Additions to domain/ and workspace/ chron-note packages

chron-core/errors.go

@@ -0,0 +1 @@
+package chroncore

chron-core/go.mod

@@ -0,0 +1,8 @@
+module git.michelsen.id/phill/chron/chron-core
+
+go 1.25.7
+
+require (
+	github.com/klauspost/cpuid/v2 v2.0.9 // indirect
+	lukechampine.com/blake3 v1.4.1 // indirect
+)

chron-core/go.sum

@@ -0,0 +1,4 @@
+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=

chron-core/interfaces.go

@@ -1,18 +1,24 @@
-package core
+package chroncore
 
-import (
-	"context"
-)
+import "context"
 
 type EntryStore interface {
 	Store(ctx context.Context, entry Entry) error
 	Load(ctx context.Context, id EntryID) (Entry, error)
 	Exists(ctx context.Context, id EntryID) (bool, error)
 	Delete(ctx context.Context, id EntryID) error
+
+	StoreBatch(ctx context.Context, entries []Entry) error
+	LoadBatch(ctx context.Context, ids []EntryID) ([]Entry, error)
 }
 
 type ReferenceStore interface {
 	Set(ctx context.Context, name string, entryID EntryID) error
 	Get(ctx context.Context, name string) (EntryID, bool, error)
 	Delete(ctx context.Context, name string) error
+
+	List(ctx context.Context, prefix string) (map[string]EntryID, error)
+
+	SetBatch(ctx context.Context, refs map[string]EntryID) error
+	GetBatch(ctx context.Context, names []string) (map[string]EntryID, error)
 }

chron-core/ledger.go

@@ -0,0 +1,302 @@
+package chroncore
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"slices"
+	"sort"
+	"time"
+)
+
+var (
+	ErrHeadNotSet      = errors.New("HEAD not set")
+	ErrEntryIDMismatch = errors.New("entry id mismatch")
+	ErrBatchLoadSize   = errors.New("LoadBatch returned unexpected number of entries")
+)
+
+type Ledger struct {
+	entryStore     EntryStore
+	referenceStore ReferenceStore
+}
+
+func NewLedger(entryStore EntryStore, referenceStore ReferenceStore) (*Ledger, error) {
+	return &Ledger{
+		entryStore:     entryStore,
+		referenceStore: referenceStore,
+	}, nil
+}
+
+func (l *Ledger) Add(ctx context.Context, parents []EntryID, payload []byte) (EntryID, error) {
+	ps := normalizeParents(parents)
+
+	ts := time.Now()
+	id := ComputeEntryID(ps, ts, payload)
+
+	e := Entry{
+		EntryID:   id,
+		Parents:   ps,
+		Timestamp: ts,
+		Payload:   payload,
+	}
+
+	if err := l.VerifyEntry(e); err != nil {
+		return EntryID{}, err
+	}
+
+	if err := l.entryStore.Store(ctx, e); err != nil {
+		return EntryID{}, err
+	}
+
+	return id, nil
+}
+
+func (l *Ledger) Append(ctx context.Context, payload []byte) (EntryID, error) {
+	head, ok, err := l.referenceStore.Get(ctx, "HEAD")
+	if err != nil {
+		return EntryID{}, err
+	}
+
+	var parents []EntryID
+	if ok {
+		parents = []EntryID{head}
+	} else {
+		parents = nil
+	}
+
+	id, err := l.Add(ctx, parents, payload)
+	if err != nil {
+		return EntryID{}, err
+	}
+
+	if err := l.referenceStore.Set(ctx, "HEAD", id); err != nil {
+		return EntryID{}, err
+	}
+
+	return id, nil
+}
+
+func (l *Ledger) AppendTo(ctx context.Context, parent EntryID, payload []byte) (EntryID, error) {
+	return l.Add(ctx, []EntryID{parent}, payload)
+}
+
+func (l *Ledger) Get(ctx context.Context, id EntryID) (Entry, error) {
+	return l.entryStore.Load(ctx, id)
+}
+
+func (l *Ledger) Exists(ctx context.Context, id EntryID) (bool, error) {
+	return l.entryStore.Exists(ctx, id)
+}
+
+func (l *Ledger) Verify(ctx context.Context, id EntryID) error {
+	e, err := l.entryStore.Load(ctx, id)
+	if err != nil {
+		return err
+	}
+	return l.VerifyEntry(e)
+}
+
+func (l *Ledger) VerifyEntry(e Entry) error {
+	want := ComputeEntryID(e.Parents, e.Timestamp, e.Payload)
+	if want != e.EntryID {
+		return ErrEntryIDMismatch
+	}
+	return nil
+}
+
+func (l *Ledger) GetRef(ctx context.Context, name string) (EntryID, bool, error) {
+	return l.referenceStore.Get(ctx, name)
+}
+
+func (l *Ledger) SetRef(ctx context.Context, name string, id EntryID) error {
+	return l.referenceStore.Set(ctx, name, id)
+}
+
+func (l *Ledger) DeleteRef(ctx context.Context, name string) error {
+	return l.referenceStore.Delete(ctx, name)
+}
+
+func (l *Ledger) ListRefs(ctx context.Context, prefix string) (map[string]EntryID, error) {
+	return l.referenceStore.List(ctx, prefix)
+}
+
+func (l *Ledger) SetRefs(ctx context.Context, refs map[string]EntryID) error {
+	return l.referenceStore.SetBatch(ctx, refs)
+}
+
+func (l *Ledger) GetRefs(ctx context.Context, names []string) (map[string]EntryID, error) {
+	return l.referenceStore.GetBatch(ctx, names)
+}
+
+func (l *Ledger) GetHead(ctx context.Context) (EntryID, bool, error) {
+	return l.referenceStore.Get(ctx, "HEAD")
+}
+
+func (l *Ledger) SetHead(ctx context.Context, id EntryID) error {
+	return l.referenceStore.Set(ctx, "HEAD", id)
+}
+
+func (l *Ledger) GetHeads(ctx context.Context, prefix string) ([]EntryID, error) {
+	m, err := l.referenceStore.List(ctx, prefix)
+	if err != nil {
+		return nil, err
+	}
+
+	seen := make(map[EntryID]struct{}, len(m))
+	for _, id := range m {
+		seen[id] = struct{}{}
+	}
+
+	out := make([]EntryID, 0, len(seen))
+	for id := range seen {
+		out = append(out, id)
+	}
+
+	sort.Slice(out, func(i, j int) bool {
+		return bytes.Compare(out[i][:], out[j][:]) < 0
+	})
+
+	return out, nil
+}
+
+func (l *Ledger) WalkAncestors(ctx context.Context, start []EntryID, fn func(Entry) bool) error {
+	frontier := dedupeIDs(start)
+	visited := make(map[EntryID]struct{}, 1024)
+
+	for len(frontier) > 0 {
+		batchIDs := make([]EntryID, 0, len(frontier))
+		for _, id := range frontier {
+			if _, ok := visited[id]; ok {
+				continue
+			}
+			visited[id] = struct{}{}
+			batchIDs = append(batchIDs, id)
+		}
+		if len(batchIDs) == 0 {
+			return nil
+		}
+
+		entries, err := l.entryStore.LoadBatch(ctx, batchIDs)
+		if err != nil {
+			return err
+		}
+		if len(entries) != len(batchIDs) {
+			return ErrBatchLoadSize
+		}
+
+		next := make([]EntryID, 0, len(batchIDs)*2)
+
+		for _, e := range entries {
+			if err := l.VerifyEntry(e); err != nil {
+				return err
+			}
+
+			if !fn(e) {
+				return nil
+			}
+
+			for _, p := range e.Parents {
+				next = append(next, p)
+			}
+		}
+
+		frontier = dedupeIDs(next)
+	}
+
+	return nil
+}
+
+func (l *Ledger) IsAncestor(ctx context.Context, ancestor, descendant EntryID) (bool, error) {
+	if ancestor == descendant {
+		return true, nil
+	}
+
+	found := false
+	err := l.WalkAncestors(ctx, []EntryID{descendant}, func(e Entry) bool {
+		if slices.Contains(e.Parents, ancestor) {
+			found = true
+			return false
+		}
+		return true
+	})
+	if err != nil {
+		return false, err
+	}
+	return found, nil
+}
+
+func (l *Ledger) CommonAncestors(ctx context.Context, a, b []EntryID, limit int) ([]EntryID, error) {
+	aSet := make(map[EntryID]struct{}, 1024)
+
+	if err := l.WalkAncestors(ctx, a, func(e Entry) bool {
+		aSet[e.EntryID] = struct{}{}
+		return true
+	}); err != nil {
+		return nil, err
+	}
+
+	var out []EntryID
+	seen := make(map[EntryID]struct{}, 64)
+
+	err := l.WalkAncestors(ctx, b, func(e Entry) bool {
+		if _, ok := aSet[e.EntryID]; ok {
+			if _, dup := seen[e.EntryID]; !dup {
+				seen[e.EntryID] = struct{}{}
+				out = append(out, e.EntryID)
+				if limit > 0 && len(out) >= limit {
+					return false
+				}
+			}
+		}
+		return true
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return out, nil
+}
+
+func normalizeParents(parents []EntryID) []EntryID {
+	if len(parents) == 0 {
+		return nil
+	}
+
+	ps := make([]EntryID, len(parents))
+	copy(ps, parents)
+
+	sort.Slice(ps, func(i, j int) bool {
+		return bytes.Compare(ps[i][:], ps[j][:]) < 0
+	})
+
+	out := ps[:0]
+	var last EntryID
+	for i, p := range ps {
+		if i == 0 || p != last {
+			out = append(out, p)
+			last = p
+		}
+	}
+	return out
+}
+
+func dedupeIDs(ids []EntryID) []EntryID {
+	if len(ids) == 0 {
+		return nil
+	}
+
+	tmp := make([]EntryID, len(ids))
+	copy(tmp, ids)
+	sort.Slice(tmp, func(i, j int) bool {
+		return bytes.Compare(tmp[i][:], tmp[j][:]) < 0
+	})
+	out := tmp[:0]
+	var last EntryID
+	for i, id := range tmp {
+		if i == 0 || id != last {
+			out = append(out, id)
+			last = id
+		}
+	}
+	return out
+}

chron-core/types.go

@@ -1,7 +1,9 @@
-package core
+package chroncore
 
 import (
+	"bytes"
 	"encoding/binary"
+	"sort"
 	"time"
 
 	"lukechampine.com/blake3"
@@ -12,25 +14,35 @@ type EntryID [32]byte
 type Entry struct {
 	EntryID EntryID
 
-	Previous EntryID
+	Parents []EntryID
 
 	Timestamp time.Time
 	Payload   []byte
 }
 
-func ComputeEntryID(prev EntryID, ts time.Time, payload []byte) EntryID {
+func ComputeEntryID(parents []EntryID, ts time.Time, payload []byte) EntryID {
 	h := blake3.New(32, nil)
 
-	h.Write(prev[:])
+	ps := make([]EntryID, len(parents))
+	copy(ps, parents)
+	sort.Slice(ps, func(i, j int) bool {
+		return bytes.Compare(ps[i][:], ps[j][:]) < 0
+	})
+
+	var u32 [4]byte
+	binary.LittleEndian.PutUint32(u32[:], uint32(len(ps)))
+	h.Write(u32[:])
+
+	for _, p := range ps {
+		h.Write(p[:])
+	}
 
 	var i64 [8]byte
 	binary.LittleEndian.PutUint64(i64[:], uint64(ts.UTC().UnixNano()))
 	h.Write(i64[:])
 
-	var u32 [4]byte
 	binary.LittleEndian.PutUint32(u32[:], uint32(len(payload)))
 	h.Write(u32[:])
-
 	h.Write(payload)
 
 	var id EntryID

chron-note/cmd/chron-note/main.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"git.michelsen.id/phill/chron/chron-note/internal/domain"
+	"git.michelsen.id/phill/chron/chron-note/internal/workspace"
+)
+
+func must(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+func main() {
+	root := "."
+
+	if len(os.Args) > 1 {
+		root = os.Args[1]
+	}
+
+	ws, err := workspace.Open(root)
+	must(err)
+
+	fmt.Println("Workspace directory:")
+	fmt.Println(ws.Dir)
+	fmt.Println()
+
+	fmt.Println("Creating objects...")
+
+	var ids []domain.ObjectID
+
+	for i := range 3 {
+		id, err := domain.NewObjectID()
+		must(err)
+
+		content := fmt.Sprintf("object %d\nid: %s\n", i, id.String())
+
+		must(ws.Write(id, []byte(content)))
+
+		ids = append(ids, id)
+
+		fmt.Printf("Created object %s\n", id)
+		fmt.Printf("Path: %s\n\n", ws.ObjectPath(id))
+	}
+
+	fmt.Println("Listing workspace objects:")
+	fmt.Println()
+
+	list, err := ws.ListObjectIDs()
+	must(err)
+
+	for _, id := range list {
+		fi, err := ws.Stat(id)
+		must(err)
+
+		fmt.Printf("Object: %s\n", id)
+		fmt.Printf("Size:   %d bytes\n", fi.Size())
+		fmt.Printf("Path:   %s\n", ws.ObjectPath(id))
+		fmt.Println()
+	}
+
+	fmt.Println("Reading objects back:")
+	fmt.Println()
+
+	for _, id := range ids {
+		data, err := ws.Read(id)
+		must(err)
+
+		fmt.Printf("Object %s contents:\n", id)
+		fmt.Println(string(data))
+		fmt.Println("---")
+	}
+
+	fmt.Println()
+	fmt.Println("Filesystem view:")
+	fmt.Println(filepath.Join(ws.Dir, "..."))
+}

chron-note/go.mod

@@ -0,0 +1,3 @@
+module git.michelsen.id/phill/chron/chron-note
+
+go 1.25.7

chron-note/internal/app/app.go

@@ -0,0 +1 @@
+package app

chron-note/internal/config/config.go

@@ -0,0 +1 @@
+package config

chron-note/internal/config/defaults.go

@@ -0,0 +1 @@
+package config

chron-note/internal/domain/errors.go

@@ -0,0 +1,11 @@
+package domain
+
+import "errors"
+
+var (
+	ErrInvalidObjectID  = errors.New("invalid object id")
+	ErrInvalidBlobID    = errors.New("invalid blob id")
+	ErrUnknownEventType = errors.New("unknown event type")
+	ErrInvalidEvent     = errors.New("invalid event")
+	ErrDecode           = errors.New("decode error")
+)

chron-note/internal/domain/event.go

@@ -0,0 +1,137 @@
+package domain
+
+import (
+	"fmt"
+
+	"git.michelsen.id/phill/chron/chron-note/internal/util"
+)
+
+type EventType uint8
+
+const (
+	EventObjectUpsert EventType = 1
+	EventObjectDelete EventType = 2
+)
+
+const encodingVersion uint8 = 1
+
+type ObjectUpsert struct {
+	ObjectID ObjectID
+	Name     string
+	Tags     []string
+
+	HasBlob bool
+	Blob    BlobID
+}
+
+type ObjectDelete struct {
+	ObjectID ObjectID
+}
+
+type Event struct {
+	Type EventType
+
+	Upsert *ObjectUpsert
+	Delete *ObjectDelete
+}
+
+func EncodeEvent(e Event) ([]byte, error) {
+	enc := util.NewEncoder(nil)
+	enc.U8(encodingVersion)
+	enc.U8(uint8(e.Type))
+
+	switch e.Type {
+	case EventObjectUpsert:
+		if e.Upsert == nil {
+			return nil, ErrInvalidEvent
+		}
+		u := e.Upsert
+
+		var flags uint8
+		if u.HasBlob {
+			flags |= 0x01
+		}
+		enc.U8(flags)
+
+		enc.BytesFixed(u.ObjectID[:])
+		enc.String(u.Name)
+		enc.StringSlice(u.Tags)
+
+		if u.HasBlob {
+			enc.BytesFixed(u.Blob[:])
+		}
+
+	case EventObjectDelete:
+		if e.Delete == nil {
+			return nil, ErrInvalidEvent
+		}
+		enc.BytesFixed(e.Delete.ObjectID[:])
+
+	default:
+		return nil, ErrUnknownEventType
+	}
+
+	if err := enc.Err(); err != nil {
+		return nil, err
+	}
+	return enc.Bytes(), nil
+}
+
+func DecodeEvent(b []byte) (Event, error) {
+	dec := util.NewDecoder(b)
+
+	ver := dec.U8()
+	if dec.Err() != nil {
+		return Event{}, ErrDecode
+	}
+	if ver != encodingVersion {
+		return Event{}, fmt.Errorf("%w: unsupported encoding version %d", ErrDecode, ver)
+	}
+
+	typ := EventType(dec.U8())
+	if dec.Err() != nil {
+		return Event{}, ErrDecode
+	}
+
+	switch typ {
+	case EventObjectUpsert:
+		flags := dec.U8()
+		var objID ObjectID
+		copy(objID[:], dec.BytesFixed(len(objID)))
+
+		name := dec.String()
+		tags := dec.StringSlice()
+
+		hasBlob := (flags & 0x01) != 0
+		var blob BlobID
+		if hasBlob {
+			copy(blob[:], dec.BytesFixed(len(blob)))
+		}
+
+		if dec.Err() != nil {
+			return Event{}, ErrDecode
+		}
+
+		return Event{
+			Type: typ,
+			Upsert: &ObjectUpsert{
+				ObjectID: objID,
+				Name:     NormalizeName(name),
+				Tags:     NormalizeTags(tags),
+				HasBlob:  hasBlob,
+				Blob:     blob,
+			},
+		}, nil
+
+	case EventObjectDelete:
+		var objID ObjectID
+		copy(objID[:], dec.BytesFixed(len(objID)))
+		if dec.Err() != nil {
+			return Event{}, ErrDecode
+		}
+		return Event{Type: typ, Delete: &ObjectDelete{ObjectID: objID}}, nil
+
+	default:
+		return Event{}, ErrUnknownEventType
+	}
+}

chron-note/internal/domain/object.go

@@ -0,0 +1,74 @@
+package domain
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"strings"
+)
+
+type ObjectID [16]byte
+type BlobID [32]byte
+
+func NewObjectID() (ObjectID, error) {
+	var id ObjectID
+	_, err := rand.Read(id[:])
+	return id, err
+}
+
+func ParseObjectID(s string) (ObjectID, error) {
+	s = strings.TrimSpace(s)
+	b, err := hex.DecodeString(s)
+	if err != nil || len(b) != len(ObjectID{}) {
+		return ObjectID{}, ErrInvalidObjectID
+	}
+	var id ObjectID
+	copy(id[:], b)
+	return id, nil
+}
+
+func (id ObjectID) String() string { return hex.EncodeToString(id[:]) }
+
+func ParseBlobID(s string) (BlobID, error) {
+	s = strings.TrimSpace(s)
+	b, err := hex.DecodeString(s)
+	if err != nil || len(b) != len(BlobID{}) {
+		return BlobID{}, ErrInvalidBlobID
+	}
+	var id BlobID
+	copy(id[:], b)
+	return id, nil
+}
+
+func (id BlobID) String() string { return hex.EncodeToString(id[:]) }
+
+type ObjectState struct {
+	ID      ObjectID
+	Name    string
+	Tags    []string
+	Blob    BlobID
+	HasBlob bool
+	Deleted bool
+}
+
+// Keep normalization here so all layers agree.
+func NormalizeName(s string) string {
+	s = strings.TrimSpace(s)
+	return s
+}
+
+func NormalizeTags(tags []string) []string {
+	out := make([]string, 0, len(tags))
+	seen := make(map[string]struct{}, len(tags))
+	for _, t := range tags {
+		t = strings.TrimSpace(strings.ToLower(t))
+		if t == "" {
+			continue
+		}
+		if _, ok := seen[t]; ok {
+			continue
+		}
+		seen[t] = struct{}{}
+		out = append(out, t)
+	}
+	return out
+}

chron-note/internal/state/reduce.go

@@ -0,0 +1 @@
+package state

chron-note/internal/state/state.go

@@ -0,0 +1 @@
+package state

chron-note/internal/stores/cas/cas.go

@@ -0,0 +1,14 @@
+package cas
+
+import (
+	"context"
+
+	"git.michelsen.id/phill/chron/chron-note/internal/domain"
+)
+
+type Store interface {
+	Put(ctx context.Context, data []byte) (domain.BlobID, error) // id = blake3-256(data)
+	Get(ctx context.Context, id domain.BlobID) ([]byte, error)
+	Has(ctx context.Context, id domain.BlobID) (bool, error)
+	Remove(ctx context.Context, id domain.BlobID) error
+}

chron-note/internal/stores/cas/fs.go

@@ -0,0 +1,93 @@
+package cas
+
+import (
+	"context"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"git.michelsen.id/phill/chron/chron-note/internal/domain"
+	"git.michelsen.id/phill/chron/chron-note/internal/util"
+)
+
+var ErrBlobNotFound = errors.New("blob not found")
+
+type FS struct {
+	root string
+}
+
+func NewFS(root string) *FS {
+	return &FS{root: root}
+}
+
+func (s *FS) Put(ctx context.Context, data []byte) (domain.BlobID, error) {
+	_ = ctx
+
+	sum := util.Hash256(data)
+	var id domain.BlobID
+	copy(id[:], sum[:])
+
+	p := s.pathFor(id)
+
+	// Fast path: already exists
+	if _, err := os.Stat(p); err == nil {
+		return id, nil
+	}
+
+	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+		return domain.BlobID{}, err
+	}
+
+	tmp := p + ".tmp"
+	if err := os.WriteFile(tmp, data, 0o644); err != nil {
+		return domain.BlobID{}, err
+	}
+	if err := os.Rename(tmp, p); err != nil {
+		_ = os.Remove(tmp)
+		// If another writer won the race, accept it.
+		if _, statErr := os.Stat(p); statErr == nil {
+			return id, nil
+		}
+		return domain.BlobID{}, err
+	}
+
+	return id, nil
+}
+
+func (s *FS) Get(ctx context.Context, id domain.BlobID) ([]byte, error) {
+	_ = ctx
+	p := s.pathFor(id)
+	b, err := os.ReadFile(p)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, ErrBlobNotFound
+		}
+		return nil, err
+	}
+	return b, nil
+}
+
+func (s *FS) Has(ctx context.Context, id domain.BlobID) (bool, error) {
+	_ = ctx
+	p := s.pathFor(id)
+	_, err := os.Stat(p)
+	if err == nil {
+		return true, nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return false, err
+}
+
+func (s *FS) pathFor(id domain.BlobID) string {
+	hexID := hex.EncodeToString(id[:])
+	if len(hexID) < 4 {
+		// should never happen
+		return filepath.Join(s.root, fmt.Sprintf("bad-%s", hexID))
+	}
+	// git-style fanout
+	return filepath.Join(s.root, hexID[:2], hexID[2:4], hexID)
+}

chron-note/internal/util/encoding.go

@@ -0,0 +1,133 @@
+package util
+
+import (
+	"encoding/binary"
+	"errors"
+)
+
+var ErrDecode = errors.New("decode")
+
+type Encoder struct {
+	b   []byte
+	err error
+}
+
+func NewEncoder(dst []byte) *Encoder { return &Encoder{b: dst} }
+func (e *Encoder) Bytes() []byte     { return e.b }
+func (e *Encoder) Err() error        { return e.err }
+
+func (e *Encoder) U8(v uint8) {
+	if e.err != nil {
+		return
+	}
+	e.b = append(e.b, v)
+}
+
+func (e *Encoder) U32(v uint32) {
+	if e.err != nil {
+		return
+	}
+	var tmp [4]byte
+	binary.LittleEndian.PutUint32(tmp[:], v)
+	e.b = append(e.b, tmp[:]...)
+}
+
+func (e *Encoder) BytesFixed(p []byte) {
+	if e.err != nil {
+		return
+	}
+	e.b = append(e.b, p...)
+}
+
+func (e *Encoder) BytesLen(p []byte) {
+	if e.err != nil {
+		return
+	}
+	e.U32(uint32(len(p)))
+	e.b = append(e.b, p...)
+}
+
+func (e *Encoder) String(s string) {
+	e.BytesLen([]byte(s))
+}
+
+func (e *Encoder) StringSlice(ss []string) {
+	if e.err != nil {
+		return
+	}
+	e.U32(uint32(len(ss)))
+	for _, s := range ss {
+		e.String(s)
+	}
+}
+
+type Decoder struct {
+	b   []byte
+	off int
+	err error
+}
+
+func NewDecoder(src []byte) *Decoder { return &Decoder{b: src} }
+func (d *Decoder) Err() error        { return d.err }
+
+func (d *Decoder) need(n int) bool {
+	if d.err != nil {
+		return false
+	}
+	if n < 0 || d.off+n > len(d.b) {
+		d.err = ErrDecode
+		return false
+	}
+	return true
+}
+
+func (d *Decoder) U8() uint8 {
+	if !d.need(1) {
+		return 0
+	}
+	v := d.b[d.off]
+	d.off++
+	return v
+}
+
+func (d *Decoder) U32() uint32 {
+	if !d.need(4) {
+		return 0
+	}
+	v := binary.LittleEndian.Uint32(d.b[d.off : d.off+4])
+	d.off += 4
+	return v
+}
+
+func (d *Decoder) BytesFixed(n int) []byte {
+	if !d.need(n) {
+		return nil
+	}
+	out := d.b[d.off : d.off+n]
+	d.off += n
+	return out
+}
+
+func (d *Decoder) BytesLen() []byte {
+	n := int(d.U32())
+	return d.BytesFixed(n)
+}
+
+func (d *Decoder) String() string {
+	return string(d.BytesLen())
+}
+
+func (d *Decoder) StringSlice() []string {
+	n := int(d.U32())
+	if d.Err() != nil {
+		return nil
+	}
+	out := make([]string, 0, n)
+	for range n {
+		out = append(out, d.String())
+		if d.Err() != nil {
+			return nil
+		}
+	}
+	return out
+}

chron-note/internal/util/hash.go

@@ -0,0 +1,8 @@
+package util
+
+import "lukechampine.com/blake3"
+
+func Hash256(b []byte) [32]byte {
+	h := blake3.Sum256(b)
+	return h
+}

chron-note/internal/workspace/io.go

@@ -0,0 +1,69 @@
+package workspace
+
+import (
+	"fmt"
+	"os"
+
+	"git.michelsen.id/phill/chron/chron-note/internal/domain"
+)
+
+func (ws *Workspace) Exists(id domain.ObjectID) (bool, error) {
+	_, err := os.Stat(ws.ObjectPath(id))
+	if err == nil {
+		return true, nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return false, fmt.Errorf("stat object %s: %w", id.String(), err)
+}
+
+func (ws *Workspace) Read(id domain.ObjectID) ([]byte, error) {
+	b, err := os.ReadFile(ws.ObjectPath(id))
+	if err != nil {
+		return nil, fmt.Errorf("read object %s: %w", id.String(), err)
+	}
+	return b, nil
+}
+
+func (ws *Workspace) Write(id domain.ObjectID, b []byte) error {
+	if err := os.MkdirAll(ws.Dir, 0o755); err != nil {
+		return fmt.Errorf("mkdir workspace dir: %w", err)
+	}
+
+	dst := ws.ObjectPath(id)
+
+	f, err := os.CreateTemp(ws.Dir, id.String()+".*.tmp")
+	if err != nil {
+		return fmt.Errorf("create temp for object %s: %w", id.String(), err)
+	}
+	tmp := f.Name()
+
+	// Best-effort cleanup on failure.
+	defer func() { _ = os.Remove(tmp) }()
+
+	if _, err := f.Write(b); err != nil {
+		_ = f.Close()
+		return fmt.Errorf("write temp for object %s: %w", id.String(), err)
+	}
+	if err := f.Close(); err != nil {
+		return fmt.Errorf("close temp for object %s: %w", id.String(), err)
+	}
+
+	if err := os.Rename(tmp, dst); err != nil {
+		return fmt.Errorf("rename temp for object %s: %w", id.String(), err)
+	}
+
+	// Rename succeeded; prevent deferred cleanup.
+	_ = os.Remove(tmp)
+	return nil
+}
+
+func (ws *Workspace) Delete(id domain.ObjectID) error {
+	p := ws.ObjectPath(id)
+	err := os.Remove(p)
+	if err == nil || os.IsNotExist(err) {
+		return nil
+	}
+	return fmt.Errorf("delete object %s: %w", id.String(), err)
+}

chron-note/internal/workspace/list.go

@@ -0,0 +1,46 @@
+package workspace
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+
+	"git.michelsen.id/phill/chron/chron-note/internal/domain"
+)
+
+func (ws *Workspace) ListObjectIDs() ([]domain.ObjectID, error) {
+	entries, err := os.ReadDir(ws.Dir)
+	if err != nil {
+		return nil, fmt.Errorf("readdir workspace dir: %w", err)
+	}
+
+	out := make([]domain.ObjectID, 0, len(entries))
+	for _, e := range entries {
+		if e.IsDir() {
+			continue
+		}
+		info, err := e.Info()
+		if err != nil {
+			return nil, fmt.Errorf("stat workspace entry: %w", err)
+		}
+		if !info.Mode().IsRegular() {
+			continue
+		}
+
+		id, err := domain.ParseObjectID(e.Name())
+		if err != nil {
+			continue
+		}
+		out = append(out, id)
+	}
+
+	return out, nil
+}
+
+func (ws *Workspace) Stat(id domain.ObjectID) (fs.FileInfo, error) {
+	fi, err := os.Stat(ws.ObjectPath(id))
+	if err != nil {
+		return nil, fmt.Errorf("stat object %s: %w", id.String(), err)
+	}
+	return fi, nil
+}

chron-note/internal/workspace/snapshot.go

@@ -0,0 +1,52 @@
+package workspace
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"git.michelsen.id/phill/chron/chron-note/internal/domain"
+)
+
+type SnapshotObject struct {
+	ID    domain.ObjectID
+	Size  int64
+	ModNS int64
+}
+
+func (ws *Workspace) Snapshot(ctx context.Context) ([]SnapshotObject, error) {
+	entries, err := os.ReadDir(ws.Dir)
+	if err != nil {
+		return nil, fmt.Errorf("readdir workspace dir: %w", err)
+	}
+
+	out := make([]SnapshotObject, 0, len(entries))
+	for _, e := range entries {
+		if ctx.Err() != nil {
+			return nil, ctx.Err()
+		}
+		if e.IsDir() {
+			continue
+		}
+		info, err := e.Info()
+		if err != nil {
+			return nil, fmt.Errorf("stat workspace entry: %w", err)
+		}
+		if !info.Mode().IsRegular() {
+			continue
+		}
+
+		id, err := domain.ParseObjectID(e.Name())
+		if err != nil {
+			continue
+		}
+
+		out = append(out, SnapshotObject{
+			ID:    id,
+			Size:  info.Size(),
+			ModNS: info.ModTime().UnixNano(),
+		})
+	}
+
+	return out, nil
+}

chron-note/internal/workspace/workspace.go

@@ -0,0 +1,32 @@
+package workspace
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"git.michelsen.id/phill/chron/chron-note/internal/domain"
+)
+
+type Workspace struct {
+	Root string
+	Dir  string
+}
+
+func Open(root string) (*Workspace, error) {
+	root = filepath.Clean(root)
+	dir := filepath.Join(root, ".chron", "workspace")
+
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return nil, fmt.Errorf("mkdir workspace dir: %w", err)
+	}
+
+	return &Workspace{
+		Root: root,
+		Dir:  dir,
+	}, nil
+}
+
+func (ws *Workspace) ObjectPath(id domain.ObjectID) string {
+	return filepath.Join(ws.Dir, id.String())
+}

cmd/chron-cli/main.go

@@ -1,140 +0,0 @@
-package main
-
-import (
-	"context"
-	"encoding/hex"
-	"errors"
-	"fmt"
-	"sort"
-
-	"git.michelsen.id/chron/core"
-)
-
-type InProcEntryStore struct {
-	entries map[core.EntryID]core.Entry
-}
-
-func (e *InProcEntryStore) Store(ctx context.Context, entry core.Entry) error {
-	if _, ok := e.entries[entry.EntryID]; ok {
-		return errors.New("entry already exists")
-	}
-	e.entries[entry.EntryID] = entry
-	return nil
-}
-
-func (e *InProcEntryStore) Load(ctx context.Context, id core.EntryID) (core.Entry, error) {
-	entry, ok := e.entries[id]
-	if !ok {
-		return core.Entry{}, errors.New("entry does not exist")
-	}
-	return entry, nil
-}
-
-func (e *InProcEntryStore) Exists(ctx context.Context, id core.EntryID) (bool, error) {
-	_, ok := e.entries[id]
-	return ok, nil
-}
-
-func (e *InProcEntryStore) Delete(ctx context.Context, id core.EntryID) error {
-	if _, ok := e.entries[id]; !ok {
-		return errors.New("entry does not exist")
-	}
-	delete(e.entries, id)
-	return nil
-}
-
-type InProcReferenceStore struct {
-	references map[string]core.EntryID
-}
-
-func (r *InProcReferenceStore) Set(ctx context.Context, name string, entryID core.EntryID) error {
-	r.references[name] = entryID
-	return nil
-}
-
-func (r *InProcReferenceStore) Get(ctx context.Context, name string) (core.EntryID, bool, error) {
-	entryID, ok := r.references[name]
-	if !ok {
-		return core.EntryID{}, false, nil
-	}
-	return entryID, true, nil
-}
-
-func (r *InProcReferenceStore) Delete(ctx context.Context, name string) error {
-	if _, ok := r.references[name]; !ok {
-		return errors.New("reference does not exist")
-	}
-	delete(r.references, name)
-	return nil
-}
-
-func main() {
-	ctx := context.TODO()
-
-	entryStore := InProcEntryStore{
-		entries: make(map[core.EntryID]core.Entry),
-	}
-	referenceStore := InProcReferenceStore{
-		references: make(map[string]core.EntryID),
-	}
-
-	ledger, err := core.NewLedger(&entryStore, &referenceStore)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-
-	for i := range 500 {
-		data := fmt.Sprintf("test%d", i)
-
-		err = ledger.Append(ctx, []byte(data))
-		if err != nil {
-			fmt.Println(err)
-			return
-		}
-	}
-
-	entries := make([]core.Entry, 0, len(entryStore.entries))
-	for _, e := range entryStore.entries {
-		entries = append(entries, e)
-	}
-
-	sort.Slice(entries, func(i, j int) bool {
-		if entries[i].Timestamp.Equal(entries[j].Timestamp) {
-			return hex.EncodeToString(entries[i].EntryID[:]) <
-				hex.EncodeToString(entries[j].EntryID[:])
-		}
-		return entries[i].Timestamp.Before(entries[j].Timestamp)
-	})
-
-	fmt.Println("Entries:")
-	if len(entries) == 0 {
-		fmt.Println("  (none)")
-	} else {
-		for _, e := range entries {
-			fmt.Printf("  ts=%d id=%s prev=%s payload=%q\n",
-				e.Timestamp.UnixNano(),
-				hex.EncodeToString(e.EntryID[:]),
-				hex.EncodeToString(e.Previous[:]),
-				e.Payload,
-			)
-		}
-	}
-
-	// ---- Print references (name -> EntryID hex) ----
-	names := make([]string, 0, len(referenceStore.references))
-	for name := range referenceStore.references {
-		names = append(names, name)
-	}
-	sort.Strings(names)
-
-	fmt.Println("References:")
-	if len(names) == 0 {
-		fmt.Println("  (none)")
-	} else {
-		for _, name := range names {
-			id := referenceStore.references[name]
-			fmt.Printf("  %s -> %s\n", name, hex.EncodeToString(id[:]))
-		}
-	}
-}

core/errors.go

@@ -1 +0,0 @@
-package core

core/ledger.go

@@ -1,128 +0,0 @@
-package core
-
-import (
-	"context"
-	"errors"
-	"time"
-)
-
-type Ledger struct {
-	entryStore     EntryStore
-	referenceStore ReferenceStore
-}
-
-func NewLedger(entryStore EntryStore, referenceStore ReferenceStore) (*Ledger, error) {
-	return &Ledger{
-		entryStore:     entryStore,
-		referenceStore: referenceStore,
-	}, nil
-}
-
-func (l *Ledger) Append(ctx context.Context, payload []byte) error {
-	currentHeadEntryID, ok, err := l.referenceStore.Get(ctx, "HEAD")
-	if err != nil {
-		return err
-	}
-
-	if !ok {
-		l.referenceStore.Set(ctx, "HEAD", EntryID{})
-		currentHeadEntryID = EntryID{}
-	}
-
-	entryTime := time.Now()
-	entryID := ComputeEntryID(currentHeadEntryID, entryTime, payload)
-
-	entry := Entry{
-		EntryID:   entryID,
-		Previous:  currentHeadEntryID,
-		Timestamp: entryTime,
-		Payload:   payload,
-	}
-
-	if ComputeEntryID(entry.Previous, entry.Timestamp, entry.Payload) != entryID {
-		panic("EntryID hash mismatch fuckup")
-	}
-
-	err = l.entryStore.Store(ctx, entry)
-	if err != nil {
-		return err
-	}
-
-	err = l.referenceStore.Set(ctx, "HEAD", entry.EntryID)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (l *Ledger) AppendTo(ctx context.Context, prevEntryID EntryID, payload []byte) error {
-	entryTime := time.Now()
-	entryID := ComputeEntryID(prevEntryID, entryTime, payload)
-
-	entry := Entry{
-		EntryID:   entryID,
-		Previous:  prevEntryID,
-		Timestamp: entryTime,
-		Payload:   payload,
-	}
-
-	if ComputeEntryID(entry.Previous, entry.Timestamp, entry.Payload) != entryID {
-		panic("EntryID hash mismatch fuckup")
-	}
-
-	err := l.entryStore.Store(ctx, entry)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (l *Ledger) Get(ctx context.Context) (Entry, error) {
-	headEntryID, ok, err := l.referenceStore.Get(ctx, "HEAD")
-	if err != nil {
-		return Entry{}, err
-	}
-
-	if !ok {
-		return Entry{}, errors.New("HEAD not set")
-	}
-
-	entry, err := l.entryStore.Load(ctx, headEntryID)
-	if err != nil {
-		return Entry{}, err
-	}
-
-	return entry, nil
-}
-
-func (l *Ledger) GetFromReference(ctx context.Context, reference string) (Entry, error) {
-	referenceEntryID, ok, err := l.referenceStore.Get(ctx, reference)
-	if err != nil {
-		return Entry{}, err
-	}
-
-	if !ok {
-		return Entry{}, errors.New("HEAD not set")
-	}
-
-	entry, err := l.entryStore.Load(ctx, referenceEntryID)
-	if err != nil {
-		return Entry{}, err
-	}
-
-	return entry, nil
-}
-
-func (l *Ledger) SetHead(ctx context.Context, entryID EntryID) error {
-	return l.referenceStore.Set(ctx, "HEAD", entryID)
-}
-
-func (l *Ledger) SetReference(ctx context.Context, reference string, entryID EntryID) error {
-	return l.referenceStore.Set(ctx, reference, entryID)
-}
-
-func (l *Ledger) RemoveReference(ctx context.Context, reference string) error {
-	return l.referenceStore.Delete(ctx, reference)
-}

go.mod

@@ -1,20 +0,0 @@
-module git.michelsen.id/chron
-
-go 1.25.5
-
-require github.com/google/uuid v1.6.0
-
-require (
-	github.com/dustin/go-humanize v1.0.1 // indirect
-	github.com/klauspost/cpuid/v2 v2.0.9 // indirect
-	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/ncruces/go-strftime v1.0.0 // indirect
-	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
-	golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
-	golang.org/x/sys v0.37.0 // indirect
-	lukechampine.com/blake3 v1.4.1 // indirect
-	modernc.org/libc v1.67.6 // indirect
-	modernc.org/mathutil v1.7.1 // indirect
-	modernc.org/memory v1.11.0 // indirect
-	modernc.org/sqlite v1.45.0 // indirect
-)

go.sum

@@ -1,27 +0,0 @@
-github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
-github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
-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=
-github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
-github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
-github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
-github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
-github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
-github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
-golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 h1:mgKeJMpvi0yx/sU5GsxQ7p6s2wtOnGAHZWCHUM4KGzY=
-golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546/go.mod h1:j/pmGrbnkbPtQfxEe5D0VQhZC6qKbfKifgD0oM7sR70=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
-golang.org/x/sys v0.37.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
-lukechampine.com/blake3 v1.4.1 h1:I3Smz7gso8w4/TunLKec6K2fn+kyKtDxr/xcQEN84Wg=
-lukechampine.com/blake3 v1.4.1/go.mod h1:QFosUxmjB8mnrWFSNwKmvxHpfY72bmD2tQ0kBMM3kwo=
-modernc.org/libc v1.67.6 h1:eVOQvpModVLKOdT+LvBPjdQqfrZq+pC39BygcT+E7OI=
-modernc.org/libc v1.67.6/go.mod h1:JAhxUVlolfYDErnwiqaLvUqc8nfb2r6S6slAgZOnaiE=
-modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
-modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
-modernc.org/memory v1.11.0 h1:o4QC8aMQzmcwCK3t3Ux/ZHmwFPzE6hf2Y5LbkRs+hbI=
-modernc.org/memory v1.11.0/go.mod h1:/JP4VbVC+K5sU2wZi9bHoq2MAkCnrt2r98UGeSK7Mjw=
-modernc.org/sqlite v1.45.0 h1:r51cSGzKpbptxnby+EIIz5fop4VuE4qFoVEjNvWoObs=
-modernc.org/sqlite v1.45.0/go.mod h1:CzbrU2lSB1DKUusvwGz7rqEKIq+NUd8GWuBBZDs9/nA=

go.work

@@ -0,0 +1,6 @@
+go 1.25.7
+
+use (
+	./chron-core
+	./chron-note
+)