - itemstack3.getMaxStackSize() -> maxStack
+                                int maxStack = Math.min(itemstack3.getMaxStackSize(), slot2.getMaxStackSize());
+                                if (j1 > 0 && j1 + itemstack3.count <= maxStack) {
+                                    // CraftBukkit end
                                     itemstack3.count += j1;
                                     itemstack1 = slot2.a(j1);
                                     if (itemstack1.count == 0) {
@@ -276,11 +349,24 @@
                                     }
 
                                     slot2.a(entityhuman, playerinventory.getCarried());
+                                // CraftBukkit start - Update client cursor if we didn't empty it
+                                } else if (entityhuman instanceof EntityPlayer) {
+                                    ((EntityPlayer) entityhuman).playerConnection.sendPacket(new PacketPlayOutSetSlot(-1, -1, entityhuman.inventory.getCarried()));
                                 }
+                                // CraftBukkit end
                             }
                         }
 
                         slot2.f();
+                        // CraftBukkit start - Make sure the client has the right slot contents
+                        if (entityhuman instanceof EntityPlayer && slot2.getMaxStackSize() != 64) {
+                            ((EntityPlayer) entityhuman).playerConnection.sendPacket(new PacketPlayOutSetSlot(this.windowId, slot2.rawSlotIndex, slot2.getItem()));
+                            // Updating a crafting inventory makes the client reset the result slot, have to send it again
+                            if (this.getBukkitView().getType() == InventoryType.WORKBENCH || this.getBukkitView().getType() == InventoryType.CRAFTING) {
+                                ((EntityPlayer) entityhuman).playerConnection.sendPacket(new PacketPlayOutSetSlot(this.windowId, 0, this.getSlot(0).getItem()));
+                            }
+                        }
+                        // CraftBukkit end
                     }
                 }
             } else if (inventoryclicktype == InventoryClickType.SWAP && j >= 0 && j < 9) {
@@ -434,14 +520,17 @@
                 if (itemstack1 != null && a(itemstack, itemstack1)) {
                     int l = itemstack1.count + itemstack.count;
 
-                    if (l <= itemstack.getMaxStackSize()) {
+                    // CraftBukkit start - itemstack.getMaxStackSize() -> maxStack
+                    int maxStack = Math.min(itemstack.getMaxStackSize(), slot.getMaxStackSize());
+                    if (l <= maxStack) {
                         itemstack.count = 0;
                         itemstack1.count = l;
                         slot.f();
                         flag1 = true;
-                    } else if (itemstack1.count < itemstack.getMaxStackSize()) {
-                        itemstack.count -= itemstack.getMaxStackSize() - itemstack1.count;
-                        itemstack1.count = itemstack.getMaxStackSize();
+                    } else if (itemstack1.count < maxStack) {
+                        itemstack.count -= maxStack - itemstack1.count;
+                        itemstack1.count = maxStack;
+                        // CraftBukkit end
                         slot.f();
                         flag1 = true;
                     }