Add metadata package

Author: Jordan Halterman

pkg/meta/meta.go

@@ -0,0 +1,128 @@
+// SPDX-FileCopyrightText: 2022-present Intel Corporation
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package meta
+
+import (
+	runtimev1 "github.com/atomix/runtime/api/atomix/runtime/v1"
+	"github.com/atomix/runtime/pkg/time"
+)
+
+func Equal(m1, m2 runtimev1.ObjectMeta) bool {
+	return FromProto(m1).Equal(FromProto(m2))
+}
+
+// NewRevision creates a new object metadata with the given revision
+func NewRevision(revision Revision) ObjectMeta {
+	return ObjectMeta{
+		Revision: revision,
+	}
+}
+
+// NewTimestamped creates a new object metadata with the given timestamp
+func NewTimestamped(timestamp time.Timestamp) ObjectMeta {
+	return ObjectMeta{
+		Timestamp: timestamp,
+	}
+}
+
+// FromProto creates new object metadata from the given proto metadata
+func FromProto(meta runtimev1.ObjectMeta) ObjectMeta {
+	var revision Revision
+	if meta.Revision != 0 {
+		revision = Revision(meta.Revision)
+	}
+	var timestamp time.Timestamp
+	if meta.Timestamp != nil {
+		timestamp = time.NewTimestamp(*meta.Timestamp)
+	}
+	return ObjectMeta{
+		Revision:  revision,
+		Timestamp: timestamp,
+		Tombstone: meta.Type == runtimev1.ObjectMeta_TOMBSTONE,
+	}
+}
+
+// Object is an interface for objects
+type Object interface {
+	// Meta returns the object metadata
+	Meta() ObjectMeta
+}
+
+// ObjectMeta contains metadata about an object
+type ObjectMeta struct {
+	Revision  Revision
+	Timestamp time.Timestamp
+	Tombstone bool
+}
+
+// AsObject returns the metadata as a non-tombstone
+func (m ObjectMeta) AsObject() ObjectMeta {
+	copy := m
+	copy.Tombstone = false
+	return copy
+}
+
+// AsTombstone returns the metadata as a tombstone
+func (m ObjectMeta) AsTombstone() ObjectMeta {
+	copy := m
+	copy.Tombstone = true
+	return copy
+}
+
+// Meta implements the Object interface
+func (m ObjectMeta) Meta() ObjectMeta {
+	return m
+}
+
+// Proto returns the metadata in Protobuf format
+func (m ObjectMeta) Proto() runtimev1.ObjectMeta {
+	meta := runtimev1.ObjectMeta{}
+	if m.Revision > 0 {
+		meta.Revision = runtimev1.Revision(m.Revision)
+	}
+	if m.Timestamp != nil {
+		timestamp := m.Timestamp.Scheme().Codec().EncodeTimestamp(m.Timestamp)
+		meta.Timestamp = &timestamp
+	}
+	if m.Tombstone {
+		meta.Type = runtimev1.ObjectMeta_TOMBSTONE
+	} else {
+		meta.Type = runtimev1.ObjectMeta_OBJECT
+	}
+	return meta
+}
+
+func (m ObjectMeta) Equal(meta ObjectMeta) bool {
+	if m.Revision != meta.Revision {
+		return false
+	}
+	if m.Timestamp != nil && meta.Timestamp != nil && !m.Timestamp.Equal(meta.Timestamp) {
+		return false
+	}
+	return true
+}
+
+func (m ObjectMeta) Before(meta ObjectMeta) bool {
+	if m.Revision != 0 && meta.Revision != 0 && m.Revision >= meta.Revision {
+		return false
+	}
+	if m.Timestamp != nil && meta.Timestamp != nil && !m.Timestamp.Before(meta.Timestamp) {
+		return false
+	}
+	return true
+}
+
+func (m ObjectMeta) After(meta ObjectMeta) bool {
+	if m.Revision != 0 && meta.Revision != 0 && m.Revision <= meta.Revision {
+		return false
+	}
+	if m.Timestamp != nil && meta.Timestamp != nil && !m.Timestamp.After(meta.Timestamp) {
+		return false
+	}
+	return true
+}
+
+// Revision is a revision number
+type Revision uint64