Add service component type

option/service.go

@@ -0,0 +1,47 @@
+package option
+
+import (
+	"context"
+
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/json"
+	"github.com/sagernet/sing/common/json/badjson"
+	"github.com/sagernet/sing/service"
+)
+
+type ServiceOptionsRegistry interface {
+	CreateOptions(serviceType string) (any, bool)
+}
+
+type _Service struct {
+	Type    string `json:"type"`
+	Tag     string `json:"tag,omitempty"`
+	Options any    `json:"-"`
+}
+
+type Service _Service
+
+func (h *Service) MarshalJSONContext(ctx context.Context) ([]byte, error) {
+	return badjson.MarshallObjectsContext(ctx, (*_Service)(h), h.Options)
+}
+
+func (h *Service) UnmarshalJSONContext(ctx context.Context, content []byte) error {
+	err := json.UnmarshalContext(ctx, content, (*_Service)(h))
+	if err != nil {
+		return err
+	}
+	registry := service.FromContext[ServiceOptionsRegistry](ctx)
+	if registry == nil {
+		return E.New("missing service fields registry in context")
+	}
+	options, loaded := registry.CreateOptions(h.Type)
+	if !loaded {
+		return E.New("unknown inbound type: ", h.Type)
+	}
+	err = badjson.UnmarshallExcludedContext(ctx, content, (*_Service)(h), options)
+	if err != nil {
+		return err
+	}
+	h.Options = options
+	return nil
+}