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7 package poll
8
9 import "syscall"
10
11
12
13 const maxSendfileSize int = 4 << 20
14
15
16 func SendFile(dstFD *FD, src int, pos, remain int64) (int64, error, bool) {
17 if err := dstFD.writeLock(); err != nil {
18 return 0, err, false
19 }
20 defer dstFD.writeUnlock()
21 if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil {
22 return 0, err, false
23 }
24
25 dst := dstFD.Sysfd
26 var (
27 written int64
28 err error
29 handled = true
30 )
31 for remain > 0 {
32 n := maxSendfileSize
33 if int64(n) > remain {
34 n = int(remain)
35 }
36 pos1 := pos
37 n, err1 := syscall.Sendfile(dst, src, &pos1, n)
38 if n > 0 {
39 pos += int64(n)
40 written += int64(n)
41 remain -= int64(n)
42 } else if n == 0 && err1 == nil {
43 break
44 }
45 if err1 == syscall.EINTR {
46 continue
47 }
48 if err1 == syscall.EAGAIN {
49 if err1 = dstFD.pd.waitWrite(dstFD.isFile); err1 == nil {
50 continue
51 }
52 }
53 if err1 != nil {
54
55
56
57 err = err1
58 handled = false
59 break
60 }
61 }
62 return written, err, handled
63 }
64
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