Add canonical canvas rows, stable identity migration and model operations

2026-11-07 22:26:06 +08:00
parent 19884b2a90
commit b85e8bd2ca
10 changed files with 1996 additions and 3 deletions
@@ -0,0 +1,407 @@
+package platform
+
+import (
+	"encoding/json"
+	"errors"
+	"math"
+	"reflect"
+	"sort"
+	"strings"
+)
+
+const canvasModelFormat = 1
+const canvasModelProtocol = 2
+
+var errCanvasModel = errors.New("invalid_canvas_model")
+var errModelConflict = errors.New("canvas_model_field_conflict")
+
+type modelParent struct {
+	CanvasID       string `json:"canvasId"`
+	EntryElementID string `json:"entryElementId"`
+}
+type modelCanvas struct {
+	ID     string       `json:"id"`
+	Parent *modelParent `json:"parent"`
+}
+type canvasModel struct {
+	Root       string
+	Canvases   map[string]modelCanvas
+	Elements   map[string]map[string]any
+	Tombstones map[string]int64
+	Versions   map[string]int64
+}
+type modelView struct {
+	Format     int              `json:"documentFormatVersion"`
+	ProjectID  string           `json:"projectId"`
+	Canvases   []modelCanvas    `json:"canvases"`
+	Elements   []map[string]any `json:"elements"`
+	Tombstones map[string]int64 `json:"tombstones"`
+	Versions   map[string]int64 `json:"versions"`
+	Complete   bool             `json:"complete"`
+	Removed    []string         `json:"removedCanvasIds"`
+}
+type modelTarget struct {
+	ID          string `json:"id"`
+	Incarnation int64  `json:"incarnation"`
+}
+type modelChange struct {
+	Kind          string          `json:"kind"`
+	ID            string          `json:"id,omitempty"`
+	Target        modelTarget     `json:"target,omitempty"`
+	Field         string          `json:"field,omitempty"`
+	Before        json.RawMessage `json:"before"`
+	After         json.RawMessage `json:"after"`
+	BeforePresent *bool           `json:"beforePresent,omitempty"`
+	AfterPresent  *bool           `json:"afterPresent,omitempty"`
+}
+type modelOperation struct {
+	ID      string        `json:"id"`
+	Changes []modelChange `json:"changes"`
+}
+type modelBatch struct {
+	ProtocolVersion int              `json:"protocol_version"`
+	RequestID       string           `json:"request_id"`
+	Expected        map[string]int64 `json:"expected_versions"`
+	Operations      []modelOperation `json:"operations"`
+}
+
+func emptyModel(root string) canvasModel {
+	return canvasModel{Root: root, Canvases: map[string]modelCanvas{}, Elements: map[string]map[string]any{}, Tombstones: map[string]int64{}, Versions: map[string]int64{}}
+}
+func modelString(value any) string { text, _ := value.(string); return text }
+func modelInt(value any) int64 {
+	number, ok := value.(float64)
+	if !ok || number < 1 || number > 9007199254740991 || math.Trunc(number) != number {
+		return 0
+	}
+	return int64(number)
+}
+func modelEqual(left, right any) bool {
+	// Round-trip numeric Go structs and JSON records to the same JSON value domain.
+	a, ea := json.Marshal(left)
+	b, eb := json.Marshal(right)
+	if ea != nil || eb != nil {
+		return false
+	}
+	var av, bv any
+	return json.Unmarshal(a, &av) == nil && json.Unmarshal(b, &bv) == nil && reflect.DeepEqual(av, bv)
+}
+func (model canvasModel) view(participants map[string]int64) modelView {
+	view := modelView{Format: canvasModelFormat, ProjectID: model.Root, Canvases: []modelCanvas{}, Elements: []map[string]any{}, Tombstones: map[string]int64{}, Versions: map[string]int64{}, Complete: participants == nil, Removed: []string{}}
+	for _, id := range sortedKeys(model.Canvases) {
+		if participants != nil {
+			if _, exists := participants[id]; !exists {
+				continue
+			}
+		}
+		view.Canvases = append(view.Canvases, model.Canvases[id])
+		view.Versions[id] = model.Versions[id]
+	}
+	for _, id := range sortedKeys(model.Elements) {
+		element := model.Elements[id]
+		if participants != nil {
+			if _, exists := participants[modelString(element["ownerCanvasId"])]; !exists {
+				continue
+			}
+		}
+		view.Elements = append(view.Elements, element)
+	}
+	// Tombstones are small identity facts, not payloads; include them for safe incarnation checks.
+	for id, incarnation := range model.Tombstones {
+		view.Tombstones[id] = incarnation
+	}
+	for _, id := range sortedKeys(model.Versions) {
+		if participants != nil {
+			if _, exists := participants[id]; !exists {
+				continue
+			}
+		}
+		view.Versions[id] = model.Versions[id]
+		if _, exists := model.Canvases[id]; !exists {
+			view.Removed = append(view.Removed, id)
+		}
+	}
+	return view
+}
+func sortedKeys[T any](values map[string]T) []string {
+	keys := make([]string, 0, len(values))
+	for key := range values {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	return keys
+}
+func cloneModel(model canvasModel) canvasModel {
+	raw, _ := json.Marshal(model)
+	var copy canvasModel
+	_ = json.Unmarshal(raw, &copy)
+	return copy
+}
+func modelAncestors(model canvasModel, id string) ([]string, error) {
+	path, seen := []string{}, map[string]bool{}
+	for id != "" {
+		canvas, exists := model.Canvases[id]
+		if !exists || seen[id] || len(path) > 8 {
+			return nil, errCanvasModel
+		}
+		seen[id] = true
+		path = append(path, id)
+		id = ""
+		if canvas.Parent != nil {
+			id = canvas.Parent.CanvasID
+		}
+	}
+	return path, nil
+}
+func modelCommonCanvas(model canvasModel, left, right string) (string, error) {
+	a, err := modelAncestors(model, left)
+	if err != nil {
+		return "", err
+	}
+	b, err := modelAncestors(model, right)
+	if err != nil {
+		return "", err
+	}
+	seen := map[string]bool{}
+	for _, id := range a {
+		seen[id] = true
+	}
+	for _, id := range b {
+		if seen[id] {
+			return id, nil
+		}
+	}
+	return "", errCanvasModel
+}
+func validateCanvasModel(model canvasModel) error {
+	if !uuidSlugPattern.MatchString(model.Root) || len(model.Canvases) == 0 || len(model.Canvases) > 256 || len(model.Elements) > 128000 {
+		return errCanvasModel
+	}
+	roots, entries, counts := 0, map[string]bool{}, map[string][2]int{}
+	for id, canvas := range model.Canvases {
+		if id != canvas.ID || !uuidSlugPattern.MatchString(id) {
+			return errCanvasModel
+		}
+		if _, err := modelAncestors(model, id); err != nil {
+			return err
+		}
+		if canvas.Parent == nil {
+			roots++
+			if id != model.Root {
+				return errCanvasModel
+			}
+			continue
+		}
+		entry := model.Elements[canvas.Parent.EntryElementID]
+		if entry == nil || entry["structure"] != "node" || entry["ownerCanvasId"] != canvas.Parent.CanvasID || entries[canvas.Parent.EntryElementID] {
+			return errCanvasModel
+		}
+		entries[canvas.Parent.EntryElementID] = true
+	}
+	if roots != 1 {
+		return errCanvasModel
+	}
+	for id, incarnation := range model.Tombstones {
+		if !canvasID.MatchString(id) || incarnation < 1 || incarnation > 9007199254740991 {
+			return errCanvasModel
+		}
+	}
+	for id, element := range model.Elements {
+		owner, component := modelString(element["ownerCanvasId"]), modelString(element["componentId"])
+		_, canvasExists := model.Canvases[owner]
+		incarnation, version := modelInt(element["incarnation"]), modelInt(element["dataVersion"])
+		data, dataOK := element["data"].(map[string]any)
+		if !canvasID.MatchString(id) || element["id"] != id || !canvasExists || incarnation == 0 || incarnation <= model.Tombstones[id] || version == 0 || component == "" || len(component) > 128 || !dataOK || data == nil {
+			return errCanvasModel
+		}
+		encoded, err := json.Marshal(element)
+		if err != nil || len(encoded) > 1<<20 {
+			return errCanvasModel
+		}
+		count := counts[owner]
+		switch element["structure"] {
+		case "node":
+			count[0]++
+			geometry, ok := element["geometry"].(map[string]any)
+			if !ok || !canvasNumber(geometry["x"], -1e6, 1e6) || !canvasNumber(geometry["y"], -1e6, 1e6) || !canvasNumber(geometry["width"], 0.000001, 1e6) || !canvasNumber(geometry["height"], 0.000001, 1e6) || !canvasNumber(geometry["rotation"], 0, math.Nextafter(360, 0)) {
+				return errCanvasModel
+			}
+			if version == 1 && canvasChoice(component, "text", "image", "script", "plain-text", "plain-image", "icon", "frame") {
+				if !canvasString(data["title"], 300) || !canvasString(data["text"], 100000) || component == "frame" && geometry["rotation"] != float64(0) {
+					return errCanvasModel
+				}
+				if ai, exists := data["ai"]; exists && !validCanvasAI(ai, component) {
+					return errCanvasModel
+				}
+				if asset, exists := data["assetId"]; exists && (!canvasChoice(component, "image", "plain-image") || !uuidSlugPattern.MatchString(modelString(asset))) {
+					return errCanvasModel
+				}
+			}
+		case "connection":
+			count[1]++
+			source, sourceOK := element["source"].(map[string]any)
+			target, targetOK := element["target"].(map[string]any)
+			if !sourceOK || !targetOK {
+				return errCanvasModel
+			}
+			a, b := model.Elements[modelString(source["elementId"])], model.Elements[modelString(target["elementId"])]
+			if a == nil || b == nil || a["structure"] != "node" || b["structure"] != "node" {
+				return errCanvasModel
+			}
+			for _, endpoint := range []map[string]any{source, target} {
+				if port, exists := endpoint["portId"]; exists && (!canvasString(port, 256) || modelString(port) == "") {
+					return errCanvasModel
+				}
+			}
+			common, err := modelCommonCanvas(model, modelString(a["ownerCanvasId"]), modelString(b["ownerCanvasId"]))
+			if err != nil || common != owner {
+				return errCanvasModel
+			}
+		default:
+			return errCanvasModel
+		}
+		if count[0] > 500 || count[1] > 2000 {
+			return errGraphCapacity
+		}
+		counts[owner] = count
+	}
+	return nil
+}
+
+// Pure transaction reducer. Unknown component data/envelope fields are retained.
+func applyModelOperations(initial canvasModel, operations []modelOperation) (canvasModel, map[string]bool, error) {
+	model, touched, seen := cloneModel(initial), map[string]bool{}, map[string]bool{}
+	if len(operations) == 0 || len(operations) > 2500 {
+		return model, nil, errCanvasModel
+	}
+	changeCount := 0
+	for _, operation := range operations {
+		if !uuidSlugPattern.MatchString(operation.ID) || seen[operation.ID] || len(operation.Changes) == 0 {
+			return model, nil, errCanvasModel
+		}
+		seen[operation.ID] = true
+		for _, change := range operation.Changes {
+			changeCount++
+			if changeCount > 10000 {
+				return model, nil, errGraphCapacity
+			}
+			var before, after any
+			if json.Unmarshal(change.Before, &before) != nil || json.Unmarshal(change.After, &after) != nil {
+				return model, nil, errCanvasModel
+			}
+			switch change.Kind {
+			case "field":
+				element := model.Elements[change.Target.ID]
+				if element == nil || modelInt(element["incarnation"]) != change.Target.Incarnation {
+					return model, nil, errModelConflict
+				}
+				touched[modelString(element["ownerCanvasId"])] = true
+				if strings.HasPrefix(change.Field, "data.") {
+					key := strings.TrimPrefix(change.Field, "data.")
+					if key == "" || canvasChoice(key, "__proto__", "constructor", "prototype") {
+						return model, nil, errCanvasModel
+					}
+					data := element["data"].(map[string]any)
+					prior, present := data[key]
+					if present != (change.BeforePresent == nil || *change.BeforePresent) || !modelEqual(prior, before) {
+						return model, nil, errModelConflict
+					}
+					if change.AfterPresent != nil && !*change.AfterPresent {
+						delete(data, key)
+					} else {
+						data[key] = after
+					}
+				} else {
+					if !canvasChoice(change.Field, "geometry", "ownerCanvasId", "source", "target", "path") {
+						return model, nil, errCanvasModel
+					}
+					if !modelEqual(element[change.Field], before) {
+						return model, nil, errModelConflict
+					}
+					element[change.Field] = after
+					if change.Field == "ownerCanvasId" {
+						touched[modelString(after)] = true
+					}
+				}
+			case "element":
+				if !canvasID.MatchString(change.ID) || !modelEqual(model.Elements[change.ID], before) {
+					return model, nil, errModelConflict
+				}
+				if prior := model.Elements[change.ID]; prior != nil {
+					touched[modelString(prior["ownerCanvasId"])] = true
+				}
+				if after == nil {
+					if prior := model.Elements[change.ID]; prior != nil {
+						model.Tombstones[change.ID] = modelInt(prior["incarnation"])
+					}
+					delete(model.Elements, change.ID)
+				} else {
+					record, ok := after.(map[string]any)
+					if !ok || record["id"] != change.ID {
+						return model, nil, errCanvasModel
+					}
+					if before == nil && modelInt(record["incarnation"]) != model.Tombstones[change.ID]+1 {
+						return model, nil, errModelConflict
+					}
+					if prior := model.Elements[change.ID]; prior != nil && modelInt(record["incarnation"]) != modelInt(prior["incarnation"]) {
+						return model, nil, errModelConflict
+					}
+					model.Elements[change.ID] = record
+					touched[modelString(record["ownerCanvasId"])] = true
+				}
+			case "canvas":
+				prior, exists := model.Canvases[change.ID]
+				var priorValue any
+				if exists {
+					priorValue = prior
+				}
+				if !uuidSlugPattern.MatchString(change.ID) || !modelEqual(priorValue, before) {
+					return model, nil, errModelConflict
+				}
+				touched[change.ID] = true
+				if prior.Parent != nil {
+					touched[prior.Parent.CanvasID] = true
+				}
+				if after == nil {
+					delete(model.Canvases, change.ID)
+				} else {
+					var canvas modelCanvas
+					if json.Unmarshal(change.After, &canvas) != nil || canvas.ID != change.ID {
+						return model, nil, errCanvasModel
+					}
+					model.Canvases[change.ID] = canvas
+					if canvas.Parent != nil {
+						touched[canvas.Parent.CanvasID] = true
+					}
+				}
+			default:
+				return model, nil, errCanvasModel
+			}
+		}
+	}
+	if err := validateCanvasModel(model); err != nil {
+		return model, nil, err
+	}
+	// Endpoint owners are read participants, guarding against delete/restore races in child canvases.
+	for _, operation := range operations {
+		for _, change := range operation.Changes {
+			if change.Kind == "element" && string(change.Before) == "null" || change.Kind == "field" && (change.Field == "source" || change.Field == "target") {
+				id := change.ID
+				if change.Kind == "field" {
+					id = change.Target.ID
+				}
+				element := model.Elements[id]
+				if element != nil && element["structure"] == "connection" {
+					for _, field := range []string{"source", "target"} {
+						endpoint := element[field].(map[string]any)
+						touched[modelString(model.Elements[modelString(endpoint["elementId"])]["ownerCanvasId"])] = true
+					}
+				}
+			}
+		}
+	}
+	for id := range touched {
+		model.Versions[id] = initial.Versions[id] + 1
+	}
+	return model, touched, nil
+}