prevent http `closeWait` future from being cancelled (#486)

* simplify `closeWait` implementations
  * remove redundant cancellation callbacks
  * use `noCancel` to avoid forgetting the right future flags
* add a few missing raises trackers
* enforce `OwnCancelSchedule` on manually created futures that don't raise `CancelledError`
* ensure cancellations don't reach internal futures

chronos/apps/http/httpbodyrw.nim

@@ -43,7 +43,7 @@ proc closeWait*(bstream: HttpBodyReader) {.async: (raises: []).} =
   ## Close and free resource allocated by body reader.
   if bstream.bstate == HttpState.Alive:
     bstream.bstate = HttpState.Closing
-    var res = newSeq[Future[void]]()
+    var res = newSeq[Future[void].Raising([])]()
     # We closing streams in reversed order because stream at position [0], uses
     # data from stream at position [1].
     for index in countdown((len(bstream.streams) - 1), 0):
@@ -68,7 +68,7 @@ proc closeWait*(bstream: HttpBodyWriter) {.async: (raises: []).} =
   ## Close and free all the resources allocated by body writer.
   if bstream.bstate == HttpState.Alive:
     bstream.bstate = HttpState.Closing
-    var res = newSeq[Future[void]]()
+    var res = newSeq[Future[void].Raising([])]()
     for index in countdown(len(bstream.streams) - 1, 0):
       res.add(bstream.streams[index].closeWait())
     await noCancel(allFutures(res))

chronos/apps/http/httpclient.nim

@@ -294,7 +294,7 @@ proc new*(t: typedesc[HttpSessionRef],
     if HttpClientFlag.Http11Pipeline in flags:
       sessionWatcher(res)
     else:
-      Future[void].Raising([]).init("session.watcher.placeholder")
+      nil
   res
 
 proc getTLSFlags(flags: HttpClientFlags): set[TLSFlags] =
@@ -607,7 +607,7 @@ proc closeWait(conn: HttpClientConnectionRef) {.async: (raises: []).} =
     conn.state = HttpClientConnectionState.Closing
     let pending =
       block:
-        var res: seq[Future[void]]
+        var res: seq[Future[void].Raising([])]
         if not(isNil(conn.reader)) and not(conn.reader.closed()):
           res.add(conn.reader.closeWait())
         if not(isNil(conn.writer)) and not(conn.writer.closed()):
@@ -847,14 +847,14 @@ proc sessionWatcher(session: HttpSessionRef) {.async: (raises: []).} =
         break
 
 proc closeWait*(request: HttpClientRequestRef) {.async: (raises: []).} =
-  var pending: seq[FutureBase]
+  var pending: seq[Future[void].Raising([])]
   if request.state notin {HttpReqRespState.Closing, HttpReqRespState.Closed}:
     request.state = HttpReqRespState.Closing
     if not(isNil(request.writer)):
       if not(request.writer.closed()):
-        pending.add(FutureBase(request.writer.closeWait()))
+        pending.add(request.writer.closeWait())
       request.writer = nil
-    pending.add(FutureBase(request.releaseConnection()))
+    pending.add(request.releaseConnection())
     await noCancel(allFutures(pending))
     request.session = nil
     request.error = nil
@@ -862,14 +862,14 @@ proc closeWait*(request: HttpClientRequestRef) {.async: (raises: []).} =
     untrackCounter(HttpClientRequestTrackerName)
 
 proc closeWait*(response: HttpClientResponseRef) {.async: (raises: []).} =
-  var pending: seq[FutureBase]
+  var pending: seq[Future[void].Raising([])]
   if response.state notin {HttpReqRespState.Closing, HttpReqRespState.Closed}:
     response.state = HttpReqRespState.Closing
     if not(isNil(response.reader)):
       if not(response.reader.closed()):
-        pending.add(FutureBase(response.reader.closeWait()))
+        pending.add(response.reader.closeWait())
       response.reader = nil
-    pending.add(FutureBase(response.releaseConnection()))
+    pending.add(response.releaseConnection())
     await noCancel(allFutures(pending))
     response.session = nil
     response.error = nil

chronos/asyncsync.nim

@@ -523,15 +523,13 @@ proc closeWait*(ab: AsyncEventQueue): Future[void] {.
                                   {FutureFlag.OwnCancelSchedule})
   proc continuation(udata: pointer) {.gcsafe.} =
     retFuture.complete()
-  proc cancellation(udata: pointer) {.gcsafe.} =
+
-    # We are not going to change the state of `retFuture` to cancelled, so we
+  # Ignore cancellation requests - we'll complete the future soon enough
-    # will prevent the entire sequence of Futures from being cancelled.
+  retFuture.cancelCallback = nil
-    discard
 
   ab.close()
   # Schedule `continuation` to be called only after all the `reader`
   # notifications will be scheduled and processed.
-  retFuture.cancelCallback = cancellation
   callSoon(continuation)
   retFuture
 

chronos/futures.nim

@@ -34,6 +34,19 @@ type
 
   FutureFlag* {.pure.} = enum
     OwnCancelSchedule
+      ## When OwnCancelSchedule is set, the owner of the future is responsible
+      ## for implementing cancellation in one of 3 ways:
+      ##
+      ## * ensure that cancellation requests never reach the future by means of
+      ##   not exposing it to user code, `await` and `tryCancel`
+      ## * set `cancelCallback` to `nil` to stop cancellation propagation - this
+      ##   is appropriate when it is expected that the future will be completed
+      ##   in a regular way "soon"
+      ## * set `cancelCallback` to a handler that implements cancellation in an
+      ##   operation-specific way
+      ##
+      ## If `cancelCallback` is not set and the future gets cancelled, a
+      ## `Defect` will be raised.
 
   FutureFlags* = set[FutureFlag]
 
@@ -104,6 +117,12 @@ proc internalInitFutureBase*(fut: FutureBase, loc: ptr SrcLoc,
   fut.internalState = state
   fut.internalLocation[LocationKind.Create] = loc
   fut.internalFlags = flags
+  if FutureFlag.OwnCancelSchedule in flags:
+    # Owners must replace `cancelCallback` with `nil` if they want to ignore
+    # cancellations
+    fut.internalCancelcb = proc(_: pointer) =
+      raiseAssert "Cancellation request for non-cancellable future"
+
   if state != FutureState.Pending:
     fut.internalLocation[LocationKind.Finish] = loc
 

chronos/internal/asyncfutures.nim

@@ -1013,6 +1013,7 @@ proc cancelAndWait*(future: FutureBase, loc: ptr SrcLoc): Future[void] {.
   if future.finished():
     retFuture.complete()
   else:
+    retFuture.cancelCallback = nil
     cancelSoon(future, continuation, cast[pointer](retFuture), loc)
 
   retFuture
@@ -1057,6 +1058,7 @@ proc noCancel*[F: SomeFuture](future: F): auto = # async: (raw: true, raises: as
   if future.finished():
     completeFuture()
   else:
+    retFuture.cancelCallback = nil
     future.addCallback(continuation)
   retFuture
 

chronos/internal/raisesfutures.nim

@@ -18,45 +18,6 @@ proc makeNoRaises*(): NimNode {.compileTime.} =
 
   ident"void"
 
-macro Raising*[T](F: typedesc[Future[T]], E: varargs[typedesc]): untyped =
-  ## Given a Future type instance, return a type storing `{.raises.}`
-  ## information
-  ##
-  ## Note; this type may change in the future
-  E.expectKind(nnkBracket)
-
-  let raises = if E.len == 0:
-    makeNoRaises()
-  else:
-    nnkTupleConstr.newTree(E.mapIt(it))
-  nnkBracketExpr.newTree(
-    ident "InternalRaisesFuture",
-    nnkDotExpr.newTree(F, ident"T"),
-    raises
-  )
-
-template init*[T, E](
-    F: type InternalRaisesFuture[T, E], fromProc: static[string] = ""): F =
-  ## Creates a new pending future.
-  ##
-  ## Specifying ``fromProc``, which is a string specifying the name of the proc
-  ## that this future belongs to, is a good habit as it helps with debugging.
-  let res = F()
-  internalInitFutureBase(res, getSrcLocation(fromProc), FutureState.Pending, {})
-  res
-
-template init*[T, E](
-    F: type InternalRaisesFuture[T, E], fromProc: static[string] = "",
-    flags: static[FutureFlags]): F =
-  ## Creates a new pending future.
-  ##
-  ## Specifying ``fromProc``, which is a string specifying the name of the proc
-  ## that this future belongs to, is a good habit as it helps with debugging.
-  let res = F()
-  internalInitFutureBase(
-    res, getSrcLocation(fromProc), FutureState.Pending, flags)
-  res
-
 proc dig(n: NimNode): NimNode {.compileTime.} =
   # Dig through the layers of type to find the raises list
   if n.eqIdent("void"):
@@ -87,6 +48,58 @@ proc members(tup: NimNode): seq[NimNode] {.compileTime.} =
   for t in tup.members():
     result.add(t)
 
+macro hasException(raises: typedesc, ident: static string): bool =
+  newLit(raises.members.anyIt(it.eqIdent(ident)))
+
+macro Raising*[T](F: typedesc[Future[T]], E: varargs[typedesc]): untyped =
+  ## Given a Future type instance, return a type storing `{.raises.}`
+  ## information
+  ##
+  ## Note; this type may change in the future
+  E.expectKind(nnkBracket)
+
+  let raises = if E.len == 0:
+    makeNoRaises()
+  else:
+    nnkTupleConstr.newTree(E.mapIt(it))
+  nnkBracketExpr.newTree(
+    ident "InternalRaisesFuture",
+    nnkDotExpr.newTree(F, ident"T"),
+    raises
+  )
+
+template init*[T, E](
+    F: type InternalRaisesFuture[T, E], fromProc: static[string] = ""): F =
+  ## Creates a new pending future.
+  ##
+  ## Specifying ``fromProc``, which is a string specifying the name of the proc
+  ## that this future belongs to, is a good habit as it helps with debugging.
+  when not hasException(type(E), "CancelledError"):
+    static:
+      raiseAssert "Manually created futures must either own cancellation schedule or raise CancelledError"
+
+
+  let res = F()
+  internalInitFutureBase(res, getSrcLocation(fromProc), FutureState.Pending, {})
+  res
+
+template init*[T, E](
+    F: type InternalRaisesFuture[T, E], fromProc: static[string] = "",
+    flags: static[FutureFlags]): F =
+  ## Creates a new pending future.
+  ##
+  ## Specifying ``fromProc``, which is a string specifying the name of the proc
+  ## that this future belongs to, is a good habit as it helps with debugging.
+  let res = F()
+  when not hasException(type(E), "CancelledError"):
+    static:
+      doAssert FutureFlag.OwnCancelSchedule in flags,
+        "Manually created futures must either own cancellation schedule or raise CancelledError"
+
+  internalInitFutureBase(
+    res, getSrcLocation(fromProc), FutureState.Pending, flags)
+  res
+
 proc containsSignature(members: openArray[NimNode], typ: NimNode): bool {.compileTime.} =
   let typHash = signatureHash(typ)
 

chronos/streams/asyncstream.nim

@@ -77,7 +77,7 @@ type
     udata: pointer
     error*: ref AsyncStreamError
     bytesCount*: uint64
-    future: Future[void]
+    future: Future[void].Raising([])
 
   AsyncStreamWriter* = ref object of RootRef
     wsource*: AsyncStreamWriter
@@ -88,7 +88,7 @@ type
     error*: ref AsyncStreamError
     udata: pointer
     bytesCount*: uint64
-    future: Future[void]
+    future: Future[void].Raising([])
 
   AsyncStream* = object of RootObj
     reader*: AsyncStreamReader
@@ -897,44 +897,27 @@ proc close*(rw: AsyncStreamRW) =
           rw.future.addCallback(continuation)
           rw.future.cancelSoon()
 
-proc closeWait*(rw: AsyncStreamRW): Future[void] {.
+proc closeWait*(rw: AsyncStreamRW): Future[void] {.async: (raises: []).} =
-     async: (raw: true, raises: []).} =
   ## Close and frees resources of stream ``rw``.
-  const FutureName =
+  if not rw.closed():
-    when rw is AsyncStreamReader:
-      "async.stream.reader.closeWait"
-    else:
-      "async.stream.writer.closeWait"
-
-  let retFuture = Future[void].Raising([]).init(FutureName)
-
-  if rw.closed():
-    retFuture.complete()
-    return retFuture
-
-  proc continuation(udata: pointer) {.gcsafe, raises:[].} =
-    retFuture.complete()
-
     rw.close()
-  if rw.future.finished():
+    await noCancel(rw.join())
-    retFuture.complete()
-  else:
-    rw.future.addCallback(continuation, cast[pointer](retFuture))
-  retFuture
 
 proc startReader(rstream: AsyncStreamReader) =
   rstream.state = Running
   if not isNil(rstream.readerLoop):
     rstream.future = rstream.readerLoop(rstream)
   else:
-    rstream.future = newFuture[void]("async.stream.empty.reader")
+    rstream.future = Future[void].Raising([]).init(
+      "async.stream.empty.reader", {FutureFlag.OwnCancelSchedule})
 
 proc startWriter(wstream: AsyncStreamWriter) =
   wstream.state = Running
   if not isNil(wstream.writerLoop):
     wstream.future = wstream.writerLoop(wstream)
   else:
-    wstream.future = newFuture[void]("async.stream.empty.writer")
+    wstream.future = Future[void].Raising([]).init(
+      "async.stream.empty.writer", {FutureFlag.OwnCancelSchedule})
 
 proc init*(child, wsource: AsyncStreamWriter, loop: StreamWriterLoop,
            queueSize = AsyncStreamDefaultQueueSize) =

chronos/transports/common.nim

@@ -73,7 +73,7 @@ when defined(windows) or defined(nimdoc):
       udata*: pointer               # User-defined pointer
       flags*: set[ServerFlags]      # Flags
       bufferSize*: int              # Size of internal transports' buffer
-      loopFuture*: Future[void]     # Server's main Future
+      loopFuture*: Future[void].Raising([])     # Server's main Future
       domain*: Domain               # Current server domain (IPv4 or IPv6)
       apending*: bool
       asock*: AsyncFD               # Current AcceptEx() socket
@@ -92,7 +92,7 @@ else:
       udata*: pointer               # User-defined pointer
       flags*: set[ServerFlags]      # Flags
       bufferSize*: int              # Size of internal transports' buffer
-      loopFuture*: Future[void]     # Server's main Future
+      loopFuture*: Future[void].Raising([]) # Server's main Future
       errorCode*: OSErrorCode       # Current error code
       dualstack*: DualStackType     # IPv4/IPv6 dualstack parameters
 

chronos/transports/datagram.nim

@@ -44,7 +44,7 @@ type
     remote: TransportAddress        # Remote address
     udata*: pointer                 # User-driven pointer
     function: DatagramCallback      # Receive data callback
-    future: Future[void]            # Transport's life future
+    future: Future[void].Raising([]) # Transport's life future
     raddr: Sockaddr_storage         # Reader address storage
     ralen: SockLen                  # Reader address length
     waddr: Sockaddr_storage         # Writer address storage
@@ -359,7 +359,8 @@ when defined(windows):
     res.queue = initDeque[GramVector]()
     res.udata = udata
     res.state = {ReadPaused, WritePaused}
-    res.future = newFuture[void]("datagram.transport")
+    res.future = Future[void].Raising([]).init(
+      "datagram.transport", {FutureFlag.OwnCancelSchedule})
     res.rovl.data = CompletionData(cb: readDatagramLoop,
                                       udata: cast[pointer](res))
     res.wovl.data = CompletionData(cb: writeDatagramLoop,
@@ -568,7 +569,8 @@ else:
     res.queue = initDeque[GramVector]()
     res.udata = udata
     res.state = {ReadPaused, WritePaused}
-    res.future = newFuture[void]("datagram.transport")
+    res.future = Future[void].Raising([]).init(
+      "datagram.transport", {FutureFlag.OwnCancelSchedule})
     GC_ref(res)
     # Start tracking transport
     trackCounter(DgramTransportTrackerName)
@@ -840,31 +842,16 @@ proc join*(transp: DatagramTransport): Future[void] {.
 
   return retFuture
 
+proc closed*(transp: DatagramTransport): bool {.inline.} =
+  ## Returns ``true`` if transport in closed state.
+  {ReadClosed, WriteClosed} * transp.state != {}
+
 proc closeWait*(transp: DatagramTransport): Future[void] {.
-    async: (raw: true, raises: []).} =
+    async: (raises: []).} =
   ## Close transport ``transp`` and release all resources.
-  let retFuture = newFuture[void](
+  if not transp.closed():
-    "datagram.transport.closeWait", {FutureFlag.OwnCancelSchedule})
-
-  if {ReadClosed, WriteClosed} * transp.state != {}:
-    retFuture.complete()
-    return retFuture
-
-  proc continuation(udata: pointer) {.gcsafe.} =
-    retFuture.complete()
-
-  proc cancellation(udata: pointer) {.gcsafe.} =
-    # We are not going to change the state of `retFuture` to cancelled, so we
-    # will prevent the entire sequence of Futures from being cancelled.
-    discard
-
     transp.close()
-  if transp.future.finished():
+    await noCancel(transp.join())
-    retFuture.complete()
-  else:
-    transp.future.addCallback(continuation, cast[pointer](retFuture))
-    retFuture.cancelCallback = cancellation
-  retFuture
 
 proc send*(transp: DatagramTransport, pbytes: pointer,
            nbytes: int): Future[void] {.
@@ -1020,7 +1007,3 @@ proc getMessage*(transp: DatagramTransport): seq[byte] {.
 proc getUserData*[T](transp: DatagramTransport): T {.inline.} =
   ## Obtain user data stored in ``transp`` object.
   cast[T](transp.udata)
-
-proc closed*(transp: DatagramTransport): bool {.inline.} =
-  ## Returns ``true`` if transport in closed state.
-  {ReadClosed, WriteClosed} * transp.state != {}

chronos/transports/stream.nim

@@ -76,7 +76,7 @@ when defined(windows):
       offset: int                     # Reading buffer offset
       error: ref TransportError       # Current error
       queue: Deque[StreamVector]      # Writer queue
-      future: Future[void]            # Stream life future
+      future: Future[void].Raising([]) # Stream life future
       # Windows specific part
       rwsabuf: WSABUF                 # Reader WSABUF
       wwsabuf: WSABUF                 # Writer WSABUF
@@ -103,7 +103,7 @@ else:
       offset: int                     # Reading buffer offset
       error: ref TransportError       # Current error
       queue: Deque[StreamVector]      # Writer queue
-      future: Future[void]            # Stream life future
+      future: Future[void].Raising([]) # Stream life future
       case kind*: TransportKind
       of TransportKind.Socket:
         domain: Domain                # Socket transport domain (IPv4/IPv6)
@@ -598,7 +598,8 @@ when defined(windows):
     transp.buffer = newSeq[byte](bufsize)
     transp.state = {ReadPaused, WritePaused}
     transp.queue = initDeque[StreamVector]()
-    transp.future = newFuture[void]("stream.socket.transport")
+    transp.future = Future[void].Raising([]).init(
+      "stream.socket.transport", {FutureFlag.OwnCancelSchedule})
     GC_ref(transp)
     transp
 
@@ -619,7 +620,8 @@ when defined(windows):
     transp.flags = flags
     transp.state = {ReadPaused, WritePaused}
     transp.queue = initDeque[StreamVector]()
-    transp.future = newFuture[void]("stream.pipe.transport")
+    transp.future = Future[void].Raising([]).init(
+      "stream.pipe.transport", {FutureFlag.OwnCancelSchedule})
     GC_ref(transp)
     transp
 
@@ -1457,7 +1459,8 @@ else:
     transp.buffer = newSeq[byte](bufsize)
     transp.state = {ReadPaused, WritePaused}
     transp.queue = initDeque[StreamVector]()
-    transp.future = newFuture[void]("socket.stream.transport")
+    transp.future = Future[void].Raising([]).init(
+      "socket.stream.transport", {FutureFlag.OwnCancelSchedule})
     GC_ref(transp)
     transp
 
@@ -1473,7 +1476,8 @@ else:
     transp.buffer = newSeq[byte](bufsize)
     transp.state = {ReadPaused, WritePaused}
     transp.queue = initDeque[StreamVector]()
-    transp.future = newFuture[void]("pipe.stream.transport")
+    transp.future = Future[void].Raising([]).init(
+      "pipe.stream.transport", {FutureFlag.OwnCancelSchedule})
     GC_ref(transp)
     transp
 
@@ -1806,6 +1810,9 @@ proc connect*(address: TransportAddress,
   if TcpNoDelay in flags: mappedFlags.incl(SocketFlags.TcpNoDelay)
   connect(address, bufferSize, child, localAddress, mappedFlags, dualstack)
 
+proc closed*(server: StreamServer): bool =
+  server.status == ServerStatus.Closed
+
 proc close*(server: StreamServer) =
   ## Release ``server`` resources.
   ##
@@ -1832,22 +1839,11 @@ proc close*(server: StreamServer) =
     else:
       server.sock.closeSocket(continuation)
 
-proc closeWait*(server: StreamServer): Future[void] {.
+proc closeWait*(server: StreamServer): Future[void] {.async: (raises: []).} =
-     async: (raw: true, raises: []).} =
   ## Close server ``server`` and release all resources.
-  let retFuture = newFuture[void](
+  if not server.closed():
-    "stream.server.closeWait", {FutureFlag.OwnCancelSchedule})
-
-  proc continuation(udata: pointer) =
-    retFuture.complete()
-
     server.close()
-
+    await noCancel(server.join())
-  if not(server.loopFuture.finished()):
-    server.loopFuture.addCallback(continuation, cast[pointer](retFuture))
-  else:
-    retFuture.complete()
-  retFuture
 
 proc getBacklogSize(backlog: int): cint =
   doAssert(backlog >= 0 and backlog <= high(int32))
@@ -2058,7 +2054,9 @@ proc createStreamServer*(host: TransportAddress,
   sres.init = init
   sres.bufferSize = bufferSize
   sres.status = Starting
-  sres.loopFuture = newFuture[void]("stream.transport.server")
+  sres.loopFuture = asyncloop.init(
+    Future[void].Raising([]), "stream.transport.server",
+    {FutureFlag.OwnCancelSchedule})
   sres.udata = udata
   sres.dualstack = dualstack
   if localAddress.family == AddressFamily.None:
@@ -2630,6 +2628,23 @@ proc join*(transp: StreamTransport): Future[void] {.
     retFuture.complete()
   return retFuture
 
+proc closed*(transp: StreamTransport): bool {.inline.} =
+  ## Returns ``true`` if transport in closed state.
+  ({ReadClosed, WriteClosed} * transp.state != {})
+
+proc finished*(transp: StreamTransport): bool {.inline.} =
+  ## Returns ``true`` if transport in finished (EOF) state.
+  ({ReadEof, WriteEof} * transp.state != {})
+
+proc failed*(transp: StreamTransport): bool {.inline.} =
+  ## Returns ``true`` if transport in error state.
+  ({ReadError, WriteError} * transp.state != {})
+
+proc running*(transp: StreamTransport): bool {.inline.} =
+  ## Returns ``true`` if transport is still pending.
+  ({ReadClosed, ReadEof, ReadError,
+    WriteClosed, WriteEof, WriteError} * transp.state == {})
+
 proc close*(transp: StreamTransport) =
   ## Closes and frees resources of transport ``transp``.
   ##
@@ -2672,31 +2687,11 @@ proc close*(transp: StreamTransport) =
       elif transp.kind == TransportKind.Socket:
         closeSocket(transp.fd, continuation)
 
-proc closeWait*(transp: StreamTransport): Future[void] {.
+proc closeWait*(transp: StreamTransport): Future[void] {.async: (raises: []).} =
-    async: (raw: true, raises: []).} =
   ## Close and frees resources of transport ``transp``.
-  let retFuture = newFuture[void](
+  if not transp.closed():
-    "stream.transport.closeWait", {FutureFlag.OwnCancelSchedule})
-
-  if {ReadClosed, WriteClosed} * transp.state != {}:
-    retFuture.complete()
-    return retFuture
-
-  proc continuation(udata: pointer) {.gcsafe.} =
-    retFuture.complete()
-
-  proc cancellation(udata: pointer) {.gcsafe.} =
-    # We are not going to change the state of `retFuture` to cancelled, so we
-    # will prevent the entire sequence of Futures from being cancelled.
-    discard
-
     transp.close()
-  if transp.future.finished():
+    await noCancel(transp.join())
-    retFuture.complete()
-  else:
-    transp.future.addCallback(continuation, cast[pointer](retFuture))
-    retFuture.cancelCallback = cancellation
-  retFuture
 
 proc shutdownWait*(transp: StreamTransport): Future[void] {.
     async: (raw: true, raises: [TransportError, CancelledError]).} =
@@ -2756,23 +2751,6 @@ proc shutdownWait*(transp: StreamTransport): Future[void] {.
       callSoon(continuation, nil)
     retFuture
 
-proc closed*(transp: StreamTransport): bool {.inline.} =
-  ## Returns ``true`` if transport in closed state.
-  ({ReadClosed, WriteClosed} * transp.state != {})
-
-proc finished*(transp: StreamTransport): bool {.inline.} =
-  ## Returns ``true`` if transport in finished (EOF) state.
-  ({ReadEof, WriteEof} * transp.state != {})
-
-proc failed*(transp: StreamTransport): bool {.inline.} =
-  ## Returns ``true`` if transport in error state.
-  ({ReadError, WriteError} * transp.state != {})
-
-proc running*(transp: StreamTransport): bool {.inline.} =
-  ## Returns ``true`` if transport is still pending.
-  ({ReadClosed, ReadEof, ReadError,
-    WriteClosed, WriteEof, WriteError} * transp.state == {})
-
 proc fromPipe2*(fd: AsyncFD, child: StreamTransport = nil,
                 bufferSize = DefaultStreamBufferSize
                ): Result[StreamTransport, OSErrorCode] =