| // Copyright 2013 Matt T. Proud |
| // |
| // 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 pbutil |
| |
| import ( |
| "encoding/binary" |
| "io" |
| |
| "github.com/golang/protobuf/proto" |
| ) |
| |
| // WriteDelimited encodes and dumps a message to the provided writer prefixed |
| // with a 32-bit varint indicating the length of the encoded message, producing |
| // a length-delimited record stream, which can be used to chain together |
| // encoded messages of the same type together in a file. It returns the total |
| // number of bytes written and any applicable error. This is roughly |
| // equivalent to the companion Java API's MessageLite#writeDelimitedTo. |
| func WriteDelimited(w io.Writer, m proto.Message) (n int, err error) { |
| buffer, err := proto.Marshal(m) |
| if err != nil { |
| return 0, err |
| } |
| |
| buf := make([]byte, binary.MaxVarintLen32) |
| encodedLength := binary.PutUvarint(buf, uint64(len(buffer))) |
| |
| sync, err := w.Write(buf[:encodedLength]) |
| if err != nil { |
| return sync, err |
| } |
| |
| n, err = w.Write(buffer) |
| return n + sync, err |
| } |
