git.iko.soy/crush
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crush/vendor/github.com/google/uuid/node.go
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1// Copyright 2016 Google Inc. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
5package uuid
7import (
8 "sync"
9)
11var (
12 nodeMu sync.Mutex
13 ifname string // name of interface being used
14 nodeID [6]byte // hardware for version 1 UUIDs
15 zeroID [6]byte // nodeID with only 0's
18// NodeInterface returns the name of the interface from which the NodeID was
19// derived. The interface "user" is returned if the NodeID was set by
20// SetNodeID.
21func NodeInterface() string {
22 defer nodeMu.Unlock()
23 nodeMu.Lock()
24 return ifname
27// SetNodeInterface selects the hardware address to be used for Version 1 UUIDs.
28// If name is "" then the first usable interface found will be used or a random
29// Node ID will be generated. If a named interface cannot be found then false
30// is returned.
31//
32// SetNodeInterface never fails when name is "".
33func SetNodeInterface(name string) bool {
34 defer nodeMu.Unlock()
35 nodeMu.Lock()
36 return setNodeInterface(name)
39func setNodeInterface(name string) bool {
40 iname, addr := getHardwareInterface(name) // null implementation for js
41 if iname != "" && addr != nil {
42 ifname = iname
43 copy(nodeID[:], addr)
44 return true
45 }
47 // We found no interfaces with a valid hardware address. If name
48 // does not specify a specific interface generate a random Node ID
49 // (section 4.1.6)
50 if name == "" {
51 ifname = "random"
52 randomBits(nodeID[:])
53 return true
54 }
55 return false
58// NodeID returns a slice of a copy of the current Node ID, setting the Node ID
59// if not already set.
60func NodeID() []byte {
61 defer nodeMu.Unlock()
62 nodeMu.Lock()
63 if nodeID == zeroID {
64 setNodeInterface("")
65 }
66 nid := nodeID
67 return nid[:]
70// SetNodeID sets the Node ID to be used for Version 1 UUIDs. The first 6 bytes
71// of id are used. If id is less than 6 bytes then false is returned and the
72// Node ID is not set.
73func SetNodeID(id []byte) bool {
74 if len(id) < 6 {
75 return false
76 }
77 defer nodeMu.Unlock()
78 nodeMu.Lock()
79 copy(nodeID[:], id)
80 ifname = "user"
81 return true
84// NodeID returns the 6 byte node id encoded in uuid. It returns nil if uuid is
85// not valid. The NodeID is only well defined for version 1 and 2 UUIDs.
86func (uuid UUID) NodeID() []byte {
87 var node [6]byte
88 copy(node[:], uuid[10:])
89 return node[:]