From fa72f09d6ff8ee204f331a69d3f5e825223c9e11 Mon Sep 17 00:00:00 2001
From: MarcoFalke <*~=`'#}+{/-|&$^_@721217.xyz>
Date: Mon, 11 Sep 2023 15:47:52 +0200
Subject: [PATCH] Remove CHashWriter type

The type is only ever set, but never read via GetType(), so remove it.
Also, remove SerializeHash to avoid silent merge conflicts and use the
already existing GetHash() boilerplate consistently.
---
 src/hash.h                     | 13 +------------
 src/primitives/block.cpp       |  2 +-
 src/primitives/transaction.cpp |  6 +++---
 src/test/hash_tests.cpp        |  2 +-
 src/test/serialize_tests.cpp   |  2 +-
 src/test/sighash_tests.cpp     |  2 +-
 6 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/src/hash.h b/src/hash.h
index f2b627ff4f7..d355b703ff4 100644
--- a/src/hash.h
+++ b/src/hash.h
@@ -149,13 +149,11 @@ public:
 class CHashWriter : public HashWriter
 {
 private:
-    const int nType;
     const int nVersion;
 
 public:
-    CHashWriter(int nTypeIn, int nVersionIn) : nType(nTypeIn), nVersion(nVersionIn) {}
+    CHashWriter(int nVersionIn) : nVersion{nVersionIn} {}
 
-    int GetType() const { return nType; }
     int GetVersion() const { return nVersion; }
 
     template<typename T>
@@ -223,15 +221,6 @@ public:
     }
 };
 
-/** Compute the 256-bit hash of an object's serialization. */
-template<typename T>
-uint256 SerializeHash(const T& obj, int nType=SER_GETHASH, int nVersion=PROTOCOL_VERSION)
-{
-    CHashWriter ss(nType, nVersion);
-    ss << obj;
-    return ss.GetHash();
-}
-
 /** Single-SHA256 a 32-byte input (represented as uint256). */
 [[nodiscard]] uint256 SHA256Uint256(const uint256& input);
 
diff --git a/src/primitives/block.cpp b/src/primitives/block.cpp
index 50a30cb511d..3d217088203 100644
--- a/src/primitives/block.cpp
+++ b/src/primitives/block.cpp
@@ -10,7 +10,7 @@
 
 uint256 CBlockHeader::GetHash() const
 {
-    return SerializeHash(*this);
+    return (CHashWriter{PROTOCOL_VERSION} << *this).GetHash();
 }
 
 std::string CBlock::ToString() const
diff --git a/src/primitives/transaction.cpp b/src/primitives/transaction.cpp
index 3060746909e..2c913bf4327 100644
--- a/src/primitives/transaction.cpp
+++ b/src/primitives/transaction.cpp
@@ -67,12 +67,12 @@ CMutableTransaction::CMutableTransaction(const CTransaction& tx) : vin(tx.vin),
 
 uint256 CMutableTransaction::GetHash() const
 {
-    return SerializeHash(*this, SER_GETHASH, SERIALIZE_TRANSACTION_NO_WITNESS);
+    return (CHashWriter{SERIALIZE_TRANSACTION_NO_WITNESS} << *this).GetHash();
 }
 
 uint256 CTransaction::ComputeHash() const
 {
-    return SerializeHash(*this, SER_GETHASH, SERIALIZE_TRANSACTION_NO_WITNESS);
+    return (CHashWriter{SERIALIZE_TRANSACTION_NO_WITNESS} << *this).GetHash();
 }
 
 uint256 CTransaction::ComputeWitnessHash() const
@@ -80,7 +80,7 @@ uint256 CTransaction::ComputeWitnessHash() const
     if (!HasWitness()) {
         return hash;
     }
-    return SerializeHash(*this, SER_GETHASH, 0);
+    return (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()} {}
diff --git a/src/test/hash_tests.cpp b/src/test/hash_tests.cpp
index a990797ca7c..54afcef9897 100644
--- a/src/test/hash_tests.cpp
+++ b/src/test/hash_tests.cpp
@@ -122,7 +122,7 @@ BOOST_AUTO_TEST_CASE(siphash)
                      (uint64_t(x+4)<<32)|(uint64_t(x+5)<<40)|(uint64_t(x+6)<<48)|(uint64_t(x+7)<<56));
     }
 
-    CHashWriter ss(SER_DISK, CLIENT_VERSION);
+    CHashWriter ss{CLIENT_VERSION};
     CMutableTransaction tx;
     // Note these tests were originally written with tx.nVersion=1
     // and the test would be affected by default tx version bumps if not fixed.
diff --git a/src/test/serialize_tests.cpp b/src/test/serialize_tests.cpp
index 2f2bb6698c2..d18d2623b11 100644
--- a/src/test/serialize_tests.cpp
+++ b/src/test/serialize_tests.cpp
@@ -176,7 +176,7 @@ BOOST_AUTO_TEST_CASE(vector_bool)
     std::vector<bool> vec2{1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1};
 
     BOOST_CHECK(vec1 == std::vector<uint8_t>(vec2.begin(), vec2.end()));
-    BOOST_CHECK(SerializeHash(vec1) == SerializeHash(vec2));
+    BOOST_CHECK((HashWriter{} << vec1).GetHash() == (HashWriter{} << vec2).GetHash());
 }
 
 BOOST_AUTO_TEST_CASE(noncanonical)
diff --git a/src/test/sighash_tests.cpp b/src/test/sighash_tests.cpp
index d1c0e1349e8..178b16772b7 100644
--- a/src/test/sighash_tests.cpp
+++ b/src/test/sighash_tests.cpp
@@ -78,7 +78,7 @@ uint256 static SignatureHashOld(CScript scriptCode, const CTransaction& txTo, un
     }
 
     // Serialize and hash
-    CHashWriter ss(SER_GETHASH, SERIALIZE_TRANSACTION_NO_WITNESS);
+    CHashWriter ss{SERIALIZE_TRANSACTION_NO_WITNESS};
     ss << txTmp << nHashType;
     return ss.GetHash();
 }