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- package xid
- import (
- "bytes"
- "crypto/md5"
- "crypto/rand"
- "database/sql/driver"
- "encoding/binary"
- "errors"
- "fmt"
- "hash/crc32"
- "io/ioutil"
- "os"
- "sort"
- "sync/atomic"
- "time"
- )
- type ID [rawLen]byte
- const (
- encodedLen = 20
- rawLen = 12
-
-
- encoding = "0123456789abcdefghijklmnopqrstuv"
- )
- var (
-
- ErrInvalidID = errors.New("xid: invalid ID")
-
-
-
- objectIDCounter = randInt()
-
-
- machineID = readMachineID()
-
- pid = os.Getpid()
- nilID ID
-
- dec [256]byte
- )
- func init() {
- for i := 0; i < len(dec); i++ {
- dec[i] = 0xFF
- }
- for i := 0; i < len(encoding); i++ {
- dec[encoding[i]] = byte(i)
- }
-
-
-
- b, err := ioutil.ReadFile("/proc/self/cpuset")
- if err == nil && len(b) > 1 {
- pid ^= int(crc32.ChecksumIEEE(b))
- }
- }
- func readMachineID() []byte {
- id := make([]byte, 3)
- hid, err := readPlatformMachineID()
- if err != nil || len(hid) == 0 {
- hid, err = os.Hostname()
- }
- if err == nil && len(hid) != 0 {
- hw := md5.New()
- hw.Write([]byte(hid))
- copy(id, hw.Sum(nil))
- } else {
-
- if _, randErr := rand.Reader.Read(id); randErr != nil {
- panic(fmt.Errorf("xid: cannot get hostname nor generate a random number: %v; %v", err, randErr))
- }
- }
- return id
- }
- func randInt() uint32 {
- b := make([]byte, 3)
- if _, err := rand.Reader.Read(b); err != nil {
- panic(fmt.Errorf("xid: cannot generate random number: %v;", err))
- }
- return uint32(b[0])<<16 | uint32(b[1])<<8 | uint32(b[2])
- }
- func New() ID {
- return NewWithTime(time.Now())
- }
- func NewWithTime(t time.Time) ID {
- var id ID
-
- binary.BigEndian.PutUint32(id[:], uint32(t.Unix()))
-
- id[4] = machineID[0]
- id[5] = machineID[1]
- id[6] = machineID[2]
-
- id[7] = byte(pid >> 8)
- id[8] = byte(pid)
-
- i := atomic.AddUint32(&objectIDCounter, 1)
- id[9] = byte(i >> 16)
- id[10] = byte(i >> 8)
- id[11] = byte(i)
- return id
- }
- func FromString(id string) (ID, error) {
- i := &ID{}
- err := i.UnmarshalText([]byte(id))
- return *i, err
- }
- func (id ID) String() string {
- text := make([]byte, encodedLen)
- encode(text, id[:])
- return string(text)
- }
- func (id ID) MarshalText() ([]byte, error) {
- text := make([]byte, encodedLen)
- encode(text, id[:])
- return text, nil
- }
- func (id ID) MarshalJSON() ([]byte, error) {
- if id.IsNil() {
- return []byte("null"), nil
- }
- text, err := id.MarshalText()
- return []byte(`"` + string(text) + `"`), err
- }
- func encode(dst, id []byte) {
- dst[0] = encoding[id[0]>>3]
- dst[1] = encoding[(id[1]>>6)&0x1F|(id[0]<<2)&0x1F]
- dst[2] = encoding[(id[1]>>1)&0x1F]
- dst[3] = encoding[(id[2]>>4)&0x1F|(id[1]<<4)&0x1F]
- dst[4] = encoding[id[3]>>7|(id[2]<<1)&0x1F]
- dst[5] = encoding[(id[3]>>2)&0x1F]
- dst[6] = encoding[id[4]>>5|(id[3]<<3)&0x1F]
- dst[7] = encoding[id[4]&0x1F]
- dst[8] = encoding[id[5]>>3]
- dst[9] = encoding[(id[6]>>6)&0x1F|(id[5]<<2)&0x1F]
- dst[10] = encoding[(id[6]>>1)&0x1F]
- dst[11] = encoding[(id[7]>>4)&0x1F|(id[6]<<4)&0x1F]
- dst[12] = encoding[id[8]>>7|(id[7]<<1)&0x1F]
- dst[13] = encoding[(id[8]>>2)&0x1F]
- dst[14] = encoding[(id[9]>>5)|(id[8]<<3)&0x1F]
- dst[15] = encoding[id[9]&0x1F]
- dst[16] = encoding[id[10]>>3]
- dst[17] = encoding[(id[11]>>6)&0x1F|(id[10]<<2)&0x1F]
- dst[18] = encoding[(id[11]>>1)&0x1F]
- dst[19] = encoding[(id[11]<<4)&0x1F]
- }
- func (id *ID) UnmarshalText(text []byte) error {
- if len(text) != encodedLen {
- return ErrInvalidID
- }
- for _, c := range text {
- if dec[c] == 0xFF {
- return ErrInvalidID
- }
- }
- decode(id, text)
- return nil
- }
- func (id *ID) UnmarshalJSON(b []byte) error {
- s := string(b)
- if s == "null" {
- *id = nilID
- return nil
- }
- return id.UnmarshalText(b[1 : len(b)-1])
- }
- func decode(id *ID, src []byte) {
- id[0] = dec[src[0]]<<3 | dec[src[1]]>>2
- id[1] = dec[src[1]]<<6 | dec[src[2]]<<1 | dec[src[3]]>>4
- id[2] = dec[src[3]]<<4 | dec[src[4]]>>1
- id[3] = dec[src[4]]<<7 | dec[src[5]]<<2 | dec[src[6]]>>3
- id[4] = dec[src[6]]<<5 | dec[src[7]]
- id[5] = dec[src[8]]<<3 | dec[src[9]]>>2
- id[6] = dec[src[9]]<<6 | dec[src[10]]<<1 | dec[src[11]]>>4
- id[7] = dec[src[11]]<<4 | dec[src[12]]>>1
- id[8] = dec[src[12]]<<7 | dec[src[13]]<<2 | dec[src[14]]>>3
- id[9] = dec[src[14]]<<5 | dec[src[15]]
- id[10] = dec[src[16]]<<3 | dec[src[17]]>>2
- id[11] = dec[src[17]]<<6 | dec[src[18]]<<1 | dec[src[19]]>>4
- }
- func (id ID) Time() time.Time {
-
- secs := int64(binary.BigEndian.Uint32(id[0:4]))
- return time.Unix(secs, 0)
- }
- func (id ID) Machine() []byte {
- return id[4:7]
- }
- func (id ID) Pid() uint16 {
- return binary.BigEndian.Uint16(id[7:9])
- }
- func (id ID) Counter() int32 {
- b := id[9:12]
-
- return int32(uint32(b[0])<<16 | uint32(b[1])<<8 | uint32(b[2]))
- }
- func (id ID) Value() (driver.Value, error) {
- if id.IsNil() {
- return nil, nil
- }
- b, err := id.MarshalText()
- return string(b), err
- }
- func (id *ID) Scan(value interface{}) (err error) {
- switch val := value.(type) {
- case string:
- return id.UnmarshalText([]byte(val))
- case []byte:
- return id.UnmarshalText(val)
- case nil:
- *id = nilID
- return nil
- default:
- return fmt.Errorf("xid: scanning unsupported type: %T", value)
- }
- }
- func (id ID) IsNil() bool {
- return id == nilID
- }
- func NilID() ID {
- return nilID
- }
- func (id ID) Bytes() []byte {
- return id[:]
- }
- func FromBytes(b []byte) (ID, error) {
- var id ID
- if len(b) != rawLen {
- return id, ErrInvalidID
- }
- copy(id[:], b)
- return id, nil
- }
- func (id ID) Compare(other ID) int {
- return bytes.Compare(id[:], other[:])
- }
- type sorter []ID
- func (s sorter) Len() int {
- return len(s)
- }
- func (s sorter) Less(i, j int) bool {
- return s[i].Compare(s[j]) < 0
- }
- func (s sorter) Swap(i, j int) {
- s[i], s[j] = s[j], s[i]
- }
- func Sort(ids []ID) {
- sort.Sort(sorter(ids))
- }
|