Added Windows asyncfile implementation.

lib/pure/asyncdispatch.nim

@@ -226,8 +226,8 @@ when defined(windows) or defined(nimdoc):
     TCompletionKey = Dword
 
     TCompletionData* = object
-      sock: TAsyncFD
-      cb: proc (sock: TAsyncFD, bytesTransferred: Dword,
+      sock*: TAsyncFD # TODO: Rename this.
+      cb*: proc (sock: TAsyncFD, bytesTransferred: Dword,
                 errcode: OSErrorCode) {.closure,gcsafe.}
 
     PDispatcher* = ref object of PDispatcherBase
@@ -237,7 +237,7 @@ when defined(windows) or defined(nimdoc):
     TCustomOverlapped = object of TOVERLAPPED
       data*: TCompletionData
 
-    PCustomOverlapped = ref TCustomOverlapped
+    PCustomOverlapped* = ref TCustomOverlapped
 
     TAsyncFD* = distinct int
 
@@ -247,7 +247,7 @@ when defined(windows) or defined(nimdoc):
   proc newDispatcher*(): PDispatcher =
     ## Creates a new Dispatcher instance.
     new result
-    result.ioPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, 0, 0, 1)
+    result.ioPort = createIoCompletionPort(INVALID_HANDLE_VALUE, 0, 0, 1)
     result.handles = initSet[TAsyncFD]()
     result.timers = @[]
 
@@ -260,7 +260,7 @@ when defined(windows) or defined(nimdoc):
   proc register*(sock: TAsyncFD) =
     ## Registers ``sock`` with the dispatcher.
     let p = getGlobalDispatcher()
-    if CreateIoCompletionPort(sock.THandle, p.ioPort,
+    if createIoCompletionPort(sock.THandle, p.ioPort,
                               cast[TCompletionKey](sock), 1) == 0:
       raiseOSError(osLastError())
     p.handles.incl(sock)
@@ -286,7 +286,7 @@ when defined(windows) or defined(nimdoc):
     var lpNumberOfBytesTransferred: Dword
     var lpCompletionKey: ULONG
     var customOverlapped: PCustomOverlapped
-    let res = GetQueuedCompletionStatus(p.ioPort,
+    let res = getQueuedCompletionStatus(p.ioPort,
         addr lpNumberOfBytesTransferred, addr lpCompletionKey,
         cast[ptr POVERLAPPED](addr customOverlapped), llTimeout).bool
 
@@ -1231,10 +1231,9 @@ proc runForever*() =
   while true:
     poll()
 
-proc waitFor*[T](fut: PFuture[T]) =
+proc waitFor*[T](fut: PFuture[T]): T =
   ## **Blocks** the current thread until the specified future completes.
   while not fut.finished:
     poll()
 
-  if fut.failed:
-    raise fut.error
+  fut.read

lib/windows/winlean.nim

@@ -104,11 +104,11 @@ proc closeHandle*(hObject: THandle): WINBOOL {.stdcall, dynlib: "kernel32",
     importc: "CloseHandle".}
     
 proc readFile*(hFile: THandle, Buffer: pointer, nNumberOfBytesToRead: int32,
-               lpNumberOfBytesRead: var int32, lpOverlapped: pointer): WINBOOL{.
+               lpNumberOfBytesRead: ptr int32, lpOverlapped: pointer): WINBOOL{.
     stdcall, dynlib: "kernel32", importc: "ReadFile".}
     
 proc writeFile*(hFile: THandle, Buffer: pointer, nNumberOfBytesToWrite: int32,
-                lpNumberOfBytesWritten: var int32, 
+                lpNumberOfBytesWritten: ptr int32, 
                 lpOverlapped: pointer): WINBOOL{.
     stdcall, dynlib: "kernel32", importc: "WriteFile".}
 
@@ -573,12 +573,14 @@ proc waitForMultipleObjects*(nCount: DWORD, lpHandles: PWOHandleArray,
 
 const
   GENERIC_READ* = 0x80000000'i32
+  GENERIC_WRITE* = 0x40000000'i32
   GENERIC_ALL* = 0x10000000'i32
   FILE_SHARE_READ* = 1'i32
   FILE_SHARE_DELETE* = 4'i32
   FILE_SHARE_WRITE* = 2'i32
  
   CREATE_ALWAYS* = 2'i32
+  CREATE_NEW* = 1'i32
   OPEN_EXISTING* = 3'i32
   FILE_BEGIN* = 0'i32
   INVALID_SET_FILE_POINTER* = -1'i32
@@ -595,6 +597,7 @@ const
 # Error Constants
 const
   ERROR_ACCESS_DENIED* = 5
+  ERROR_HANDLE_EOF* = 38
 
 when useWinUnicode:
   proc createFileW*(lpFileName: WideCString, dwDesiredAccess, dwShareMode: DWORD,
@@ -649,10 +652,10 @@ proc unmapViewOfFile*(lpBaseAddress: pointer): WINBOOL {.stdcall,
 
 type
   TOVERLAPPED* {.pure, inheritable.} = object
-    Internal*: PULONG
-    InternalHigh*: PULONG
-    Offset*: DWORD
-    OffsetHigh*: DWORD
+    internal*: PULONG
+    internalHigh*: PULONG
+    offset*: DWORD
+    offsetHigh*: DWORD
     hEvent*: THandle
 
   POVERLAPPED* = ptr TOVERLAPPED
@@ -668,6 +671,7 @@ type
 
 const
   ERROR_IO_PENDING* = 997 # a.k.a WSA_IO_PENDING
+  FILE_FLAG_OVERLAPPED* = 1073741824
   WSAECONNABORTED* = 10053
   WSAECONNRESET* = 10054
   WSAEDISCON* = 10101
@@ -675,17 +679,21 @@ const
   WSAETIMEDOUT* = 10060
   ERROR_NETNAME_DELETED* = 64
 
-proc CreateIoCompletionPort*(FileHandle: THandle, ExistingCompletionPort: THandle,
+proc createIoCompletionPort*(FileHandle: THandle, ExistingCompletionPort: THandle,
                              CompletionKey: DWORD,
                              NumberOfConcurrentThreads: DWORD): THandle{.stdcall,
     dynlib: "kernel32", importc: "CreateIoCompletionPort".}
 
-proc GetQueuedCompletionStatus*(CompletionPort: THandle,
+proc getQueuedCompletionStatus*(CompletionPort: THandle,
     lpNumberOfBytesTransferred: PDWORD, lpCompletionKey: PULONG,
                                 lpOverlapped: ptr POVERLAPPED,
                                 dwMilliseconds: DWORD): WINBOOL{.stdcall,
     dynlib: "kernel32", importc: "GetQueuedCompletionStatus".}
 
+proc getOverlappedResult*(hFile: THandle, lpOverlapped: TOverlapped,
+              lpNumberOfBytesTransferred: var DWORD, bWait: WINBOOL): WINBOOL{.
+    stdcall, dynlib: "kernel32", importc: "GetOverlappedResult".}
+
 const 
  IOC_OUT* = 0x40000000
  IOC_IN*  = 0x80000000

tests/async/tasyncfile.nim

@@ -0,0 +1,14 @@
+discard """
+  file: "tasyncexceptions.nim"
+  exitcode: 0
+"""
+import asyncfile, asyncdispatch, os
+
+proc main() {.async.} =
+  var file = openAsync(getTempDir() / "foobar.txt", fmReadWrite)
+  await file.write("test")
+  file.setFilePos(0)
+  let data = await file.readAll()
+  doAssert data == "test"
+
+waitFor main()