implement ippool

1. support vlan ippool management
2. support calico ippool management

Signed-off-by: Duan Jiong <djduanjiong@gmail.com>

pkg/controller/network/utils/utils.go

@@ -0,0 +1,71 @@
+package utils
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"sort"
+)
+
+// IsDeletionCandidate checks if object is candidate to be deleted
+func IsDeletionCandidate(obj metav1.Object, finalizer string) bool {
+	return obj.GetDeletionTimestamp() != nil && ContainsString(obj.GetFinalizers(),
+		finalizer, nil)
+}
+
+// NeedToAddFinalizer checks if need to add finalizer to object
+func NeedToAddFinalizer(obj metav1.Object, finalizer string) bool {
+	return obj.GetDeletionTimestamp() == nil && !ContainsString(obj.GetFinalizers(),
+		finalizer, nil)
+}
+
+// CopyStrings copies the contents of the specified string slice
+// into a new slice.
+func CopyStrings(s []string) []string {
+	if s == nil {
+		return nil
+	}
+	c := make([]string, len(s))
+	copy(c, s)
+	return c
+}
+
+// SortStrings sorts the specified string slice in place. It returns the same
+// slice that was provided in order to facilitate method chaining.
+func SortStrings(s []string) []string {
+	sort.Strings(s)
+	return s
+}
+
+// ContainsString checks if a given slice of strings contains the provided string.
+// If a modifier func is provided, it is called with the slice item before the comparation.
+func ContainsString(slice []string, s string, modifier func(s string) string) bool {
+	for _, item := range slice {
+		if item == s {
+			return true
+		}
+		if modifier != nil && modifier(item) == s {
+			return true
+		}
+	}
+	return false
+}
+
+// RemoveString returns a newly created []string that contains all items from slice that
+// are not equal to s and modifier(s) in case modifier func is provided.
+func RemoveString(slice []string, s string, modifier func(s string) string) []string {
+	newSlice := make([]string, 0)
+	for _, item := range slice {
+		if item == s {
+			continue
+		}
+		if modifier != nil && modifier(item) == s {
+			continue
+		}
+		newSlice = append(newSlice, item)
+	}
+	if len(newSlice) == 0 {
+		// Sanitize for unit tests so we don't need to distinguish empty array
+		// and nil.
+		newSlice = nil
+	}
+	return newSlice
+}