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Diffstat (limited to 'vendor/github.com/pborman/uuid/node.go')
-rw-r--r-- | vendor/github.com/pborman/uuid/node.go | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/vendor/github.com/pborman/uuid/node.go b/vendor/github.com/pborman/uuid/node.go new file mode 100644 index 00000000..42d60da8 --- /dev/null +++ b/vendor/github.com/pborman/uuid/node.go @@ -0,0 +1,117 @@ +// Copyright 2011 Google Inc. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package uuid + +import ( + "net" + "sync" +) + +var ( + nodeMu sync.Mutex + interfaces []net.Interface // cached list of interfaces + ifname string // name of interface being used + nodeID []byte // hardware for version 1 UUIDs +) + +// NodeInterface returns the name of the interface from which the NodeID was +// derived. The interface "user" is returned if the NodeID was set by +// SetNodeID. +func NodeInterface() string { + defer nodeMu.Unlock() + nodeMu.Lock() + return ifname +} + +// SetNodeInterface selects the hardware address to be used for Version 1 UUIDs. +// If name is "" then the first usable interface found will be used or a random +// Node ID will be generated. If a named interface cannot be found then false +// is returned. +// +// SetNodeInterface never fails when name is "". +func SetNodeInterface(name string) bool { + defer nodeMu.Unlock() + nodeMu.Lock() + return setNodeInterface(name) +} + +func setNodeInterface(name string) bool { + if interfaces == nil { + var err error + interfaces, err = net.Interfaces() + if err != nil && name != "" { + return false + } + } + + for _, ifs := range interfaces { + if len(ifs.HardwareAddr) >= 6 && (name == "" || name == ifs.Name) { + if setNodeID(ifs.HardwareAddr) { + ifname = ifs.Name + return true + } + } + } + + // We found no interfaces with a valid hardware address. If name + // does not specify a specific interface generate a random Node ID + // (section 4.1.6) + if name == "" { + if nodeID == nil { + nodeID = make([]byte, 6) + } + randomBits(nodeID) + return true + } + return false +} + +// NodeID returns a slice of a copy of the current Node ID, setting the Node ID +// if not already set. +func NodeID() []byte { + defer nodeMu.Unlock() + nodeMu.Lock() + if nodeID == nil { + setNodeInterface("") + } + nid := make([]byte, 6) + copy(nid, nodeID) + return nid +} + +// SetNodeID sets the Node ID to be used for Version 1 UUIDs. The first 6 bytes +// of id are used. If id is less than 6 bytes then false is returned and the +// Node ID is not set. +func SetNodeID(id []byte) bool { + defer nodeMu.Unlock() + nodeMu.Lock() + if setNodeID(id) { + ifname = "user" + return true + } + return false +} + +func setNodeID(id []byte) bool { + if len(id) < 6 { + return false + } + if nodeID == nil { + nodeID = make([]byte, 6) + } + copy(nodeID, id) + return true +} + +// NodeID returns the 6 byte node id encoded in uuid. It returns nil if uuid is +// not valid. The NodeID is only well defined for version 1 and 2 UUIDs. +func (uuid UUID) NodeID() []byte { + if len(uuid) != 16 { + return nil + } + node := make([]byte, 6) + copy(node, uuid[10:]) + return node +} |