56 lines
1.2 KiB
Go
56 lines
1.2 KiB
Go
// 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 net
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import (
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"io"
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"os"
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"syscall"
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)
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// sendFile copies the contents of r to c using the TransmitFile
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// system call to minimize copies.
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//
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// if handled == true, sendFile returns the number of bytes copied and any
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// non-EOF error.
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//
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// if handled == false, sendFile performed no work.
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//
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// Note that sendfile for windows does not suppport >2GB file.
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func sendFile(fd *netFD, r io.Reader) (written int64, err error, handled bool) {
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var n int64 = 0 // by default, copy until EOF
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lr, ok := r.(*io.LimitedReader)
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if ok {
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n, r = lr.N, lr.R
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if n <= 0 {
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return 0, nil, true
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}
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}
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f, ok := r.(*os.File)
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if !ok {
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return 0, nil, false
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}
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if err := fd.writeLock(); err != nil {
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return 0, err, true
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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 = syscall.Handle(f.Fd())
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done, err := wsrv.ExecIO(o, "TransmitFile", 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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return 0, err, false
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}
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if lr != nil {
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lr.N -= int64(done)
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}
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return int64(done), nil, true
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}
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