From 3e6d38656d773cde85615f6572b4c72b31ce74c8 Mon Sep 17 00:00:00 2001
From: Mononaut <github@monospace.live>
Date: Thu, 11 Apr 2024 08:09:28 +0000
Subject: [PATCH] Add sequence number to mempool block updates

---
 backend/src/api/websocket-handler.ts           | 12 ++++++++++++
 frontend/src/app/services/state.service.ts     |  1 +
 frontend/src/app/services/websocket.service.ts |  9 ++++++++-
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/backend/src/api/websocket-handler.ts b/backend/src/api/websocket-handler.ts
index 621f2996a..d4ff7efe3 100644
--- a/backend/src/api/websocket-handler.ts
+++ b/backend/src/api/websocket-handler.ts
@@ -54,6 +54,7 @@ class WebsocketHandler {
   private socketData: { [key: string]: string } = {};
   private serializedInitData: string = '{}';
   private lastRbfSummary: ReplacementInfo[] | null = null;
+  private mempoolSequence: number = 0;
 
   constructor() { }
 
@@ -317,6 +318,7 @@ class WebsocketHandler {
               const mBlocksWithTransactions = mempoolBlocks.getMempoolBlocksWithTransactions();
               response['projected-block-transactions'] = JSON.stringify({
                 index: index,
+                sequence: this.mempoolSequence,
                 blockTransactions: (mBlocksWithTransactions[index]?.transactions || []).map(mempoolBlocks.compressTx),
               });
             } else {
@@ -602,6 +604,10 @@ class WebsocketHandler {
     const addressCache = this.makeAddressCache(newTransactions);
     const removedAddressCache = this.makeAddressCache(deletedTransactions);
 
+    if (memPool.isInSync()) {
+      this.mempoolSequence++;
+    }
+
     // TODO - Fix indentation after PR is merged
     for (const server of this.webSocketServers) {
     server.clients.forEach(async (client) => {
@@ -825,6 +831,7 @@ class WebsocketHandler {
         if (mBlockDeltas[index]) {
           response['projected-block-transactions'] = getCachedResponse(`projected-block-transactions-${index}`, {
             index: index,
+            sequence: this.mempoolSequence,
             delta: mBlockDeltas[index],
           });
         }
@@ -993,6 +1000,9 @@ class WebsocketHandler {
       return responseCache[key];
     }
 
+    if (memPool.isInSync()) {
+      this.mempoolSequence++;
+    }
 
     // TODO - Fix indentation after PR is merged
     for (const server of this.webSocketServers) {
@@ -1162,11 +1172,13 @@ class WebsocketHandler {
           if (mBlockDeltas[index].added.length > (mBlocksWithTransactions[index]?.transactions.length / 2)) {
             response['projected-block-transactions'] = getCachedResponse(`projected-block-transactions-full-${index}`, {
               index: index,
+              sequence: this.mempoolSequence,
               blockTransactions: mBlocksWithTransactions[index].transactions.map(mempoolBlocks.compressTx),
             });
           } else {
             response['projected-block-transactions'] = getCachedResponse(`projected-block-transactions-delta-${index}`, {
               index: index,
+              sequence: this.mempoolSequence,
               delta: mBlockDeltas[index],
             });
           }
diff --git a/frontend/src/app/services/state.service.ts b/frontend/src/app/services/state.service.ts
index 6d99d278a..174388b7e 100644
--- a/frontend/src/app/services/state.service.ts
+++ b/frontend/src/app/services/state.service.ts
@@ -96,6 +96,7 @@ export class StateService {
   env: Env;
   latestBlockHeight = -1;
   blocks: BlockExtended[] = [];
+  mempoolSequence: number;
 
   backend$ = new BehaviorSubject<'esplora' | 'electrum' | 'none'>('esplora');
   networkChanged$ = new ReplaySubject<string>(1);
diff --git a/frontend/src/app/services/websocket.service.ts b/frontend/src/app/services/websocket.service.ts
index de5170cbe..414f60bc5 100644
--- a/frontend/src/app/services/websocket.service.ts
+++ b/frontend/src/app/services/websocket.service.ts
@@ -400,9 +400,16 @@ export class WebsocketService {
     if (response['projected-block-transactions']) {
       if (response['projected-block-transactions'].index == this.trackingMempoolBlock) {
         if (response['projected-block-transactions'].blockTransactions) {
+          this.stateService.mempoolSequence = response['projected-block-transactions'].sequence;
           this.stateService.mempoolBlockTransactions$.next(response['projected-block-transactions'].blockTransactions.map(uncompressTx));
         } else if (response['projected-block-transactions'].delta) {
-          this.stateService.mempoolBlockDelta$.next(uncompressDeltaChange(response['projected-block-transactions'].delta));
+          if (this.stateService.mempoolSequence && response['projected-block-transactions'].sequence !== this.stateService.mempoolSequence + 1) {
+            this.stateService.mempoolSequence = 0;
+            this.startTrackMempoolBlock(this.trackingMempoolBlock, true);
+          } else {
+            this.stateService.mempoolSequence = response['projected-block-transactions'].sequence;
+            this.stateService.mempoolBlockDelta$.next(uncompressDeltaChange(response['projected-block-transactions'].delta));
+          }
         }
       }
     }