Mimic Core's ordering for equal-score transactions

backend/src/__tests__/gbt/gbt-tests.ts

@@ -1,7 +1,6 @@
 import fs from 'fs';
-import { GbtGenerator } from '../../../rust-gbt';
+import { GbtGenerator, ThreadTransaction } from '../../../rust-gbt';
 import path from 'path';
-import { CompactThreadTransaction } from '../../mempool.interfaces';
 
 const baseline = require('./test-data/target-template.json');
 const testVector = require('./test-data/test-data-ids.json');
@@ -28,18 +27,20 @@ describe('Rust GBT', () => {
   });
 });
 
-function mempoolFromArrayBuffer(buf: ArrayBuffer): CompactThreadTransaction[] {
+function mempoolFromArrayBuffer(buf: ArrayBuffer): ThreadTransaction[] {
   const view = new DataView(buf);
   const count = view.getUint32(0, false);
-  const txs: CompactThreadTransaction[] = [];
+  const txs: ThreadTransaction[] = [];
   let offset = 4;
   for (let i = 0; i < count; i++) {
-    const tx: CompactThreadTransaction = {
-      uid: view.getUint32(offset, false),
+    const uid = view.getUint32(offset, false);
+    const tx: ThreadTransaction = {
+      uid,
+      order: txidToOrdering(vectorUidMap.get(uid) as string),
       fee: view.getFloat64(offset + 4, false),
       weight: view.getUint32(offset + 12, false),
       sigops: view.getUint32(offset + 16, false),
-      feePerVsize: view.getFloat64(offset + 20, false),
+      // feePerVsize: view.getFloat64(offset + 20, false),
       effectiveFeePerVsize: view.getFloat64(offset + 28, false),
       inputs: [],
     };
@@ -53,3 +54,7 @@ function mempoolFromArrayBuffer(buf: ArrayBuffer): CompactThreadTransaction[] {
   }
   return txs;
 }
+
+function txidToOrdering(txid: string): number {
+  return parseInt(txid.slice(56).match(/../g)?.reverse().join('') as string, 16);
+}

backend/src/api/mempool.ts

@@ -89,6 +89,9 @@ class Mempool {
       if (this.mempoolCache[txid].sigops == null || this.mempoolCache[txid].effectiveFeePerVsize == null) {
         this.mempoolCache[txid] = transactionUtils.extendMempoolTransaction(this.mempoolCache[txid]);
       }
+      if (this.mempoolCache[txid].order == null) {
+        this.mempoolCache[txid].order = transactionUtils.txidToOrdering(txid);
+      }
       count++;
     }
     if (this.mempoolChangedCallback) {

backend/src/api/transaction-utils.ts

@@ -76,6 +76,7 @@ class TransactionUtils {
     const adjustedFeePerVsize = Math.max(Common.isLiquid() ? 0.1 : 1,
       (transaction.fee || 0) / adjustedVsize);
     const transactionExtended: MempoolTransactionExtended = Object.assign(transaction, {
+      order: this.txidToOrdering(transaction.txid),
       vsize: Math.round(transaction.weight / 4),
       adjustedVsize,
       sigops,
@@ -154,6 +155,11 @@ class TransactionUtils {
 
     return sigops;
   }
+
+  // returns the most significant 4 bytes of the txid as an integer
+  public txidToOrdering(txid: string): number {
+    return parseInt(txid.slice(56).match(/../g)?.reverse().join('') as string, 16);
+  }
 }
 
 export default new TransactionUtils();

backend/src/mempool.interfaces.ts

@@ -93,6 +93,7 @@ export interface TransactionExtended extends IEsploraApi.Transaction {
 }
 
 export interface MempoolTransactionExtended extends TransactionExtended {
+  order: number;
   sigops: number;
   adjustedVsize: number;
   adjustedFeePerVsize: number;