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go/src/net/sendfile_windows.go
Damien Neil b384ee7ceb net, os, internal/poll: test for use of sendfile
The net package's sendfile tests exercise various paths where
we expect sendfile to be used, but don't verify that sendfile
was in fact used.

Add a hook to internal/poll.SendFile to let us verify that
sendfile was called when expected. Update os package tests
(which use their own hook mechanism) to use this hook as well.

For #66988

Change-Id: I7afb130dcfe0063d60c6ea0f8560cf8665ad5a81
Reviewed-on: https://go-review.googlesource.com/c/go/+/581778
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2024-04-26 18:12:56 +00:00

50 lines
1.1 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 (
"internal/poll"
"io"
"os"
"syscall"
)
const supportsSendfile = true
// sendFile copies the contents of r to c using the TransmitFile
// 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(fd *netFD, r io.Reader) (written int64, err error, handled bool) {
var n int64 = 0 // by default, copy until EOF.
lr, ok := r.(*io.LimitedReader)
if ok {
n, r = lr.N, lr.R
if n <= 0 {
return 0, nil, true
}
}
f, ok := r.(*os.File)
if !ok {
return 0, nil, false
}
written, err = poll.SendFile(&fd.pfd, syscall.Handle(f.Fd()), n)
if err != nil {
err = wrapSyscallError("transmitfile", err)
}
// If any byte was copied, regardless of any error
// encountered mid-way, handled must be set to true.
handled = written > 0
return
}