WIP Implementing core/ledger

cmd/chron-cli/main.go

@@ -1,4 +1,46 @@
 package main
 
+import (
+	"fmt"
+	"time"
+
+	"git.michelsen.id/chron/core"
+	"github.com/google/uuid"
+	"lukechampine.com/blake3"
+)
+
 func main() {
+	payload := []byte{0, 1, 0, 1}
+	payloadDigest := blake3.Sum256(payload)
+
+	entryID, err := uuid.NewV7()
+	entryIDBytes, err := entryID.MarshalBinary()
+	if err != nil {
+		return
+	}
+	ledgerID, err := uuid.NewV7()
+	ledgerIDBytes, err := ledgerID.MarshalBinary()
+	if err != nil {
+		return
+	}
+	payloadID, err := uuid.NewV7()
+	payloadIDBytes, err := payloadID.MarshalBinary()
+	if err != nil {
+		return
+	}
+
+	entry := core.Entry{
+		EntryID:       core.EntryID(entryIDBytes),
+		LedgerID:      core.LedgerID(ledgerIDBytes),
+		Seq:           1,
+		Timestamp:     time.Now(),
+		PayloadID:     core.PayloadID(payloadIDBytes),
+		PayloadDigest: payloadDigest,
+	}
+
+	entryHash := core.HashEntry(entry)
+	entry.EntryHash = entryHash
+
+	fmt.Printf("Entry: %+v\n", entry)
+	fmt.Printf("EntryHash: %x\n", entryHash)
 }

core/interfaces.go

@@ -2,24 +2,27 @@ package core
 
 import (
 	"context"
-	"io"
 )
 
 type EntryStore interface {
-	Append(ctx context.Context, entry Entry) (EntryID, error)
-
-	Redact(ctx context.Context, entryID EntryID) error
-
+	Append(ctx context.Context, entry Entry) error
 	Get(ctx context.Context, entryID EntryID) (Entry, error)
-
-	ScanForwards(ctx context.Context, entryID EntryID) ([]EntryID, error)
-	ScanBackwards(ctx context.Context, entryID EntryID) ([]EntryID, error)
+	GetBySeq(ctx context.Context, ledgerID LedgerID, seq uint64) (Entry, error)
+	Delete(ctx context.Context, entryID EntryID) error
 
 	Head(ctx context.Context, ledgerID LedgerID) (EntryID, error)
-	IsEmpty(ctx context.Context, ledgerID LedgerID) bool
+	HeadSeq(context.Context, LedgerID) (uint64, error)
+	Tail(ctx context.Context, ledgerID LedgerID) (EntryID, error)
+	Iterator(ctx context.Context, ledgerLedgerID, startSeq uint64) (EntryIterator, error)
+}
+
+type EntryIterator interface {
+	Next() bool
+	Entry() Entry
 }
 
 type PayloadStore interface {
-	Put(ctx context.Context, reader io.Reader) (PayloadID, error)
+	Put(ctx context.Context, payload []byte) (PayloadID, error)
+	Get(ctx context.Context, payloadID PayloadID) ([]byte, error)
 	Delete(ctx context.Context, payloadID PayloadID) error
 }

core/ledger.go

@@ -1,12 +1,107 @@
 package core
 
+import (
+	"context"
+	"time"
+
+	"github.com/google/uuid"
+	"lukechampine.com/blake3"
+)
+
 type Ledger struct {
+	LedgerID LedgerID
+
 	entryStore   EntryStore
 	payloadStore PayloadStore
 
-	LedgerID LedgerID
+	hashChaining bool
 }
 
 func NewLedger(entryStore EntryStore, payloadStore PayloadStore) (*Ledger, error) {
+	id, err := uuid.NewV7()
+	if err != nil {
+		return nil, err
+	}
+
+	idByes, err := id.MarshalBinary()
+	if err != nil {
+		return nil, err
+	}
+
+	return &Ledger{
+		LedgerID:     LedgerID(idByes),
+		entryStore:   entryStore,
+		payloadStore: payloadStore,
+	}, nil
+}
+
+func (l *Ledger) ID() LedgerID {
+	return l.LedgerID
+}
+
+func (l *Ledger) Head() (Entry, error) {
+	panic("unimplemented")
+}
+
+func (l *Ledger) Append(ctx context.Context, payload []byte) (EntryID, error) {
+	payloadDigest := blake3.Sum256(payload)
+	payloadID, err := l.payloadStore.Put(ctx, payload)
+	if err != nil {
+		return EntryID{}, err
+	}
+
+	entryID, err := uuid.NewV7()
+	entryIDBytes, err := entryID.MarshalBinary()
+	if err != nil {
+		return EntryID{}, err
+	}
+
+	head, err := l.Head()
+	if err != nil {
+		return EntryID{}, err
+	}
+
+	entry := Entry{
+		EntryID:       EntryID(entryIDBytes),
+		LedgerID:      l.LedgerID,
+		Seq:           head.Seq + 1,
+		Timestamp:     time.Now(),
+		PayloadID:     payloadID,
+		PayloadDigest: payloadDigest,
+	}
+
+	entryHash := HashEntry(entry)
+	entry.EntryHash = entryHash
+
+	err = l.entryStore.Append(ctx, entry)
+	if err != nil {
+		return EntryID{}, err
+	}
+
+	return EntryID(entryIDBytes), nil
+}
+
+func (l *Ledger) Get(ctx context.Context, seq uint64) (Entry, []byte, error) {
+	entry, err := l.entryStore.GetBySeq(ctx, l.LedgerID, seq)
+	if err != nil {
+		return Entry{}, nil, err
+	}
+	payload, err := l.payloadStore.Get(ctx, entry.PayloadID)
+	if err != nil {
+		return Entry{}, nil, err
+	}
+
+	return entry, payload, nil
+}
+
+func (l *Ledger) GetEntry(ctx context.Context, seq uint64) (Entry, error) {
+	panic("unimplemented")
+}
+
+func (l *Ledger) GetPayload(ctx context.Context, seq uint64) ([]byte, error) {
+	panic("unimplemented")
+}
+
+func (l *Ledger) Iter(ctx context.Context, startSeq uint64) (EntryIterator, error) {
 	panic("unimplemented")
 }

core/types.go

@@ -1,15 +1,17 @@
 package core
 
 import (
+	"encoding/binary"
 	"time"
+
+	"lukechampine.com/blake3"
 )
 
 type LedgerID [16]byte
-
 type EntryID [16]byte
 type PayloadID [16]byte
 
-type Hash [32]byte
+type Hash32 [32]byte
 
 type Entry struct {
 	EntryID EntryID
@@ -19,9 +21,31 @@ type Entry struct {
 
 	Timestamp time.Time
 
-	Nonce      [16]byte
-	Commitment Hash
+	PayloadID     PayloadID
+	PayloadDigest Hash32
 
-	PreviousHash Hash
-	EntryHash    Hash
+	PreviousHash Hash32
+	EntryHash    Hash32
+}
+
+func HashEntry(e Entry) Hash32 {
+	b := make([]byte, 0, 128)
+
+	b = append(b, "chron.entry.v1"...)
+	b = append(b, e.LedgerID[:]...)
+
+	var buf [8]byte
+	binary.LittleEndian.PutUint64(buf[:], e.Seq)
+	b = append(b, buf[:]...)
+
+	binary.LittleEndian.PutUint64(buf[:], uint64(e.Timestamp.UTC().UnixNano()))
+	b = append(b, buf[:]...)
+
+	b = append(b, e.EntryID[:]...)
+	b = append(b, e.PayloadID[:]...)
+	b = append(b, e.PayloadDigest[:]...)
+	b = append(b, e.PreviousHash[:]...)
+
+	sum := blake3.Sum256(b)
+	return Hash32(sum)
 }

go.mod

@@ -3,3 +3,8 @@ module git.michelsen.id/chron
 go 1.25.5
 
 require github.com/google/uuid v1.6.0
+
+require (
+	github.com/klauspost/cpuid/v2 v2.0.9 // indirect
+	lukechampine.com/blake3 v1.4.1 // indirect
+)

go.sum

@@ -1,2 +1,6 @@
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/klauspost/cpuid/v2 v2.0.9 h1:lgaqFMSdTdQYdZ04uHyN2d/eKdOMyi2YLSvlQIBFYa4=
+github.com/klauspost/cpuid/v2 v2.0.9/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
+lukechampine.com/blake3 v1.4.1 h1:I3Smz7gso8w4/TunLKec6K2fn+kyKtDxr/xcQEN84Wg=
+lukechampine.com/blake3 v1.4.1/go.mod h1:QFosUxmjB8mnrWFSNwKmvxHpfY72bmD2tQ0kBMM3kwo=