status-im/status-go

package persistence

import (
    "encoding/binary"
    "errors"

    "github.com/waku-org/go-waku/waku/v2/hash"
)

const (
    TimestampLength   = 8
    HashLength        = 32
    DigestLength      = HashLength
    PubsubTopicLength = HashLength
    DBKeyLength       = TimestampLength + PubsubTopicLength + DigestLength
)

type Hash [HashLength]byte

var (
    // ErrInvalidByteSize is returned when DBKey can't be created
    // from a byte slice because it has invalid length.
    ErrInvalidByteSize = errors.New("byte slice has invalid length")
)

// DBKey key to be stored in a db.
type DBKey struct {
    raw []byte
}

// Bytes returns a bytes representation of the DBKey.
func (k *DBKey) Bytes() []byte {
    return k.raw
}

// NewDBKey creates a new DBKey with the given values.
func NewDBKey(senderTimestamp uint64, receiverTimestamp uint64, pubsubTopic string, digest []byte) *DBKey {
    pubSubHash := make([]byte, PubsubTopicLength)
    if pubsubTopic != "" {
        pubSubHash = hash.SHA256([]byte(pubsubTopic))
    }

    var k DBKey
    k.raw = make([]byte, DBKeyLength)

    if senderTimestamp == 0 {
        binary.BigEndian.PutUint64(k.raw, receiverTimestamp)
    } else {
        binary.BigEndian.PutUint64(k.raw, senderTimestamp)
    }

    copy(k.raw[TimestampLength:], pubSubHash[:])
    copy(k.raw[TimestampLength+PubsubTopicLength:], digest)

    return &k
}