Merge #1627

1627: CancelIoEx and overal review of Win32-network r=coot a=coot

The primary goal of this PR was to add `CancelIoEx` to fix #1574.  In doing so I changed the interface and the end result is that:

* we don't use C type level wrappers for windows syscalls any more (apart from `GetQueuedCompletionStatus` where we need to use a windwo kernel C macro.
* using `GADTs` to ensure that we use the right combination of `OVERLAPPED` / `WSAOVERLAPPED`, `HANDLE` / `SOCKET` and `ErrCode` / `WsaErrCode`.
* there is a closed type family which ensures that some of the `castPtr` usage is actually safe, it is not exposed.  It could be removed, but then using `castPtr` would leak out to various modules - so I preferred the more elegant and local, though type havier approach.
* more tests, especially for error conditions in which we need to assure that we are not deallocating the stable pointer twice 💣 

This PR is done on top of `coot/windows-vectored-io` (and it merges into that branch) - this makes the scope of this PR adequate for the proposed changes.  For the moment the windows stuff is stacked on CI, but when devops will help with it I will be able to merge all the PRs in turn.

Co-authored-by: Marcin Szamotulski <[email protected]>

Win32-network/NOTICE

@@ -13,13 +13,9 @@ Copyright 2019 Input Output (Hong Kong) Ltd.
    limitations under the License.
 
 
-Parts of this project is based on 
+The project was initially based on:
 http://hackage.haskell.org/package/winio-0.1
 
-The following license applies to:
-  * ./cbits/Win32Async.c
-  * ./src/System/Win32/Async.hs
-
 Copyright 2007-2009 Felix Martini.
 
 Redistribution and use in source and binary forms, with or without

Win32-network/README.md

@@ -0,0 +1,21 @@
+# Asynchronious IO for Windows
+
+`Win32-network` provides low level api for doing IO / networking on Windows
+using Overlapped (or asynchronous) IO.  It supports:
+
+* `File` Api
+* `NamedPipes` Api
+* `winsock2` - Berkeley sockets api on Windows
+
+`NamedPipes` provide a good alternative for the lack of Unix Sockets on
+Windows, and there are ways of providing abstraction for both, though this is
+not present in this package.
+
+An application which is using this package should use `-threaded` option, as
+the io manager thread runs a blocking ffi call (e.g.
+[GetQueuedCompletionStatus](https://docs.microsoft.com/en-us/windows/win32/api/ioapiset/nf-ioapiset-getqueuedcompletionstatus)).
+
+## Acknowledgement
+
+The initial version of this library was based on
+[winio](https://hackage.haskell.org/package/winio) by Felix Martini.

Win32-network/Win32-network.cabal

@@ -12,7 +12,7 @@ maintainer:          [email protected], [email protected]
 copyright:           2019 Input Output (Hong Kong) Ltd.
 category:            System
 build-type:          Simple
--- extra-source-files:  ChangeLog.md
+extra-source-files:  include/Win32-network.h
 cabal-version:       >=1.10
 
 flag demo
@@ -27,13 +27,14 @@ library
                        System.Win32.Async.File
                        System.Win32.Async.ErrCode
                        System.Win32.Async.IOManager
-                       System.Win32.Async.Internal
-                       System.Win32.Async.WSABuf
                        System.Win32.Async.Socket
                        System.Win32.Async.Socket.ByteString
                        System.Win32.Async.Socket.ByteString.Lazy
-    c-sources:         cbits/Win32Async.c
-                       cbits/Win32Socket.c
+    other-modules:     System.Win32.Async.IOData
+                       System.Win32.Async.Overlapped
+                       System.Win32.Async.Socket.Syscalls
+                       System.Win32.Async.WSABuf
+    include-dirs:      include
     build-depends:     base              >= 4.5  && < 4.13,
                        bytestring        >= 0.10 && < 0.11,
                        network           >= 3.1  && < 3.2,

Win32-network/include/Win32-network.h

@@ -0,0 +1,19 @@
+#include <winsock2.h>
+#include <windows.h>
+#include <HsFFI.h>
+
+// each OVERLAPPED struct is wrapped in IO_DATA;  It is important to keep
+// OVERLAPPED as the first member of the record.  This allows us to cast
+// an OVERLAPPED pointer to _IODATA and recover the second member..
+typedef struct _IODATA {
+    OVERLAPPED  iodOverlapped;
+    HsStablePtr iodData;
+} IODATA;
+
+
+// As for _IODATA: it is vital to keep WSAOVERLAPPED as the first member of
+// the struct.
+typedef struct _WSAIODATA {
+    WSAOVERLAPPED  iodOverlapped;
+    HsStablePtr    iodData;
+} WSAIODATA;