Allow items to decide if they can or cannot have book enchantments applied

patches/minecraft/net/minecraft/inventory/ContainerRepair.java.patch

@@ -0,0 +1,22 @@
+--- ../src_base/minecraft/net/minecraft/inventory/ContainerRepair.java
++++ ../src_work/minecraft/net/minecraft/inventory/ContainerRepair.java
+@@ -305,6 +305,11 @@
+                 k = Math.max(1, k / 2);
+             }
+ 
++            if (flag && itemstack1!=null && !Item.itemsList[itemstack1.itemID].isBookEnchantable(itemstack1,itemstack2))
++            {
++                itemstack1 = null;
++            }
++
+             this.maximumCost = k + i;
+ 
+             if (i <= 0)
+@@ -322,6 +327,7 @@
+             {
+                 itemstack1 = null;
+             }
++
+ 
+             if (itemstack1 != null)
+             {

patches/minecraft/net/minecraft/item/Item.java.patch

@@ -47,7 +47,7 @@
          Vec3 vec31 = vec3.addVector((double)f7 * d3, (double)f6 * d3, (double)f8 * d3);
          return par1World.rayTraceBlocks_do_do(vec3, vec31, par3, !par3);
      }
-@@ -720,4 +730,324 @@
+@@ -720,4 +730,336 @@
      {
          StatList.initStats();
      }
@@ -329,7 +329,7 @@
 +
 +    /**
 +     * Determines if the specific ItemStack can be placed in the specified armor slot.
-+     * 
++     *
 +     * @param stack The ItemStack
 +     * @param armorType Armor slot ID: 0: Helmet, 1: Chest, 2: Legs, 3: Boots
 +     * @return True if the given ItemStack can be inserted in the slot
@@ -348,10 +348,10 @@
 +
 +        return false;
 +    }
-+    
++
 +    /**
 +     * ItemStack sensitive version of isPotionIngredient
-+     * 
++     *
 +     * @param stack The item stack
 +     * @return True if this stack can be used as a potion ingredient
 +     */
@@ -362,7 +362,7 @@
 +
 +    /**
 +     * ItemStack sensitive version of getPotionEffect
-+     * 
++     *
 +     * @param stack The item stack
 +     * @return A string containing the bit manipulation to apply the the potion.
 +     */
@@ -370,5 +370,17 @@
 +    {
 +        return getPotionEffect();
 +    }
++
++    /**
++     * Allow or forbid the specific book/item combination as an anvil enchant
++     *
++     * @param itemstack1 The item
++     * @param itemstack2 The book
++     * @return if the enchantment is allowed
++     */
++    public boolean isBookEnchantable(ItemStack itemstack1, ItemStack itemstack2)
++    {
++        return true;
++    }
 +
  }