1 files changed, 73 insertions, 0 deletions
diff --git a/src/foundation.gentoo.org/golang/members/maintenance/memberroll.go b/src/foundation.gentoo.org/golang/members/maintenance/memberroll.go
new file mode 100644
index 0000000..05017ea
--- /dev/null
+++ b/src/foundation.gentoo.org/golang/members/maintenance/memberroll.go
@@ -0,0 +1,73 @@
+package maintenance
+
+import (
+  "io/ioutil"
+
+  "github.com/golang/protobuf/proto"
+  pb "foundation.gentoo.org/golang/members/data"
+)
+
+// Struct MemberRoll defines operations on a MemberRoll
+// and holds the underlying data.
+type MemberRoll struct {
+  roll *pb.MemberRoll
+}
+
+// Create a new memberRoll from a file.
+func NewMemberRoll (path string) (*MemberRoll, error) {
+	in, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+		// something
+	}
+	r := &pb.MemberRoll{}
+	if err = proto.Unmarshal(in, r); err != nil {
+		return nil, err
+		// something
+	}
+	mr := &MemberRoll{roll: r}
+	return mr, nil
+}
+
+// NewEmptyMemberRoll creates an empty MemberRoll
+func NewEmptyMemberRoll() (*MemberRoll) {
+	// The first member gets ID 1.
+	return &MemberRoll{
+		roll: &pb.MemberRoll {
+			NextMemberId: proto.Int64(1),
+		},
+	}
+}
+
+// Save will write the MemberRoll to file at path.
+func (mr *MemberRoll) Save(path string) (bool, error) {
+	bytes, err := proto.Marshal(mr.roll)
+	if err != nil { return false, err }
+	if err = ioutil.WriteFile(path, bytes, 0644); err != nil {
+		return false, err
+	}
+	return true, nil
+}
+
+// GetMaxMemberId computes the largest ID amongst a memberroll.
+// This works by assuming members are not removed from a roll.
+func (mr *MemberRoll) GetMaxMemberId() (int64) {
+	var id int64 = 0;
+	for _, member := range (mr.roll.GetMembers()) {
+		member_id := member.GetId()
+		if member_id > id {
+			id = member_id
+		}
+	}
+	return id
+}
+
+func (mr *MemberRoll) GetNextMemberId() (int64) {
+	id := mr.GetNextMemberId()
+	// If the member roll lost its ID (not a required field.)
+	// Recalculate based on existing membership.
+	if id == 0 {
+		id = mr.GetMaxMemberId()
+	}
+	return id
+}