Async readLine now works. Fixes recv issues.

When using MSG_PEEK and data is retrieved ``lpNumberOfBytesRecvd`` will
not be set to the number of bytes read by WSARecv. The buffer must
therefore be checked to ensure it's empty when determining whether
``recv`` shall return "" to signal disconnection as we want to read as
much data as has been received by the system.

lib/pure/asyncio2.nim

@@ -99,7 +99,8 @@ when defined(windows):
 
     TCompletionData* = object
       sock: TSocketHandle
-      cb: proc (sock: TSocketHandle, errcode: TOSErrorCode) {.closure.}
+      cb: proc (sock: TSocketHandle, bytesTransferred: DWORD,
+                errcode: TOSErrorCode) {.closure.}
 
     PDispatcher* = ref object
       ioPort: THandle
@@ -143,13 +144,15 @@ when defined(windows):
       # This is useful for ensuring the reliability of the overlapped struct.
       assert customOverlapped.data.sock == lpCompletionKey.TSocketHandle
 
-      customOverlapped.data.cb(customOverlapped.data.sock, TOSErrorCode(-1))
+      customOverlapped.data.cb(customOverlapped.data.sock,
+          lpNumberOfBytesTransferred, TOSErrorCode(-1))
       dealloc(customOverlapped)
     else:
       let errCode = OSLastError()
       if lpOverlapped != nil:
         assert customOverlapped.data.sock == lpCompletionKey.TSocketHandle
-        customOverlapped.data.cb(customOverlapped.data.sock, errCode)
+        customOverlapped.data.cb(customOverlapped.data.sock,
+            lpNumberOfBytesTransferred, errCode)
         dealloc(customOverlapped)
       else:
         if errCode.int32 == WAIT_TIMEOUT:
@@ -248,7 +251,7 @@ when defined(windows):
       # http://blogs.msdn.com/b/oldnewthing/archive/2011/02/02/10123392.aspx
       var ol = cast[PCustomOverlapped](alloc0(sizeof(TCustomOverlapped)))
       ol.data = TCompletionData(sock: socket, cb:
-        proc (sock: TSocketHandle, errcode: TOSErrorCode) =
+        proc (sock: TSocketHandle, bytesCount: DWord, errcode: TOSErrorCode) =
           if not retFuture.finished:
             if errcode == TOSErrorCode(-1):
               retFuture.complete(0)
@@ -297,12 +300,15 @@ when defined(windows):
     var flagsio = flags.dword
     var ol = cast[PCustomOverlapped](alloc0(sizeof(TCustomOverlapped)))
     ol.data = TCompletionData(sock: socket, cb:
-      proc (sock: TSocketHandle, errcode: TOSErrorCode) =
+      proc (sock: TSocketHandle, bytesCount: DWord, errcode: TOSErrorCode) =
         if not retFuture.finished:
           if errcode == TOSErrorCode(-1):
-            var data = newString(size)
+            if bytesCount == 0 and dataBuf.buf[0] == '\0':
-            copyMem(addr data[0], addr dataBuf.buf[0], size)
+              retFuture.complete("")
-            retFuture.complete($data)
+            else:
+              var data = newString(size)
+              copyMem(addr data[0], addr dataBuf.buf[0], size)
+              retFuture.complete($data)
           else:
             retFuture.fail(newException(EOS, osErrorMsg(errcode)))
     )
@@ -314,8 +320,13 @@ when defined(windows):
       if err.int32 != ERROR_IO_PENDING:
         retFuture.fail(newException(EOS, osErrorMsg(err)))
         dealloc(ol)
-    elif ret == 0 and bytesReceived == 0:
+    elif ret == 0 and bytesReceived == 0 and dataBuf.buf[0] == '\0':
-      # Disconnected
+      # We have to ensure that the buffer is empty because WSARecv will tell
+      # us immediatelly when it was disconnected, even when there is still
+      # data in the buffer.
+      # We want to give the user as much data as we can. So we only return
+      # the empty string (which signals a disconnection) when there is
+      # nothing left to read.
       retFuture.complete("")
       # TODO: "For message-oriented sockets, where a zero byte message is often 
       # allowable, a failure with an error code of WSAEDISCON is used to 
@@ -343,7 +354,7 @@ when defined(windows):
     var bytesReceived, flags: DWord
     var ol = cast[PCustomOverlapped](alloc0(sizeof(TCustomOverlapped)))
     ol.data = TCompletionData(sock: socket, cb:
-      proc (sock: TSocketHandle, errcode: TOSErrorCode) =
+      proc (sock: TSocketHandle, bytesCount: DWord, errcode: TOSErrorCode) =
         if not retFuture.finished:
           if errcode == TOSErrorCode(-1):
             retFuture.complete(0)
@@ -404,7 +415,7 @@ when defined(windows):
 
     var ol = cast[PCustomOverlapped](alloc0(sizeof(TCustomOverlapped)))
     ol.data = TCompletionData(sock: socket, cb:
-      proc (sock: TSocketHandle, errcode: TOSErrorCode) =
+      proc (sock: TSocketHandle, bytesCount: DWord, errcode: TOSErrorCode) =
         if not retFuture.finished:
           if errcode == TOSErrorCode(-1):
             completeAccept()
@@ -525,6 +536,15 @@ proc processBody(node, retFutureSym: PNimrodNode): PNimrodNode {.compileTime.} =
     for i in 0 .. <node.len:
       result[i] = processBody(node[i], retFutureSym)
 
+proc getName(node: PNimrodNode): string {.compileTime.} =
+  case node.kind
+  of nnkPostfix:
+    return $node[1].ident
+  of nnkIdent:
+    return $node.ident
+  else:
+    assert false
+
 macro async*(prc: stmt): stmt {.immediate.} =
   expectKind(prc, nnkProcDef)
 
@@ -553,7 +573,7 @@ macro async*(prc: stmt): stmt {.immediate.} =
   # ->   var result: T
   # ->   <proc_body>
   # ->   complete(retFuture, result)
-  var iteratorNameSym = newIdentNode($prc[0].ident & "Iter") #genSym(nskIterator, $prc[0].ident & "Iter")
+  var iteratorNameSym = newIdentNode($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
@@ -568,7 +588,7 @@ macro async*(prc: stmt): stmt {.immediate.} =
 
   # -> var nameIterVar = nameIter
   # -> var first = nameIterVar()
-  var varNameIterSym = newIdentNode($prc[0].ident & "IterVar") #genSym(nskVar, $prc[0].ident & "IterVar")
+  var varNameIterSym = newIdentNode($prc[0].getName & "IterVar") #genSym(nskVar, $prc[0].ident & "IterVar")
   var varNameIter = newVarStmt(varNameIterSym, iteratorNameSym)
   outerProcBody.add varNameIter
   var varFirstSym = genSym(nskVar, "first")
@@ -600,18 +620,14 @@ macro async*(prc: stmt): stmt {.immediate.} =
   echo(toStrLit(result))
 
 proc recvLine*(p: PDispatcher, socket: TSocketHandle): PFuture[string] {.async.} =
-  ## Reads a line of data from ``socket``.
+  ## Reads a line of data from ``socket``. Returned future will complete once
+  ## a full line is read or an error occurs.
   ##
   ## If a full line is read ``\r\L`` is not
   ## added to ``line``, however if solely ``\r\L`` is read then ``line``
   ## will be set to it.
   ## 
   ## If the socket is disconnected, ``line`` will be set to ``""``.
-  ##
-  ## An EOS exception will be raised in the case of a socket error.
-  ##
-  ## A timeout can be specified in miliseconds, if data is not received within
-  ## the specified time an ETimeout exception will be raised.
   
   template addNLIfEmpty(): stmt =
     if result.len == 0:
@@ -645,7 +661,7 @@ when isMainModule:
   when true:
     # Await tests
     proc main(p: PDispatcher): PFuture[int] {.async.} =
-      discard await p.connect(sock, "localhost", TPort(6667))
+      discard await p.connect(sock, "irc.freenode.net", TPort(6667))
       while true:
         var line = await p.recvLine(sock)
         echo("Line is: ", line.repr)
@@ -653,6 +669,16 @@ when isMainModule:
           echo "Disconnected"
           break
 
+    proc peekTest(p: PDispatcher): PFuture[int] {.async.} =
+      discard await p.connect(sock, "localhost", TPort(6667))
+      while true:
+        var line = await p.recv(sock, 1, MSG_PEEK)
+        var line2 = await p.recv(sock, 1)
+        echo(line.repr)
+        echo(line2.repr)
+        echo("---")
+        if line2 == "": break
+        sleep(500)
 
     var f = main(p)