Add awareness

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ucla-irl/ndnts-aux",
-  "version": "1.0.10",
+  "version": "1.0.11-rc1",
   "description": "NDNts Auxiliary Package for Web and Deno",
   "scripts": {
     "test": "deno test --no-check",
@@ -22,6 +22,7 @@
     "eventemitter3": "^5.0.1",
     "jose": "^5.2.0",
     "tslib": "^2.6.2",
+    "y-protocols": "^1.0.6",
     "yjs": "^13.6.11"
   },
   "devDependencies": {

src/adaptors/yjs-ndn-adaptor.ts

@@ -1,5 +1,6 @@
 import { SyncAgent } from '../sync-agent/mod.ts';
 import * as Y from 'yjs';
+import { Awareness } from 'y-protocols/awareness.js';
 
 /**
  * NDN SVS Provider for Yjs. Wraps update into `SyncAgent`'s `update` channel.
@@ -13,6 +14,14 @@ import * as Y from 'yjs';
  */
 export class NdnSvsAdaptor {
   private readonly callback = this.docUpdateHandler.bind(this);
+  private readonly awarenessCallback = this.awarenessUpdateHandler.bind(this);
+
+  #awarenessDocId: string | undefined;
+  #awareness: Awareness | undefined;
+  // Required as a Yjs provider
+  public get awareness() {
+    return this.#awareness;
+  }
 
   constructor(
     public syncAgent: SyncAgent,
@@ -23,9 +32,24 @@ export class NdnSvsAdaptor {
     doc.on('update', this.callback);
   }
 
+  public bindAwareness(subDoc: Y.Doc, docId: string) {
+    this.#awarenessDocId = docId;
+    this.#awareness = new Awareness(subDoc); // TODO: Should we do so?
+    this.#awareness.on('update', this.awarenessCallback);
+    this.syncAgent.register('status', this.topic, (content) => this.handleAwarenessUpdate(content));
+  }
+
+  public cancelAwareness() {
+    this.#awarenessDocId = undefined;
+    this.syncAgent.unregister('status', this.topic);
+    this.#awareness?.off('update', this.awarenessCallback);
+    this.#awareness?.destroy();
+  }
+
   public destroy() {
-    this.syncAgent.unregister('update', this.topic);
+    this.cancelAwareness();
     this.doc.off('update', this.callback);
+    this.syncAgent.unregister('update', this.topic);
   }
 
   private docUpdateHandler(update: Uint8Array, origin: undefined) {
@@ -34,6 +58,25 @@ export class NdnSvsAdaptor {
     }
   }
 
+  private awarenessUpdateHandler(_updatedClients: {
+    added: number[];
+    updated: number[];
+    removed: number[];
+  }, origin: unknown | 'local') {
+    if (origin !== 'local') {
+      // Only capture local updates
+      return;
+    }
+    // Capture and publish local state
+    const localState = this.#awareness!.getLocalState();
+    const encodedState = JSON.stringify({
+      clientId: this.#awareness!.clientID,
+      docId: this.#awarenessDocId,
+      state: localState,
+    });
+    this.syncAgent.publishStatus(this.topic, new TextEncoder().encode(encodedState));
+  }
+
   private async produce(content: Uint8Array) {
     await this.syncAgent.publishUpdate(this.topic, content);
   }
@@ -49,4 +92,40 @@ export class NdnSvsAdaptor {
     // https://github.com/yjs/yjs/blob/fe36ffd122a6f2384293098afd52d2c0025fce2a/src/utils/Transaction.js#L415-L426
     Y.applyUpdate(this.doc, content, this);
   }
+
+  public handleAwarenessUpdate(content: Uint8Array) {
+    const encodedState = JSON.parse(new TextDecoder().decode(content));
+    const { clientId, docId, state } = encodedState as {
+      clientId: number;
+      docId: string;
+      state: Record<string, unknown> | null;
+    };
+    const awareness = this.#awareness;
+    if (!awareness) {
+      return;
+    }
+
+    const prevMeta = awareness.meta.get(clientId);
+    let op: 'added' | 'updated' | 'removed';
+    if (prevMeta === undefined && docId === this.#awarenessDocId && state !== null) {
+      op = 'added';
+    } else if (prevMeta !== undefined && (docId !== this.#awarenessDocId || state === null)) {
+      op = 'removed';
+    } else if (docId === this.#awarenessDocId) {
+      op = 'updated';
+    } else {
+      return;
+    }
+
+    if (op === 'removed' || !state) {
+      awareness.states.delete(clientId);
+    } else {
+      awareness.states.set(clientId, state);
+    }
+    awareness.meta.set(clientId, {
+      clock: 0,
+      lastUpdated: Date.now(),
+    });
+    awareness.emit('change', [{ added: [], updated: [], removed: [], [op]: [clientId] }, this]);
+  }
 }

src/namespace/name-pattern.ts

@@ -15,6 +15,8 @@ export type PatternComponent = {
 
 export type Pattern = Array<PatternComponent | Component>;
 
+export type Mapping = Record<string, MatchValue>;
+
 export const patternComponentToString = (comp: PatternComponent) => `<${comp.type}=${comp.tag}:${comp.kind}>`;
 
 export const componentToString = (comp: PatternComponent | Component) =>
@@ -30,7 +32,7 @@ export const toString = (pat: Pattern) => '/' + pat.map(componentToString).join(
 export const matchStep = (
   pattern: PatternComponent | Component,
   subject: Component,
-  mapping: Record<string, MatchValue>,
+  mapping: Mapping,
 ) => {
   if (pattern.type !== subject.type) {
     return false;
@@ -41,7 +43,7 @@ export const matchStep = (
     mapping[pattern.tag] = subject.value;
     return true;
   } else if (pattern.kind === 'string') {
-    mapping[pattern.tag] = new TextDecoder().decode(subject.value);
+    mapping[pattern.tag] = subject.text;
     return true;
   } else {
     try {
@@ -66,7 +68,7 @@ export const matchStep = (
 export const match = (
   pattern: Pattern,
   subject: Name,
-  mapping: Record<string, MatchValue>,
+  mapping: Mapping,
 ) => {
   // Remove automatically added component
   // ImplicitSha256DigestComponent(0x01) and ParametersSha256DigestComponent(0x02)
@@ -87,7 +89,7 @@ export const match = (
 
 export const makeStep = (
   pattern: PatternComponent | Component,
-  mapping: Record<string, MatchValue>,
+  mapping: Mapping,
 ) => {
   if (pattern instanceof Component) {
     return pattern;
@@ -112,10 +114,10 @@ export const makeStep = (
  */
 export const make = (
   pattern: Pattern,
-  mapping: Record<string, MatchValue>,
+  mapping: Mapping,
 ) => new Name(pattern.map((p) => makeStep(p, mapping)));
 
-export const componentFromString = (value: string) => {
+export const componentFromString = (value: string): Component | PatternComponent => {
   if (value.length === 0) {
     return new Component();
   }
@@ -128,17 +130,17 @@ export const componentFromString = (value: string) => {
     }
     return {
       type: parseInt(matching.groups.type),
-      kind: matching.groups.kind as PatternKind,
+      kind: matching.groups.kind as PatternKind, // Assume correct, no check
       tag: matching.groups.tag,
-    } as PatternComponent;
+    };
   }
 };
 
-export const fromString = (value: string) => {
+export const fromString = (value: string): Pattern => {
   if (value[0] === '/') {
     value = value.substring(1);
   }
-  return value.split('/').map(componentFromString) as Pattern;
+  return value.split('/').map(componentFromString);
 };
 
 export const pattern = ([value]: TemplateStringsArray) => {