Initial QSfera import

Server/vendor/github.com/testcontainers/testcontainers-go/wait/walk.go

@@ -0,0 +1,81 @@
+package wait
+
+import (
+	"errors"
+	"slices"
+)
+
+var (
+	// ErrVisitStop is used as a return value from [VisitFunc] to stop the walk.
+	// It is not returned as an error by any function.
+	ErrVisitStop = errors.New("stop the walk")
+
+	// Deprecated: use [ErrVisitStop] instead.
+	VisitStop = ErrVisitStop
+
+	// ErrVisitRemove is used as a return value from [VisitFunc] to have the current node removed.
+	// It is not returned as an error by any function.
+	ErrVisitRemove = errors.New("remove this strategy")
+
+	// Deprecated: use [ErrVisitRemove] instead.
+	VisitRemove = ErrVisitRemove
+)
+
+// VisitFunc is a function that visits a strategy node.
+// If it returns [ErrVisitStop], the walk stops.
+// If it returns [ErrVisitRemove], the current node is removed.
+type VisitFunc func(root Strategy) error
+
+// Walk walks the strategies tree and calls the visit function for each node.
+func Walk(root *Strategy, visit VisitFunc) error {
+	if root == nil {
+		return errors.New("root strategy is nil")
+	}
+
+	if err := walk(root, visit); err != nil {
+		if errors.Is(err, ErrVisitRemove) || errors.Is(err, ErrVisitStop) {
+			return nil
+		}
+		return err
+	}
+
+	return nil
+}
+
+// walk walks the strategies tree and calls the visit function for each node.
+// It returns an error if the visit function returns an error.
+func walk(root *Strategy, visit VisitFunc) error {
+	if *root == nil {
+		// No strategy.
+		return nil
+	}
+
+	// Allow the visit function to customize the behaviour of the walk before visiting the children.
+	if err := visit(*root); err != nil {
+		if errors.Is(err, ErrVisitRemove) {
+			*root = nil
+		}
+
+		return err
+	}
+
+	if s, ok := (*root).(*MultiStrategy); ok {
+		var i int
+		for range s.Strategies {
+			if err := walk(&s.Strategies[i], visit); err != nil {
+				if errors.Is(err, ErrVisitRemove) {
+					s.Strategies = slices.Delete(s.Strategies, i, i+1)
+					if errors.Is(err, VisitStop) {
+						return VisitStop
+					}
+					continue
+				}
+
+				return err
+			}
+			i++
+		}
+	}
+
+	return nil
+}