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go/src/net/sendfile_linux.go
Mikio Hara ac2f84d524 net: make unexposed methods start with lowercase letters
This change makes unexposed methods start with lowercase letters for
avoiding unnecessary confusion because the net package uses many
embedding structures and intrefaces for controlling exposure of APIs.

Note that this change leaves DNS-related methods as they are.

Change-Id: I253758d1659175c5d0af6b2efcd30ce83f46543d
Reviewed-on: https://go-review.googlesource.com/20784
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-03-17 21:43:41 +00:00

80 lines
1.6 KiB
Go

// 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 (
"io"
"os"
"syscall"
)
// maxSendfileSize is the largest chunk size we ask the kernel to copy
// at a time.
const maxSendfileSize int = 4 << 20
// sendFile copies the contents of r to c using the sendfile
// 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.
func sendFile(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
}
}
f, ok := r.(*os.File)
if !ok {
return 0, nil, false
}
if err := c.writeLock(); err != nil {
return 0, err, true
}
defer c.writeUnlock()
dst := c.sysfd
src := int(f.Fd())
for remain > 0 {
n := maxSendfileSize
if int64(n) > remain {
n = int(remain)
}
n, err1 := syscall.Sendfile(dst, src, nil, n)
if n > 0 {
written += int64(n)
remain -= int64(n)
}
if n == 0 && err1 == nil {
break
}
if err1 == syscall.EAGAIN {
if err1 = c.pd.waitWrite(); err1 == nil {
continue
}
}
if err1 != nil {
// This includes syscall.ENOSYS (no kernel
// support) and syscall.EINVAL (fd types which
// don't implement sendfile)
err = err1
break
}
}
if lr != nil {
lr.N = remain
}
if err != nil {
err = os.NewSyscallError("sendfile", err)
}
return written, err, written > 0
}