futures: sinkify and lentify

this avoids copies here and there throughout the pipeline - ie
`copyString` and friends can often be avoided when moving things into
and out of futures

annoyingly, one has to sprinkle the codebase liberally with `sink` and
`move` for the pipeline to work well - sink stuff _generally_ works
better in orc/arc

chronos/internal/asyncfutures.nim

@@ -202,14 +202,14 @@ proc finish(fut: FutureBase, state: FutureState) =
   when chronosFutureTracking:
     scheduleDestructor(fut)
 
-proc complete[T](future: Future[T], val: T, loc: ptr SrcLoc) =
+proc complete[T](future: Future[T], val: sink T, loc: ptr SrcLoc) =
   if not(future.cancelled()):
     checkFinished(future, loc)
     doAssert(isNil(future.internalError))
-    future.internalValue = val
+    future.internalValue = move(val)
     future.finish(FutureState.Completed)
 
-template complete*[T](future: Future[T], val: T) =
+template complete*[T](future: Future[T], val: sink T) =
   ## Completes ``future`` with value ``val``.
   complete(future, val, getSrcLocation())
 

chronos/internal/asyncmacro.nim

@@ -157,7 +157,7 @@ proc wrapInTryFinally(
               newCall(ident "complete", fut)
             ),
             nnkElseExpr.newTree(
-              newCall(ident "complete", fut, ident "result")
+              newCall(ident "complete", fut, newCall(ident "move", ident "result"))
             )
           )
         )

chronos/streams/asyncstream.nim

@@ -755,7 +755,7 @@ proc write*(wstream: AsyncStreamWriter, sbytes: sink seq[byte],
   if isNil(wstream.wsource):
     var res: int
     try:
-      res = await write(wstream.tsource, sbytes, length)
+      res = await write(wstream.tsource, move(sbytes), length)
     except CancelledError as exc:
       raise exc
     except CatchableError as exc:
@@ -765,17 +765,11 @@ proc write*(wstream: AsyncStreamWriter, sbytes: sink seq[byte],
     wstream.bytesCount = wstream.bytesCount + uint64(length)
   else:
     if isNil(wstream.writerLoop):
-      await write(wstream.wsource, sbytes, length)
+      await write(wstream.wsource, move(sbytes), length)
       wstream.bytesCount = wstream.bytesCount + uint64(length)
     else:
       var item = WriteItem(kind: Sequence)
-      when declared(shallowCopy):
+      item.dataSeq = move(sbytes)
-        if not(isLiteral(sbytes)):
-          shallowCopy(item.dataSeq, sbytes)
-        else:
-          item.dataSeq = sbytes
-      else:
-        item.dataSeq = sbytes
       item.size = length
       item.future = newFuture[void]("async.stream.write(seq)")
       try:
@@ -808,7 +802,7 @@ proc write*(wstream: AsyncStreamWriter, sbytes: sink string,
   if isNil(wstream.wsource):
     var res: int
     try:
-      res = await write(wstream.tsource, sbytes, length)
+      res = await write(wstream.tsource, move(sbytes), length)
     except CancelledError as exc:
       raise exc
     except CatchableError as exc:
@@ -818,17 +812,11 @@ proc write*(wstream: AsyncStreamWriter, sbytes: sink string,
     wstream.bytesCount = wstream.bytesCount + uint64(length)
   else:
     if isNil(wstream.writerLoop):
-      await write(wstream.wsource, sbytes, length)
+      await write(wstream.wsource, move(sbytes), length)
       wstream.bytesCount = wstream.bytesCount + uint64(length)
     else:
       var item = WriteItem(kind: String)
-      when declared(shallowCopy):
+      item.dataStr = move(sbytes)
-        if not(isLiteral(sbytes)):
-          shallowCopy(item.dataStr, sbytes)
-        else:
-          item.dataStr = sbytes
-      else:
-        item.dataStr = sbytes
       item.size = length
       item.future = newFuture[void]("async.stream.write(string)")
       try:

chronos/streams/tlsstream.nim

@@ -59,7 +59,7 @@ type
 
   PEMContext = ref object
     data: seq[byte]
-  
+
   TrustAnchorStore* = ref object
     anchors: seq[X509TrustAnchor]
 
@@ -155,7 +155,7 @@ proc tlsWriteRec(engine: ptr SslEngineContext,
     var length = 0'u
     var buf = sslEngineSendrecBuf(engine[], length)
     doAssert(length != 0 and not isNil(buf))
-    await writer.wsource.write(buf, int(length))
+    await writer.wsource.write(move(buf), int(length))
     sslEngineSendrecAck(engine[], length)
     TLSResult.Success
   except AsyncStreamError as exc:
@@ -468,7 +468,7 @@ proc newTLSClientAsyncStream*(
   ## ``minVersion`` of bigger then ``maxVersion`` you will get an error.
   ##
   ## ``flags`` - custom TLS connection flags.
-  ## 
+  ##
   ## ``trustAnchors`` - use this if you want to use certificate trust
   ## anchors other than the default Mozilla trust anchors. If you pass
   ## a ``TrustAnchorStore`` you should reuse the same instance for

chronos/transports/stream.nim

@@ -10,8 +10,9 @@
 {.push raises: [].}
 
 import std/deques
+import stew/ptrops
 import ".."/[asyncloop, handles, osdefs, osutils, oserrno]
-import common
+import ./common
 
 type
   VectorKind = enum
@@ -770,7 +771,7 @@ when defined(windows):
         # Continue only if `retFuture` is not cancelled.
         if not(retFuture.finished()):
           let
-            pipeSuffix = $cast[cstring](unsafeAddr address.address_un[0])
+            pipeSuffix = $cast[cstring](baseAddr address.address_un)
             pipeAsciiName = PipeHeaderName & pipeSuffix[1 .. ^1]
             pipeName = toWideString(pipeAsciiName).valueOr:
               retFuture.fail(getTransportOsError(error))
@@ -806,7 +807,7 @@ when defined(windows):
 
   proc createAcceptPipe(server: StreamServer): Result[AsyncFD, OSErrorCode] =
     let
-      pipeSuffix = $cast[cstring](addr server.local.address_un)
+      pipeSuffix = $cast[cstring](baseAddr server.local.address_un)
       pipeName = ? toWideString(PipeHeaderName & pipeSuffix)
       openMode =
         if FirstPipe notin server.flags:
@@ -878,7 +879,7 @@ when defined(windows):
         if server.status notin {ServerStatus.Stopped, ServerStatus.Closed}:
           server.apending = true
           let
-            pipeSuffix = $cast[cstring](addr server.local.address_un)
+            pipeSuffix = $cast[cstring](baseAddr server.local.address_un)
             pipeAsciiName = PipeHeaderName & pipeSuffix
             pipeName = toWideString(pipeAsciiName).valueOr:
               raiseOsDefect(error, "acceptPipeLoop(): Unable to create name " &
@@ -2011,7 +2012,7 @@ proc createStreamServer*(host: TransportAddress,
     elif host.family in {AddressFamily.Unix}:
       # We do not care about result here, because if file cannot be removed,
       # `bindSocket` will return EADDRINUSE.
-      discard osdefs.unlink(cast[cstring](unsafeAddr host.address_un[0]))
+      discard osdefs.unlink(cast[cstring](baseAddr host.address_un))
 
     host.toSAddr(saddr, slen)
     if osdefs.bindSocket(SocketHandle(serverSocket),
@@ -2240,12 +2241,11 @@ proc write*(transp: StreamTransport, msg: sink string,
   var retFuture = newFuture[int]("stream.transport.write(string)")
   transp.checkClosed(retFuture)
   transp.checkWriteEof(retFuture)
-
   let
     nbytes = if msglen <= 0: len(msg) else: msglen
 
   var
-    pbytes = cast[ptr byte](unsafeAddr msg[0])
+    pbytes = cast[ptr byte](baseAddr msg)
     rbytes = nbytes
 
   fastWrite(transp, pbytes, rbytes, nbytes)
@@ -2253,7 +2253,7 @@ proc write*(transp: StreamTransport, msg: sink string,
   let
     written = nbytes - rbytes # In case fastWrite wrote some
 
-  var localCopy = msg
+  var localCopy = move(msg)
   retFuture.addCallback(proc(_: pointer) = reset(localCopy))
 
   pbytes = cast[ptr byte](addr localCopy[written])
@@ -2278,7 +2278,7 @@ proc write*[T](transp: StreamTransport, msg: sink seq[T],
     nbytes = if msglen <= 0: (len(msg) * sizeof(T)) else: (msglen * sizeof(T))
 
   var
-    pbytes = cast[ptr byte](unsafeAddr msg[0])
+    pbytes = cast[ptr byte](baseAddr msg)
     rbytes = nbytes
 
   fastWrite(transp, pbytes, rbytes, nbytes)
@@ -2286,7 +2286,7 @@ proc write*[T](transp: StreamTransport, msg: sink seq[T],
   let
     written = nbytes - rbytes # In case fastWrite wrote some
 
-  var localCopy = msg
+  var localCopy = move(msg)
   retFuture.addCallback(proc(_: pointer) = reset(localCopy))
 
   pbytes = cast[ptr byte](addr localCopy[written])