Golang datastore.VersionedCtx类代码示例

// Returns all (z, y, x0, x1) Spans in sorted order: z, then y, then x0.
func getSpans(ctx *datastore.VersionedCtx, minIndex, maxIndex indexRLE) ([]dvid.Span, error) {
	db, err := ctx.GetOrderedKeyValueDB()
	if err != nil {
		return nil, err
	}
	spans := []dvid.Span{}

	var f storage.ChunkFunc = func(chunk *storage.Chunk) error {
		ibytes, err := chunk.K.ClassBytes(keyROI)
		if err != nil {
			return err
		}
		index := new(indexRLE)
		if err = index.IndexFromBytes(ibytes); err != nil {
			return fmt.Errorf("Unable to get indexRLE out of []byte encoding: %v\n", err)
		}
		z := index.start.Value(2)
		y := index.start.Value(1)
		x0 := index.start.Value(0)
		x1 := x0 + int32(index.span) - 1
		spans = append(spans, dvid.Span{z, y, x0, x1})
		return nil
	}
	mintk := storage.NewTKey(keyROI, minIndex.Bytes())
	maxtk := storage.NewTKey(keyROI, maxIndex.Bytes())
	err = db.ProcessRange(ctx, mintk, maxtk, &storage.ChunkOp{}, f)
	return spans, err
}

// Goroutine that handles splits across a lot of blocks for one label.
func (d *Data) splitBlock(ctx *datastore.VersionedCtx, op splitOp) {
	defer d.MutDone(op.mutID)

	store, err := d.GetOrderedKeyValueDB()
	if err != nil {
		dvid.Errorf("Data type labelblk had error initializing store: %v\n", err)
		return
	}

	// Read the block.
	tk := NewTKeyByCoord(op.block)
	data, err := store.Get(ctx, tk)
	if err != nil {
		dvid.Errorf("Error on GET of labelblk with coord string %v\n", []byte(op.block))
		return
	}
	if data == nil {
		dvid.Errorf("nil label block where split was done, coord %v\n", []byte(op.block))
		return
	}
	blockData, _, err := dvid.DeserializeData(data, true)
	if err != nil {
		dvid.Criticalf("unable to deserialize label block in '%s' key %v: %v\n", d.DataName(), []byte(op.block), err)
		return
	}
	blockBytes := int(d.BlockSize().Prod() * 8)
	if len(blockData) != blockBytes {
		dvid.Criticalf("splitBlock: coord %v got back %d bytes, expected %d bytes\n", []byte(op.block), len(blockData), blockBytes)
		return
	}

	// Modify the block using either voxel-level changes or coarser block-level mods.
	if op.rles != nil {
		if err := d.storeRLEs(blockData, op.newLabel, op.block, op.rles); err != nil {
			dvid.Errorf("can't store label %d RLEs into block %s: %v\n", op.newLabel, op.block, err)
			return
		}
	} else {
		// We are doing coarse split and will replace all
		if err := d.replaceLabel(blockData, op.oldLabel, op.newLabel); err != nil {
			dvid.Errorf("can't replace label %d with %d in block %s: %v\n", op.oldLabel, op.newLabel, op.block, err)
			return
		}
	}

	// Write the modified block.
	serialization, err := dvid.SerializeData(blockData, d.Compression(), d.Checksum())
	if err != nil {
		dvid.Criticalf("Unable to serialize block %s in %q: %v\n", op.block, d.DataName(), err)
		return
	}
	if err := store.Put(ctx, tk, serialization); err != nil {
		dvid.Errorf("Error in putting key %v: %v\n", tk, err)
	}

	// Notify any downstream downres instance.
	d.publishBlockChange(ctx.VersionID(), op.mutID, op.block, blockData)
}

// handles relabeling of blocks during a merge operation.
func (d *Data) mergeBlock(ctx *datastore.VersionedCtx, op mergeOp) {
	defer d.MutDone(op.mutID)

	store, err := d.GetKeyValueDB()
	if err != nil {
		dvid.Errorf("Data type labelblk had error initializing store: %v\n", err)
		return
	}

	tk := NewTKeyByCoord(op.block)
	data, err := store.Get(ctx, tk)
	if err != nil {
		dvid.Errorf("Error on GET of labelblk with coord string %q\n", op.block)
		return
	}
	if data == nil {
		dvid.Errorf("nil label block where merge was done!\n")
		return
	}

	blockData, _, err := dvid.DeserializeData(data, true)
	if err != nil {
		dvid.Criticalf("unable to deserialize label block in '%s': %v\n", d.DataName(), err)
		return
	}
	blockBytes := int(d.BlockSize().Prod() * 8)
	if len(blockData) != blockBytes {
		dvid.Criticalf("After labelblk deserialization got back %d bytes, expected %d bytes\n", len(blockData), blockBytes)
		return
	}

	// Iterate through this block of labels and relabel if label in merge.
	for i := 0; i < blockBytes; i += 8 {
		label := binary.LittleEndian.Uint64(blockData[i : i+8])
		if _, merged := op.Merged[label]; merged {
			binary.LittleEndian.PutUint64(blockData[i:i+8], op.Target)
		}
	}

	// Store this block.
	serialization, err := dvid.SerializeData(blockData, d.Compression(), d.Checksum())
	if err != nil {
		dvid.Criticalf("Unable to serialize block in %q: %v\n", d.DataName(), err)
		return
	}
	if err := store.Put(ctx, tk, serialization); err != nil {
		dvid.Errorf("Error in putting key %v: %v\n", tk, err)
	}

	// Notify any downstream downres instance.
	d.publishBlockChange(ctx.VersionID(), op.mutID, op.block, blockData)
}

func putElements(ctx *datastore.VersionedCtx, tk storage.TKey, elems interface{}) error {
	val, err := json.Marshal(elems)
	if err != nil {
		return err
	}
	store, err := ctx.GetOrderedKeyValueDB()
	if err != nil {
		return err
	}
	if err := store.Put(ctx, tk, val); err != nil {
		return err
	}
	return nil
}

func (d *Data) deleteElementInLabel(ctx *datastore.VersionedCtx, batch storage.Batch, pt dvid.Point3d) error {
	labelData := d.GetSyncedLabelblk()
	if labelData == nil {
		return nil // no synced labels
	}
	label, err := labelData.GetLabelAtPoint(ctx.VersionID(), pt)
	if err != nil {
		return err
	}
	tk := NewLabelTKey(label)
	elems, err := getElementsNR(ctx, tk)
	if err != nil {
		return fmt.Errorf("err getting elements for label %d: %v\n", label, err)
	}

	// Note all elements to be deleted.
	var delta DeltaModifyElements
	var toDel []int
	for i, elem := range elems {
		if pt.Equals(elem.Pos) {
			delta.Del = append(delta.Del, ElementPos{Label: label, Kind: elem.Kind, Pos: elem.Pos})
			toDel = append(toDel, i)
		}
	}
	if len(toDel) == 0 {
		return nil
	}

	// Delete them from high index to low index due while reusing slice.
	for i := len(toDel) - 1; i >= 0; i-- {
		d := toDel[i]
		elems[d] = elems[len(elems)-1]
		elems[len(elems)-1] = ElementNR{}
		elems = elems[:len(elems)-1]
	}

	// Put the modified list of elements
	if err := putBatchElements(batch, tk, elems); err != nil {
		return err
	}

	// Notify any subscribers of label annotation changes.
	evt := datastore.SyncEvent{Data: d.DataUUID(), Event: ModifyElementsEvent}
	msg := datastore.SyncMessage{Event: ModifyElementsEvent, Version: ctx.VersionID(), Delta: delta}
	if err := datastore.NotifySubscribers(evt, msg); err != nil {
		return err
	}
	return nil
}

// makes sure that no relationships are returned since they could be out of date.
func getElementsNR(ctx *datastore.VersionedCtx, tk storage.TKey) (ElementsNR, error) {
	store, err := ctx.GetOrderedKeyValueDB()
	if err != nil {
		return nil, err
	}
	val, err := store.Get(ctx, tk)
	if err != nil {
		return nil, err
	}
	if val == nil {
		return nil, nil
	}
	var elems ElementsNR
	if err := json.Unmarshal(val, &elems); err != nil {
		return nil, err
	}
	return elems, nil
}

func (d *Data) moveElementInLabels(ctx *datastore.VersionedCtx, batch storage.Batch, from, to dvid.Point3d, moved ElementNR) error {
	labelData := d.GetSyncedLabelblk()
	if labelData == nil {
		return nil // no label denormalization possible
	}
	oldLabel, err := labelData.GetLabelAtPoint(ctx.VersionID(), from)
	if err != nil {
		return err
	}
	newLabel, err := labelData.GetLabelAtPoint(ctx.VersionID(), to)
	if err != nil {
		return err
	}
	if oldLabel == newLabel {
		return nil
	}

	var delta DeltaModifyElements
	if oldLabel != 0 {
		tk := NewLabelTKey(oldLabel)
		elems, err := getElementsNR(ctx, tk)
		if err != nil {
			return fmt.Errorf("err getting elements for label %d: %v", oldLabel, err)
		}
		if _, changed := elems.delete(from); changed {
			if err := putBatchElements(batch, tk, elems); err != nil {
				return fmt.Errorf("err putting deleted label %d element: %v", oldLabel, err)
			}
			delta.Del = append(delta.Del, ElementPos{Label: oldLabel, Kind: moved.Kind, Pos: from})
		}
	}
	if newLabel != 0 {
		tk := NewLabelTKey(newLabel)
		elems, err := getElementsNR(ctx, tk)
		if err != nil {
			return fmt.Errorf("err getting elements for label %d: %v", newLabel, err)
		}
		elems.add(ElementsNR{moved})
		if err := putBatchElements(batch, tk, elems); err != nil {
			return err
		}
		delta.Add = append(delta.Add, ElementPos{Label: newLabel, Kind: moved.Kind, Pos: to})
	}

	// Notify any subscribers of label annotation changes.
	if len(delta.Del) != 0 || len(delta.Add) != 0 {
		evt := datastore.SyncEvent{Data: d.DataUUID(), Event: ModifyElementsEvent}
		msg := datastore.SyncMessage{Event: ModifyElementsEvent, Version: ctx.VersionID(), Delta: delta}
		if err := datastore.NotifySubscribers(evt, msg); err != nil {
			return err
		}
	}

	return nil
}

func (d *Data) DeleteBlocks(ctx *datastore.VersionedCtx, start dvid.ChunkPoint3d, span int) error {
	store, err := storage.MutableStore()
	if err != nil {
		return fmt.Errorf("Data type labelblk had error initializing store: %v\n", err)
	}
	batcher, ok := store.(storage.KeyValueBatcher)
	if !ok {
		return fmt.Errorf("Data type labelblk requires batch-enabled store, which %q is not\n", store)
	}

	indexBeg := dvid.IndexZYX(start)
	end := start
	end[0] += int32(span - 1)
	indexEnd := dvid.IndexZYX(end)
	begTKey := NewTKey(&indexBeg)
	endTKey := NewTKey(&indexEnd)

	iv := dvid.InstanceVersion{d.DataName(), ctx.VersionID()}
	mapping := labels.MergeCache.LabelMap(iv)

	kvs, err := store.GetRange(ctx, begTKey, endTKey)
	if err != nil {
		return err
	}

	batch := batcher.NewBatch(ctx)
	uncompress := true
	for _, kv := range kvs {
		izyx, err := DecodeTKey(kv.K)
		if err != nil {
			return err
		}

		// Delete the labelblk (really tombstones it)
		batch.Delete(kv.K)

		// Send data to delete associated labelvol for labels in this block
		block, _, err := dvid.DeserializeData(kv.V, uncompress)
		if err != nil {
			return fmt.Errorf("Unable to deserialize block, %s (%v): %v", ctx, kv.K, err)
		}
		if mapping != nil {
			n := len(block) / 8
			for i := 0; i < n; i++ {
				orig := binary.LittleEndian.Uint64(block[i*8 : i*8+8])
				mapped, found := mapping.FinalLabel(orig)
				if !found {
					mapped = orig
				}
				binary.LittleEndian.PutUint64(block[i*8:i*8+8], mapped)
			}
		}

		// Notify any subscribers that we've deleted this block.
		evt := datastore.SyncEvent{d.DataName(), labels.DeleteBlockEvent}
		msg := datastore.SyncMessage{ctx.VersionID(), labels.DeleteBlock{izyx, block}}
		if err := datastore.NotifySubscribers(evt, msg); err != nil {
			return err
		}

	}
	return batch.Commit()
}

// ServeHTTP handles all incoming HTTP requests for this data.
func (d *Data) ServeHTTP(uuid dvid.UUID, ctx *datastore.VersionedCtx, w http.ResponseWriter, r *http.Request) {
	timedLog := dvid.NewTimeLog()

	// Get the action (GET, POST)
	action := strings.ToLower(r.Method)
	switch action {
	case "get":
	case "post":
	default:
		server.BadRequest(w, r, "Can only handle GET or POST HTTP verbs")
		return
	}

	// Break URL request into arguments
	url := r.URL.Path[len(server.WebAPIPath):]
	parts := strings.Split(url, "/")
	if len(parts[len(parts)-1]) == 0 {
		parts = parts[:len(parts)-1]
	}
	if len(parts) < 4 {
		server.BadRequest(w, r, "Incomplete API request")
		return
	}

	// Process help and info.
	switch parts[3] {
	case "help":
		w.Header().Set("Content-Type", "text/plain")
		fmt.Fprintln(w, d.Help())
		return
	case "info":
		jsonBytes, err := d.MarshalJSON()
		if err != nil {
			server.BadRequest(w, r, err)
			return
		}
		w.Header().Set("Content-Type", "application/json")
		fmt.Fprintf(w, string(jsonBytes))
		return
	default:
	}

	// Get the data name and parse out the channel number or see if composite is required.
	var channelNum int32
	channumStr := strings.TrimPrefix(parts[2], string(d.DataName()))
	if len(channumStr) == 0 {
		channelNum = 0
	} else {
		n, err := strconv.ParseInt(channumStr, 10, 32)
		if err != nil {
			server.BadRequest(w, r, "Error parsing channel number from data name '%s': %v", parts[2], err)
			return
		}
		if int(n) > d.NumChannels {
			minChannelName := fmt.Sprintf("%s1", d.DataName())
			maxChannelName := fmt.Sprintf("%s%d", d.DataName(), d.NumChannels)
			server.BadRequest(w, r, "Data only has %d channels.  Use names '%s' -> '%s'", d.NumChannels,
				minChannelName, maxChannelName)
			return
		}
		channelNum = int32(n)
	}

	// Get the data shape.
	shapeStr := dvid.DataShapeString(parts[3])
	dataShape, err := shapeStr.DataShape()
	if err != nil {
		server.BadRequest(w, r, "Bad data shape given '%s'", shapeStr)
		return
	}

	switch dataShape.ShapeDimensions() {
	case 2:
		sizeStr, offsetStr := parts[4], parts[5]
		slice, err := dvid.NewSliceFromStrings(shapeStr, offsetStr, sizeStr, "_")
		if err != nil {
			server.BadRequest(w, r, err)
			return
		}
		if action == "post" {
			server.BadRequest(w, r, "DVID does not yet support POST of slices into multichannel data")
			return
		} else {
			if d.NumChannels == 0 || d.Data.Values == nil {
				server.BadRequest(w, r, "Cannot retrieve absent data '%d'.  Please load data.", d.DataName())
				return
			}
			values := d.Data.Values
			if len(values) <= int(channelNum) {
				server.BadRequest(w, r, "Must choose channel from 0 to %d", len(values))
				return
			}
			stride := slice.Size().Value(0) * values.BytesPerElement()
			dataValues := dvid.DataValues{values[channelNum]}
			data := make([]uint8, int(slice.NumVoxels()))
			v := imageblk.NewVoxels(slice, dataValues, data, stride)
			channel := &Channel{
				Voxels:     v,
				channelNum: channelNum,
//.........这里部分代码省略.........

func (d *Data) mutateBlock(ctx *datastore.VersionedCtx, block imageblk.MutatedBlock, batcher storage.KeyValueBatcher) {
	// Iterate through previous and current labels, detecting set of previous labels and RLEs for current labels.
	blockBytes := len(block.Data)
	if blockBytes != int(d.BlockSize.Prod())*8 {
		dvid.Criticalf("Deserialized label block %d bytes, not uint64 size times %d block elements\n",
			blockBytes, d.BlockSize.Prod())
		return
	}
	labelRLEs := make(map[uint64]dvid.RLEs, 10)
	labelDiff := make(map[uint64]bool, 10)

	firstPt := block.Index.MinPoint(d.BlockSize)
	lastPt := block.Index.MaxPoint(d.BlockSize)

	var curStart dvid.Point3d
	var voxelLabel, curLabel, maxLabel uint64
	var z, y, x, curRun int32
	start := 0
	for z = firstPt.Value(2); z <= lastPt.Value(2); z++ {
		for y = firstPt.Value(1); y <= lastPt.Value(1); y++ {
			for x = firstPt.Value(0); x <= lastPt.Value(0); x++ {
				var pastLabel uint64
				if block.Prev == nil || len(block.Prev) == 0 {
					pastLabel = 0
				} else {
					pastLabel = binary.LittleEndian.Uint64(block.Prev[start : start+8])
				}
				voxelLabel = binary.LittleEndian.Uint64(block.Data[start : start+8])
				if maxLabel < voxelLabel {
					maxLabel = voxelLabel
				}
				if pastLabel != 0 {
					if pastLabel != voxelLabel {
						labelDiff[pastLabel] = true
					} else {
						_, found := labelDiff[pastLabel]
						if !found {
							labelDiff[pastLabel] = false
						}
					}
				}
				start += 8

				// If we hit background or have switched label, save old run and start new one.
				if voxelLabel == 0 || voxelLabel != curLabel {
					// Save old run
					if curRun > 0 {
						labelRLEs[curLabel] = append(labelRLEs[curLabel], dvid.NewRLE(curStart, curRun))
					}
					// Start new one if not zero label.
					if voxelLabel != 0 {
						curStart = dvid.Point3d{x, y, z}
						curRun = 1
					} else {
						curRun = 0
					}
					curLabel = voxelLabel
				} else {
					curRun++
				}
			}
			// Force break of any runs when we finish x scan.
			if curRun > 0 {
				labelRLEs[curLabel] = append(labelRLEs[curLabel], dvid.NewRLE(curStart, curRun))
				curLabel = 0
				curRun = 0
			}
		}
	}

	// If a previous label has no change with current label RLE, then delete the label RLE since no changes
	// are necessary.  Else if previous label is not present in current label RLEs, delete labelvol.
	var deletes []storage.TKey
	blockStr := block.Index.ToIZYXString()
	for label, diff := range labelDiff {
		_, found := labelRLEs[label]
		if diff && !found {
			// mark previous label's RLEs for deletion
			tk := NewTKey(label, blockStr)
			deletes = append(deletes, tk)
		} else if !diff && found {
			// delete current label's RLEs because there's no difference with past RLE
			delete(labelRLEs, label)
		}
	}
	if len(deletes) > 0 {
		batch := batcher.NewBatch(ctx)
		for _, tk := range deletes {
			batch.Delete(tk)
		}
		if err := batch.Commit(); err != nil {
			dvid.Errorf("batch commit on deleting previous labels' labelvols: %v\n", err)
		}
	}

	// Store the RLEs for each label in this block that are new or modified.
	if len(labelRLEs) > 0 {
		batch := batcher.NewBatch(ctx)
		for label, rles := range labelRLEs {
			tk := NewTKey(label, blockStr)
//.........这里部分代码省略.........

// If a block of labels is deleted, the associated synapse elements should be changed to zero label elements.
func (d *Data) deleteBlock(ctx *datastore.VersionedCtx, block labels.DeleteBlock, batcher storage.KeyValueBatcher) {
	// Get the synaptic elements for this block
	chunkPt := dvid.ChunkPoint3d(*block.Index)
	tk := NewBlockTKey(chunkPt)
	elems, err := getElements(ctx, tk)
	if err != nil {
		dvid.Errorf("err getting elements for block %s: %v\n", chunkPt, err)
		return
	}
	if len(elems) == 0 {
		return
	}
	blockSize := d.blockSize()
	batch := batcher.NewBatch(ctx)

	// Compute the strides (in bytes)
	bX := blockSize[0] * 8
	bY := blockSize[1] * bX

	// Iterate through all element positions, finding corresponding label and storing elements.
	toDel := LabelPoints{}
	for _, elem := range elems {
		pt := elem.Pos.Point3dInChunk(blockSize)
		i := pt[2]*bY + pt[1]*bX + pt[0]*8
		label := binary.LittleEndian.Uint64(block.Data[i : i+8])
		toDel.add(label, elem.Pos)
	}

	// Delete any non-zero label elements from their respective label k/v.
	var delta DeltaModifyElements
	for label, pts := range toDel {
		tk := NewLabelTKey(label)
		elems, err := getElements(ctx, tk)
		if err != nil {
			dvid.Errorf("err getting elements for label %d: %v\n", label, err)
			return
		}
		save := false
		for _, pt := range pts {
			deleted, changed := elems.delete(pt)
			if changed {
				save = true
				delta.Del = append(delta.Del, ElementPos{Label: label, Kind: deleted.Kind, Pos: pt})
			}
		}
		if save {
			if len(elems) == 0 {
				batch.Delete(tk)
			} else {
				val, err := json.Marshal(elems)
				if err != nil {
					dvid.Errorf("couldn't serialize annotation elements in instance %q: %v\n", d.DataName(), err)
					return
				}
				batch.Put(tk, val)
			}
		}
	}

	if err := batch.Commit(); err != nil {
		dvid.Criticalf("bad commit in annotations %q after delete block: %v\n", d.DataName(), err)
		return
	}

	// Notify any subscribers of label annotation changes.
	evt := datastore.SyncEvent{Data: d.DataUUID(), Event: ModifyElementsEvent}
	msg := datastore.SyncMessage{Event: ModifyElementsEvent, Version: ctx.VersionID(), Delta: delta}
	if err := datastore.NotifySubscribers(evt, msg); err != nil {
		dvid.Criticalf("unable to notify subscribers of event %s: %v\n", evt, err)
	}
}

// Note that this does not delete any removed labels in the block since we only get the CURRENT block
// and not PAST blocks.  To allow mutation of label blocks, not just ingestion, we need another function.
func (d *Data) ingestBlock(ctx *datastore.VersionedCtx, block imageblk.Block, batcher storage.KeyValueBatcher) {

	// Iterate through this block of labels and create RLEs for each label.
	blockBytes := len(block.Data)
	if blockBytes != int(d.BlockSize.Prod())*8 {
		dvid.Criticalf("Deserialized label block %d bytes, not uint64 size times %d block elements\n",
			blockBytes, d.BlockSize.Prod())
		return
	}
	labelRLEs := make(map[uint64]dvid.RLEs, 10)
	firstPt := block.Index.MinPoint(d.BlockSize)
	lastPt := block.Index.MaxPoint(d.BlockSize)

	var curStart dvid.Point3d
	var voxelLabel, curLabel, maxLabel uint64
	var z, y, x, curRun int32
	start := 0
	for z = firstPt.Value(2); z <= lastPt.Value(2); z++ {
		for y = firstPt.Value(1); y <= lastPt.Value(1); y++ {
			for x = firstPt.Value(0); x <= lastPt.Value(0); x++ {
				voxelLabel = binary.LittleEndian.Uint64(block.Data[start : start+8])
				if maxLabel < voxelLabel {
					maxLabel = voxelLabel
				}
				start += 8

				// If we hit background or have switched label, save old run and start new one.
				if voxelLabel == 0 || voxelLabel != curLabel {
					// Save old run
					if curRun > 0 {
						labelRLEs[curLabel] = append(labelRLEs[curLabel], dvid.NewRLE(curStart, curRun))
					}
					// Start new one if not zero label.
					if voxelLabel != 0 {
						curStart = dvid.Point3d{x, y, z}
						curRun = 1
					} else {
						curRun = 0
					}
					curLabel = voxelLabel
				} else {
					curRun++
				}
			}
			// Force break of any runs when we finish x scan.
			if curRun > 0 {
				labelRLEs[curLabel] = append(labelRLEs[curLabel], dvid.NewRLE(curStart, curRun))
				curLabel = 0
				curRun = 0
			}
		}
	}

	// Store the RLEs for each label in this block.
	if maxLabel > 0 {
		batch := batcher.NewBatch(ctx)
		blockStr := block.Index.ToIZYXString()
		for label, rles := range labelRLEs {
			tk := NewTKey(label, blockStr)
			rleBytes, err := rles.MarshalBinary()
			if err != nil {
				dvid.Errorf("Bad encoding labelvol keys for label %d: %v\n", label, err)
				return
			}
			batch.Put(tk, rleBytes)
		}
		// compare-and-set MaxLabel and batch commit
		d.casMaxLabel(batch, ctx.VersionID(), maxLabel)
	}
}

// ServeHTTP handles all incoming HTTP requests for this data.
func (d *Data) ServeHTTP(uuid dvid.UUID, ctx *datastore.VersionedCtx, w http.ResponseWriter, r *http.Request) {
	timedLog := dvid.NewTimeLog()

	// Get the action (GET, POST)
	action := strings.ToLower(r.Method)
	switch action {
	case "get":
	case "post":
	default:
		server.BadRequest(w, r, "Can only handle GET or POST HTTP verbs")
		return
	}

	// Break URL request into arguments
	url := r.URL.Path[len(server.WebAPIPath):]
	parts := strings.Split(url, "/")
	if len(parts[len(parts)-1]) == 0 {
		parts = parts[:len(parts)-1]
	}

	// Get query strings and possible roi
	var roiptr *ROI
	queryValues := r.URL.Query()
	roiname := dvid.InstanceName(queryValues.Get("roi"))
	if len(roiname) != 0 {
		roiptr = new(ROI)
		attenuationStr := queryValues.Get("attenuation")
		if len(attenuationStr) != 0 {
			attenuation, err := strconv.Atoi(attenuationStr)
			if err != nil {
				server.BadRequest(w, r, err)
				return
			}
			if attenuation < 1 || attenuation > 7 {
				server.BadRequest(w, r, "Attenuation should be from 1 to 7 (divides by 2^n)")
				return
			}
			roiptr.attenuation = uint8(attenuation)
		}
	}

	// Handle POST on data -> setting of configuration
	if len(parts) == 3 && action == "put" {
		fmt.Printf("Setting configuration of data '%s'\n", d.DataName())
		config, err := server.DecodeJSON(r)
		if err != nil {
			server.BadRequest(w, r, err)
			return
		}
		if err := d.ModifyConfig(config); err != nil {
			server.BadRequest(w, r, err)
			return
		}
		if err := datastore.SaveDataByUUID(uuid, d); err != nil {
			server.BadRequest(w, r, err)
			return
		}
		fmt.Fprintf(w, "Changed '%s' based on received configuration:\n%s\n", d.DataName(), config)
		return
	}

	if len(parts) < 4 {
		server.BadRequest(w, r, "Incomplete API request")
		return
	}

	// Process help and info.
	switch parts[3] {
	case "help":
		w.Header().Set("Content-Type", "text/plain")
		fmt.Fprintln(w, d.Help())
		return

	case "metadata":
		jsonStr, err := d.NdDataMetadata()
		if err != nil {
			server.BadRequest(w, r, err)
			return
		}
		w.Header().Set("Content-Type", "application/vnd.dvid-nd-data+json")
		fmt.Fprintln(w, jsonStr)
		return

	case "info":
		jsonBytes, err := d.MarshalJSON()
		if err != nil {
			server.BadRequest(w, r, err)
			return
		}
		w.Header().Set("Content-Type", "application/json")
		fmt.Fprintf(w, string(jsonBytes))
		return

	case "rawkey":
		// GET <api URL>/node/<UUID>/<data name>/rawkey?x=<block x>&y=<block y>&z=<block z>
		if len(parts) != 4 {
			server.BadRequest(w, r, "rawkey endpoint should be followed by query strings (x, y, and z) giving block coord")
			return
		}
//.........这里部分代码省略.........

// ServeHTTP handles all incoming HTTP requests for this data.
func (d *Data) ServeHTTP(uuid dvid.UUID, ctx *datastore.VersionedCtx, w http.ResponseWriter, r *http.Request) {
	timedLog := dvid.NewTimeLog()

	// Break URL request into arguments
	url := r.URL.Path[len(server.WebAPIPath):]
	parts := strings.Split(url, "/")
	if len(parts[len(parts)-1]) == 0 {
		parts = parts[:len(parts)-1]
	}

	if len(parts) < 4 {
		server.BadRequest(w, r, "incomplete API specification")
		return
	}

	// Process help and info.
	switch parts[3] {
	case "help":
		w.Header().Set("Content-Type", "text/plain")
		fmt.Fprintln(w, d.Help())
		return
	case "info":
		jsonBytes, err := d.MarshalJSON()
		if err != nil {
			server.BadRequest(w, r, err)
			return
		}
		w.Header().Set("Content-Type", "application/json")
		fmt.Fprintf(w, string(jsonBytes))
		return
	default:
	}

	// Get the key and process request
	var comment string
	command := parts[3]
	method := strings.ToLower(r.Method)
	switch command {
	case "roi":
		switch method {
		case "get":
			if !d.Ready {
				w.WriteHeader(http.StatusPartialContent)
			}
			jsonBytes, err := Get(ctx)
			if err != nil {
				server.BadRequest(w, r, err)
				return
			}
			w.Header().Set("Content-Type", "application/json")
			fmt.Fprintf(w, string(jsonBytes))
			comment = fmt.Sprintf("HTTP GET ROI %q: %d bytes\n", d.DataName(), len(jsonBytes))
		case "post":
			data, err := ioutil.ReadAll(r.Body)
			if err != nil {
				server.BadRequest(w, r, err)
				return
			}
			err = d.PutJSON(ctx.VersionID(), data)
			if err != nil {
				server.BadRequest(w, r, err)
				return
			}
			comment = fmt.Sprintf("HTTP POST ROI %q: %d bytes\n", d.DataName(), len(data))
		case "delete":
			if err := d.Delete(ctx); err != nil {
				server.BadRequest(w, r, err)
				return
			}
			comment = fmt.Sprintf("HTTP DELETE ROI %q\n", d.DataName())
		}
	case "mask":
		if method != "get" {
			server.BadRequest(w, r, "ROI mask only supports GET")
			return
		}
		if len(parts) < 7 {
			server.BadRequest(w, r, "%q must be followed by shape/size/offset", command)
			return
		}
		shapeStr, sizeStr, offsetStr := parts[4], parts[5], parts[6]
		planeStr := dvid.DataShapeString(shapeStr)
		plane, err := planeStr.DataShape()
		if err != nil {
			server.BadRequest(w, r, err)
			return
		}
		switch plane.ShapeDimensions() {
		case 3:
			subvol, err := dvid.NewSubvolumeFromStrings(offsetStr, sizeStr, "_")
			if err != nil {
				server.BadRequest(w, r, err)
				return
			}
			data, err := d.GetMask(ctx, subvol)
			if err != nil {
				server.BadRequest(w, r, err)
				return
			}
//.........这里部分代码省略.........

// stores synaptic elements arranged by label, replacing any
// elements at same position.
func (d *Data) storeLabelElements(ctx *datastore.VersionedCtx, batch storage.Batch, be blockElements) error {
	labelData := d.GetSyncedLabelblk()
	if labelData == nil {
		dvid.Infof("No synced labels for annotation %q, skipping label-aware denormalization.\n", d.DataName())
		return nil // no synced labels
	}

	// Compute the strides (in bytes)
	blockSize := d.blockSize()
	bX := blockSize[0] * 8
	bY := blockSize[1] * bX
	blockBytes := int(blockSize[0] * blockSize[1] * blockSize[2] * 8)

	toAdd := LabelElements{}
	for izyxStr, elems := range be {
		blockCoord, err := izyxStr.ToChunkPoint3d()
		if err != nil {
			return err
		}

		// Get the labels for this block
		labels, err := labelData.GetLabelBlock(ctx.VersionID(), blockCoord)
		if err != nil {
			return err
		}
		if len(labels) == 0 {
			continue
		}
		if len(labels) != blockBytes {
			return fmt.Errorf("Expected %d bytes in %q label block, got %d instead.  Aborting.", blockBytes, d.DataName(), len(labels))
		}

		// Group annotations by label
		for _, elem := range elems {
			pt := elem.Pos.Point3dInChunk(blockSize)
			i := pt[2]*bY + pt[1]*bX + pt[0]*8
			label := binary.LittleEndian.Uint64(labels[i : i+8])
			if label != 0 {
				toAdd.add(label, elem.ElementNR)
			}
		}
	}

	// Store all the added annotations to the appropriate labels.
	var delta DeltaModifyElements
	for label, additions := range toAdd {
		tk := NewLabelTKey(label)
		elems, err := getElementsNR(ctx, tk)
		if err != nil {
			return fmt.Errorf("err getting elements for label %d: %v\n", label, err)
		}

		// Check if these annotations already exist.
		emap := make(map[string]int)
		for i, elem := range elems {
			emap[elem.Pos.MapKey()] = i
		}
		for _, elem := range additions {
			i, found := emap[elem.Pos.MapKey()]
			if !found {
				elems = append(elems, elem)
				delta.Add = append(delta.Add, ElementPos{Label: label, Kind: elem.Kind, Pos: elem.Pos})
			} else {
				elems[i] = elem // replace properties if same position
			}
		}
		if err := putBatchElements(batch, tk, elems); err != nil {
			return fmt.Errorf("couldn't serialize label %d annotations in instance %q: %v\n", label, d.DataName(), err)
		}
	}

	// Notify any subscribers of label annotation changes.
	evt := datastore.SyncEvent{Data: d.DataUUID(), Event: ModifyElementsEvent}
	msg := datastore.SyncMessage{Event: ModifyElementsEvent, Version: ctx.VersionID(), Delta: delta}
	if err := datastore.NotifySubscribers(evt, msg); err != nil {
		return err
	}

	return nil
}