File size: 652 Bytes
6380833 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | package syncx
import (
"context"
"sync"
)
// OnceValues executes a function at most once and returns the cached result.
// This function behaves like sync.OnceValues, including caching both return
// values from the first call, but with a context argument to the function.
//
// Can be used to do lazy database lookups that may be needed by multiple callbacks but should execute at most once.
func OnceValues[T1, T2 any](fn func(context.Context) (T1, T2)) func(context.Context) (T1, T2) {
var (
once sync.Once
v1 T1
v2 T2
)
return func(ctx context.Context) (T1, T2) {
once.Do(func() {
v1, v2 = fn(ctx)
})
return v1, v2
}
}
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