net: Sendfile for win32.
implement using TransmitFile().
R=bsiegert, bradfitz, alex.brainman, rsc, go.peter.90
CC=golang-dev
https://golang.org/cl/4536076
diff --git a/src/pkg/net/sendfile_windows.go b/src/pkg/net/sendfile_windows.go
new file mode 100644
index 0000000..34abc54
--- /dev/null
+++ b/src/pkg/net/sendfile_windows.go
@@ -0,0 +1,68 @@
+// Copyright 2011 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 net
+
+import (
+ "io"
+ "os"
+ "syscall"
+)
+
+type sendfileOp struct {
+ anOp
+ src int32 // source
+ n uint32
+}
+
+func (o *sendfileOp) Submit() (errno int) {
+ return syscall.TransmitFile(int32(o.fd.sysfd), o.src, o.n, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
+}
+
+func (o *sendfileOp) Name() string {
+ return "TransmitFile"
+}
+
+// sendFile copies the contents of r to c using the TransmitFile
+// system call to minimize copies.
+//
+// if handled == true, sendFile returns the number of bytes copied and any
+// non-EOF error.
+//
+// if handled == false, sendFile performed no work.
+//
+// Note that sendfile for windows does not suppport >2GB file.
+func sendFile(c *netFD, r io.Reader) (written int64, err os.Error, handled bool) {
+ var n int64 = 0 // by default, copy until EOF
+
+ lr, ok := r.(*io.LimitedReader)
+ if ok {
+ n, r = lr.N, lr.R
+ if n <= 0 {
+ return 0, nil, true
+ }
+ }
+ f, ok := r.(*os.File)
+ if !ok {
+ return 0, nil, false
+ }
+
+ c.wio.Lock()
+ defer c.wio.Unlock()
+ c.incref()
+ defer c.decref()
+
+ var o sendfileOp
+ o.Init(c)
+ o.n = uint32(n)
+ o.src = int32(f.Fd())
+ done, err := iosrv.ExecIO(&o, 0)
+ if err != nil {
+ return 0, err, false
+ }
+ if lr != nil {
+ lr.N -= int64(done)
+ }
+ return int64(done), nil, true
+}
