removed nullable array from transport device, as channels close() is more than enough

src/commonMain/kotlin/net/sergeych/kiloparsec/Transport.kt

@@ -41,7 +41,7 @@ class Transport<S>(
          * Input blocks. When the device is disconnected, it should send one null to this channel
          * to notify the owner. When [close] is called, the channel should be closed.
          */
-        val input: ReceiveChannel<UByteArray?>
+        val input: ReceiveChannel<UByteArray>
 
         /**
          * Send a binary block to a remote party where it should be received and put into [input]
@@ -139,7 +139,7 @@ class Transport<S>(
             debug { "awaiting incoming blocks" }
             while (isActive && !isClosed) {
                 try {
-                    device.input.receive()?.let { packed ->
+                    device.input.receive().let { packed ->
                         debug { "<<<\n${packed.toDump()}" }
                         val b = unpack<Block>(packed)
                         debug { "<<$ $b" }
@@ -181,9 +181,6 @@ class Transport<S>(
                                     .also { debug { "command executed: ${b.name}" } }
                             }
                         }
-                    } ?: run {
-                        debug { "remote channel close received" }
-                        isClosed = true
                     }
                 } catch (_: CancellationException) {
                     info { "loop is cancelled" }

src/commonMain/kotlin/net/sergeych/kiloparsec/adapter/InetTransportDevice.kt

@@ -7,7 +7,7 @@ import kotlinx.coroutines.channels.Channel
  */
 @Suppress("unused")
 class InetTransportDevice(
-    inputChannel: Channel<UByteArray?>,
+    inputChannel: Channel<UByteArray>,
     outputChannel: Channel<UByteArray>,
     val remoteAddress: NetworkAddress,
     val flush: suspend ()->Unit = {},

src/commonMain/kotlin/net/sergeych/kiloparsec/adapter/ProxyDevice.kt

@@ -6,11 +6,11 @@ import kotlinx.coroutines.channels.SendChannel
 import net.sergeych.kiloparsec.Transport
 
 open class ProxyDevice(
-    inputChannel: Channel<UByteArray?>,
+    inputChannel: Channel<UByteArray>,
     outputChannel: Channel<UByteArray>,
     private val onClose: suspend ()->Unit = {}): Transport.Device {
 
-    override val input: ReceiveChannel<UByteArray?> = inputChannel
+    override val input: ReceiveChannel<UByteArray> = inputChannel
     override val output: SendChannel<UByteArray> = outputChannel
     override suspend fun close() {
         onClose()

src/commonTest/kotlin/TransportTest.kt

@@ -6,7 +6,6 @@ import kotlinx.coroutines.channels.SendChannel
 import kotlinx.coroutines.test.runTest
 import net.sergeych.crypto.Key
 import net.sergeych.crypto.initCrypto
-import net.sergeych.kiloparsec.command
 import net.sergeych.kiloparsec.*
 import net.sergeych.mp_logger.Log
 import kotlin.test.*
@@ -17,7 +16,7 @@ fun createTestDevice(): Pair<Transport.Device, Transport.Device> {
     val p2 = Channel<UByteArray>(256)
     val id = ++dcnt
     val d1 = object : Transport.Device {
-        override val input: ReceiveChannel<UByteArray?> = p1
+        override val input: ReceiveChannel<UByteArray> = p1
         override val output: SendChannel<UByteArray> = p2
         override suspend fun close() {
             p2.close()
@@ -28,7 +27,7 @@ fun createTestDevice(): Pair<Transport.Device, Transport.Device> {
         }
     }
     val d2 = object : Transport.Device {
-        override val input: ReceiveChannel<UByteArray?> = p2
+        override val input: ReceiveChannel<UByteArray> = p2
         override val output: SendChannel<UByteArray> = p1
         override suspend fun close() {
             p1.close()

src/jvmMain/kotlin/net/sergeych/kiloparsec/adapter/asyncSocketToDevice.kt

@@ -98,7 +98,7 @@ suspend fun asyncSocketToDevice(socket: AsynchronousSocketChannel): InetTranspor
                 }
             }
             // transport device copes with blocks:
-            val inputBlocks = Channel<UByteArray?>()
+            val inputBlocks = Channel<UByteArray>()
             // decode blocks from a byte channel read from the socket:
             launch {
                 try {
@@ -116,9 +116,7 @@ suspend fun asyncSocketToDevice(socket: AsynchronousSocketChannel): InetTranspor
                         }
                     }
                 } catch (_: CancellationException) {
-                    inputBlocks.send(null)
                 } catch (_: ClosedReceiveChannelException) {
-                    inputBlocks.send(null)
                     stop()
                 }
                 receiving.value = false