feat(json-crdt): 🎸 start debug file format implementation

Author: streamich

src/json-crdt/file/File.ts

@@ -0,0 +1,92 @@
+import {Model} from "../model";
+import {PatchLog} from "./PatchLog";
+import {FileModelEncoding} from "./constants";
+import {Encoder as SidecarEncoder} from '../codec/sidecar/binary/Encoder';
+import {Encoder as StructuralEncoderCompact} from '../codec/structural/compact/Encoder';
+import {Encoder as StructuralEncoderVerbose} from '../codec/structural/verbose/Encoder';
+import {encode as encodeCompact} from '../../json-crdt-patch/codec/compact/encode';
+import {encode as encodeVerbose} from '../../json-crdt-patch/codec/verbose/encode';
+import type * as types from "./types";
+
+export class File {
+  public static fromModel(model: Model): File {
+    return new File(model, PatchLog.fromModel(model));
+  }
+
+  constructor(
+    public readonly model: Model,
+    public readonly history: PatchLog,
+  ) {}
+
+  public serialize(params: types.FileSerializeParams = {}): types.FileWriteSequence {
+    const view = this.model.view();
+    const metadata: types.FileMetadata = [
+      {},
+      FileModelEncoding.SidecarBinary,
+    ];
+    let model: Uint8Array | unknown | null = null;
+    const modelFormat = params.model ?? 'sidecar';
+    switch (modelFormat) {
+      case 'sidecar': {
+        metadata[1] = FileModelEncoding.SidecarBinary;
+        const encoder = new SidecarEncoder();
+        const [, uint8] = encoder.encode(this.model);
+        model = uint8;
+        break;
+      }
+      case 'binary': {
+        metadata[1] = FileModelEncoding.StructuralBinary;
+        model = this.model.toBinary();
+        break;
+      }
+      case 'compact': {
+        metadata[1] = FileModelEncoding.StructuralCompact;
+        model = new StructuralEncoderCompact().encode(this.model);
+        break;
+      }
+      case 'verbose': {
+        metadata[1] = FileModelEncoding.StructuralVerbose;
+        model = new StructuralEncoderVerbose().encode(this.model);
+        break;
+      }
+      default:
+        throw new Error(`Invalid model format: ${modelFormat}`);
+    }
+    const history: types.FileWriteSequenceHistory = [
+      null,
+      [],
+    ];
+    const patchFormat = params.history ?? 'binary';
+    switch (patchFormat) {
+      case 'binary': {
+        history[0] = this.history.start.toBinary();
+        this.history.patches.forEach(({v}) => {
+          history[1].push(v.toBinary());
+        });
+        break;
+      }
+      case 'compact': {
+        history[0] = new StructuralEncoderCompact().encode(this.history.start);
+        this.history.patches.forEach(({v}) => {
+          history[1].push(encodeCompact(v));
+        });
+        break;
+      }
+      case 'verbose': {
+        history[0] = new StructuralEncoderVerbose().encode(this.history.start);
+        this.history.patches.forEach(({v}) => {
+          history[1].push(encodeVerbose(v));
+        });
+        break;
+      }
+      default:
+        throw new Error(`Invalid history format: ${patchFormat}`);
+    }
+    return [
+      view,
+      metadata,
+      model,
+      history,
+    ];
+  }
+}

src/json-crdt/file/PatchLog.ts

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+import {ITimestampStruct, Patch, ServerClockVector, compare} from "../../json-crdt-patch";
+import {AvlMap} from "../../util/trees/avl/AvlMap";
+import {Model} from "../model";
+
+export class PatchLog {
+  public static fromModel (model: Model): PatchLog {
+    const start = new Model(model.clock.clone());
+    const log = new PatchLog(start);
+    if (model.api.builder.patch.ops.length) {
+      const patch = model.api.flush();
+      log.push(patch);
+    }
+    return log;
+  }
+
+  public readonly patches = new AvlMap<ITimestampStruct, Patch>(compare);
+
+  constructor (public readonly start: Model) {}
+
+  public push(patch: Patch): void {
+    const id = patch.getId();
+    if (!id) return;
+    this.patches.set(id, patch);
+  }
+}

src/json-crdt/file/constants.ts

@@ -0,0 +1,7 @@
+export const enum FileModelEncoding {
+  None = 0,
+  SidecarBinary = 1,
+  StructuralBinary = 5,
+  StructuralCompact = 6,
+  StructuralVerbose = 7,
+}

src/json-crdt/file/types.ts

@@ -0,0 +1,29 @@
+import type {FileModelEncoding} from "./constants";
+
+export type FileMetadata = [
+  map: {},
+  modelFormat: FileModelEncoding,
+];
+
+export type FileWriteSequence = [
+  view: unknown | null,
+  metadata: FileMetadata,
+  model: Uint8Array | unknown | null,
+  history: FileWriteSequenceHistory,
+];
+
+export type FileWriteSequenceHistory = [
+  model: Uint8Array | unknown | null,
+  patches: Array<Uint8Array | unknown>,
+];
+
+export type FileReadSequence = [
+  ...FileWriteSequence,
+  ...frontier: Array<Uint8Array | unknown>,
+];
+
+export interface FileSerializeParams {
+  noView?: boolean;
+  model?: 'sidecar' | 'binary' | 'compact' | 'verbose';
+  history?: 'binary' | 'compact' | 'verbose';
+}