Support specify IP network type (ipv4, ipv6, in arbitrary combination and priority)

1 files changed, 29 insertions, 0 deletions

diff --git a/common/errors.go b/common/errors.go
new file mode 100644
index 0000000..ba686f1
--- /dev/null
+++ b/common/errors.go
@@ -0,0 +1,29 @@
+package common
+
+import (
+	"errors"
+	"reflect"
+)
+
+// IsErrorOfType is a modified version of errors.Is, which loosen the check condition
+func IsErrorOfType(err, target error) bool {
+	if target == nil {
+		return err == target
+	}
+
+	isComparable := reflect.TypeOf(target).Comparable()
+	for {
+		if isComparable && reflect.TypeOf(target) == reflect.TypeOf(err) {
+			return true
+		}
+		if x, ok := err.(interface{ Is(error) bool }); ok && x.Is(target) {
+			return true
+		}
+		// TODO: consider supporting target.Is(err). This would allow
+		// user-definable predicates, but also may allow for coping with sloppy
+		// APIs, thereby making it easier to get away with them.
+		if err = errors.Unwrap(err); err == nil {
+			return false
+		}
+	}
+}