func propertiesToProto()

in datastore/save.go [225:307]
79 lines of code
25 McCabe index (conditional complexity)

func propertiesToProto(defaultAppID string, key *Key, props []Property) (*pb.EntityProto, error) {
	e := &pb.EntityProto{
		Key: keyToProto(defaultAppID, key),
	}
	if key.parent == nil {
		e.EntityGroup = &pb.Path{}
	} else {
		e.EntityGroup = keyToProto(defaultAppID, key.root()).Path
	}
	prevMultiple := make(map[string]bool)

	for _, p := range props {
		if pm, ok := prevMultiple[p.Name]; ok {
			if !pm || !p.Multiple {
				return nil, fmt.Errorf("datastore: multiple Properties with Name %q, but Multiple is false", p.Name)
			}
		} else {
			prevMultiple[p.Name] = p.Multiple
		}

		x := &pb.Property{
			Name:     proto.String(p.Name),
			Value:    new(pb.PropertyValue),
			Multiple: proto.Bool(p.Multiple),
		}
		switch v := p.Value.(type) {
		case int64:
			x.Value.Int64Value = proto.Int64(v)
		case bool:
			x.Value.BooleanValue = proto.Bool(v)
		case string:
			x.Value.StringValue = proto.String(v)
			if p.NoIndex {
				x.Meaning = pb.Property_TEXT.Enum()
			}
		case float64:
			x.Value.DoubleValue = proto.Float64(v)
		case *Key:
			if v != nil {
				x.Value.Referencevalue = keyToReferenceValue(defaultAppID, v)
			}
		case time.Time:
			if v.Before(minTime) || v.After(maxTime) {
				return nil, fmt.Errorf("datastore: time value out of range")
			}
			x.Value.Int64Value = proto.Int64(toUnixMicro(v))
			x.Meaning = pb.Property_GD_WHEN.Enum()
		case appengine.BlobKey:
			x.Value.StringValue = proto.String(string(v))
			x.Meaning = pb.Property_BLOBKEY.Enum()
		case appengine.GeoPoint:
			if !v.Valid() {
				return nil, fmt.Errorf("datastore: invalid GeoPoint value")
			}
			// NOTE: Strangely, latitude maps to X, longitude to Y.
			x.Value.Pointvalue = &pb.PropertyValue_PointValue{X: &v.Lat, Y: &v.Lng}
			x.Meaning = pb.Property_GEORSS_POINT.Enum()
		case []byte:
			x.Value.StringValue = proto.String(string(v))
			x.Meaning = pb.Property_BLOB.Enum()
			if !p.NoIndex {
				return nil, fmt.Errorf("datastore: cannot index a []byte valued Property with Name %q", p.Name)
			}
		case ByteString:
			x.Value.StringValue = proto.String(string(v))
			x.Meaning = pb.Property_BYTESTRING.Enum()
		default:
			if p.Value != nil {
				return nil, fmt.Errorf("datastore: invalid Value type for a Property with Name %q", p.Name)
			}
		}

		if p.NoIndex {
			e.RawProperty = append(e.RawProperty, x)
		} else {
			e.Property = append(e.Property, x)
			if len(e.Property) > maxIndexedProperties {
				return nil, errors.New("datastore: too many indexed properties")
			}
		}
	}
	return e, nil
}