1 files changed, 156 insertions, 0 deletions
diff --git a/src/runtime/netpoll_windows.go b/src/runtime/netpoll_windows.go
new file mode 100644
index 000000000..23d5dc00f
--- /dev/null
+++ b/src/runtime/netpoll_windows.go
@@ -0,0 +1,156 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+import (
+	"unsafe"
+)
+
+const _DWORD_MAX = 0xffffffff
+
+//go:cgo_import_dynamic runtime._CreateIoCompletionPort CreateIoCompletionPort "kernel32.dll"
+//go:cgo_import_dynamic runtime._GetQueuedCompletionStatus GetQueuedCompletionStatus "kernel32.dll"
+//go:cgo_import_dynamic runtime._WSAGetOverlappedResult WSAGetOverlappedResult "ws2_32.dll"
+
+var (
+	_CreateIoCompletionPort,
+	_GetQueuedCompletionStatus,
+	_WSAGetOverlappedResult stdFunction
+)
+
+const _INVALID_HANDLE_VALUE = ^uintptr(0)
+
+// net_op must be the same as beginning of net.operation. Keep these in sync.
+type net_op struct {
+	// used by windows
+	o overlapped
+	// used by netpoll
+	pd    *pollDesc
+	mode  int32
+	errno int32
+	qty   uint32
+}
+
+type overlappedEntry struct {
+	key      uintptr
+	op       *net_op // In reality it's *overlapped, but we cast it to *net_op anyway.
+	internal uintptr
+	qty      uint32
+}
+
+var iocphandle uintptr = _INVALID_HANDLE_VALUE // completion port io handle
+
+func netpollinit() {
+	iocphandle = uintptr(stdcall4(_CreateIoCompletionPort, _INVALID_HANDLE_VALUE, 0, 0, _DWORD_MAX))
+	if iocphandle == 0 {
+		println("netpoll: failed to create iocp handle (errno=", getlasterror(), ")")
+		gothrow("netpoll: failed to create iocp handle")
+	}
+}
+
+func netpollopen(fd uintptr, pd *pollDesc) int32 {
+	if stdcall4(_CreateIoCompletionPort, fd, iocphandle, 0, 0) == 0 {
+		return -int32(getlasterror())
+	}
+	return 0
+}
+
+func netpollclose(fd uintptr) int32 {
+	// nothing to do
+	return 0
+}
+
+func netpollarm(pd *pollDesc, mode int) {
+	gothrow("unused")
+}
+
+// Polls for completed network IO.
+// Returns list of goroutines that become runnable.
+func netpoll(block bool) *g {
+	var entries [64]overlappedEntry
+	var wait, qty, key, flags, n, i uint32
+	var errno int32
+	var op *net_op
+	var gp *g
+
+	mp := getg().m
+
+	if iocphandle == _INVALID_HANDLE_VALUE {
+		return nil
+	}
+	gp = nil
+	wait = 0
+	if block {
+		wait = _INFINITE
+	}
+retry:
+	if _GetQueuedCompletionStatusEx != nil {
+		n = uint32(len(entries) / int(gomaxprocs))
+		if n < 8 {
+			n = 8
+		}
+		if block {
+			mp.blocked = true
+		}
+		if stdcall6(_GetQueuedCompletionStatusEx, iocphandle, uintptr(unsafe.Pointer(&entries[0])), uintptr(n), uintptr(unsafe.Pointer(&n)), uintptr(wait), 0) == 0 {
+			mp.blocked = false
+			errno = int32(getlasterror())
+			if !block && errno == _WAIT_TIMEOUT {
+				return nil
+			}
+			println("netpoll: GetQueuedCompletionStatusEx failed (errno=", errno, ")")
+			gothrow("netpoll: GetQueuedCompletionStatusEx failed")
+		}
+		mp.blocked = false
+		for i = 0; i < n; i++ {
+			op = entries[i].op
+			errno = 0
+			qty = 0
+			if stdcall5(_WSAGetOverlappedResult, op.pd.fd, uintptr(unsafe.Pointer(op)), uintptr(unsafe.Pointer(&qty)), 0, uintptr(unsafe.Pointer(&flags))) == 0 {
+				errno = int32(getlasterror())
+			}
+			handlecompletion(&gp, op, errno, qty)
+		}
+	} else {
+		op = nil
+		errno = 0
+		qty = 0
+		if block {
+			mp.blocked = true
+		}
+		if stdcall5(_GetQueuedCompletionStatus, iocphandle, uintptr(unsafe.Pointer(&qty)), uintptr(unsafe.Pointer(&key)), uintptr(unsafe.Pointer(&op)), uintptr(wait)) == 0 {
+			mp.blocked = false
+			errno = int32(getlasterror())
+			if !block && errno == _WAIT_TIMEOUT {
+				return nil
+			}
+			if op == nil {
+				println("netpoll: GetQueuedCompletionStatus failed (errno=", errno, ")")
+				gothrow("netpoll: GetQueuedCompletionStatus failed")
+			}
+			// dequeued failed IO packet, so report that
+		}
+		mp.blocked = false
+		handlecompletion(&gp, op, errno, qty)
+	}
+	if block && gp == nil {
+		goto retry
+	}
+	return gp
+}
+
+func handlecompletion(gpp **g, op *net_op, errno int32, qty uint32) {
+	if op == nil {
+		gothrow("netpoll: GetQueuedCompletionStatus returned op == nil")
+	}
+	mode := op.mode
+	if mode != 'r' && mode != 'w' {
+		println("netpoll: GetQueuedCompletionStatus returned invalid mode=", mode)
+		gothrow("netpoll: GetQueuedCompletionStatus returned invalid mode")
+	}
+	op.errno = errno
+	op.qty = qty
+	netpollready((**g)(noescape(unsafe.Pointer(gpp))), op.pd, mode)
+}