protocodec: make a few tweaks to allow inlining

protocodec/backend_getter_v2.go

@@ -30,19 +30,22 @@ func (b backendGetterV2[C, T]) Get(ctx context.Context, key string, dest galaxyc
 	if bgErr != nil {
 		return bgErr
 	}
-	switch d := dest.(type) {
-	case *CodecV2[C, T]:
+	if d, ok := dest.(*CodecV2[C, T]); ok {
 		d.Set(out)
-	default:
-		vs, mErr := proto.Marshal(out)
-		if mErr != nil {
-			return fmt.Errorf("failed to marshal value as bytes: %w", mErr)
-		}
-
-		if uErr := dest.UnmarshalBinary(vs); uErr != nil {
-			return fmt.Errorf("destination codec (type %T) Unmarshal failed: %w", dest, uErr)
-		}
+		return nil
 	}
+	return b.setSlow(out, dest)
 
+}
+
+func (b backendGetterV2[C, T]) setSlow(out T, dest galaxycache.Codec) error {
+	vs, mErr := proto.Marshal(out)
+	if mErr != nil {
+		return fmt.Errorf("failed to marshal value as bytes: %w", mErr)
+	}
+
+	if uErr := dest.UnmarshalBinary(vs); uErr != nil {
+		return fmt.Errorf("destination codec (type %T) Unmarshal failed: %w", dest, uErr)
+	}
 	return nil
 }

protocodec/galaxywrap_v2.go

@@ -10,11 +10,11 @@ import (
 
 // GalaxyGet is a simple wrapper around a Galaxy.Get method-call that takes
 // care of constructing the protocodec.CodecV2, etc. (making the interface more idiomatic for Go)
-func GalaxyGet[C any, T pointerMessage[C]](ctx context.Context, g *galaxycache.Galaxy, key string) (T, error) {
-	pc := NewV2[C, T]()
-	getErr := g.Get(ctx, key, &pc)
+func GalaxyGet[C any, T pointerMessage[C]](ctx context.Context, g *galaxycache.Galaxy, key string) (m T, getErr error) {
+	pc := CodecV2[C, T]{}
+	getErr = g.Get(ctx, key, &pc)
 	if getErr != nil {
-		return nil, getErr
+		return // use named return values to bring the inlining cost down
 	}
-	return pc.Get(), nil
+	return pc.msg, nil
 }