Naveen Sampath | 04696f7 | 2022-06-13 15:19:14 +0530 | [diff] [blame^] | 1 | // Copyright (c) 2017 Uber Technologies, Inc. |
| 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 utils |
| 16 | |
| 17 | import ( |
| 18 | "math/rand" |
| 19 | "sync" |
| 20 | ) |
| 21 | |
| 22 | // lockedSource allows a random number generator to be used by multiple goroutines concurrently. |
| 23 | // The code is very similar to math/rand.lockedSource, which is unfortunately not exposed. |
| 24 | type lockedSource struct { |
| 25 | mut sync.Mutex |
| 26 | src rand.Source |
| 27 | } |
| 28 | |
| 29 | // NewRand returns a rand.Rand that is threadsafe. |
| 30 | func NewRand(seed int64) *rand.Rand { |
| 31 | return rand.New(&lockedSource{src: rand.NewSource(seed)}) |
| 32 | } |
| 33 | |
| 34 | func (r *lockedSource) Int63() (n int64) { |
| 35 | r.mut.Lock() |
| 36 | n = r.src.Int63() |
| 37 | r.mut.Unlock() |
| 38 | return |
| 39 | } |
| 40 | |
| 41 | // Seed implements Seed() of Source |
| 42 | func (r *lockedSource) Seed(seed int64) { |
| 43 | r.mut.Lock() |
| 44 | r.src.Seed(seed) |
| 45 | r.mut.Unlock() |
| 46 | } |