From af1d2ff88344e1545ac8d9ad09f8e37e264da712 Mon Sep 17 00:00:00 2001
From: dergoegge <n.goeggi@gmail.com>
Date: Wed, 1 Nov 2023 14:04:44 +0000
Subject: [PATCH] [primitives] Precompute result of CTransaction::HasWitness

---
 src/primitives/transaction.cpp | 12 ++++++++++--
 src/primitives/transaction.h   | 13 ++++---------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/primitives/transaction.cpp b/src/primitives/transaction.cpp
index 1ad8345fcb4..77a363f7b6e 100644
--- a/src/primitives/transaction.cpp
+++ b/src/primitives/transaction.cpp
@@ -15,6 +15,7 @@
 #include <util/transaction_identifier.h>
 #include <version.h>
 
+#include <algorithm>
 #include <cassert>
 #include <stdexcept>
 
@@ -71,6 +72,13 @@ Txid CMutableTransaction::GetHash() const
     return Txid::FromUint256((CHashWriter{SERIALIZE_TRANSACTION_NO_WITNESS} << *this).GetHash());
 }
 
+bool CTransaction::ComputeHasWitness() const
+{
+    return std::any_of(vin.begin(), vin.end(), [](const auto& input) {
+        return !input.scriptWitness.IsNull();
+    });
+}
+
 Txid CTransaction::ComputeHash() const
 {
     return Txid::FromUint256((CHashWriter{SERIALIZE_TRANSACTION_NO_WITNESS} << *this).GetHash());
@@ -85,8 +93,8 @@ Wtxid CTransaction::ComputeWitnessHash() const
     return Wtxid::FromUint256((CHashWriter{0} << *this).GetHash());
 }
 
-CTransaction::CTransaction(const CMutableTransaction& tx) : vin(tx.vin), vout(tx.vout), nVersion(tx.nVersion), nLockTime(tx.nLockTime), hash{ComputeHash()}, m_witness_hash{ComputeWitnessHash()} {}
-CTransaction::CTransaction(CMutableTransaction&& tx) : vin(std::move(tx.vin)), vout(std::move(tx.vout)), nVersion(tx.nVersion), nLockTime(tx.nLockTime), hash{ComputeHash()}, m_witness_hash{ComputeWitnessHash()} {}
+CTransaction::CTransaction(const CMutableTransaction& tx) : vin(tx.vin), vout(tx.vout), nVersion(tx.nVersion), nLockTime(tx.nLockTime), m_has_witness{ComputeHasWitness()}, hash{ComputeHash()}, m_witness_hash{ComputeWitnessHash()} {}
+CTransaction::CTransaction(CMutableTransaction&& tx) : vin(std::move(tx.vin)), vout(std::move(tx.vout)), nVersion(tx.nVersion), nLockTime(tx.nLockTime), m_has_witness{ComputeHasWitness()}, hash{ComputeHash()}, m_witness_hash{ComputeWitnessHash()} {}
 
 CAmount CTransaction::GetValueOut() const
 {
diff --git a/src/primitives/transaction.h b/src/primitives/transaction.h
index 89deb9de4d8..594168bbccd 100644
--- a/src/primitives/transaction.h
+++ b/src/primitives/transaction.h
@@ -310,12 +310,15 @@ public:
 
 private:
     /** Memory only. */
+    const bool m_has_witness;
     const Txid hash;
     const Wtxid m_witness_hash;
 
     Txid ComputeHash() const;
     Wtxid ComputeWitnessHash() const;
 
+    bool ComputeHasWitness() const;
+
 public:
     /** Convert a CMutableTransaction into a CTransaction. */
     explicit CTransaction(const CMutableTransaction& tx);
@@ -365,15 +368,7 @@ public:
 
     std::string ToString() const;
 
-    bool HasWitness() const
-    {
-        for (size_t i = 0; i < vin.size(); i++) {
-            if (!vin[i].scriptWitness.IsNull()) {
-                return true;
-            }
-        }
-        return false;
-    }
+    bool HasWitness() const { return m_has_witness; }
 };
 
 /** A mutable version of CTransaction. */