| // Copyright (c) 2017 Uber Technologies, Inc. |
| // |
| // 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 utils |
| |
| import ( |
| "math/rand" |
| "sync" |
| ) |
| |
| // lockedSource allows a random number generator to be used by multiple goroutines concurrently. |
| // The code is very similar to math/rand.lockedSource, which is unfortunately not exposed. |
| type lockedSource struct { |
| mut sync.Mutex |
| src rand.Source |
| } |
| |
| // NewRand returns a rand.Rand that is threadsafe. |
| func NewRand(seed int64) *rand.Rand { |
| return rand.New(&lockedSource{src: rand.NewSource(seed)}) |
| } |
| |
| func (r *lockedSource) Int63() (n int64) { |
| r.mut.Lock() |
| n = r.src.Int63() |
| r.mut.Unlock() |
| return |
| } |
| |
| // Seed implements Seed() of Source |
| func (r *lockedSource) Seed(seed int64) { |
| r.mut.Lock() |
| r.src.Seed(seed) |
| r.mut.Unlock() |
| } |