vendor: update buildkit to f238f1e

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/containerd/ttrpc/codec.go

@@ -0,0 +1,42 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package ttrpc
+
+import (
+	"github.com/gogo/protobuf/proto"
+	"github.com/pkg/errors"
+)
+
+type codec struct{}
+
+func (c codec) Marshal(msg interface{}) ([]byte, error) {
+	switch v := msg.(type) {
+	case proto.Message:
+		return proto.Marshal(v)
+	default:
+		return nil, errors.Errorf("ttrpc: cannot marshal unknown type: %T", msg)
+	}
+}
+
+func (c codec) Unmarshal(p []byte, msg interface{}) error {
+	switch v := msg.(type) {
+	case proto.Message:
+		return proto.Unmarshal(p, v)
+	default:
+		return errors.Errorf("ttrpc: cannot unmarshal into unknown type: %T", msg)
+	}
+}