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// 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")
}
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