Merge #13309: Directly operate with CMutableTransaction in SignSignature

6b8b63af1461dc11ffd813401e2c36fa44656715 Generic TransactionSignatureCreator works with both CTransaction and CMutableTransaction (Martin Ankerl)

Pull request description:

  Refactored `TransactionSignatureCreator` into a templated `GenericTransactionSignatureCreator` that works with both `CMutableTransaction` and `CTransaction`.

  The advantage is that now in `SignSignature`, the `MutableTransactionSignatureCreator` can now operate directly with the `CMutableTransaction` without the need to copy the data into a `CTransaction`.

  Running all unit tests brings a very noticable speedup on my machine:

      48.4 sec before this change
      36.4 sec with this change
      --------
      12.0 seconds saved

  running only `--run_test=transaction_tests/test_big_witness_transaction`:

      16.7 sec before this change
       5.9 sec with this change
      --------
      10.8 seconds saved

  This relates to my first attempt with the const_cast hack #13202, and to the slow unit test issue #10026.

  Also see #13050 which modifies the tests but not the production code (like this PR) to get a speedup.

Tree-SHA512: 2cff0e9699f484f26120a40e431a24c8bc8f9e780fd89cb0ecf20c5be3eab6c43f9c359cde244abd9f3620d06c7c354e3b9dd3da41fa2ca1ac1e09386fea25fb

1 files changed, 2 insertions, 4 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 36c5f2c5de..3987e8e70a 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2608,7 +2608,6 @@ bool CWallet::SignTransaction(CMutableTransaction &tx)
     AssertLockHeld(cs_wallet); // mapWallet
 
     // sign the new tx
-    CTransaction txNewConst(tx);
     int nIn = 0;
     for (const auto& input : tx.vin) {
         std::map<uint256, CWalletTx>::const_iterator mi = mapWallet.find(input.prevout.hash);
@@ -2618,7 +2617,7 @@ bool CWallet::SignTransaction(CMutableTransaction &tx)
         const CScript& scriptPubKey = mi->second.tx->vout[input.prevout.n].scriptPubKey;
         const CAmount& amount = mi->second.tx->vout[input.prevout.n].nValue;
         SignatureData sigdata;
-        if (!ProduceSignature(*this, TransactionSignatureCreator(&txNewConst, nIn, amount, SIGHASH_ALL), scriptPubKey, sigdata)) {
+        if (!ProduceSignature(*this, MutableTransactionSignatureCreator(&tx, nIn, amount, SIGHASH_ALL), scriptPubKey, sigdata)) {
             return false;
         }
         UpdateTransaction(tx, nIn, sigdata);
@@ -3040,14 +3039,13 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CTransac
 
         if (sign)
         {
-            CTransaction txNewConst(txNew);
             int nIn = 0;
             for (const auto& coin : selected_coins)
             {
                 const CScript& scriptPubKey = coin.txout.scriptPubKey;
                 SignatureData sigdata;
 
-                if (!ProduceSignature(*this, TransactionSignatureCreator(&txNewConst, nIn, coin.txout.nValue, SIGHASH_ALL), scriptPubKey, sigdata))
+                if (!ProduceSignature(*this, MutableTransactionSignatureCreator(&txNew, nIn, coin.txout.nValue, SIGHASH_ALL), scriptPubKey, sigdata))
                 {
                     strFailReason = _("Signing transaction failed");
                     return false;