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Source file src/net/splice_linux.go

Documentation: net

  // Copyright 2018 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"
  )
  
  // splice transfers data from r to c using the splice system call to minimize
  // copies from and to userspace. c must be a TCP connection. Currently, splice
  // is only enabled if r is also a TCP connection.
  //
  // If splice returns handled == false, it has performed no work.
  func splice(c *netFD, r io.Reader) (written int64, err error, handled bool) {
  	var remain int64 = 1 << 62 // by default, copy until EOF
  	lr, ok := r.(*io.LimitedReader)
  	if ok {
  		remain, r = lr.N, lr.R
  		if remain <= 0 {
  			return 0, nil, true
  		}
  	}
  	s, ok := r.(*TCPConn)
  	if !ok {
  		return 0, nil, false
  	}
  	written, handled, sc, err := poll.Splice(&c.pfd, &s.fd.pfd, remain)
  	if lr != nil {
  		lr.N -= written
  	}
  	return written, wrapSyscallError(sc, err), handled
  }
  

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