Add typed wrapper for lists of capabilities.

capnpc-go/capnpc-go.go

@@ -744,7 +744,15 @@ func makeTypeRef(t schema.Type, rel *node, nodes nodeMap) (typeRef, error) {
 			ref.name = ref.name + "_List"
 			ref.newfunc = "New" + ref.name
 			return ref, nil
-		case schema.Type_Which_anyPointer, schema.Type_Which_list, schema.Type_Which_interface:
+		case schema.Type_Which_interface:
+			ref, err := nodeRef(lt.Interface().TypeId())
+			if err != nil {
+				return ref, err
+			}
+			ref.name = ref.name + "_List"
+			ref.newfunc = "New" + ref.name
+			return ref, nil
+		case schema.Type_Which_anyPointer, schema.Type_Which_list:
 			return typeRef{name: "PointerList", newfunc: "NewPointerList", imp: capnpImportSpec}, nil
 		}
 	case schema.Type_Which_anyPointer:
@@ -1095,6 +1103,11 @@ func (g *generator) defineInterface(n *node) error {
 	if err != nil {
 		return fmt.Errorf("interface server %s: %v", n, err)
 	}
+
+	err = g.r.Render(interfaceListParams{
+		G:    g,
+		Node: n,
+	})
 	return nil
 }
 

capnpc-go/templateparams.go

@@ -164,6 +164,11 @@ type promiseFieldInterfaceParams struct {
 	Interface *node
 }
 
+type interfaceListParams struct {
+	G    *generator
+	Node *node
+}
+
 type interfaceClientParams struct {
 	G           *generator
 	Node        *node

capnpc-go/templates/interfaceList

@@ -0,0 +1,9 @@
+
+// {{.Node.Name}}_List is a list of {{.Node.Name}}.
+type {{.Node.Name}}_List = {{.G.Capnp}}.CapList[{{.Node.Name}}]
+
+// New{{.Node.Name}} creates a new list of {{.Node.Name}}.
+func New{{.Node.Name}}_List(s *{{.G.Capnp}}.Segment, sz int32) ({{.Node.Name}}_List, error) {
+	l, err := {{.G.Capnp}}.NewPointerList(s, sz)
+	return {{.G.Capnp}}.CapList[{{.Node.Name}}](l), err
+}

list.go

@@ -1037,6 +1037,23 @@ func (s StructList[T]) String() string {
 	return buf.String()
 }
 
+type CapList[T ~struct{ Client *Client }] PointerList
+
+func (c CapList[T]) At(i int) (T, error) {
+	ptr, err := PointerList(c).At(i)
+	if err != nil {
+		return T{}, err
+	}
+	return T{Client: ptr.Interface().Client()}, nil
+}
+
+func (c CapList[T]) Set(i int, v T) error {
+	pl := PointerList(c)
+	seg := pl.List.Segment()
+	capId := seg.Message().AddCap(struct{ Client *Client }(v).Client)
+	return pl.Set(i, NewInterface(seg, capId).ToPtr())
+}
+
 type listFlags uint8
 
 const (

pogs/pogs_test.go

@@ -1215,7 +1215,7 @@ func zfill(c air.Z, g *Z) error {
 			if !ee.Client.IsValid() {
 				continue
 			}
-			err := e.Set(i, capnp.NewInterface(e.Segment(), e.Message().AddCap(ee.Client)).ToPtr())
+			err := e.Set(i, ee)
 			if err != nil {
 				return err
 			}