Temporarily add go-agentx (w/ fixes to lexico ordering)

go-agentx/list_handler.go

@@ -0,0 +1,66 @@
+// Copyright 2018 The agentx authors
+// Licensed under the LGPLv3 with static-linking exception.
+// See LICENCE file for details.
+
+package agentx
+
+import (
+	"github.com/posteo/go-agentx/pdu"
+	"github.com/posteo/go-agentx/value"
+)
+
+// ListHandler is a helper that takes a list of oids and implements
+// a default behaviour for that list.
+type ListHandler struct {
+	oids  []value.OID
+	items map[string]*ListItem
+}
+
+// Add adds a list item for the provided oid and returns it.
+func (l *ListHandler) Add(oid string) *ListItem {
+	if l.items == nil {
+		l.items = make(map[string]*ListItem)
+	}
+
+	parsedOID := value.MustParseOID(oid)
+	l.oids = append(l.oids, parsedOID)
+	value.SortOIDs(l.oids)
+	item := &ListItem{}
+	l.items[oid] = item
+	return item
+}
+
+// Get tries to find the provided oid and returns the corresponding value.
+func (l *ListHandler) Get(oid value.OID) (value.OID, pdu.VariableType, interface{}, error) {
+	if l.items == nil {
+		return nil, pdu.VariableTypeNoSuchObject, nil, nil
+	}
+
+	item, ok := l.items[oid.String()]
+	if ok {
+		return oid, item.Type, item.Value, nil
+	}
+	return nil, pdu.VariableTypeNoSuchObject, nil, nil
+}
+
+// GetNext tries to find the value that follows the provided oid and returns it.
+func (l *ListHandler) GetNext(from value.OID, includeFrom bool, to value.OID) (value.OID, pdu.VariableType, interface{}, error) {
+	if l.items == nil {
+		return nil, pdu.VariableTypeNoSuchObject, nil, nil
+	}
+
+	for _, oid := range l.oids {
+		if oidWithin(oid, from, includeFrom, to) {
+			return l.Get(oid)
+		}
+	}
+
+	return nil, pdu.VariableTypeNoSuchObject, nil, nil
+}
+
+func oidWithin(oid value.OID, from value.OID, includeFrom bool, to value.OID) bool {
+	fromCompare := value.CompareOIDs(from, oid)
+	toCompare := value.CompareOIDs(to, oid)
+
+	return (fromCompare == -1 || (fromCompare == 0 && includeFrom)) && (toCompare == 1)
+}