// DoRPC acts as a switchboard for RPC commands.
func (d *Data) DoRPC(request datastore.Request, reply *datastore.Response) error {
	switch request.TypeCommand() {
	default:
		return fmt.Errorf("Unknown command.  Data type '%s' [%s] does not support '%s' command.",
			d.DataName(), d.TypeName(), request.TypeCommand())
	}
}

// put handles a PUT command-line request.
func (d *Data) put(cmd datastore.Request, reply *datastore.Response) error {
	if len(cmd.Command) < 5 {
		return fmt.Errorf("The key name must be specified after 'put'")
	}
	if len(cmd.Input) == 0 {
		return fmt.Errorf("No data was passed into standard input")
	}
	var uuidStr, dataName, cmdStr, keyStr string
	cmd.CommandArgs(1, &uuidStr, &dataName, &cmdStr, &keyStr)

	_, versionID, err := datastore.MatchingUUID(uuidStr)
	if err != nil {
		return err
	}

	// Store data
	if !d.Versioned() {
		// Map everything to root version.
		versionID, err = datastore.GetRepoRootVersion(versionID)
		if err != nil {
			return err
		}
	}
	ctx := datastore.NewVersionedCtx(d, versionID)
	if err = d.PutData(ctx, keyStr, cmd.Input); err != nil {
		return fmt.Errorf("Error on put to key %q for keyvalue %q: %v\n", keyStr, d.DataName(), err)
	}

	reply.Output = []byte(fmt.Sprintf("Put %d bytes into key %q for keyvalue %q, uuid %s\n",
		len(cmd.Input), keyStr, d.DataName(), uuidStr))
	return nil
}

// Do acts as a switchboard for RPC commands.
func (d *Data) DoRPC(request datastore.Request, reply *datastore.Response) error {
	if request.TypeCommand() != "load" {
		return fmt.Errorf("Unknown command.  Data type '%s' [%s] does not support '%s' command.",
			d.DataName(), d.TypeName(), request.TypeCommand())
	}
	if len(request.Command) < 5 {
		return fmt.Errorf("Poorly formatted load command.  See command-line help.")
	}
	return d.LoadLocal(request, reply)
}

// ForegroundROI creates a new ROI by determining all non-background blocks.
func (d *Data) ForegroundROI(req datastore.Request, reply *datastore.Response) error {
	if d.Values.BytesPerElement() != 1 {
		return fmt.Errorf("Foreground ROI command only implemented for 1 byte/voxel data!")
	}

	// Parse the request
	var uuidStr, dataName, cmdStr, destName, backgroundStr string
	req.CommandArgs(1, &uuidStr, &dataName, &cmdStr, &destName, &backgroundStr)

	// Get the version and repo
	uuid, versionID, err := datastore.MatchingUUID(uuidStr)
	if err != nil {
		return err
	}
	if err = datastore.AddToNodeLog(uuid, []string{req.Command.String()}); err != nil {
		return err
	}

	// Use existing destination data or a new ROI data.
	var dest *roi.Data
	dest, err = roi.GetByUUID(uuid, dvid.InstanceName(destName))
	if err != nil {
		config := dvid.NewConfig()
		typeservice, err := datastore.TypeServiceByName("roi")
		if err != nil {
			return err
		}
		dataservice, err := datastore.NewData(uuid, typeservice, dvid.InstanceName(destName), config)
		if err != nil {
			return err
		}
		var ok bool
		dest, ok = dataservice.(*roi.Data)
		if !ok {
			return fmt.Errorf("Could not create ROI data instance")
		}
	}

	// Asynchronously process the voxels.
	background, err := dvid.StringToPointNd(backgroundStr, ",")
	if err != nil {
		return err
	}
	go d.foregroundROI(versionID, dest, background)

	return nil
}

// Do handles command-line requests to the Google BrainMaps API
func (dtype *Type) Do(cmd datastore.Request, reply *datastore.Response) error {
	switch cmd.Argument(1) {
	case "volumes":
		// Read in the JSON Web Token
		jwtdata, err := ioutil.ReadFile(cmd.Argument(2))
		if err != nil {
			return fmt.Errorf("Cannot load JSON Web Token file (%s): %v", cmd.Argument(2), err)
		}
		conf, err := google.JWTConfigFromJSON(jwtdata, "https://www.googleapis.com/auth/brainmaps")
		if err != nil {
			return fmt.Errorf("Cannot establish JWT Config file from Google: %v", err)
		}
		client := conf.Client(oauth2.NoContext)

		// Make the call.
		url := fmt.Sprintf("%s/volumes", bmapsPrefix)
		resp, err := client.Get(url)
		if err != nil {
			return fmt.Errorf("Error getting volumes metadata from Google: %v", err)
		}
		if resp.StatusCode != http.StatusOK {
			return fmt.Errorf("Unexpected status code %d returned when getting volumes for user", resp.StatusCode)
		}
		metadata, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			return err
		}
		resp.Body.Close()
		reply.Text = string(metadata)
		return nil

	default:
		return fmt.Errorf("unknown command for type %s", dtype.GetTypeName())
	}
}

// DoRPC handles the 'generate' command.
func (d *Data) DoRPC(request datastore.Request, reply *datastore.Response) error {
	if request.TypeCommand() != "generate" {
		return fmt.Errorf("Unknown command.  Data instance '%s' [%s] does not support '%s' command.",
			d.DataName(), d.TypeName(), request.TypeCommand())
	}
	var uuidStr, dataName, cmdStr string
	request.CommandArgs(1, &uuidStr, &dataName, &cmdStr)

	// Get the imagetile generation configuration from a file or stdin.
	var err error
	var tileSpec TileSpec
	if request.Input != nil {
		tileSpec, err = LoadTileSpec(request.Input)
		if err != nil {
			return err
		}
	} else {
		config := request.Settings()
		filename, found, err := config.GetString("filename")
		if err != nil {
			return err
		}
		if found {
			configData, err := storage.DataFromFile(filename)
			if err != nil {
				return err
			}
			tileSpec, err = LoadTileSpec(configData)
			if err != nil {
				return err
			}
			dvid.Infof("Using tile spec file: %s\n", filename)
		} else {
			dvid.Infof("Using default tile generation method since no tile spec file was given...\n")
			tileSpec, err = d.DefaultTileSpec(uuidStr)
			if err != nil {
				return err
			}
		}
	}
	reply.Text = fmt.Sprintf("Tiling data instance %q @ node %s...\n", dataName, uuidStr)
	go func() {
		err := d.ConstructTiles(uuidStr, tileSpec, request)
		if err != nil {
			dvid.Errorf("Cannot construct tiles for data instance %q @ node %s: %v\n", dataName, uuidStr, err)
		}
	}()
	return nil
}

// DoRPC acts as a switchboard for RPC commands.
func (d *Data) DoRPC(req datastore.Request, reply *datastore.Response) error {
	switch req.TypeCommand() {
	case "load":
		if len(req.Command) < 5 {
			return fmt.Errorf("Poorly formatted load command.  See command-line help.")
		}
		// Parse the request
		var uuidStr, dataName, cmdStr, offsetStr string
		filenames, err := req.FilenameArgs(1, &uuidStr, &dataName, &cmdStr, &offsetStr)
		if err != nil {
			return err
		}
		if len(filenames) == 0 {
			return fmt.Errorf("Need to include at least one file to add: %s", req)
		}

		// Get offset
		offset, err := dvid.StringToPoint(offsetStr, ",")
		if err != nil {
			return fmt.Errorf("Illegal offset specification: %s: %v", offsetStr, err)
		}

		// Get list of files to add
		var addedFiles string
		if len(filenames) == 1 {
			addedFiles = filenames[0]
		} else {
			addedFiles = fmt.Sprintf("filenames: %s [%d more]", filenames[0], len(filenames)-1)
		}
		dvid.Debugf(addedFiles + "\n")

		uuid, versionID, err := datastore.MatchingUUID(uuidStr)
		if err != nil {
			return err
		}
		if err = datastore.AddToNodeLog(uuid, []string{req.Command.String()}); err != nil {
			return err
		}
		if err = d.LoadImages(versionID, offset, filenames); err != nil {
			return err
		}
		if err := datastore.SaveDataByUUID(uuid, d); err != nil {
			return err
		}
		return nil

	case "composite":
		if len(req.Command) < 6 {
			return fmt.Errorf("Poorly formatted composite command.  See command-line help.")
		}
		return d.CreateComposite(req, reply)

	default:
		return fmt.Errorf("Unknown command.  Data type '%s' [%s] does not support '%s' command.",
			d.DataName(), d.TypeName(), req.TypeCommand())
	}
	return nil
}

// LoadLocal adds image data to a version node.  See HelpMessage for example of
// command-line use of "load local".
func (d *Data) LoadLocal(request datastore.Request, reply *datastore.Response) error {
	timedLog := dvid.NewTimeLog()

	// Parse the request
	var uuidStr, dataName, cmdStr, sourceStr, filename string
	_ = request.CommandArgs(1, &uuidStr, &dataName, &cmdStr, &sourceStr, &filename)

	// Get the uuid from a uniquely identifiable string
	uuid, versionID, err := datastore.MatchingUUID(uuidStr)
	if err != nil {
		return fmt.Errorf("Could not find node with UUID %s: %v", uuidStr, err)
	}

	// Load the V3D Raw file.
	ext := filepath.Ext(filename)
	switch ext {
	case ".raw", ".v3draw":
	default:
		return fmt.Errorf("Unknown extension '%s' when expected V3D Raw file", ext)
	}
	file, err := os.Open(filename)
	if err != nil {
		return err
	}
	unmarshaler := V3DRawMarshaler{}
	channels, err := unmarshaler.UnmarshalV3DRaw(file)
	if err != nil {
		return err
	}

	// Store the metadata
	d.NumChannels = len(channels)
	d.Properties.Values = make(dvid.DataValues, d.NumChannels)
	if d.NumChannels > 0 {
		reply.Text = fmt.Sprintf("Loaded %s into data '%s': found %d channels\n",
			d.DataName(), filename, d.NumChannels)
		reply.Text += fmt.Sprintf(" %s", channels[0])
	} else {
		reply.Text = fmt.Sprintf("Found no channels in file %s\n", filename)
		return nil
	}
	for i, channel := range channels {
		d.Properties.Values[i] = channel.Voxels.Values()[0]
	}

	// Get repo and save it.
	if err := datastore.SaveDataByUUID(uuid, d); err != nil {
		return err
	}

	// PUT each channel of the file into the datastore using a separate data name.
	for _, channel := range channels {
		dvid.Infof("Processing channel %d... \n", channel.channelNum)
		err = d.PutVoxels(versionID, channel.Voxels, nil)
		if err != nil {
			return err
		}
	}

	// Create a RGB composite from the first 3 channels.  This is considered to be channel 0
	// or can be accessed with the base data name.
	dvid.Infof("Creating composite image from channels...\n")
	err = d.storeComposite(versionID, channels)
	if err != nil {
		return err
	}

	timedLog.Infof("RPC load local '%s' completed", filename)
	return nil
}

func (d *Data) ConstructTiles(uuidStr string, tileSpec TileSpec, request datastore.Request) error {
	config := request.Settings()
	uuid, versionID, err := datastore.MatchingUUID(uuidStr)
	if err != nil {
		return err
	}
	if err = datastore.AddToNodeLog(uuid, []string{request.Command.String()}); err != nil {
		return err
	}

	source, err := datastore.GetDataByUUID(uuid, d.Source)
	if err != nil {
		return err
	}
	src, ok := source.(*imageblk.Data)
	if !ok {
		return fmt.Errorf("Cannot construct imagetile for non-voxels data: %s", d.Source)
	}

	// Save the current tile specification
	d.Levels = tileSpec
	if err := datastore.SaveDataByUUID(uuid, d); err != nil {
		return err
	}

	// Get size of tile at lowest resolution.
	lastLevel := Scaling(len(tileSpec) - 1)
	loresSpec, found := tileSpec[lastLevel]
	if !found {
		return fmt.Errorf("Illegal tile spec.  Should have levels 0 to absent %d.", lastLevel)
	}
	var loresSize [3]float64
	for i := 0; i < 3; i++ {
		loresSize[i] = float64(loresSpec.Resolution[i]) * float64(DefaultTileSize[i])
	}
	loresMag := dvid.Point3d{1, 1, 1}
	for i := Scaling(0); i < lastLevel; i++ {
		levelMag := tileSpec[i].levelMag
		loresMag[0] *= levelMag[0]
		loresMag[1] *= levelMag[1]
		loresMag[2] *= levelMag[2]
	}

	// Get min and max points in terms of distance.
	var minPtDist, maxPtDist [3]float64
	for i := uint8(0); i < 3; i++ {
		minPtDist[i] = float64(src.MinPoint.Value(i)) * float64(src.VoxelSize[i])
		maxPtDist[i] = float64(src.MaxPoint.Value(i)) * float64(src.VoxelSize[i])
	}

	// Adjust min and max points for the tileable surface at lowest resolution.
	var minTiledPt, maxTiledPt dvid.Point3d
	for i := 0; i < 3; i++ {
		minInt, _ := math.Modf(minPtDist[i] / loresSize[i])
		maxInt, _ := math.Modf(maxPtDist[i] / loresSize[i])
		minTileCoord := int32(minInt)
		maxTileCoord := int32(maxInt)
		minTiledPt[i] = minTileCoord * DefaultTileSize[i] * loresMag[i]
		maxTiledPt[i] = (maxTileCoord+1)*DefaultTileSize[i]*loresMag[i] - 1
	}
	sizeVolume := maxTiledPt.Sub(minTiledPt).AddScalar(1)

	// Setup swappable ExtData buffers (the stitched slices) so we can be generating tiles
	// at same time we are reading and stitching them.
	var bufferLock [2]sync.Mutex
	var sliceBuffers [2]*imageblk.Voxels
	var bufferNum int

	// Get the planes we should tile.
	planes, err := config.GetShapes("planes", ";")
	if planes == nil {
		// If no planes are specified, construct imagetile for 3 orthogonal planes.
		planes = []dvid.DataShape{dvid.XY, dvid.XZ, dvid.YZ}
	}

	outF, err := d.putTileFunc(versionID)

	// sort the tile spec keys to iterate from highest to lowest resolution
	var sortedKeys []int
	for scaling, _ := range tileSpec {
		sortedKeys = append(sortedKeys, int(scaling))
	}
	sort.Ints(sortedKeys)

	for _, plane := range planes {
		timedLog := dvid.NewTimeLog()
		offset := minTiledPt.Duplicate()

		switch {

		case plane.Equals(dvid.XY):
			width, height, err := plane.GetSize2D(sizeVolume)
			if err != nil {
				return err
			}
			dvid.Debugf("Tiling XY image %d x %d pixels\n", width, height)
			for z := src.MinPoint.Value(2); z <= src.MaxPoint.Value(2); z++ {
				server.BlockOnInteractiveRequests("imagetile.ConstructTiles [xy]")

				sliceLog := dvid.NewTimeLog()
//.........这里部分代码省略.........

// PutLocal adds image data to a version node, altering underlying blocks if the image
// intersects the block.
//
// The image filename glob MUST BE absolute file paths that are visible to the server.
// This function is meant for mass ingestion of large data files, and it is inappropriate
// to read gigabytes of data just to send it over the network to a local DVID.
func (d *Data) PutLocal(request datastore.Request, reply *datastore.Response) error {
	timedLog := dvid.NewTimeLog()

	// Parse the request
	var uuidStr, dataName, cmdStr, sourceStr, planeStr, offsetStr string
	filenames := request.CommandArgs(1, &uuidStr, &dataName, &cmdStr, &sourceStr,
		&planeStr, &offsetStr)
	if len(filenames) == 0 {
		return fmt.Errorf("Need to include at least one file to add: %s", request)
	}

	// Get offset
	offset, err := dvid.StringToPoint(offsetStr, ",")
	if err != nil {
		return fmt.Errorf("Illegal offset specification: %s: %v", offsetStr, err)
	}

	// Get list of files to add
	var addedFiles string
	if len(filenames) == 1 {
		addedFiles = filenames[0]
	} else {
		addedFiles = fmt.Sprintf("filenames: %s [%d more]", filenames[0], len(filenames)-1)
	}
	dvid.Debugf(addedFiles + "\n")

	// Get plane
	plane, err := dvid.DataShapeString(planeStr).DataShape()
	if err != nil {
		return err
	}

	// Get Repo and IDs
	uuid, versionID, err := datastore.MatchingUUID(uuidStr)
	if err != nil {
		return err
	}

	// Load and PUT each image.
	numSuccessful := 0
	for _, filename := range filenames {
		sliceLog := dvid.NewTimeLog()
		img, _, err := dvid.GoImageFromFile(filename)
		if err != nil {
			return fmt.Errorf("Error after %d images successfully added: %v", numSuccessful, err)
		}
		slice, err := dvid.NewOrthogSlice(plane, offset, dvid.RectSize(img.Bounds()))
		if err != nil {
			return fmt.Errorf("Unable to determine slice: %v", err)
		}

		vox, err := d.NewVoxels(slice, img)
		if err != nil {
			return err
		}
		storage.FileBytesRead <- len(vox.Data())
		if err = d.PutVoxels(versionID, vox, nil); err != nil {
			return err
		}
		sliceLog.Debugf("%s put local %s", d.DataName(), slice)
		numSuccessful++
		offset = offset.Add(dvid.Point3d{0, 0, 1})
	}

	if err := datastore.AddToNodeLog(uuid, []string{request.Command.String()}); err != nil {
		return err
	}
	timedLog.Infof("RPC put local (%s) completed", addedFiles)
	return nil
}

// DoRPC acts as a switchboard for RPC commands.
func (d *Data) DoRPC(req datastore.Request, reply *datastore.Response) error {
	switch req.TypeCommand() {
	case "load":
		if len(req.Command) < 5 {
			return fmt.Errorf("Poorly formatted load command.  See command-line help.")
		}
		// Parse the request
		var uuidStr, dataName, cmdStr, offsetStr string
		filenames, err := req.FilenameArgs(1, &uuidStr, &dataName, &cmdStr, &offsetStr)
		if err != nil {
			return err
		}
		if len(filenames) == 0 {
			hostname, _ := os.Hostname()
			return fmt.Errorf("Couldn't find any files to add.  Are they visible to DVID server on %s?",
				hostname)
		}

		// Get offset
		offset, err := dvid.StringToPoint(offsetStr, ",")
		if err != nil {
			return fmt.Errorf("Illegal offset specification: %s: %v", offsetStr, err)
		}

		// Get list of files to add
		var addedFiles string
		if len(filenames) == 1 {
			addedFiles = filenames[0]
		} else {
			addedFiles = fmt.Sprintf("filenames: %s [%d more]", filenames[0], len(filenames)-1)
		}
		dvid.Debugf(addedFiles + "\n")

		uuid, versionID, err := datastore.MatchingUUID(uuidStr)
		if err != nil {
			return err
		}
		if err = datastore.AddToNodeLog(uuid, []string{req.Command.String()}); err != nil {
			return err
		}
		return d.LoadImages(versionID, offset, filenames)

	case "put":
		if len(req.Command) < 7 {
			return fmt.Errorf("Poorly formatted put command.  See command-line help.")
		}
		source := req.Command[4]
		switch source {
		case "local":
			return d.PutLocal(req, reply)
		case "remote":
			return fmt.Errorf("put remote not yet implemented")
		default:
			return fmt.Errorf("Unknown command.  Data instance '%s' [%s] does not support '%s' command.",
				d.DataName(), d.TypeName(), req.TypeCommand())
		}

	case "roi":
		if len(req.Command) < 6 {
			return fmt.Errorf("Poorly formatted roi command. See command-line help.")
		}
		return d.ForegroundROI(req, reply)

	default:
		return fmt.Errorf("Unknown command.  Data instance '%s' [%s] does not support '%s' command.",
			d.DataName(), d.TypeName(), req.TypeCommand())
	}
	return nil
}

// CreateComposite creates a new rgba8 image by combining hash of labels + the grayscale
func (d *Data) CreateComposite(request datastore.Request, reply *datastore.Response) error {
	timedLog := dvid.NewTimeLog()

	// Parse the request
	var uuidStr, dataName, cmdStr, grayscaleName, destName string
	request.CommandArgs(1, &uuidStr, &dataName, &cmdStr, &grayscaleName, &destName)

	// Get the version
	uuid, v, err := datastore.MatchingUUID(uuidStr)
	if err != nil {
		return err
	}

	// Log request
	if err = datastore.AddToNodeLog(uuid, []string{request.Command.String()}); err != nil {
		return err
	}

	// Get the grayscale data.
	dataservice, err := datastore.GetDataByUUIDName(uuid, dvid.InstanceName(grayscaleName))
	if err != nil {
		return err
	}
	grayscale, ok := dataservice.(*imageblk.Data)
	if !ok {
		return fmt.Errorf("%s is not the name of uint8 data", grayscaleName)
	}

	// Create a new rgba8blk data.
	var compservice datastore.DataService
	compservice, err = datastore.GetDataByUUIDName(uuid, dvid.InstanceName(destName))
	if err == nil {
		return fmt.Errorf("Data instance with name %q already exists", destName)
	}
	typeService, err := datastore.TypeServiceByName("rgba8blk")
	if err != nil {
		return fmt.Errorf("Could not get rgba8 type service from DVID")
	}
	config := dvid.NewConfig()
	compservice, err = datastore.NewData(uuid, typeService, dvid.InstanceName(destName), config)
	if err != nil {
		return err
	}
	composite, ok := compservice.(*imageblk.Data)
	if !ok {
		return fmt.Errorf("Error: %s was unable to be set to rgba8 data", destName)
	}

	// Iterate through all labels and grayscale chunks incrementally in Z, a layer at a time.
	wg := new(sync.WaitGroup)
	op := &compositeOp{grayscale, composite, v}
	chunkOp := &storage.ChunkOp{op, wg}

	store, err := d.GetOrderedKeyValueDB()
	if err != nil {
		return err
	}
	ctx := datastore.NewVersionedCtx(d, v)
	extents := d.Extents()
	blockBeg := imageblk.NewTKey(extents.MinIndex)
	blockEnd := imageblk.NewTKey(extents.MaxIndex)
	err = store.ProcessRange(ctx, blockBeg, blockEnd, chunkOp, storage.ChunkFunc(d.CreateCompositeChunk))
	wg.Wait()

	// Set new mapped data to same extents.
	composite.Properties.Extents = grayscale.Properties.Extents
	if err := datastore.SaveDataByUUID(uuid, composite); err != nil {
		dvid.Infof("Could not save new data '%s': %v\n", destName, err)
	}

	timedLog.Infof("Created composite of %s and %s", grayscaleName, destName)
	return nil
}

// Do acts as a switchboard for remote command execution
func (c *RPCConnection) Do(cmd datastore.Request, reply *datastore.Response) error {
	if reply == nil {
		dvid.Debugf("reply is nil coming in!\n")
		return nil
	}
	if cmd.Name() == "" {
		return fmt.Errorf("Server error: got empty command!")
	}

	switch cmd.Name() {

	case "help":
		reply.Text = fmt.Sprintf(RPCHelpMessage, config.RPCAddress(), config.HTTPAddress())

	case "shutdown":
		Shutdown()
		// Make this process shutdown in a second to allow time for RPC to finish.
		// TODO -- Better way to do this?
		log.Printf("DVID server halted due to 'shutdown' command.")
		reply.Text = fmt.Sprintf("DVID server at %s has been halted.\n", config.RPCAddress())
		go func() {
			time.Sleep(1 * time.Second)
			os.Exit(0)
		}()

	case "types":
		if len(cmd.Command) == 1 {
			text := "\nData Types within this DVID Server\n"
			text += "----------------------------------\n"
			mapTypes, err := datastore.Types()
			if err != nil {
				return fmt.Errorf("Error trying to retrieve data types within this DVID server!")
			}
			for url, typeservice := range mapTypes {
				text += fmt.Sprintf("%-20s %s\n", typeservice.GetTypeName(), url)
			}
			reply.Text = text
		} else {
			if len(cmd.Command) != 3 || cmd.Command[2] != "help" {
				return fmt.Errorf("Unknown types command: %q", cmd.Command)
			}
			var typename string
			cmd.CommandArgs(1, &typename)
			typeservice, err := datastore.TypeServiceByName(dvid.TypeString(typename))
			if err != nil {
				return err
			}
			reply.Text = typeservice.Help()
		}

	case "repos":
		var subcommand, alias, description, uuidStr string
		cmd.CommandArgs(1, &subcommand, &alias, &description, &uuidStr)
		switch subcommand {
		case "new":
			var assign *dvid.UUID
			if uuidStr == "" {
				assign = nil
			} else {
				u := dvid.UUID(uuidStr)
				assign = &u
			}
			root, err := datastore.NewRepo(alias, description, assign)
			if err != nil {
				return err
			}
			if err := datastore.SetRepoAlias(root, alias); err != nil {
				return err
			}
			if err := datastore.SetRepoDescription(root, description); err != nil {
				return err
			}
			reply.Text = fmt.Sprintf("New repo %q created with head node %s\n", alias, root)
		default:
			return fmt.Errorf("Unknown repos command: %q", subcommand)
		}

	case "repo":
		var uuidStr, subcommand string
		cmd.CommandArgs(1, &uuidStr, &subcommand)
		uuid, _, err := datastore.MatchingUUID(uuidStr)
		if err != nil {
			return err
		}

		switch subcommand {
		case "new":
			var typename, dataname string
			cmd.CommandArgs(3, &typename, &dataname)

			// Get TypeService
			typeservice, err := datastore.TypeServiceByName(dvid.TypeString(typename))
			if err != nil {
				return err
			}

			// Create new data
			config := cmd.Settings()
			_, err = datastore.NewData(uuid, typeservice, dvid.InstanceName(dataname), config)
//.........这里部分代码省略.........

// switchboard for remote command execution
func handleCommand(cmd *datastore.Request) (reply *datastore.Response, err error) {
	if cmd.Name() == "" {
		err = fmt.Errorf("Server error: got empty command!")
		return
	}
	reply = new(datastore.Response)

	switch cmd.Name() {

	case "help":
		reply.Text = fmt.Sprintf(RPCHelpMessage, config.RPCAddress(), config.HTTPAddress())

	case "shutdown":
		dvid.Infof("DVID server halting due to 'shutdown' command.")
		reply.Text = fmt.Sprintf("DVID server at %s is being shutdown...\n", config.RPCAddress())
		// launch goroutine shutdown so we can concurrently return shutdown message to client.
		go Shutdown()

	case "types":
		if len(cmd.Command) == 1 {
			text := "\nData Types within this DVID Server\n"
			text += "----------------------------------\n"
			var mapTypes map[dvid.URLString]datastore.TypeService
			if mapTypes, err = datastore.Types(); err != nil {
				err = fmt.Errorf("Error trying to retrieve data types within this DVID server!")
				return
			}
			for url, typeservice := range mapTypes {
				text += fmt.Sprintf("%-20s %s\n", typeservice.GetTypeName(), url)
			}
			reply.Text = text
		} else {
			if len(cmd.Command) != 3 || cmd.Command[2] != "help" {
				err = fmt.Errorf("Unknown types command: %q", cmd.Command)
				return
			}
			var typename string
			var typeservice datastore.TypeService
			cmd.CommandArgs(1, &typename)
			if typeservice, err = datastore.TypeServiceByName(dvid.TypeString(typename)); err != nil {
				return
			}
			reply.Text = typeservice.Help()
		}

	case "repos":
		var subcommand string
		cmd.CommandArgs(1, &subcommand)

		switch subcommand {
		case "new":
			var alias, description string
			cmd.CommandArgs(2, &alias, &description)

			config := cmd.Settings()
			var uuidStr, passcode string
			var found bool
			if uuidStr, found, err = config.GetString("uuid"); err != nil {
				return
			}
			var assign *dvid.UUID
			if !found {
				assign = nil
			} else {
				uuid := dvid.UUID(uuidStr)
				assign = &uuid
			}
			if passcode, found, err = config.GetString("passcode"); err != nil {
				return
			}
			var root dvid.UUID
			root, err = datastore.NewRepo(alias, description, assign, passcode)
			if err != nil {
				return
			}
			if err = datastore.SetRepoAlias(root, alias); err != nil {
				return
			}
			if err = datastore.SetRepoDescription(root, description); err != nil {
				return
			}
			reply.Text = fmt.Sprintf("New repo %q created with head node %s\n", alias, root)

		case "delete":
			var uuidStr, passcode string
			cmd.CommandArgs(2, &uuidStr, &passcode)

			var uuid dvid.UUID
			if uuid, _, err = datastore.MatchingUUID(uuidStr); err != nil {
				return
			}
			if err = datastore.DeleteRepo(uuid, passcode); err != nil {
				return
			}
			reply.Text = fmt.Sprintf("Started deletion of repo %s.\n", uuid)

		default:
			err = fmt.Errorf("Unknown repos command: %q", subcommand)
			return
//.........这里部分代码省略.........