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 ) 12 13 // sendFile copies the contents of r to c using the sendfile 14 // system call to minimize copies. 15 // 16 // if handled == true, sendFile returns the number of bytes copied and any 17 // non-EOF error. 18 // 19 // if handled == false, sendFile performed no work. 20 func sendFile(c *netFD, r io.Reader) (written int64, err error, handled bool) { 21 var remain int64 = 1 << 62 // by default, copy until EOF 22 23 lr, ok := r.(*io.LimitedReader) 24 if ok { 25 remain, r = lr.N, lr.R 26 if remain <= 0 { 27 return 0, nil, true 28 } 29 } 30 f, ok := r.(*os.File) 31 if !ok { 32 return 0, nil, false 33 } 34 35 written, err = poll.SendFile(&c.pfd, int(f.Fd()), remain) 36 37 if lr != nil { 38 lr.N = remain - written 39 } 40 return written, wrapSyscallError("sendfile", err), written > 0 41 } 42
