feat: add projection layer to eventstore

pkg/es/event/events.go

@@ -1,11 +1,13 @@
 package event
 
 import (
+	"context"
 	"crypto/rand"
 	"encoding"
 	"encoding/json"
 	"fmt"
 	"io"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -129,6 +131,10 @@ func (m Meta) Created() time.Time {
 }
 func (m Meta) GetEventID() string { return m.EventID.String() }
 
+func Init(ctx context.Context) error {
+	return Register(ctx, NilEvent, &eventPtr{})
+}
+
 type nilEvent struct{}
 
 func (*nilEvent) EventMeta() Meta {
@@ -144,3 +150,61 @@ func (e *nilEvent) MarshalBinary() ([]byte, error) {
 func (e *nilEvent) UnmarshalBinary(b []byte) error {
 	return json.Unmarshal(b, e)
 }
+
+type eventPtr struct {
+	streamID string
+	pos      uint64
+
+	eventMeta Meta
+}
+
+var _ Event = (*eventPtr)(nil)
+
+func NewPtr(streamID string, pos uint64) *eventPtr {
+	return &eventPtr{streamID: streamID, pos: pos}
+}
+
+// MarshalBinary implements Event
+func (e *eventPtr) MarshalBinary() (data []byte, err error) {
+	return []byte(fmt.Sprintf("%s@%d", e.streamID, e.pos)), nil
+}
+
+// UnmarshalBinary implements Event
+func (e *eventPtr) UnmarshalBinary(data []byte) error {
+	s := string(data)
+	idx := strings.LastIndex(s, "@")
+	if idx == -1 {
+		return fmt.Errorf("missing @ in: %s", s)
+	}
+	e.streamID = s[:idx]
+	var err error
+	e.pos, err = strconv.ParseUint(s[idx+1:], 10, 64)
+
+	return err
+}
+
+// EventMeta implements Event
+func (e *eventPtr) EventMeta() Meta {
+	if e == nil {
+		return Meta{}
+	}
+	return e.eventMeta
+}
+
+// SetEventMeta implements Event
+func (e *eventPtr) SetEventMeta(m Meta) {
+	if e == nil {
+		return
+	}
+	e.eventMeta = m
+}
+
+func (e *eventPtr) Values() any {
+	return struct {
+		StreamID string `json:"stream_id"`
+		Pos      uint64 `json:"pos"`
+	}{
+		e.streamID,
+		e.pos,
+	}
+}

pkg/es/event/reflect.go

@@ -9,7 +9,7 @@ import (
 	"reflect"
 	"strings"
 
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/locker"
 )
 
@@ -67,7 +67,7 @@ func (u *UnknownEvent) MarshalBinary() ([]byte, error) {
 
 // Register a type container for Unmarshalling values into. The type must implement Event and not be a nil value.
 func Register(ctx context.Context, lis ...Event) error {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	for _, e := range lis {
@@ -84,7 +84,7 @@ func Register(ctx context.Context, lis ...Event) error {
 	return nil
 }
 func RegisterName(ctx context.Context, name string, e Event) error {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	if e == nil {
@@ -107,7 +107,7 @@ func RegisterName(ctx context.Context, name string, e Event) error {
 	span.AddEvent("register: " + name)
 
 	if err := eventTypes.Modify(ctx, func(c *config) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		c.eventTypes[name] = typ
@@ -119,13 +119,13 @@ func RegisterName(ctx context.Context, name string, e Event) error {
 	return nil
 }
 func GetContainer(ctx context.Context, s string) Event {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	var e Event
 
 	eventTypes.Modify(ctx, func(c *config) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		typ, ok := c.eventTypes[s]
@@ -176,7 +176,7 @@ func MarshalBinary(e Event) (txt []byte, err error) {
 }
 
 func UnmarshalBinary(ctx context.Context, txt []byte, pos uint64) (e Event, err error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	sp := bytes.SplitN(txt, []byte{'\t'}, 4)
@@ -262,7 +262,13 @@ func Values(e Event) map[string]any {
 		}
 
 		field := v.FieldByIndex(idx.Index)
-		m[idx.Name] = field.Interface()
+
+		name := idx.Name
+		if n, ok := idx.Tag.Lookup("json"); ok {
+			name = n
+		}
+
+		m[name] = field.Interface()
 	}
 	return m
 }