| // Copyright 2021 The LUCI 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 prpc |
| |
| import ( |
| "bytes" |
| "io" |
| "sync" |
| |
| "github.com/klauspost/compress/gzip" |
| ) |
| |
| // gzipThreshold is the threshold to compress a blob. |
| // If the blob is larger than this, then compress it. |
| // The value is derived from |
| // https://webmasters.stackexchange.com/questions/31750/what-is-recommended-minimum-object-size-for-gzip-performance-benefits |
| const gzipThreshold = 1024 |
| |
| var gzipWriters sync.Pool |
| |
| func getGZipWriter(w io.Writer) *gzip.Writer { |
| if gw, _ := gzipWriters.Get().(*gzip.Writer); gw != nil { |
| gw.Reset(w) |
| return gw |
| } |
| return gzip.NewWriter(w) |
| } |
| |
| func returnGZipWriter(gw *gzip.Writer) { |
| gzipWriters.Put(gw) |
| } |
| |
| // compressBlob compresses data using gzip. |
| func compressBlob(data []byte) ([]byte, error) { |
| buf := bytes.NewBuffer(nil) |
| gz := getGZipWriter(buf) |
| defer returnGZipWriter(gz) |
| if _, err := gz.Write(data); err != nil { |
| return nil, err |
| } |
| if err := gz.Close(); err != nil { |
| return nil, err |
| } |
| return buf.Bytes(), nil |
| } |