CoW non empty indices in container

src/main/kotlin/ru/dbotthepony/mc/otm/container/MatteryContainer.kt

@@ -26,10 +26,14 @@ import ru.dbotthepony.mc.otm.core.util.ItemValueCodec
 import ru.dbotthepony.mc.otm.core.util.VarIntValueCodec
 import ru.dbotthepony.mc.otm.network.synchronizer.FieldSynchronizer
 import ru.dbotthepony.mc.otm.network.synchronizer.IField
+import java.lang.ref.PhantomReference
+import java.lang.ref.ReferenceQueue
 import java.lang.ref.WeakReference
 import java.util.*
+import java.util.concurrent.CopyOnWriteArrayList
 import java.util.function.Supplier
 import kotlin.NoSuchElementException
+import kotlin.collections.ArrayList
 
 @Suppress("UNUSED")
 open class MatteryContainer(protected val watcher: Runnable, private val size: Int) : Container, Iterable<ItemStack>, INBTSerializable<Tag?> {
@@ -41,7 +45,16 @@ open class MatteryContainer(protected val watcher: Runnable, private val size: I
 
 	private val slots = Array(size) { ItemStack.EMPTY }
 	private val nonEmptyFlags = BitSet()
-	private val nonEmptyIndices = IntArrayList()
+	private var nonEmptyIndices = IntArrayList()
+	private var indicesReferences = 0
+
+	private fun cowIndices() {
+		if (indicesReferences != 0) {
+			nonEmptyIndices = IntArrayList(nonEmptyIndices)
+			indicesReferences = 0
+		}
+	}
+
 	private val trackedSlots: Array<ItemStack> = Array(size) { ItemStack.EMPTY }
 	private val filters: Array<Item?> = arrayOfNulls(size)
 	private var filterSynchronizer: WeakReference<IField<MutableMap<Int, Item>>>? = null
@@ -196,7 +209,7 @@ open class MatteryContainer(protected val watcher: Runnable, private val size: I
 		Arrays.fill(slots, ItemStack.EMPTY)
 		Arrays.fill(filters, null)
 		nonEmptyFlags.clear()
-		nonEmptyIndices.clear()
+		nonEmptyIndices = IntArrayList()
 
 		filterSynchronizer?.get()?.value?.clear()
 
@@ -468,11 +481,13 @@ open class MatteryContainer(protected val watcher: Runnable, private val size: I
 		if (slots[slot].isEmpty) {
 			if (nonEmptyFlags[slot]) {
 				nonEmptyFlags[slot] = false
-				nonEmptyIndices.removeInt(slot)
+				cowIndices()
+				nonEmptyIndices.rem(slot)
 			}
 		} else {
 			if (!nonEmptyFlags[slot]) {
 				nonEmptyFlags[slot] = true
+				cowIndices()
 				nonEmptyIndices.addSorted(slot, IntComparators.NATURAL_COMPARATOR)
 			}
 		}
@@ -484,7 +499,7 @@ open class MatteryContainer(protected val watcher: Runnable, private val size: I
 
 	final override fun clearContent() {
 		nonEmptyFlags.clear()
-		nonEmptyIndices.clear()
+		nonEmptyIndices = IntArrayList()
 
 		Arrays.fill(trackedSlots, ItemStack.EMPTY)
 
@@ -497,7 +512,11 @@ open class MatteryContainer(protected val watcher: Runnable, private val size: I
 		}
 	}
 
-	private inner class Iterator : MutableIterator<ItemStack> {
+	private inner class Iterator : IContainerIterator {
+		init {
+			indicesReferences++
+		}
+
 		private val parent = nonEmptyIndices.intIterator()
 		private var lastIndex = -1
 
@@ -519,11 +538,37 @@ open class MatteryContainer(protected val watcher: Runnable, private val size: I
 			setItem(lastIndex, ItemStack.EMPTY)
 			lastIndex = -1
 		}
+
+		override fun setChanged() {
+			if (lastIndex == -1) {
+				throw NoSuchElementException()
+			}
+
+			setChanged(lastIndex)
+		}
 	}
 
-	final override fun iterator(): MutableIterator<ItemStack> {
+	private object EmptyIterator : IContainerIterator {
+		override fun hasNext(): Boolean {
+			return false
+		}
+
+		override fun next(): ItemStack {
+			throw NoSuchElementException()
+		}
+
+		override fun remove() {
+			throw NoSuchElementException()
+		}
+
+		override fun setChanged() {
+			throw NoSuchElementException()
+		}
+	}
+
+	final override fun iterator(): IContainerIterator {
 		if (isEmpty) {
-			return ObjectIterators.EMPTY_ITERATOR as MutableIterator<ItemStack>
+			return EmptyIterator
 		}
 
 		return Iterator()