v1.0.0

common/task/task.go

@@ -0,0 +1,52 @@
+package task
+
+import (
+	"context"
+
+	"github.com/xtls/xray-core/v1/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
+}