can now delete a collection! Is this a dangerous feature? Only enabling

deleting "benchmark" collections for now.

go/storage/cdb_map.go

@@ -64,6 +64,10 @@ func (m *cdbMap) Close() {
 	}
 }
 
+func (m *cdbMap) Destroy() error {
+	return errors.New("Can not delete readonly volumes")
+}
+
 func (m cdbMap) ContentSize() uint64 {
 	return m.FileByteCounter
 }

go/storage/needle_map.go

@@ -14,6 +14,7 @@ type NeedleMapper interface {
 	Get(key uint64) (element *NeedleValue, ok bool)
 	Delete(key uint64) error
 	Close()
+	Destroy() error
 	ContentSize() uint64
 	DeletedSize() uint64
 	FileCount() int
@@ -155,6 +156,10 @@ func (nm *NeedleMap) Delete(key uint64) error {
 func (nm *NeedleMap) Close() {
 	_ = nm.indexFile.Close()
 }
+func (nm *NeedleMap) Destroy() error {
+	nm.Close()
+	return os.Remove(nm.indexFile.Name())
+}
 func (nm NeedleMap) ContentSize() uint64 {
 	return nm.FileByteCounter
 }

go/storage/store.go

@@ -111,6 +111,20 @@ func (s *Store) AddVolume(volumeListString string, collection string, replicaPla
 	}
 	return e
 }
+func (s *Store) DeleteCollection(collection string) (e error) {
+	for _, location := range s.locations {
+		for k, v := range location.volumes {
+			if v.Collection == collection {
+				e = v.Destroy()
+				if e != nil {
+					return
+				}
+				delete(location.volumes, k)
+			}
+		}
+	}
+	return
+}
 func (s *Store) findVolume(vid VolumeId) *Volume {
 	for _, location := range s.locations {
 		if v, found := location.volumes[vid]; found {

go/storage/volume.go

@@ -197,6 +197,21 @@ func (v *Volume) isFileUnchanged(n *Needle) bool {
 	}
 	return false
 }
+
+func (v *Volume) Destroy() (err error) {
+	if v.readOnly {
+		err = fmt.Errorf("%s is read-only", v.dataFile)
+		return
+	}
+	v.Close()
+	err = os.Remove(v.dataFile.Name())
+	if err != nil {
+		return
+	}
+	err = v.nm.Destroy()
+	return
+}
+
 func (v *Volume) write(n *Needle) (size uint32, err error) {
 	if v.readOnly {
 		err = fmt.Errorf("%s is read-only", v.dataFile)