Un-promisify BTreeDB, since this is job of higher abstractions

.gitignore

@@ -39,4 +39,5 @@ bin/
 .vscode/
 
 ### Mac OS ###
-.DS_Store
+.DS_Store
+/dbtest.bdb

src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB.kt

@@ -3,36 +3,29 @@ package ru.dbotthepony.kommons.io
 import ru.dbotthepony.kommons.util.KOptional
 import java.io.Closeable
 import java.io.File
-import java.util.concurrent.CompletableFuture
 
 /**
  * For actual implementation, see [BTreeDB6].
- *
- *
  */
 abstract class BTreeDB<K, V> : Closeable {
 	abstract val file: File
 	abstract val blockSize: Int
 
-	open operator fun contains(key: K): Boolean {
+	abstract operator fun contains(key: K): Boolean
-		return hasKey(key).get()
-	}
-
-	abstract fun hasKey(key: K): CompletableFuture<Boolean>
 
 	/**
 	 * Reads data at specified [key]
 	 */
-	abstract fun read(key: K): CompletableFuture<KOptional<V>>
+	abstract fun read(key: K): KOptional<V>
-	abstract fun findAllKeys(): CompletableFuture<List<K>>
+	abstract fun findAllKeys(): List<K>
 
-	abstract fun write(key: K, value: V): CompletableFuture<*>
+	abstract fun write(key: K, value: V)
 }
 
 abstract class ByteDataBTreeDB<K> : BTreeDB<K, ByteArray>() {
-	abstract fun write(key: K, value: ByteArray, offset: Int, length: Int): CompletableFuture<*>
+	abstract fun write(key: K, value: ByteArray, offset: Int, length: Int)
 
-	final override fun write(key: K, value: ByteArray): CompletableFuture<*> {
+	final override fun write(key: K, value: ByteArray) {
 		return write(key, value, 0, value.size)
 	}
 }

src/main/kotlin/ru/dbotthepony/kommons/io/BTreeDB6.kt

@@ -46,10 +46,8 @@ private fun readHeader(reader: RandomAccessFile, required: Char) {
  * This storage does not employ any form of defragmentation, but writes try to allocate
  * (reasonably sized) continuous blocks, to avoid severe internal fragmentation.
  *
- * Specified [Executor] is utilized to execute actual I/O operations.
- *
  * [sync] determines whenever writes should be performed atomically. If [sync] is false, in event of
- * JVM crash, host system crash or power loss, there is a risk of file becoming unreadable, unless underlying filesystem
+ * host system crash or power loss, there is a risk of file becoming unreadable, unless underlying filesystem
  * and/or device ensures writes to file are performed in the same order as they were issued by code.
  * If performance is priority, specifying sync as false will yield vastly better performance for writes.
  *
@@ -65,15 +63,13 @@ private fun readHeader(reader: RandomAccessFile, required: Char) {
 // TODO: Changeset counter (to determine write-in-progress blocks/trees, to ignore them when reconstructing tree)
 // TODO: Tree rotations (rebalancing)
 // TODO: Removal of keys
-class BTreeDB6 private constructor(override val file: File, private var reader: RandomAccessFile, pool: Executor, private val sync: Boolean) : ByteDataBTreeDB<ByteKey>() {
+class BTreeDB6 private constructor(override val file: File, private var reader: RandomAccessFile, private val sync: Boolean) : ByteDataBTreeDB<ByteKey>() {
-	constructor(file: File, pool: Executor, sync: Boolean = true) : this(file, RandomAccessFile(file, "rw"), pool, sync)
+	constructor(file: File, sync: Boolean = true) : this(file, RandomAccessFile(file, "rw"), sync)
 
 	init {
 		reader.seek(0L)
 	}
 
-	private val carrier = CarriedExecutor(pool)
-
 	init {
 		readHeader(reader, 'B')
 		readHeader(reader, 'T')
@@ -86,9 +82,7 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 	}
 
 	override fun close() {
-		carrier.execute { reader.close() }
+		reader.close()
-		carrier.shutdown()
-		carrier.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS)
 	}
 
 	override val blockSize = reader.readInt()
@@ -229,7 +223,11 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 		}
 	}
 
-	private fun doRead(key: ByteKey): KOptional<ByteArray> {
+	override fun contains(key: ByteKey): Boolean {
+		return searchForBlock(key) != null
+	}
+
+	override fun read(key: ByteKey): KOptional<ByteArray> {
 		val data = searchForBlock(key)
 
 		if (data != null) {
@@ -242,18 +240,6 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 		return KOptional.empty()
 	}
 
-	override fun hasKey(key: ByteKey): CompletableFuture<Boolean> {
-		return CompletableFuture.supplyAsync(Supplier {
-			searchForBlock(key) != null
-		}, carrier)
-	}
-
-	override fun read(key: ByteKey): CompletableFuture<KOptional<ByteArray>> {
-		return CompletableFuture.supplyAsync(Supplier {
-			doRead(key)
-		}, carrier)
-	}
-
 	private fun readKeysInto(block: Block, result: MutableList<ByteKey>) {
 		when (block.type) {
 			BlockType.TREE -> {
@@ -276,7 +262,7 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 		}
 	}
 
-	private fun doFindAllKeys(): List<ByteKey> {
+	override fun findAllKeys(): List<ByteKey> {
 		if (rootBlockIndex == INVALID_BLOCK_INDEX) {
 			return emptyList()
 		}
@@ -286,13 +272,7 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 		return result
 	}
 
-	override fun findAllKeys(): CompletableFuture<List<ByteKey>> {
+	override fun write(key: ByteKey, value: ByteArray, offset: Int, length: Int) {
-		return CompletableFuture.supplyAsync(Supplier {
-			doFindAllKeys()
-		}, carrier)
-	}
-
-	private fun doWriteData(key: ByteKey, data: ByteArray, offset: Int, length: Int) {
 		if (rootBlockIndex == INVALID_BLOCK_INDEX) {
 			// create LEAF node for root
 			val block = allocBlock(BlockType.LEAF)
@@ -308,7 +288,7 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 
 			val stream = DataOutputStream(BlockOutputStream(newData))
 			stream.writeInt(length)
-			stream.write(data, offset, length)
+			stream.write(value, offset, length)
 			stream.close()
 
 			rootBlockIndex = leaf.write()
@@ -346,7 +326,7 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 			val leaf = LeafData(currentBlock)
 			val stream = DataOutputStream(BlockOutputStream(leaf.compute(key, length + 4)))
 			stream.writeInt(length)
-			stream.write(data, offset, length)
+			stream.write(value, offset, length)
 			stream.close()
 
 			if (leaf.shouldSplit) {
@@ -415,12 +395,6 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 		}
 	}
 
-	override fun write(key: ByteKey, value: ByteArray, offset: Int, length: Int): CompletableFuture<Void> {
-		return CompletableFuture.runAsync(Runnable {
-			doWriteData(key, value, offset, length)
-		}, carrier)
-	}
-
 	private fun allocBlock(type: BlockType): Block {
 		return allocBlocks(type, 1)[0]
 	}
@@ -1023,7 +997,7 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 		 */
 		@JvmStatic
 		@JvmOverloads
-		fun create(file: File, pool: Executor, blockSize: Int = 4096, sync: Boolean = true): BTreeDB6 {
+		fun create(file: File, blockSize: Int = 4096, sync: Boolean = true): BTreeDB6 {
 			require(blockSize >= 128) { "Degenerate block size: $blockSize" }
 
 			if (file.exists())
@@ -1040,7 +1014,7 @@ class BTreeDB6 private constructor(override val file: File, private var reader:
 			writer.writeInt(INVALID_BLOCK_INDEX) // free bitmap block index
 			writer.writeInt(INVALID_BLOCK_INDEX) // tree root block index
 
-			return BTreeDB6(file, writer, pool, sync)
+			return BTreeDB6(file, writer, sync)
 		}
 	}
 }

src/test/kotlin/ru/dbotthepony/kommons/test/BTreeDB6Tests.kt

@@ -14,14 +14,19 @@ object BTreeDB6Tests {
 	fun test() {
 		val file = File("dbtest.bdb")
 		if (file.exists()) file.delete()
-		val create = BTreeDB6.create(file, Executor { it.run() }, 4096, sync = false)
+		val create = BTreeDB6.create(file, 4096, sync = false)
 
 		for (i in 0 .. 8000) {
 			val s = "This is key $i"
 			val k = ByteKey("This is key $i")
-			println("This is key $i")
 			create.write(k, s.toByteArray())
-			assertEquals(s, String(create.read(k).get().get()))
+			assertEquals(s, String(create.read(k).get()))
+		}
+
+		for (i in 0 .. 8000) {
+			val s = "This is key $i"
+			val k = ByteKey("This is key $i")
+			assertEquals(s, String(create.read(k).get()))
 		}
 
 		create.close()