package task import ( "context" "v2ray.com/core/common/signal/semaphore" ) // OnSuccess executes g() after f() returns nil. func OnSuccess(f func() error, g func() error) func() error { return func() error { if err := f(); err != nil { return err } return g() } } // Run executes a list of tasks in parallel, returns the first error encountered or nil if all tasks pass. func Run(ctx context.Context, tasks ...func() error) error { n := len(tasks) s := semaphore.New(n) done := make(chan error, 1) for _, task := range tasks { <-s.Wait() go func(f func() error) { err := f() if err == nil { s.Signal() return } select { case done <- err: default: } }(task) } for i := 0; i < n; i++ { select { case err := <-done: return err case <-ctx.Done(): return ctx.Err() case <-s.Wait(): } } return nil }