khenaidoo | 59ce9dd | 2019-11-11 13:05:32 -0500 | [diff] [blame] | 1 | // Copyright 2013 Matt T. Proud |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package pbutil |
| 16 | |
| 17 | import ( |
| 18 | "encoding/binary" |
| 19 | "io" |
| 20 | |
| 21 | "github.com/golang/protobuf/proto" |
| 22 | ) |
| 23 | |
| 24 | // WriteDelimited encodes and dumps a message to the provided writer prefixed |
| 25 | // with a 32-bit varint indicating the length of the encoded message, producing |
| 26 | // a length-delimited record stream, which can be used to chain together |
| 27 | // encoded messages of the same type together in a file. It returns the total |
| 28 | // number of bytes written and any applicable error. This is roughly |
| 29 | // equivalent to the companion Java API's MessageLite#writeDelimitedTo. |
| 30 | func WriteDelimited(w io.Writer, m proto.Message) (n int, err error) { |
| 31 | buffer, err := proto.Marshal(m) |
| 32 | if err != nil { |
| 33 | return 0, err |
| 34 | } |
| 35 | |
| 36 | var buf [binary.MaxVarintLen32]byte |
| 37 | encodedLength := binary.PutUvarint(buf[:], uint64(len(buffer))) |
| 38 | |
| 39 | sync, err := w.Write(buf[:encodedLength]) |
| 40 | if err != nil { |
| 41 | return sync, err |
| 42 | } |
| 43 | |
| 44 | n, err = w.Write(buffer) |
| 45 | return n + sync, err |
| 46 | } |