statsclient: allow index as pattern

* ListStats() returns stats identifiers containing the stat name and index
* New method PrepareDirOnIndex(indexes...). Instead of the name filter
  it does not browse through all available indexes
* Stats example shows how to get the last epoch value (added "e" or "epoch" command)

Change-Id: Ibb15090fb0dfdb7f9b0ecf8ac07a5eb9a9ace8f8
Signed-off-by: Vladimir Lavor <vlavor@cisco.com>

1 files changed, 134 insertions, 103 deletions

diff --git a/adapter/statsclient/statsclient.go b/adapter/statsclient/statsclient.go
index b2d91db..16af16a 100644
--- a/adapter/statsclient/statsclient.go
+++ b/adapter/statsclient/statsclient.go
@@ -157,7 +157,7 @@ func (sc *StatsClient) Disconnect() error {
 	return nil
 }
 
-func (sc *StatsClient) ListStats(patterns ...string) ([]string, error) {
+func (sc *StatsClient) ListStats(patterns ...string) (entries []adapter.StatIdentifier, err error) {
 	if !sc.isConnected() {
 		return nil, adapter.ErrStatsDisconnected
 	}
@@ -166,76 +166,35 @@ func (sc *StatsClient) ListStats(patterns ...string) ([]string, error) {
 		return nil, adapter.ErrStatsAccessFailed
 	}
 
-	indexes, err := sc.listIndexes(patterns...)
+	entries, err = sc.getIdentifierEntries(patterns...)
 	if err != nil {
 		return nil, err
 	}
 
-	dirVector := sc.GetDirectoryVector()
-	if dirVector == nil {
-		return nil, fmt.Errorf("failed to list stats: %v", err)
-	}
-	vecLen := *(*uint32)(vectorLen(dirVector))
-
-	var names []string
-	for _, index := range indexes {
-		if index >= vecLen {
-			return nil, fmt.Errorf("stat entry index %d out of dir vector len (%d)", index, vecLen)
-		}
-		_, dirName, _ := sc.GetStatDirOnIndex(dirVector, index)
-		names = append(names, string(dirName))
-	}
-
 	if !sc.accessEnd(accessEpoch) {
 		return nil, adapter.ErrStatsDataBusy
 	}
-
-	return names, nil
+	return entries, nil
 }
 
 func (sc *StatsClient) DumpStats(patterns ...string) (entries []adapter.StatEntry, err error) {
 	if !sc.isConnected() {
 		return nil, adapter.ErrStatsDisconnected
 	}
+
 	accessEpoch := sc.accessStart()
 	if accessEpoch == 0 {
 		return nil, adapter.ErrStatsAccessFailed
 	}
 
-	indexes, err := sc.listIndexes(patterns...)
+	entries, err = sc.getStatEntries(patterns...)
 	if err != nil {
 		return nil, err
 	}
 
-	dirVector := sc.GetDirectoryVector()
-	if dirVector == nil {
-		return nil, err
-	}
-	dirLen := *(*uint32)(vectorLen(dirVector))
-
-	debugf("dumping entries for %d indexes", len(indexes))
-
-	entries = make([]adapter.StatEntry, 0, len(indexes))
-	for _, index := range indexes {
-		if index >= dirLen {
-			return nil, fmt.Errorf("stat entry index %d out of dir vector length (%d)", index, dirLen)
-		}
-		dirPtr, dirName, dirType := sc.GetStatDirOnIndex(dirVector, index)
-		if len(dirName) == 0 {
-			continue
-		}
-		entry := adapter.StatEntry{
-			Name: append([]byte(nil), dirName...),
-			Type: adapter.StatType(dirType),
-			Data: sc.CopyEntryData(dirPtr),
-		}
-		entries = append(entries, entry)
-	}
-
 	if !sc.accessEnd(accessEpoch) {
 		return nil, adapter.ErrStatsDataBusy
 	}
-
 	return entries, nil
 }
 
@@ -243,49 +202,55 @@ func (sc *StatsClient) PrepareDir(patterns ...string) (*adapter.StatDir, error)
 	if !sc.isConnected() {
 		return nil, adapter.ErrStatsDisconnected
 	}
-	dir := new(adapter.StatDir)
 
 	accessEpoch := sc.accessStart()
 	if accessEpoch == 0 {
 		return nil, adapter.ErrStatsAccessFailed
 	}
 
-	indexes, err := sc.listIndexes(patterns...)
+	entries, err := sc.getStatEntries(patterns...)
 	if err != nil {
 		return nil, err
 	}
-	dir.Indexes = indexes
 
-	dirVector := sc.GetDirectoryVector()
-	if dirVector == nil {
-		return nil, err
+	if !sc.accessEnd(accessEpoch) {
+		return nil, adapter.ErrStatsDataBusy
 	}
-	dirLen := *(*uint32)(vectorLen(dirVector))
 
-	debugf("dumping entries for %d indexes", len(indexes))
+	dir := &adapter.StatDir{
+		Epoch:   accessEpoch,
+		Entries: entries,
+	}
 
-	entries := make([]adapter.StatEntry, 0, len(indexes))
-	for _, index := range indexes {
-		if index >= dirLen {
-			return nil, fmt.Errorf("stat entry index %d out of dir vector length (%d)", index, dirLen)
-		}
-		dirPtr, dirName, dirType := sc.GetStatDirOnIndex(dirVector, index)
-		if len(dirName) == 0 {
-			continue
-		}
-		entry := adapter.StatEntry{
-			Name: append([]byte(nil), dirName...),
-			Type: adapter.StatType(dirType),
-			Data: sc.CopyEntryData(dirPtr),
-		}
-		entries = append(entries, entry)
+	return dir, nil
+}
+
+func (sc *StatsClient) PrepareDirOnIndex(indexes ...uint32) (*adapter.StatDir, error) {
+	if !sc.isConnected() {
+		return nil, adapter.ErrStatsDisconnected
+	}
+
+	accessEpoch := sc.accessStart()
+	if accessEpoch == 0 {
+		return nil, adapter.ErrStatsAccessFailed
+	}
+	vector := sc.GetDirectoryVector()
+	if vector == nil {
+		return nil, fmt.Errorf("failed to prepare dir on index: directory vector is nil")
+	}
+	entries, err := sc.getStatEntriesOnIndex(vector, indexes...)
+	if err != nil {
+		return nil, err
 	}
-	dir.Entries = entries
 
 	if !sc.accessEnd(accessEpoch) {
 		return nil, adapter.ErrStatsDataBusy
 	}
-	dir.Epoch = accessEpoch
+
+	dir := &adapter.StatDir{
+		Epoch:   accessEpoch,
+		Entries: entries,
+	}
 
 	return dir, nil
 }
@@ -304,34 +269,18 @@ func (sc *StatsClient) UpdateDir(dir *adapter.StatDir) (err error) {
 	if accessEpoch == 0 {
 		return adapter.ErrStatsAccessFailed
 	}
-
 	dirVector := sc.GetDirectoryVector()
 	if dirVector == nil {
 		return err
 	}
-	for i, index := range dir.Indexes {
-		statSegDir, dirName, dirType := sc.GetStatDirOnIndex(dirVector, index)
-		if len(dirName) == 0 {
-			continue
-		}
-		entry := &dir.Entries[i]
-		if !bytes.Equal(dirName, entry.Name) {
-			continue
-		}
-		if adapter.StatType(dirType) != entry.Type {
-			continue
-		}
-		if entry.Data == nil {
-			continue
-		}
-		if err := sc.UpdateEntryData(statSegDir, &entry.Data); err != nil {
-			return fmt.Errorf("updating stat data for entry %s failed: %v", dirName, err)
+	for i := 0; i < len(dir.Entries); i++ {
+		if err := sc.updateStatOnIndex(&dir.Entries[i], dirVector); err != nil {
+			return err
 		}
 	}
 	if !sc.accessEnd(accessEpoch) {
 		return adapter.ErrStatsDataBusy
 	}
-
 	return nil
 }
 
@@ -518,10 +467,79 @@ func (sc *StatsClient) accessEnd(accessEpoch int64) bool {
 	return true
 }
 
+// getStatEntries retrieves all stats matching desired patterns, or all stats if no pattern is provided.
+func (sc *StatsClient) getStatEntries(patterns ...string) (entries []adapter.StatEntry, err error) {
+	vector := sc.GetDirectoryVector()
+	if vector == nil {
+		return nil, fmt.Errorf("failed to get stat entries: directory vector is nil")
+	}
+	indexes, err := sc.listIndexes(vector, patterns...)
+	if err != nil {
+		return nil, err
+	}
+	return sc.getStatEntriesOnIndex(vector, indexes...)
+}
+
+// getIdentifierEntries retrieves all identifiers matching desired patterns, or all identifiers
+// if no pattern is provided.
+func (sc *StatsClient) getIdentifierEntries(patterns ...string) (identifiers []adapter.StatIdentifier, err error) {
+	vector := sc.GetDirectoryVector()
+	if vector == nil {
+		return nil, fmt.Errorf("failed to get identifier entries: directory vector is nil")
+	}
+	indexes, err := sc.listIndexes(vector, patterns...)
+	if err != nil {
+		return nil, err
+	}
+	return sc.getIdentifierEntriesOnIndex(vector, indexes...)
+}
+
+// getStatEntriesOnIndex retrieves stats on indexes, or all stats if indexes are not defined.
+func (sc *StatsClient) getStatEntriesOnIndex(vector dirVector, indexes ...uint32) (entries []adapter.StatEntry, err error) {
+	dirLen := *(*uint32)(vectorLen(vector))
+	for _, index := range indexes {
+		if index >= dirLen {
+			return nil, fmt.Errorf("stat entry index %d out of dir vector length (%d)", index, dirLen)
+		}
+		dirPtr, dirName, dirType := sc.GetStatDirOnIndex(vector, index)
+		if len(dirName) == 0 {
+			return
+		}
+		entries = append(entries, adapter.StatEntry{
+			StatIdentifier: adapter.StatIdentifier{
+				Index: index,
+				Name:  dirName,
+			},
+			Type: adapter.StatType(dirType),
+			Data: sc.CopyEntryData(dirPtr),
+		})
+	}
+	return entries, nil
+}
+
+// getIdentifierEntriesOnIndex retrieves identifiers on indexes, or all identifiers if indexes are not defined.
+func (sc *StatsClient) getIdentifierEntriesOnIndex(vector dirVector, indexes ...uint32) (identifiers []adapter.StatIdentifier, err error) {
+	dirLen := *(*uint32)(vectorLen(vector))
+	for _, index := range indexes {
+		if index >= dirLen {
+			return nil, fmt.Errorf("stat entry index %d out of dir vector length (%d)", index, dirLen)
+		}
+		_, dirName, _ := sc.GetStatDirOnIndex(vector, index)
+		if len(dirName) == 0 {
+			return
+		}
+		identifiers = append(identifiers, adapter.StatIdentifier{
+			Index: index,
+			Name:  dirName,
+		})
+	}
+	return identifiers, nil
+}
+
 // listIndexes lists indexes for all stat entries that match any of the regex patterns.
-func (sc *StatsClient) listIndexes(patterns ...string) (indexes []uint32, err error) {
+func (sc *StatsClient) listIndexes(vector dirVector, patterns ...string) (indexes []uint32, err error) {
 	if len(patterns) == 0 {
-		return sc.listIndexesFunc(nil)
+		return sc.listIndexesFunc(vector, nil)
 	}
 	var regexes = make([]*regexp.Regexp, len(patterns))
 	for i, pattern := range patterns {
@@ -531,7 +549,7 @@ func (sc *StatsClient) listIndexes(patterns ...string) (indexes []uint32, err er
 		}
 		regexes[i] = r
 	}
-	nameMatches := func(name []byte) bool {
+	nameMatches := func(name dirName) bool {
 		for _, r := range regexes {
 			if r.Match(name) {
 				return true
@@ -539,26 +557,20 @@ func (sc *StatsClient) listIndexes(patterns ...string) (indexes []uint32, err er
 		}
 		return false
 	}
-	return sc.listIndexesFunc(nameMatches)
+	return sc.listIndexesFunc(vector, nameMatches)
 }
 
 // listIndexesFunc lists stats indexes. The optional function
 // argument filters returned values or returns all if empty
-func (sc *StatsClient) listIndexesFunc(f func(name []byte) bool) (indexes []uint32, err error) {
+func (sc *StatsClient) listIndexesFunc(vector dirVector, f func(name dirName) bool) (indexes []uint32, err error) {
 	if f == nil {
 		// there is around ~3157 stats, so to avoid too many allocations
 		// we set capacity to 3200 when listing all stats
 		indexes = make([]uint32, 0, 3200)
 	}
-
-	dirVector := sc.GetDirectoryVector()
-	if dirVector == nil {
-		return nil, err
-	}
-	vecLen := *(*uint32)(vectorLen(dirVector))
-
+	vecLen := *(*uint32)(vectorLen(vector))
 	for i := uint32(0); i < vecLen; i++ {
-		_, dirName, _ := sc.GetStatDirOnIndex(dirVector, i)
+		_, dirName, _ := sc.GetStatDirOnIndex(vector, i)
 		if f != nil {
 			if len(dirName) == 0 || !f(dirName) {
 				continue
@@ -573,3 +585,22 @@ func (sc *StatsClient) listIndexesFunc(f func(name []byte) bool) (indexes []uint
 func (sc *StatsClient) isConnected() bool {
 	return atomic.LoadUint32(&sc.connected) == 1
 }
+
+// updateStatOnIndex refreshes the entry data.
+func (sc *StatsClient) updateStatOnIndex(entry *adapter.StatEntry, vector dirVector) (err error) {
+	dirLen := *(*uint32)(vectorLen(vector))
+	if entry.Index >= dirLen {
+		return fmt.Errorf("stat entry index %d out of dir vector length (%d)", entry.Index, dirLen)
+	}
+	dirPtr, dirName, dirType := sc.GetStatDirOnIndex(vector, entry.Index)
+	if len(dirName) == 0 ||
+		!bytes.Equal(dirName, entry.Name) ||
+		adapter.StatType(dirType) != entry.Type ||
+		entry.Data == nil {
+		return nil
+	}
+	if err := sc.UpdateEntryData(dirPtr, &entry.Data); err != nil {
+		err = fmt.Errorf("updating stat data for entry %s failed: %v", dirName, err)
+	}
+	return
+}