Method AssignUid

xidmap/xidmap.go:252–285

AssignUid creates new or looks up existing XID to UID mappings. It also returns if UID was created.

(xid string)

// AssignUid creates new or looks up existing XID to UID mappings. It also returns if
// UID was created.
func (m *XidMap) AssignUid(xid string) (uint64, bool) {
	sh := m.shardFor(xid)
	sh.RLock()

	uid := sh.tree.Get(farm.Fingerprint64([]byte(xid)))
	sh.RUnlock()
	if uid > 0 {
		return uid, false
	}

	sh.Lock()
	defer sh.Unlock()

	uid = sh.tree.Get(farm.Fingerprint64([]byte(xid)))
	if uid > 0 {
		return uid, false
	}

	newUid := sh.assign(m.newRanges)
	sh.tree.Set(farm.Fingerprint64([]byte(xid)), newUid)

	if m.writer != nil {
		var uidBuf [8]byte
		binary.BigEndian.PutUint64(uidBuf[:], newUid)
		m.kvBuf = append(m.kvBuf, kv{key: []byte(xid), value: uidBuf[:]})

		if len(m.kvBuf) == 64 {
			m.kvChan <- m.kvBuf
			m.kvBuf = make([]kv, 0, 64)
		}
	}

	return newUid, true
}

func (sh *shard) Current() uint64 {
	sh.RLock()