| // Copyright 2018 Google LLC |
| // |
| // 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 testutil |
| |
| import ( |
| "math/rand" |
| "sync" |
| "time" |
| ) |
| |
| // NewRand creates a new *rand.Rand seeded with t. The return value is safe for use |
| // with multiple goroutines. |
| func NewRand(t time.Time) *rand.Rand { |
| s := &lockedSource{src: rand.NewSource(t.UnixNano())} |
| return rand.New(s) |
| } |
| |
| // lockedSource makes a rand.Source safe for use by multiple goroutines. |
| type lockedSource struct { |
| mu sync.Mutex |
| src rand.Source |
| } |
| |
| func (ls *lockedSource) Int63() int64 { |
| ls.mu.Lock() |
| defer ls.mu.Unlock() |
| return ls.src.Int63() |
| } |
| |
| func (ls *lockedSource) Seed(int64) { |
| panic("shouldn't be calling Seed") |
| } |
