Count sigops & use adjusted vsizes in mempool projections

backend/src/api/transaction-utils.ts

@@ -1,7 +1,8 @@
-import { TransactionExtended, TransactionMinerInfo } from '../mempool.interfaces';
+import { TransactionExtended, MempoolTransactionExtended, TransactionMinerInfo } from '../mempool.interfaces';
 import { IEsploraApi } from './bitcoin/esplora-api.interface';
 import { Common } from './common';
 import bitcoinApi, { bitcoinCoreApi } from './bitcoin/bitcoin-api-factory';
+import * as bitcoinjs from 'bitcoinjs-lib';
 
 class TransactionUtils {
   constructor() { }
@@ -22,19 +23,27 @@ class TransactionUtils {
   }
 
   /**
-   * @param txId 
-   * @param addPrevouts 
-   * @param lazyPrevouts 
+   * @param txId
+   * @param addPrevouts
+   * @param lazyPrevouts
    * @param forceCore - See https://github.com/mempool/mempool/issues/2904
    */
-  public async $getTransactionExtended(txId: string, addPrevouts = false, lazyPrevouts = false, forceCore = false): Promise<TransactionExtended> {
+  public async $getTransactionExtended(txId: string, addPrevouts = false, lazyPrevouts = false, forceCore = false, addMempoolData = false): Promise<TransactionExtended> {
     let transaction: IEsploraApi.Transaction;
     if (forceCore === true) {
       transaction  = await bitcoinCoreApi.$getRawTransaction(txId, true);
     } else {
       transaction  = await bitcoinApi.$getRawTransaction(txId, false, addPrevouts, lazyPrevouts);
     }
-    return this.extendTransaction(transaction);
+    if (addMempoolData || !transaction?.status?.confirmed) {
+      return this.extendMempoolTransaction(transaction);
+    } else {
+      return this.extendTransaction(transaction);
+    }
+  }
+
+  public async $getMempoolTransactionExtended(txId: string, addPrevouts = false, lazyPrevouts = false, forceCore = false): Promise<MempoolTransactionExtended> {
+    return (await this.$getTransactionExtended(txId, addPrevouts, lazyPrevouts, forceCore, true)) as MempoolTransactionExtended;
   }
 
   private extendTransaction(transaction: IEsploraApi.Transaction): TransactionExtended {
@@ -50,7 +59,30 @@ class TransactionUtils {
       feePerVsize: feePerVbytes,
       effectiveFeePerVsize: feePerVbytes,
     }, transaction);
-    if (!transaction.status.confirmed) {
+    if (!transaction?.status?.confirmed) {
+      transactionExtended.firstSeen = Math.round((new Date().getTime() / 1000));
+    }
+    return transactionExtended;
+  }
+
+  public extendMempoolTransaction(transaction: IEsploraApi.Transaction): MempoolTransactionExtended {
+    const vsize = Math.ceil(transaction.weight / 4);
+    const sigops = this.countSigops(transaction);
+    // https://github.com/bitcoin/bitcoin/blob/e9262ea32a6e1d364fb7974844fadc36f931f8c6/src/policy/policy.cpp#L295-L298
+    const adjustedVsize = Math.max(vsize, sigops *  5); // adjusted vsize = Max(weight, sigops * bytes_per_sigop) / witness_scale_factor
+    const feePerVbytes = Math.max(Common.isLiquid() ? 0.1 : 1,
+      (transaction.fee || 0) / vsize);
+    const adjustedFeePerVsize = Math.max(Common.isLiquid() ? 0.1 : 1,
+      (transaction.fee || 0) / adjustedVsize);
+    const transactionExtended: MempoolTransactionExtended = Object.assign(transaction, {
+      vsize: Math.round(transaction.weight / 4),
+      adjustedVsize,
+      sigops,
+      feePerVsize: feePerVbytes,
+      adjustedFeePerVsize: adjustedFeePerVsize,
+      effectiveFeePerVsize: adjustedFeePerVsize,
+    });
+    if (!transaction?.status?.confirmed) {
       transactionExtended.firstSeen = Math.round((new Date().getTime() / 1000));
     }
     return transactionExtended;
@@ -63,6 +95,64 @@ class TransactionUtils {
     }
     return str;
   }
+
+  public countScriptSigops(script: string, isRawScript: boolean = false, witness: boolean = false): number {
+    let sigops = 0;
+    // count OP_CHECKSIG and OP_CHECKSIGVERIFY
+    sigops += (script.match(/OP_CHECKSIG/g)?.length || 0);
+
+    // count OP_CHECKMULTISIG and OP_CHECKMULTISIGVERIFY
+    if (isRawScript) {
+      // in scriptPubKey or scriptSig, always worth 20
+      sigops += 20 * (script.match(/OP_CHECKMULTISIG/g)?.length || 0);
+    } else {
+      // in redeem scripts and witnesses, worth N if preceded by OP_N, 20 otherwise
+      const matches = script.matchAll(/(?:OP_(\d+))? OP_CHECKMULTISIG/g);
+      for (const match of matches) {
+        const n = parseInt(match[1]);
+        if (Number.isInteger(n)) {
+          sigops += n;
+        } else {
+          sigops += 20;
+        }
+      }
+    }
+
+    return witness ? sigops : (sigops * 4);
+  }
+
+  public countSigops(transaction: IEsploraApi.Transaction): number {
+    let sigops = 0;
+
+    for (const input of transaction.vin) {
+      if (input.scriptsig_asm) {
+        sigops += this.countScriptSigops(input.scriptsig_asm, true);
+      }
+      if (input.prevout) {
+        switch (true) {
+          case input.prevout.scriptpubkey_type === 'p2sh' && input.witness?.length === 2 && input.scriptsig && input.scriptsig.startsWith('160014'):
+          case input.prevout.scriptpubkey_type === 'v0_p2wpkh':
+            sigops += 1;
+            break;
+
+          case input.prevout?.scriptpubkey_type === 'p2sh' && input.witness?.length && input.scriptsig && input.scriptsig.startsWith('220020'):
+          case input.prevout.scriptpubkey_type === 'v0_p2wsh':
+            if (input.witness?.length) {
+              sigops += this.countScriptSigops(bitcoinjs.script.toASM(Buffer.from(input.witness[input.witness.length - 1], 'hex')), false, true);
+            }
+            break;
+        }
+      }
+    }
+
+    for (const output of transaction.vout) {
+      if (output.scriptpubkey_asm) {
+        sigops += this.countScriptSigops(output.scriptpubkey_asm, true);
+      }
+    }
+
+    return sigops;
+  }
 }
 
 export default new TransactionUtils();