PFuture[void] now works.

Return types can also be completely ommitted. PFuture[void] will then be implicitly deduced.
2026-06-03 10:24:44 +00:00 · 2014-03-15 00:09:33 +00:00
parent 0519afba1d
commit de64e8ec22
2 changed files with 65 additions and 39 deletions
--- a/lib/pure/asyncio2.nim
+++ b/lib/pure/asyncio2.nim
@@ -43,6 +43,14 @@ proc complete*[T](future: PFuture[T], val: T) =
  if future.cb != nil:
    future.cb()

+proc complete*(future: PFuture[void]) =
+  ## Completes a void ``future``.
+  assert(not future.finished, "Future already finished, cannot finish twice.")
+  assert(future.error == nil)
+  future.finished = true
+  if future.cb != nil:
+    future.cb()
+
 proc fail*[T](future: PFuture[T], error: ref EBase) =
  ## Completes ``future`` with ``error``.
  assert(not future.finished, "Future already finished, cannot finish twice.")
@@ -76,7 +84,8 @@ proc read*[T](future: PFuture[T]): T =
  ## If the result of the future is an error then that error will be raised.
  if future.finished:
    if future.error != nil: raise future.error
-    return future.value
+    when T isnot void:
+      return future.value
  else:
    # TODO: Make a custom exception type for this?
    raise newException(EInvalidValue, "Future still in progress.")
@@ -243,13 +252,13 @@ when defined(windows) or defined(nimdoc):
                  RemoteSockaddr, RemoteSockaddrLength)

  proc connect*(p: PDispatcher, socket: TSocketHandle, address: string, port: TPort,
-    af = AF_INET): PFuture[int] =
+    af = AF_INET): PFuture[void] =
    ## Connects ``socket`` to server at ``address:port``.
    ##
    ## Returns a ``PFuture`` which will complete when the connection succeeds
    ## or an error occurs.
    verifyPresence(p, socket)
-    var retFuture = newFuture[int]()# TODO: Change to void when that regression is fixed.
+    var retFuture = newFuture[void]()
    # Apparently ``ConnectEx`` expects the socket to be initially bound:
    var saddr: Tsockaddr_in
    saddr.sin_family = int16(toInt(af))
@@ -271,7 +280,7 @@ when defined(windows) or defined(nimdoc):
        proc (sock: TSocketHandle, bytesCount: DWord, errcode: TOSErrorCode) =
          if not retFuture.finished:
            if errcode == TOSErrorCode(-1):
-              retFuture.complete(0)
+              retFuture.complete()
            else:
              retFuture.fail(newException(EOS, osErrorMsg(errcode)))
      )
@@ -281,7 +290,7 @@ when defined(windows) or defined(nimdoc):
      if ret:
        # Request to connect completed immediately.
        success = true
-        retFuture.complete(0)
+        retFuture.complete()
        # We don't deallocate ``ol`` here because even though this completed
        # immediately poll will still be notified about its completion and it will
        # free ``ol``.
@@ -362,11 +371,11 @@ when defined(windows) or defined(nimdoc):
      # free ``ol``.
    return retFuture

-  proc send*(p: PDispatcher, socket: TSocketHandle, data: string): PFuture[int] =
+  proc send*(p: PDispatcher, socket: TSocketHandle, data: string): PFuture[void] =
    ## Sends ``data`` to ``socket``. The returned future will complete once all
    ## data has been sent.
    verifyPresence(p, socket)
-    var retFuture = newFuture[int]()
+    var retFuture = newFuture[void]()

    var dataBuf: TWSABuf
    dataBuf.buf = data
@@ -378,7 +387,7 @@ when defined(windows) or defined(nimdoc):
      proc (sock: TSocketHandle, bytesCount: DWord, errcode: TOSErrorCode) =
        if not retFuture.finished:
          if errcode == TOSErrorCode(-1):
-            retFuture.complete(0)
+            retFuture.complete()
          else:
            retFuture.fail(newException(EOS, osErrorMsg(errcode)))
    )
@@ -391,7 +400,7 @@ when defined(windows) or defined(nimdoc):
        retFuture.fail(newException(EOS, osErrorMsg(err)))
        dealloc(ol)
    else:
-      retFuture.complete(0)
+      retFuture.complete()
      # We don't deallocate ``ol`` here because even though this completed
      # immediately poll will still be notified about its completion and it will
      # free ``ol``.
@@ -564,12 +573,12 @@ else:
        # (e.g. socket disconnected).
  
  proc connect*(p: PDispatcher, socket: TSocketHandle, address: string, port: TPort,
-    af = AF_INET): PFuture[int] =
-    var retFuture = newFuture[int]()
+    af = AF_INET): PFuture[void] =
+    var retFuture = newFuture[void]()
    
    proc cb(sock: TSocketHandle): bool =
      # We have connected.
-      retFuture.complete(0)
+      retFuture.complete()
      return true
    
    var aiList = getAddrInfo(address, port, af)
@@ -581,7 +590,7 @@ else:
      if ret == 0:
        # Request to connect completed immediately.
        success = true
-        retFuture.complete(0)
+        retFuture.complete()
        break
      else:
        lastError = osLastError()
@@ -635,8 +644,8 @@ else:
    addRead(p, socket, cb)
    return retFuture

-  proc send*(p: PDispatcher, socket: TSocketHandle, data: string): PFuture[int] =
-    var retFuture = newFuture[int]()
+  proc send*(p: PDispatcher, socket: TSocketHandle, data: string): PFuture[void] =
+    var retFuture = newFuture[void]()
    
    var written = 0
    
@@ -656,7 +665,7 @@ else:
        if res != netSize:
          result = false # We still have data to send.
        else:
-          retFuture.complete(0)
+          retFuture.complete()
    addWrite(p, socket, cb)
    return retFuture

@@ -789,12 +798,17 @@ macro async*(prc: stmt): stmt {.immediate.} =

  hint("Processing " & prc[0].getName & " as an async proc.")

+  let returnType = prc[3][0]
+  var subtypeName = ""
  # Verify that the return type is a PFuture[T]
-  if prc[3][0].kind == nnkIdent:
-    error("Expected return type of 'PFuture' got '" & $prc[3][0] & "'")
-  elif prc[3][0].kind == nnkBracketExpr:
-    if $prc[3][0][0] != "PFuture":
-      error("Expected return type of 'PFuture' got '" & $prc[3][0][0] & "'")
+  if returnType.kind == nnkIdent:
+    error("Expected return type of 'PFuture' got '" & $returnType & "'")
+  elif returnType.kind == nnkBracketExpr:
+    if $returnType[0] != "PFuture":
+      error("Expected return type of 'PFuture' got '" & $returnType[0] & "'")
+    subtypeName = $returnType[1].ident
+  elif returnType.kind == nnkEmpty:
+    subtypeName = "void"
  
  # TODO: Why can't I use genSym? I get illegal capture errors for Syms.
  # TODO: It seems genSym is broken. Change all usages back to genSym when fixed
@@ -807,20 +821,24 @@ macro async*(prc: stmt): stmt {.immediate.} =
    newVarStmt(retFutureSym, 
      newCall(
        newNimNode(nnkBracketExpr).add(
-          newIdentNode("newFuture"),
-          prc[3][0][1])))) # Get type from return type of this proc.
-
+          newIdentNode(!"newFuture"), # TODO: Strange bug here? Remove the `!`.
+          newIdentNode(subtypeName))))) # Get type from return type of this proc
+  echo(treeRepr(outerProcBody))
  # -> iterator nameIter(): PFutureBase {.closure.} = 
  # ->   var result: T
  # ->   <proc_body>
  # ->   complete(retFuture, result)
  var iteratorNameSym = newIdentNode($prc[0].getName & "Iter") #genSym(nskIterator, $prc[0].ident & "Iter")
  var procBody = prc[6].processBody(retFutureSym)
-  procBody.insert(0, newNimNode(nnkVarSection).add(
-    newIdentDefs(newIdentNode("result"), prc[3][0][1]))) # -> var result: T
-  procBody.add(
-    newCall(newIdentNode("complete"),
-      retFutureSym, newIdentNode("result"))) # -> complete(retFuture, result)
+  if subtypeName != "void":
+    procBody.insert(0, newNimNode(nnkVarSection).add(
+      newIdentDefs(newIdentNode("result"), returnType[1]))) # -> var result: T
+    procBody.add(
+      newCall(newIdentNode("complete"),
+        retFutureSym, newIdentNode("result"))) # -> complete(retFuture, result)
+  else:
+    # -> complete(retFuture)
+    procBody.add(newCall(newIdentNode("complete"), retFutureSym))
  
  var closureIterator = newProc(iteratorNameSym, [newIdentNode("PFutureBase")],
                                procBody, nnkIteratorDef)
@@ -855,6 +873,12 @@ macro async*(prc: stmt): stmt {.immediate.} =
  for i in 0 .. <result[4].len:
    if result[4][i].ident == !"async":
      result[4].del(i)
+  if subtypeName == "void":
+    # Add discardable pragma.
+    result[4].add(newIdentNode("discardable"))
+    if returnType.kind == nnkEmpty:
+      # Add PFuture[void]
+      result[3][0] = parseExpr("PFuture[void]")

  result[6] = outerProcBody

--- a/tests/async/tasyncawait.nim
+++ b/tests/async/tasyncawait.nim
@@ -14,18 +14,18 @@ const

 var clientCount = 0

-proc sendMessages(disp: PDispatcher, client: TSocketHandle): PFuture[int] {.async.} =
+proc sendMessages(disp: PDispatcher, client: TSocketHandle) {.async.} =
  for i in 0 .. <messagesToSend:
-    discard await disp.send(client, "Message " & $i & "\c\L")
+    await disp.send(client, "Message " & $i & "\c\L")

-proc launchSwarm(disp: PDispatcher, port: TPort): PFuture[int] {.async.} =
+proc launchSwarm(disp: PDispatcher, port: TPort) {.async.} =
  for i in 0 .. <swarmSize:
    var sock = disp.socket()

    #disp.register(sock)
-    discard await disp.connect(sock, "localhost", port)
+    await disp.connect(sock, "localhost", port)
    when true:
-      discard await sendMessages(disp, sock)
+      await sendMessages(disp, sock)
      disp.close(sock)
    else:
      # Issue #932: https://github.com/Araq/Nimrod/issues/932
@@ -34,7 +34,7 @@ proc launchSwarm(disp: PDispatcher, port: TPort): PFuture[int] {.async.} =
        proc () =
          disp.close(sock)

-proc readMessages(disp: PDispatcher, client: TSocketHandle): PFuture[int] {.async.} =
+proc readMessages(disp: PDispatcher, client: TSocketHandle) {.async.} =
  while true:
    var line = await disp.recvLine(client)
    if line == "":
@@ -47,16 +47,18 @@ proc readMessages(disp: PDispatcher, client: TSocketHandle): PFuture[int] {.asyn
      else:
        doAssert false

-proc createServer(disp: PDispatcher, port: TPort): PFuture[int] {.async.} =
+proc createServer(disp: PDispatcher, port: TPort) {.async.} =
  var server = disp.socket()
  #disp.register(server)
  server.bindAddr(port)
  server.listen()
  while true:
-    discard readMessages(disp, await disp.accept(server))
+    var client = await disp.accept(server)
+    readMessages(disp, client)
+    # TODO: Test: readMessages(disp, await disp.accept(server))

-discard disp.createServer(TPort(10335))
-discard disp.launchSwarm(TPort(10335))
+disp.createServer(TPort(10335))
+disp.launchSwarm(TPort(10335))
 while true:
  disp.poll()
  if clientCount == swarmSize: break