// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package poll
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import "syscall"
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// SendFile wraps the TransmitFile call.
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func SendFile(fd *FD, src syscall.Handle, n int64) (int64, error) {
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ft, err := syscall.GetFileType(src)
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if err != nil {
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return 0, err
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}
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// TransmitFile does not work with pipes
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if ft == syscall.FILE_TYPE_PIPE {
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return 0, syscall.ESPIPE
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}
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if err := fd.writeLock(); err != nil {
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return 0, err
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}
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defer fd.writeUnlock()
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o := &fd.wop
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o.qty = uint32(n)
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o.handle = src
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// TODO(brainman): skip calling syscall.Seek if OS allows it
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curpos, err := syscall.Seek(o.handle, 0, 1)
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if err != nil {
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return 0, err
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}
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o.o.Offset = uint32(curpos)
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o.o.OffsetHigh = uint32(curpos >> 32)
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done, err := wsrv.ExecIO(o, func(o *operation) error {
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return syscall.TransmitFile(o.fd.Sysfd, o.handle, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
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})
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if err == nil {
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// Some versions of Windows (Windows 10 1803) do not set
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// file position after TransmitFile completes.
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// So just use Seek to set file position.
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_, err = syscall.Seek(o.handle, curpos+int64(done), 0)
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}
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return int64(done), err
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}
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