85 lines
1.9 KiB
Go
85 lines
1.9 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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// maxSendfileSize is the largest chunk size we ask the kernel to copy
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// at a time.
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const maxSendfileSize int = 4 << 20
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// sendFile copies the contents of r to c using the sendfile
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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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func sendFile(c *netFD, r io.Reader) (written int64, err os.Error, handled bool) {
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var remain int64 = 1 << 62 // by default, copy until EOF
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lr, ok := r.(*io.LimitedReader)
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if ok {
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remain, r = lr.N, lr.R
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if remain <= 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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c.wio.Lock()
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defer c.wio.Unlock()
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c.incref()
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defer c.decref()
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if c.wdeadline_delta > 0 {
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// This is a little odd that we're setting the timeout
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// for the entire file but Write has the same issue
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// (if one slurps the whole file into memory and
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// do one large Write). At least they're consistent.
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c.wdeadline = pollserver.Now() + c.wdeadline_delta
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} else {
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c.wdeadline = 0
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}
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dst := c.sysfd
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src := f.Fd()
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for remain > 0 {
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n := maxSendfileSize
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if int64(n) > remain {
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n = int(remain)
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}
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n, errno := syscall.Sendfile(dst, src, nil, n)
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if n > 0 {
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written += int64(n)
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remain -= int64(n)
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}
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if n == 0 && errno == 0 {
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break
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}
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if errno == syscall.EAGAIN && c.wdeadline >= 0 {
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pollserver.WaitWrite(c)
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continue
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}
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if errno != 0 {
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// This includes syscall.ENOSYS (no kernel
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// support) and syscall.EINVAL (fd types which
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// don't implement sendfile together)
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err = &OpError{"sendfile", c.net, c.raddr, os.Errno(errno)}
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break
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}
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}
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if lr != nil {
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lr.N = remain
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}
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return written, err, written > 0
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}
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