// 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" ) // sendFile copies the contents of r to c using the sendfile // system call to minimize copies. // // if handled == true, sendFile returns the number (potentially zero) of bytes // copied and any non-EOF error. // // if handled == false, sendFile performed no work. func sendFile(c *netFD, r io.Reader) (written int64, err error, handled bool) { var remain int64 = 1<<63 - 1 // by default, copy until EOF lr, ok := r.(*io.LimitedReader) if ok { remain, r = lr.N, lr.R if remain <= 0 { return 0, nil, true } } f, ok := r.(*os.File) if !ok { return 0, nil, false } sc, err := f.SyscallConn() if err != nil { return 0, nil, false } var werr error err = sc.Read(func(fd uintptr) bool { written, werr, handled = poll.SendFile(&c.pfd, int(fd), remain) return true }) if err == nil { err = werr } if lr != nil { lr.N = remain - written } return written, wrapSyscallError("sendfile", err), handled }