Use functional options instead

kv.go

@@ -45,18 +45,14 @@ type KeyValue interface {
 	Put(key string, value []byte) (revision uint64, err error)
 	// PutString will place the string for the key into the store.
 	PutString(key string, value string) (revision uint64, err error)
-	// Create will add the key/value pair if it does not exist.
+	// Create will add the key/value pair iff it does not exist.
 	Create(key string, value []byte) (revision uint64, err error)
-	// Update will update the value if the latest revision matches.
+	// Update will update the value iff the latest revision matches.
 	Update(key string, value []byte, last uint64) (revision uint64, err error)
 	// Delete will place a delete marker and leave all revisions.
-	Delete(key string) error
-	// DeleteCond will place a delete marker and leave all revision if the latest revision matches.
-	DeleteCond(key string, last uint64) error
+	Delete(key string, opts ...DeleteOpt) error
 	// Purge will place a delete marker and remove all previous revisions.
-	Purge(key string) error
-	// PurgeCond will place a delete marker and remove all previous revisions if the latest revision matches.
-	PurgeCond(key string, last uint64) error
+	Purge(key string, opts ...DeleteOpt) error
 	// Watch for any updates to keys that match the keys argument which could include wildcards.
 	// Watch will send a nil entry when it has received all initial values.
 	Watch(keys string, opts ...WatchOpt) (KeyWatcher, error)
@@ -150,6 +146,39 @@ func MetaOnly() WatchOpt {
 	})
 }
 
+type DeleteOpt interface {
+	configureDelete(opts *deleteOpts) error
+}
+
+type deleteOpts struct {
+	// Remove all previous revisions.
+	purge bool
+	// Delete only if the latest revision matches.
+	revision uint64
+}
+
+type deleteOptFn func(opts *deleteOpts) error
+
+func (opt deleteOptFn) configureDelete(opts *deleteOpts) error {
+	return opt(opts)
+}
+
+// LastRevision deletes if the latest revision matches.
+func LastRevision(revision uint64) DeleteOpt {
+	return deleteOptFn(func(opts *deleteOpts) error {
+		opts.revision = revision
+		return nil
+	})
+}
+
+// Purge removes all previous revisions.
+func Purge() DeleteOpt {
+	return deleteOptFn(func(opts *deleteOpts) error {
+		opts.purge = true
+		return nil
+	})
+}
+
 // KeyValueConfig is for configuring a KeyValue store.
 type KeyValueConfig struct {
 	Bucket       string
@@ -441,7 +470,7 @@ func (kv *kvs) PutString(key string, value string) (revision uint64, err error)
 	return kv.Put(key, []byte(value))
 }
 
-// Create will add the key/value pair if it does not exist.
+// Create will add the key/value pair iff it does not exist.
 func (kv *kvs) Create(key string, value []byte) (revision uint64, err error) {
 	v, err := kv.Update(key, value, 0)
 	if err == nil {
@@ -457,7 +486,7 @@ func (kv *kvs) Create(key string, value []byte) (revision uint64, err error) {
 	return 0, err
 }
 
-// Update will update the value if the latest revision matches.
+// Update will update the value iff the latest revision matches.
 func (kv *kvs) Update(key string, value []byte, revision uint64) (uint64, error) {
 	if !keyValid(key) {
 		return 0, ErrInvalidKey
@@ -478,73 +507,45 @@ func (kv *kvs) Update(key string, value []byte, revision uint64) (uint64, error)
 }
 
 // Delete will place a delete marker and leave all revisions.
-func (kv *kvs) Delete(key string) error {
-	m, err := kv.buildDelete(key)
-	if err != nil {
-		return err
+func (kv *kvs) Delete(key string, opts ...DeleteOpt) error {
+	if !keyValid(key) {
+		return ErrInvalidKey
 	}
 
-	m.Header.Set(kvop, kvdel)
+	var b strings.Builder
+	b.WriteString(kv.pre)
+	b.WriteString(key)
 
-	_, err = kv.js.PublishMsg(m)
-	return err
-}
+	// DEL op marker. For watch functionality.
+	m := NewMsg(b.String())
 
-// DeleteCond will place a delete marker and leave all revisions if the latest revision matches.
-func (kv *kvs) DeleteCond(key string, revision uint64) error {
-	m, err := kv.buildDelete(key)
-	if err != nil {
-		return err
+	var o deleteOpts
+	for _, opt := range opts {
+		if opt != nil {
+			if err := opt.configureDelete(&o); err != nil {
+				return err
+			}
+		}
 	}
 
-	m.Header.Set(kvop, kvdel)
-	m.Header.Set(ExpectedLastSubjSeqHdr, strconv.FormatUint(revision, 10))
-
-	_, err = kv.js.PublishMsg(m)
-	return err
-}
-
-// Purge will remove the key and all revisions.
-func (kv *kvs) Purge(key string) error {
-	m, err := kv.buildDelete(key)
-	if err != nil {
-		return err
+	if o.purge {
+		m.Header.Set(kvop, kvpurge)
+		m.Header.Set(MsgRollup, MsgRollupSubject)
+	} else {
+		m.Header.Set(kvop, kvdel)
 	}
 
-	m.Header.Set(kvop, kvpurge)
-	m.Header.Set(MsgRollup, MsgRollupSubject)
-
-	_, err = kv.js.PublishMsg(m)
-	return err
-}
-
-// PurgeCond will remove the key and all revisions if the latest revision matches.
-func (kv *kvs) PurgeCond(key string, revision uint64) error {
-	m, err := kv.buildDelete(key)
-	if err != nil {
-		return err
+	if o.revision != 0 {
+		m.Header.Set(ExpectedLastSubjSeqHdr, strconv.FormatUint(o.revision, 10))
 	}
 
-	m.Header.Set(kvop, kvpurge)
-	m.Header.Set(MsgRollup, MsgRollupSubject)
-	m.Header.Set(ExpectedLastSubjSeqHdr, strconv.FormatUint(revision, 10))
-
-	_, err = kv.js.PublishMsg(m)
+	_, err := kv.js.PublishMsg(m)
 	return err
 }
 
-func (kv *kvs) buildDelete(key string) (*Msg, error) {
-	if !keyValid(key) {
-		return nil, ErrInvalidKey
-	}
-
-	var b strings.Builder
-	b.WriteString(kv.pre)
-	b.WriteString(key)
-
-	// DEL op marker. For watch functionality.
-	m := NewMsg(b.String())
-	return m, nil
+// Purge will remove the key and all revisions.
+func (kv *kvs) Purge(key string, opts ...DeleteOpt) error {
+	return kv.Delete(key, append(opts, Purge())...)
 }
 
 // PurgeDeletes will remove all current delete markers.

test/kv_test.go

@@ -66,9 +66,9 @@ func TestKeyValueBasics(t *testing.T) {
 	if r != 3 {
 		t.Fatalf("Expected 3 for the revision, got %d", r)
 	}
-	err = kv.DeleteCond("name", 4)
+	err = kv.Delete("name", nats.LastRevision(4))
 	expectErr(t, err)
-	err = kv.DeleteCond("name", 3)
+	err = kv.Delete("name", nats.LastRevision(3))
 	expectOk(t, err)
 
 	// Conditional Updates.