From b30c5656dfcae2463664dc0a2427ea8465a6b257 Mon Sep 17 00:00:00 2001
From: Junxiao Shi <git@mail1.yoursunny.com>
Date: Sat, 29 Jun 2024 01:04:32 +0000
Subject: [PATCH] svs: implement SvSync with FwFace.RxTx

---
 pkg/svs/src/sync.ts | 100 +++++++++++++++++++++++++++-----------------
 1 file changed, 62 insertions(+), 38 deletions(-)

diff --git a/pkg/svs/src/sync.ts b/pkg/svs/src/sync.ts
index 721b1269..d010201d 100644
--- a/pkg/svs/src/sync.ts
+++ b/pkg/svs/src/sync.ts
@@ -1,10 +1,10 @@
-import { consume, type ConsumerOptions, produce, type Producer, type ProducerHandler } from "@ndn/endpoint";
-import { Forwarder } from "@ndn/fw";
+import { Forwarder, type FwFace, FwPacket } from "@ndn/fw";
 import { Version } from "@ndn/naming-convention2";
 import { Component, Interest, Name, type NameLike, nullSigner, type Signer, type Verifier } from "@ndn/packet";
 import { type SyncNode, type SyncProtocol, SyncUpdate } from "@ndn/sync-api";
 import { Decoder, Encoder } from "@ndn/tlv";
-import { randomJitter, trackEventListener } from "@ndn/util";
+import { pushable, randomJitter, trackEventListener } from "@ndn/util";
+import { consume, map, tap } from "streaming-iterables";
 import type { Promisable } from "type-fest";
 import { TypedEventTarget } from "typescript-event-target";
 
@@ -24,6 +24,7 @@ interface DebugEntry {
 
 type EventMap = SyncProtocol.EventMap<Name> & {
   debug: CustomEvent<DebugEntry>;
+  rxerror: CustomEvent<[interest: Interest, e: unknown]>;
 };
 
 /** StateVectorSync participant. */
@@ -54,26 +55,18 @@ export class SvSync extends TypedEventTarget<EventMap> implements SyncProtocol<N
       describe,
       initialStateVector,
       svs2interest,
-      Interest.makeModifyFunc({
-        canBePrefix: true,
-        mustBeFresh: true,
-        lifetime: syncInterestLifetime,
-      }),
-      { fw, describe: `${describe}[c]`, retx: 0 },
       randomJitter(periodicTimeout[1], periodicTimeout[0]),
       svs2suppression ? suppressionTimeout :
       randomJitter(suppressionTimer[1], suppressionTimer[0]),
       svs2suppression ? suppressionPeriod : undefined,
-      signer,
-      verifier,
     );
-
     await initialize?.(sync);
-    sync.producer = produce(syncPrefix, sync.handleSyncInterest, {
+    sync.makeFace(
       fw,
-      describe: `${describe}[p]`,
-      routeCapture: false,
-    });
+      syncInterestLifetime,
+      signer,
+      verifier,
+    );
     return sync;
   }
 
@@ -82,19 +75,52 @@ export class SvSync extends TypedEventTarget<EventMap> implements SyncProtocol<N
       public readonly describe: string,
       private readonly own: StateVector,
       private readonly svs2interest: boolean,
-      private readonly modifyInterest: Interest.ModifyFunc,
-      private readonly cOpts: ConsumerOptions,
       private readonly steadyTimer: () => number,
       private readonly suppressionTimer: () => number,
       private readonly svs2suppressionPeriod: number | undefined,
-      private readonly signer: Signer,
-      private readonly verifier?: Verifier,
   ) {
     super();
   }
 
+  private makeFace(
+      fw: Forwarder,
+      syncInterestLifetime: number,
+      signer: Signer,
+      verifier?: Verifier,
+  ): void {
+    this.face = fw.addFace({
+      rx: map(async (interest) => {
+        this.debug("send");
+        interest.canBePrefix = true;
+        interest.mustBeFresh = true;
+        interest.lifetime = syncInterestLifetime;
+        await signer.sign(interest);
+        return FwPacket.create(interest);
+      }, this.txStream),
+      tx: (iterable) => consume(tap(async (pkt) => {
+        if (!(FwPacket.isEncodable(pkt) && pkt.l3 instanceof Interest)) {
+          return;
+        }
+        const interest = pkt.l3;
+        try {
+          await verifier?.verify(interest);
+          await this.handleSyncInterest(interest);
+        } catch (err: unknown) {
+          this.dispatchTypedEvent("rxerror", new CustomEvent<[interest: Interest, e: unknown]>("rxerror", {
+            detail: [interest, err],
+          }));
+        }
+      }, iterable)),
+    }, {
+      describe: this.describe,
+      routeCapture: false,
+    });
+    this.face.addRoute(this.syncPrefix);
+  }
+
   private readonly maybeHaveEventListener = trackEventListener(this);
-  private producer?: Producer;
+  private face?: FwFace;
+  private txStream = pushable<Interest>();
 
   /**
    * In steady state, undefined.
@@ -121,9 +147,10 @@ export class SvSync extends TypedEventTarget<EventMap> implements SyncProtocol<N
     }));
   }
 
+  /** Cease operations. */
   public close(): void {
     clearTimeout(this.timer);
-    this.producer?.close();
+    this.face?.close();
   }
 
   public get(id: NameLike): SyncNode<Name> {
@@ -154,7 +181,7 @@ export class SvSync extends TypedEventTarget<EventMap> implements SyncProtocol<N
    */
   private readonly nodeOp = (id: Name, n: number | undefined): number => {
     if (n !== undefined) { // setSeqNum requested
-      if (!this.producer) { // decrement/remove permitted during initialization
+      if (!this.face) { // decrement/remove permitted during initialization
         this.own.set(id, n);
       } else if (n > this.own.get(id)) { // increment only after initialization
         this.own.set(id, n);
@@ -165,8 +192,11 @@ export class SvSync extends TypedEventTarget<EventMap> implements SyncProtocol<N
     return this.own.get(id);
   };
 
-  private readonly handleSyncInterest: ProducerHandler = async (interest) => {
-    await this.verifier?.verify(interest);
+  /**
+   * Handle incoming sync Interest.
+   * @param interest - Received Interest, signature verified.
+   */
+  private async handleSyncInterest(interest: Interest): Promise<void> {
     const vComp = interest.name.at(this.syncPrefix.length);
     let decoder: Decoder;
     if (vComp.equals(V2) && !!interest.appParameters) {
@@ -203,7 +233,7 @@ export class SvSync extends TypedEventTarget<EventMap> implements SyncProtocol<N
     }
     this.resetTimer();
     return undefined;
-  };
+  }
 
   private shouldEnterSuppression(ourNewer: readonly StateVector.DiffEntry[]): boolean {
     if (this.svs2suppressionPeriod === undefined) {
@@ -228,20 +258,19 @@ export class SvSync extends TypedEventTarget<EventMap> implements SyncProtocol<N
         ourNewer: ourNewer.length,
       });
       if (ourNewer.length > 0) {
-        void this.sendSyncInterest();
+        this.sendSyncInterest();
       }
       this.aggregated = undefined;
     } else { // in steady state
       this.debug("timer");
-      void this.sendSyncInterest();
+      this.sendSyncInterest();
     }
 
     this.resetTimer();
   };
 
-  private async sendSyncInterest(): Promise<void> {
-    this.debug("send");
-
+  /** Transmit a sync Interest. */
+  private sendSyncInterest(): void {
     const interest = new Interest();
     if (this.svs2interest) {
       interest.name = this.syncPrefix.append(V2);
@@ -249,14 +278,9 @@ export class SvSync extends TypedEventTarget<EventMap> implements SyncProtocol<N
     } else {
       interest.name = this.syncPrefix.append(new Component(Encoder.encode(this.own)));
     }
-    this.modifyInterest(interest);
-    await this.signer.sign(interest);
 
-    try {
-      await consume(interest, this.cOpts);
-    } catch {
-      // not expecting a reply, so that a timeout will happen and it shall be ignored
-    }
+    this.txStream.push(interest);
+    // further modification and signing occur in the the logical face
   }
 }