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package praefect
import (
"sync"
)
// Random is the interface of the Go random number generator.
type Random interface {
// Intn returns a random integer in the range [0,n).
Intn(n int) int
// Shuffle pseudo-randomizes the order of elements. n is the number of elements.
// Shuffle panics if n < 0. swap swaps the elements with indexes i and j.
Shuffle(n int, swap func(i, j int))
}
type lockedRandom struct {
m sync.Mutex
r Random
}
// NewLockedRandom wraps the passed in Random to make it safe for concurrent use.
func NewLockedRandom(r Random) Random {
return &lockedRandom{r: r}
}
func (lr *lockedRandom) Intn(n int) int {
lr.m.Lock()
defer lr.m.Unlock()
return lr.r.Intn(n)
}
func (lr *lockedRandom) Shuffle(n int, swap func(i, j int)) {
lr.m.Lock()
defer lr.m.Unlock()
lr.r.Shuffle(n, swap)
}
type mockRandom struct {
intnFunc func(int) int
shuffleFunc func(int, func(int, int))
}
func (r mockRandom) Intn(n int) int {
return r.intnFunc(n)
}
func (r mockRandom) Shuffle(n int, swap func(i, j int)) {
r.shuffleFunc(n, swap)
}
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