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ident.go
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ident.go
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package ident
import (
"crypto/sha256"
"encoding/binary"
"encoding/hex"
"hash"
"sort"
)
type Identifiable interface {
Identity() []byte
}
type AddressProvider interface {
ContentAddress(entity Identifiable) string
}
type HexAddressProvider struct{}
func NewHexAddressProvider() *HexAddressProvider {
return &HexAddressProvider{}
}
func (*HexAddressProvider) ContentAddress(entity Identifiable) string {
return hex.EncodeToString(entity.Identity())
}
// IsContentAddress check if addr is valid content address or partial content address
func IsContentAddress(addr string) bool {
if len(addr) == 0 || len(addr) > sha256.Size*2 {
return false
}
_, err := hex.DecodeString(addr)
return err == nil
}
type AddressType uint8
const (
AddressTypeBytes AddressType = iota
AddressTypeString
AddressTypeInt64
AddressTypeStringSlice
AddressTypeStringMap
AddressTypeEmbeddedIdentifiable
)
// linter is angry because h can be an io.Writer, but we explicitly want a Hash here.
//
//nolint:interfacer
func marshalType(h hash.Hash, addressType AddressType) {
_, _ = h.Write([]byte{byte(addressType)})
}
func MarshalBytes(h hash.Hash, v []byte) {
marshalType(h, AddressTypeBytes)
MarshalInt64(h, int64(len(v)))
_, _ = h.Write(v)
}
func MarshalString(h hash.Hash, v string) {
marshalType(h, AddressTypeString)
MarshalInt64(h, int64(len(v)))
_, _ = h.Write([]byte(v))
}
func MarshalInt64(h hash.Hash, v int64) {
const int64Bytes = 8
marshalType(h, AddressTypeInt64)
_, _ = h.Write([]byte{int64Bytes})
bytes := make([]byte, int64Bytes)
binary.BigEndian.PutUint64(bytes, uint64(v))
_, _ = h.Write(bytes)
}
func MarshalStringSlice(h hash.Hash, v []string) {
marshalType(h, AddressTypeStringSlice)
MarshalInt64(h, int64(len(v)))
for _, item := range v {
MarshalString(h, item)
}
}
func MarshalStringMap(h hash.Hash, v map[string]string) {
marshalType(h, AddressTypeStringMap)
MarshalInt64(h, int64(len(v)))
keys := make([]string, len(v))
i := 0
for k := range v {
keys[i] = k
i++
}
sort.Strings(keys)
for _, k := range keys {
MarshalString(h, k)
MarshalString(h, v[k])
}
}
func MarshalIdentifiable(h hash.Hash, v Identifiable) {
marshalType(h, AddressTypeEmbeddedIdentifiable)
MarshalBytes(h, v.Identity())
}
type AddressWriter struct {
hash.Hash
}
func NewAddressWriter() *AddressWriter {
return &AddressWriter{Hash: sha256.New()}
}
func (b *AddressWriter) MarshalBytes(v []byte) *AddressWriter {
MarshalBytes(b, v)
return b
}
func (b *AddressWriter) MarshalString(v string) *AddressWriter {
MarshalString(b, v)
return b
}
func (b *AddressWriter) MarshalStringOpt(v string) *AddressWriter {
if len(v) > 0 {
MarshalString(b, v)
}
return b
}
func (b *AddressWriter) MarshalInt64(v int64) *AddressWriter {
MarshalInt64(b, v)
return b
}
func (b *AddressWriter) MarshalStringSlice(v []string) *AddressWriter {
MarshalStringSlice(b, v)
return b
}
func (b *AddressWriter) MarshalStringMap(v map[string]string) *AddressWriter {
MarshalStringMap(b, v)
return b
}
func (b *AddressWriter) MarshalIdentifiable(v Identifiable) *AddressWriter {
MarshalIdentifiable(b, v)
return b
}
func (b *AddressWriter) Identity() []byte {
return b.Sum(nil)
}