From f1cf6d36fc6c09357566c67a7093922ddb0626ec Mon Sep 17 00:00:00 2001
From: cheatfate <ka@hardcore.kiev.ua>
Date: Tue, 24 Jul 2018 16:23:35 +0300
Subject: [PATCH] Fix double completion issue in reading procedures.

---
 asyncdispatch2/transports/stream.nim | 28 ++++++----------------------
 1 file changed, 6 insertions(+), 22 deletions(-)

diff --git a/asyncdispatch2/transports/stream.nim b/asyncdispatch2/transports/stream.nim
index 4ad1af7b..99dea6ec 100644
--- a/asyncdispatch2/transports/stream.nim
+++ b/asyncdispatch2/transports/stream.nim
@@ -132,10 +132,6 @@ template setReadError(t, e: untyped) =
   (t).state.incl(ReadError)
   (t).error = newException(TransportOsError, osErrorMsg((e)))
 
-template finishReader(t: untyped) =
-  var reader = (t).reader
-  reader.complete()
-
 template checkPending(t: untyped) =
   if not isNil((t).reader):
     raise newException(TransportError, "Read operation already pending!")
@@ -319,7 +315,8 @@ when defined(windows):
           transp.setReadError(err)
         if not isNil(transp.reader):
           if not transp.reader.finished:
-            transp.finishReader()
+            transp.reader.complete()
+            transp.reader = nil
         if ReadPaused in transp.state:
           # Transport buffer is full, so we will not continue on reading.
           break
@@ -346,13 +343,15 @@ when defined(windows):
               elif int32(err) in {WSAECONNRESET, WSAENETRESET}:
                 if not isNil(transp.reader):
                   transp.state = {ReadEof, ReadPaused}
-                  transp.finishReader()
+                  transp.reader.complete()
+                  transp.reader = nil
               elif int32(err) != ERROR_IO_PENDING:
                 transp.state.excl(ReadPending)
                 transp.state.incl(ReadPaused)
                 transp.setReadError(err)
                 if not isNil(transp.reader):
-                  transp.finishReader()
+                  transp.reader.complete()
+                  transp.reader = nil
         ## Finish Loop
         break
 
@@ -967,9 +966,6 @@ proc readExactly*(transp: StreamTransport, pbytes: pointer,
       if ReadPaused in transp.state:
         transp.resumeRead()
       await transp.reader
-      # we need to clear transp.reader to avoid double completion of this
-      # Future[T], because readLoop continues working.
-      transp.reader = nil
 
 proc readOnce*(transp: StreamTransport, pbytes: pointer,
                nbytes: int): Future[int] {.async.} =
@@ -1057,9 +1053,6 @@ proc readUntil*(transp: StreamTransport, pbytes: pointer, nbytes: int,
       if ReadPaused in transp.state:
         transp.resumeRead()
       await transp.reader
-      # we need to clear transp.reader to avoid double completion of this
-      # Future[T], because readLoop continues working.
-      transp.reader = nil
 
 proc readLine*(transp: StreamTransport, limit = 0,
                sep = "\r\n"): Future[string] {.async.} =
@@ -1111,9 +1104,6 @@ proc readLine*(transp: StreamTransport, limit = 0,
       if ReadPaused in transp.state:
         transp.resumeRead()
       await transp.reader
-      # we need to clear transp.reader to avoid double completion of this
-      # Future[T], because readLoop continues working.
-      transp.reader = nil
 
 proc read*(transp: StreamTransport, n = -1): Future[seq[byte]] {.async.} =
   ## Read all bytes (n == -1) or exactly `n` bytes from transport ``transp``.
@@ -1157,9 +1147,6 @@ proc read*(transp: StreamTransport, n = -1): Future[seq[byte]] {.async.} =
     if ReadPaused in transp.state:
       transp.resumeRead()
     await transp.reader
-    # we need to clear transp.reader to avoid double completion of this
-    # Future[T], because readLoop continues working.
-    transp.reader = nil
 
 proc consume*(transp: StreamTransport, n = -1): Future[int] {.async.} =
   ## Consume all bytes (n == -1) or ``n`` bytes from transport ``transp``.
@@ -1195,9 +1182,6 @@ proc consume*(transp: StreamTransport, n = -1): Future[int] {.async.} =
     if ReadPaused in transp.state:
       transp.resumeRead()
     await transp.reader
-    # we need to clear transp.reader to avoid double completion of this
-    # Future[T], because readLoop continues working.
-    transp.reader = nil
 
 proc join*(transp: StreamTransport) {.async.} =
   ## Wait until ``transp`` will not be closed.