diff options
author | Michael Muré <batolettre@gmail.com> | 2018-07-16 23:20:23 +0200 |
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committer | Michael Muré <batolettre@gmail.com> | 2018-07-16 23:23:43 +0200 |
commit | 1d678dfdfa026968dbb19795c9bed16385603b21 (patch) | |
tree | cac862609d0103ee30da39cd0054b11884248e9d /vendor/github.com/kevinburke/go.uuid/generator.go | |
parent | 131a862d313f12808d63e832126317a27226940b (diff) | |
download | git-bug-1d678dfdfa026968dbb19795c9bed16385603b21.tar.gz |
vendor dependencies with dep
Diffstat (limited to 'vendor/github.com/kevinburke/go.uuid/generator.go')
-rw-r--r-- | vendor/github.com/kevinburke/go.uuid/generator.go | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/vendor/github.com/kevinburke/go.uuid/generator.go b/vendor/github.com/kevinburke/go.uuid/generator.go new file mode 100644 index 00000000..83abbcfd --- /dev/null +++ b/vendor/github.com/kevinburke/go.uuid/generator.go @@ -0,0 +1,256 @@ +// Copyright (C) 2013-2018 by Maxim Bublis <b@codemonkey.ru> +// +// Permission is hereby granted, free of charge, to any person obtaining +// a copy of this software and associated documentation files (the +// "Software"), to deal in the Software without restriction, including +// without limitation the rights to use, copy, modify, merge, publish, +// distribute, sublicense, and/or sell copies of the Software, and to +// permit persons to whom the Software is furnished to do so, subject to +// the following conditions: +// +// The above copyright notice and this permission notice shall be +// included in all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE +// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +package uuid + +import ( + "crypto/md5" + "crypto/rand" + "crypto/sha1" + "encoding/binary" + "hash" + "net" + "os" + "sync" + "time" +) + +// Difference in 100-nanosecond intervals between +// UUID epoch (October 15, 1582) and Unix epoch (January 1, 1970). +const epochStart = 122192928000000000 + +var ( + global = newDefaultGenerator() + + epochFunc = unixTimeFunc + posixUID = uint32(os.Getuid()) + posixGID = uint32(os.Getgid()) +) + +// NewV1 returns UUID based on current timestamp and MAC address. +func NewV1() UUID { + return global.NewV1() +} + +// NewV2 returns DCE Security UUID based on POSIX UID/GID. +func NewV2(domain byte) UUID { + return global.NewV2(domain) +} + +// NewV3 returns a UUID based on the MD5 hash of namespace UUID and name. +func NewV3(ns UUID, name string) UUID { + return global.NewV3(ns, name) +} + +// NewV4 returns a randomly generated UUID. +func NewV4() UUID { + u, err := ID4() + if err != nil { + panic(err) + } + return u +} + +// ID4 returns a randomly generated UUID, or an error if there was not enough +// entropy. +func ID4() (UUID, error) { + return global.NewV4() +} + +// NewV5 returns UUID based on SHA-1 hash of namespace UUID and name. +func NewV5(ns UUID, name string) UUID { + return global.NewV5(ns, name) +} + +// Generator provides interface for generating UUIDs. +type Generator interface { + NewV1() UUID + NewV2(domain byte) UUID + NewV3(ns UUID, name string) UUID + NewV4() UUID + NewV5(ns UUID, name string) UUID +} + +// Default generator implementation. +type generator struct { + storageOnce sync.Once + storageMutex sync.Mutex + + lastTime uint64 + clockSequence uint16 + hardwareAddr [6]byte +} + +func newDefaultGenerator() *generator { + return &generator{} +} + +// NewV1 returns UUID based on current timestamp and MAC address. +func (g *generator) NewV1() UUID { + u := UUID{} + + timeNow, clockSeq, hardwareAddr := g.getStorage() + + binary.BigEndian.PutUint32(u[0:], uint32(timeNow)) + binary.BigEndian.PutUint16(u[4:], uint16(timeNow>>32)) + binary.BigEndian.PutUint16(u[6:], uint16(timeNow>>48)) + binary.BigEndian.PutUint16(u[8:], clockSeq) + + copy(u[10:], hardwareAddr) + + u.SetVersion(V1) + u.SetVariant(VariantRFC4122) + + return u +} + +// NewV2 returns DCE Security UUID based on POSIX UID/GID. +func (g *generator) NewV2(domain byte) UUID { + u := UUID{} + + timeNow, clockSeq, hardwareAddr := g.getStorage() + + switch domain { + case DomainPerson: + binary.BigEndian.PutUint32(u[0:], posixUID) + case DomainGroup: + binary.BigEndian.PutUint32(u[0:], posixGID) + } + + binary.BigEndian.PutUint16(u[4:], uint16(timeNow>>32)) + binary.BigEndian.PutUint16(u[6:], uint16(timeNow>>48)) + binary.BigEndian.PutUint16(u[8:], clockSeq) + u[9] = domain + + copy(u[10:], hardwareAddr) + + u.SetVersion(V2) + u.SetVariant(VariantRFC4122) + + return u +} + +// NewV3 returns UUID based on MD5 hash of namespace UUID and name. +func (g *generator) NewV3(ns UUID, name string) UUID { + u := newFromHash(md5.New(), ns, name) + u.SetVersion(V3) + u.SetVariant(VariantRFC4122) + + return u +} + +// NewV4 returns random generated UUID. +func (g *generator) NewV4() (UUID, error) { + u := UUID{} + if err := g.random(u[:]); err != nil { + return u, err + } + u.SetVersion(V4) + u.SetVariant(VariantRFC4122) + + return u, nil +} + +// NewV5 returns UUID based on SHA-1 hash of namespace UUID and name. +func (g *generator) NewV5(ns UUID, name string) UUID { + u := newFromHash(sha1.New(), ns, name) + u.SetVersion(V5) + u.SetVariant(VariantRFC4122) + + return u +} + +func (g *generator) initStorage() { + g.initClockSequence() + g.initHardwareAddr() +} + +func (g *generator) initClockSequence() error { + buf := make([]byte, 2) + if err := g.random(buf); err != nil { + return err + } + g.clockSequence = binary.BigEndian.Uint16(buf) + return nil +} + +func (g *generator) initHardwareAddr() error { + interfaces, err := net.Interfaces() + if err == nil { + for _, iface := range interfaces { + if len(iface.HardwareAddr) >= 6 { + copy(g.hardwareAddr[:], iface.HardwareAddr) + return nil + } + } + } + + // Initialize hardwareAddr randomly in case + // of real network interfaces absence + if err := g.random(g.hardwareAddr[:]); err != nil { + return err + } + + // Set multicast bit as recommended in RFC 4122 + g.hardwareAddr[0] |= 0x01 + return nil +} + +func (g *generator) random(dest []byte) error { + _, err := rand.Read(dest) + return err +} + +// Returns UUID v1/v2 storage state. +// Returns epoch timestamp, clock sequence, and hardware address. +func (g *generator) getStorage() (uint64, uint16, []byte) { + g.storageOnce.Do(g.initStorage) + + g.storageMutex.Lock() + defer g.storageMutex.Unlock() + + timeNow := epochFunc() + // Clock changed backwards since last UUID generation. + // Should increase clock sequence. + if timeNow <= g.lastTime { + g.clockSequence++ + } + g.lastTime = timeNow + + return timeNow, g.clockSequence, g.hardwareAddr[:] +} + +// Returns difference in 100-nanosecond intervals between +// UUID epoch (October 15, 1582) and current time. +// This is default epoch calculation function. +func unixTimeFunc() uint64 { + return epochStart + uint64(time.Now().UnixNano()/100) +} + +// Returns UUID based on hashing of namespace UUID and name. +func newFromHash(h hash.Hash, ns UUID, name string) UUID { + u := UUID{} + h.Write(ns[:]) + h.Write([]byte(name)) + copy(u[:], h.Sum(nil)) + + return u +} |