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| // Copyright 2018 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"
| )
|
| // splice transfers data from r to c using the splice system call to minimize
| // copies from and to userspace. c must be a TCP connection. Currently, splice
| // is only enabled if r is a TCP or a stream-oriented Unix connection.
| //
| // If splice returns handled == false, it has performed no work.
| func splice(c *netFD, r io.Reader) (written int64, err error, handled bool) {
| var remain int64 = 1 << 62 // 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
| }
| }
|
| var s *netFD
| if tc, ok := r.(*TCPConn); ok {
| s = tc.fd
| } else if uc, ok := r.(*UnixConn); ok {
| if uc.fd.net != "unix" {
| return 0, nil, false
| }
| s = uc.fd
| } else {
| return 0, nil, false
| }
|
| written, handled, sc, err := poll.Splice(&c.pfd, &s.pfd, remain)
| if lr != nil {
| lr.N -= written
| }
| return written, wrapSyscallError(sc, err), handled
| }
|
|
