feat: eventMeta -> event.IsEvent

pkg/es/event/aggregate_test.go

@@ -33,24 +33,11 @@ func (a *Agg) ApplyEvent(lis ...event.Event) {
 type ValueApplied struct {
 	Value string
 
-	eventMeta event.Meta
+	event.IsEvent
 }
 
 var _ event.Event = (*ValueApplied)(nil)
 
-func (e *ValueApplied) EventMeta() event.Meta {
-	if e == nil {
-		return event.Meta{}
-	}
-	return e.eventMeta
-}
-
-func (e *ValueApplied) SetEventMeta(m event.Meta) {
-	if e != nil {
-		e.eventMeta = m
-	}
-}
-
 func (e *ValueApplied) MarshalBinary() ([]byte, error) {
 	return json.Marshal(e)
 }

pkg/es/event/events.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"crypto/rand"
 	"encoding"
-	"encoding/json"
 	"fmt"
 	"io"
 	"strconv"
@@ -156,25 +155,23 @@ func Init(ctx context.Context) error {
 }
 
 type nilEvent struct {
+	IsEvent
 }
 
-func (*nilEvent) EventMeta() Meta             { return Meta{} }
-func (*nilEvent) SetEventMeta(eventMeta Meta) {}
-
 var NilEvent = &nilEvent{}
 
 func (e *nilEvent) MarshalBinary() ([]byte, error) {
-	return json.Marshal(e)
+	return nil, nil
 }
 func (e *nilEvent) UnmarshalBinary(b []byte) error {
-	return json.Unmarshal(b, e)
+	return nil
 }
 
 type EventPtr struct {
 	StreamID string `json:"stream_id"`
 	Pos      uint64 `json:"pos"`
 
-	eventMeta Meta
+	IsEvent
 }
 
 var _ Event = (*EventPtr)(nil)
@@ -202,22 +199,6 @@ func (e *EventPtr) UnmarshalBinary(data []byte) error {
 	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"`
@@ -229,26 +210,30 @@ func (e *EventPtr) Values() any {
 }
 
 type FeedTruncated struct {
-	eventMeta Meta
-}
-
-// EventMeta implements Event
-func (e *FeedTruncated) EventMeta() Meta {
-	if e == nil {
-		return Meta{}
-	}
-	return e.eventMeta
-}
-
-// SetEventMeta implements Event
-func (e *FeedTruncated) SetEventMeta(m Meta) {
-	if e == nil {
-		return
-	}
-	e.eventMeta = m
+	IsEvent
 }
 
 func (e *FeedTruncated) Values() any {
 	return struct {
 	}{}
 }
+
+type property[T any] struct {
+	v T
+}
+
+type IsEvent = property[Meta]
+
+func (p *property[T]) EventMeta() T {
+	if p == nil {
+		var t T
+		return t
+	}
+	return p.v
+}
+
+func (p *property[T]) SetEventMeta(x T) {
+	if p != nil {
+		p.v = x
+	}
+}

pkg/es/event/events_test.go

@@ -14,21 +14,9 @@ import (
 type DummyEvent struct {
 	Value string
 
-	eventMeta event.Meta
+	event.IsEvent
 }
 
-func (e *DummyEvent) EventMeta() event.Meta {
-	if e == nil {
-		return event.Meta{}
-	}
-	return e.eventMeta
-}
-func (e *DummyEvent) SetEventMeta(eventMeta event.Meta) {
-	if e == nil {
-		return
-	}
-	e.eventMeta = eventMeta
-}
 func (e *DummyEvent) MarshalBinary() ([]byte, error) {
 	return json.Marshal(e)
 }

pkg/es/event/reflect.go

@@ -25,7 +25,7 @@ type UnknownEvent struct {
 	eventType string
 	values    map[string]json.RawMessage
 
-	eventMeta Meta
+	IsEvent
 }
 
 var _ Event = (*UnknownEvent)(nil)
@@ -48,16 +48,16 @@ func NewUnknownEventFromValues(eventType string, meta Meta, values url.Values) *
 		}
 	}
 
-	return &UnknownEvent{eventType: eventType, eventMeta: meta, values: jsonValues}
+	e := &UnknownEvent{eventType: eventType, values: jsonValues}
+	e.SetEventMeta(meta)
+	return e
 }
 func NewUnknownEventFromRaw(eventType string, meta Meta, values map[string]json.RawMessage) *UnknownEvent {
-	return &UnknownEvent{eventType: eventType, eventMeta: meta, values: values}
+	e := &UnknownEvent{eventType: eventType, values: values}
+	e.SetEventMeta(meta)
+	return e
 }
-func (u UnknownEvent) EventMeta() Meta   { return u.eventMeta }
 func (u UnknownEvent) EventType() string { return u.eventType }
-func (u *UnknownEvent) SetEventMeta(em Meta) {
-	u.eventMeta = em
-}
 func (u *UnknownEvent) UnmarshalBinary(b []byte) error {
 	return json.Unmarshal(b, &u.values)
 }