blob: bccd8b149f738e55ce61d406b1400dff25069b6b [file] [log] [blame] [edit]
// 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 (
"internal/poll"
"io"
"os"
"syscall"
)
// 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 support >2GB file.
func sendFile(fd *netFD, r io.Reader) (written int64, err 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
}
done, err := poll.SendFile(&fd.pfd, syscall.Handle(f.Fd()), n)
if err != nil {
return 0, wrapSyscallError("transmitfile", err), false
}
if lr != nil {
lr.N -= int64(done)
}
return int64(done), nil, true
}