mirror of
https://github.com/go-gitea/gitea.git
synced 2024-12-05 17:59:39 +08:00
240 lines
5.9 KiB
Go
240 lines
5.9 KiB
Go
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// Copyright (C) 2013-2018 by Maxim Bublis <b@codemonkey.ru>
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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package uuid
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import (
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"crypto/md5"
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"crypto/rand"
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"crypto/sha1"
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"encoding/binary"
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"hash"
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"net"
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"os"
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"sync"
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"time"
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)
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// Difference in 100-nanosecond intervals between
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// UUID epoch (October 15, 1582) and Unix epoch (January 1, 1970).
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const epochStart = 122192928000000000
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var (
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global = newDefaultGenerator()
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epochFunc = unixTimeFunc
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posixUID = uint32(os.Getuid())
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posixGID = uint32(os.Getgid())
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)
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// NewV1 returns UUID based on current timestamp and MAC address.
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func NewV1() UUID {
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return global.NewV1()
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}
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// NewV2 returns DCE Security UUID based on POSIX UID/GID.
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func NewV2(domain byte) UUID {
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return global.NewV2(domain)
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}
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// NewV3 returns UUID based on MD5 hash of namespace UUID and name.
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func NewV3(ns UUID, name string) UUID {
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return global.NewV3(ns, name)
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}
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// NewV4 returns random generated UUID.
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func NewV4() UUID {
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return global.NewV4()
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}
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// NewV5 returns UUID based on SHA-1 hash of namespace UUID and name.
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func NewV5(ns UUID, name string) UUID {
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return global.NewV5(ns, name)
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}
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// Generator provides interface for generating UUIDs.
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type Generator interface {
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NewV1() UUID
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NewV2(domain byte) UUID
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NewV3(ns UUID, name string) UUID
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NewV4() UUID
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NewV5(ns UUID, name string) UUID
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}
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// Default generator implementation.
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type generator struct {
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storageOnce sync.Once
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storageMutex sync.Mutex
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lastTime uint64
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clockSequence uint16
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hardwareAddr [6]byte
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}
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func newDefaultGenerator() Generator {
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return &generator{}
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}
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// NewV1 returns UUID based on current timestamp and MAC address.
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func (g *generator) NewV1() UUID {
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u := UUID{}
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timeNow, clockSeq, hardwareAddr := g.getStorage()
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binary.BigEndian.PutUint32(u[0:], uint32(timeNow))
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binary.BigEndian.PutUint16(u[4:], uint16(timeNow>>32))
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binary.BigEndian.PutUint16(u[6:], uint16(timeNow>>48))
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binary.BigEndian.PutUint16(u[8:], clockSeq)
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copy(u[10:], hardwareAddr)
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u.SetVersion(V1)
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u.SetVariant(VariantRFC4122)
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return u
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}
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// NewV2 returns DCE Security UUID based on POSIX UID/GID.
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func (g *generator) NewV2(domain byte) UUID {
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u := UUID{}
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timeNow, clockSeq, hardwareAddr := g.getStorage()
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switch domain {
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case DomainPerson:
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binary.BigEndian.PutUint32(u[0:], posixUID)
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case DomainGroup:
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binary.BigEndian.PutUint32(u[0:], posixGID)
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}
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binary.BigEndian.PutUint16(u[4:], uint16(timeNow>>32))
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binary.BigEndian.PutUint16(u[6:], uint16(timeNow>>48))
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binary.BigEndian.PutUint16(u[8:], clockSeq)
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u[9] = domain
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copy(u[10:], hardwareAddr)
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u.SetVersion(V2)
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u.SetVariant(VariantRFC4122)
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return u
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}
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// NewV3 returns UUID based on MD5 hash of namespace UUID and name.
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func (g *generator) NewV3(ns UUID, name string) UUID {
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u := newFromHash(md5.New(), ns, name)
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u.SetVersion(V3)
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u.SetVariant(VariantRFC4122)
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return u
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}
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// NewV4 returns random generated UUID.
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func (g *generator) NewV4() UUID {
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u := UUID{}
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g.safeRandom(u[:])
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u.SetVersion(V4)
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u.SetVariant(VariantRFC4122)
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return u
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}
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// NewV5 returns UUID based on SHA-1 hash of namespace UUID and name.
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func (g *generator) NewV5(ns UUID, name string) UUID {
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u := newFromHash(sha1.New(), ns, name)
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u.SetVersion(V5)
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u.SetVariant(VariantRFC4122)
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return u
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}
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func (g *generator) initStorage() {
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g.initClockSequence()
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g.initHardwareAddr()
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}
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func (g *generator) initClockSequence() {
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buf := make([]byte, 2)
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g.safeRandom(buf)
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g.clockSequence = binary.BigEndian.Uint16(buf)
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}
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func (g *generator) initHardwareAddr() {
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interfaces, err := net.Interfaces()
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if err == nil {
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for _, iface := range interfaces {
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if len(iface.HardwareAddr) >= 6 {
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copy(g.hardwareAddr[:], iface.HardwareAddr)
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return
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}
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}
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}
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// Initialize hardwareAddr randomly in case
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// of real network interfaces absence
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g.safeRandom(g.hardwareAddr[:])
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// Set multicast bit as recommended in RFC 4122
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g.hardwareAddr[0] |= 0x01
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}
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func (g *generator) safeRandom(dest []byte) {
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if _, err := rand.Read(dest); err != nil {
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panic(err)
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}
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}
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// Returns UUID v1/v2 storage state.
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// Returns epoch timestamp, clock sequence, and hardware address.
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func (g *generator) getStorage() (uint64, uint16, []byte) {
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g.storageOnce.Do(g.initStorage)
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g.storageMutex.Lock()
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defer g.storageMutex.Unlock()
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timeNow := epochFunc()
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// Clock changed backwards since last UUID generation.
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// Should increase clock sequence.
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if timeNow <= g.lastTime {
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g.clockSequence++
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}
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g.lastTime = timeNow
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return timeNow, g.clockSequence, g.hardwareAddr[:]
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}
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// Returns difference in 100-nanosecond intervals between
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// UUID epoch (October 15, 1582) and current time.
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// This is default epoch calculation function.
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func unixTimeFunc() uint64 {
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return epochStart + uint64(time.Now().UnixNano()/100)
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}
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// Returns UUID based on hashing of namespace UUID and name.
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func newFromHash(h hash.Hash, ns UUID, name string) UUID {
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u := UUID{}
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h.Write(ns[:])
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h.Write([]byte(name))
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copy(u[:], h.Sum(nil))
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return u
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}
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