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 "internal/poll" 9 "io" 10 "os" 11 "syscall" 12 ) 13 14 // sendFile copies the contents of r to c using the TransmitFile 15 // system call to minimize copies. 16 // 17 // if handled == true, sendFile returns the number of bytes copied and any 18 // non-EOF error. 19 // 20 // if handled == false, sendFile performed no work. 21 // 22 // Note that sendfile for windows does not support >2GB file. 23 func sendFile(fd *netFD, r io.Reader) (written int64, err error, handled bool) { 24 var n int64 = 0 // by default, copy until EOF 25 26 lr, ok := r.(*io.LimitedReader) 27 if ok { 28 n, r = lr.N, lr.R 29 if n <= 0 { 30 return 0, nil, true 31 } 32 } 33 f, ok := r.(*os.File) 34 if !ok { 35 return 0, nil, false 36 } 37 38 done, err := poll.SendFile(&fd.pfd, syscall.Handle(f.Fd()), n) 39 40 if err != nil { 41 return 0, wrapSyscallError("transmitfile", err), false 42 } 43 if lr != nil { 44 lr.N -= int64(done) 45 } 46 return int64(done), nil, true 47 } 48
