libgo/go/net/sendfile_windows.go

   1 // Copyright 2011 The Go Authors.  All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package net
   6
   7 import (
   8         "io"
   9         "os"
  10         "syscall"
  11 )
  12
  13 type sendfileOp struct {
  14         anOp
  15         src syscall.Handle // source
  16         n   uint32
  17 }
  18
  19 func (o *sendfileOp) Submit() (err error) {
  20         return syscall.TransmitFile(o.fd.sysfd, o.src, o.n, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
  21 }
  22
  23 func (o *sendfileOp) Name() string {
  24         return "TransmitFile"
  25 }
  26
  27 // sendFile copies the contents of r to c using the TransmitFile
  28 // system call to minimize copies.
  29 //
  30 // if handled == true, sendFile returns the number of bytes copied and any
  31 // non-EOF error.
  32 //
  33 // if handled == false, sendFile performed no work.
  34 //
  35 // Note that sendfile for windows does not suppport >2GB file.
  36 func sendFile(c *netFD, r io.Reader) (written int64, err error, handled bool) {
  37         var n int64 = 0 // by default, copy until EOF
  38
  39         lr, ok := r.(*io.LimitedReader)
  40         if ok {
  41                 n, r = lr.N, lr.R
  42                 if n <= 0 {
  43                         return 0, nil, true
  44                 }
  45         }
  46         f, ok := r.(*os.File)
  47         if !ok {
  48                 return 0, nil, false
  49         }
  50
  51         if err := c.incref(false); err != nil {
  52                 return 0, err, true
  53         }
  54         defer c.decref()
  55         c.wio.Lock()
  56         defer c.wio.Unlock()
  57
  58         var o sendfileOp
  59         o.Init(c, 'w')
  60         o.n = uint32(n)
  61         o.src = syscall.Handle(f.Fd())
  62         done, err := iosrv.ExecIO(&o, 0)
  63         if err != nil {
  64                 return 0, err, false
  65         }
  66         if lr != nil {
  67                 lr.N -= int64(done)
  68         }
  69         return int64(done), nil, true
  70 }