init: 1.0.0

pkg/syncx/timeoutlimit.go

@@ -0,0 +1,57 @@
+package syncx
+
+import (
+	"errors"
+	"time"
+)
+
+// ErrTimeout is an error that indicates the borrow timeout.
+var ErrTimeout = errors.New("borrow timeout")
+
+// A TimeoutLimit is used to borrow with timeouts.
+type TimeoutLimit struct {
+	limit Limit
+	cond  *Cond
+}
+
+// NewTimeoutLimit returns a TimeoutLimit.
+func NewTimeoutLimit(n int) TimeoutLimit {
+	return TimeoutLimit{
+		limit: NewLimit(n),
+		cond:  NewCond(),
+	}
+}
+
+// Borrow borrows with given timeout.
+func (l TimeoutLimit) Borrow(timeout time.Duration) error {
+	if l.TryBorrow() {
+		return nil
+	}
+
+	var ok bool
+	for {
+		timeout, ok = l.cond.WaitWithTimeout(timeout)
+		if ok && l.TryBorrow() {
+			return nil
+		}
+
+		if timeout <= 0 {
+			return ErrTimeout
+		}
+	}
+}
+
+// Return returns a borrow.
+func (l TimeoutLimit) Return() error {
+	if err := l.limit.Return(); err != nil {
+		return err
+	}
+
+	l.cond.Signal()
+	return nil
+}
+
+// TryBorrow tries a borrow.
+func (l TimeoutLimit) TryBorrow() bool {
+	return l.limit.TryBorrow()
+}