hunk.code_window: 	"github.com/mattermost/mattermost-server/model"
   )
   type FileBackend interface {
   	TestConnection() *model.AppError
  
hunk.labels: keep keep add keep keep keep
hunk.after_edit: type ReadCloseSeeker interface {
   	io.ReadCloser
   	io.Seeker
   }
  
hunk.file_path: services/filesstore/filesstore.go
hunk.type: add
file: // Copyright 2012 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.
  
  // +build aix darwin dragonfly freebsd netbsd openbsd solaris windows
  
  package ipv4
  
  import (
  	"net"
  	"unsafe"
  
  	"golang.org/x/net/internal/socket"
  )
  
  func (so *sockOpt) setIPMreq(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
  	mreq := ipMreq{Multiaddr: [4]byte{grp[0], grp[1], grp[2], grp[3]}}
  	if err := setIPMreqInterface(&mreq, ifi); err != nil {
  		return err
  	}
  	b := (*[sizeofIPMreq]byte)(unsafe.Pointer(&mreq))[:sizeofIPMreq]
  	return so.Set(c, b)
  }
  
  func (so *sockOpt) getMulticastIf(c *socket.Conn) (*net.Interface, error) {
  	var b [4]byte
  	if _, err := so.Get(c, b[:]); err != nil {
  		return nil, err
  	}
  	ifi, err := netIP4ToInterface(net.IPv4(b[0], b[1], b[2], b[3]))
  	if err != nil {
  		return nil, err
  	}
  	return ifi, nil
  }
  
  func (so *sockOpt) setMulticastIf(c *socket.Conn, ifi *net.Interface) error {
  	ip, err := netInterfaceToIP4(ifi)
  	if err != nil {
  		return err
  	}
  	var b [4]byte
  	copy(b[:], ip)
  	return so.Set(c, b[:])
  }
  
  func setIPMreqInterface(mreq *ipMreq, ifi *net.Interface) error {
  	if ifi == nil {
  		return nil
  	}
  	ifat, err := ifi.Addrs()
  	if err != nil {
  		return err
  	}
  	for _, ifa := range ifat {
  		switch ifa := ifa.(type) {
  		case *net.IPAddr:
  			if ip := ifa.IP.To4(); ip != nil {
  				copy(mreq.Interface[:], ip)
  				return nil
  			}
  		case *net.IPNet:
  			if ip := ifa.IP.To4(); ip != nil {
  				copy(mreq.Interface[:], ip)
  				return nil
  			}
  		}
  	}
  	return errNoSuchInterface
  }
  
  func netIP4ToInterface(ip net.IP) (*net.Interface, error) {
  	ift, err := net.Interfaces()
  	if err != nil {
  		return nil, err
  	}
  	for _, ifi := range ift {
  		ifat, err := ifi.Addrs()
  		if err != nil {
  			return nil, err
  		}
  		for _, ifa := range ifat {
  			switch ifa := ifa.(type) {
  			case *net.IPAddr:
  				if ip.Equal(ifa.IP) {
  					return &ifi, nil
  				}
  			case *net.IPNet:
  				if ip.Equal(ifa.IP) {
  					return &ifi, nil
  				}
  			}
  		}
  	}
  	return nil, errNoSuchInterface
  }
  
  func netInterfaceToIP4(ifi *net.Interface) (net.IP, error) {
  	if ifi == nil {
  		return net.IPv4zero.To4(), nil
  	}
  	ifat, err := ifi.Addrs()
  	if err != nil {
  		return nil, err
  	}
  	for _, ifa := range ifat {
  		switch ifa := ifa.(type) {
  		case *net.IPAddr:
  			if ip := ifa.IP.To4(); ip != nil {
  				return ip, nil
  			}
  		case *net.IPNet:
  			if ip := ifa.IP.To4(); ip != nil {
  				return ip, nil
  			}
  		}
  	}
  	return nil, errNoSuchInterface
  }
  