Merge #12276: Remove duplicate mapWallet lookups

039425c [wallet] Remove duplicate mapWallet lookups (João Barbosa)

Pull request description:

Tree-SHA512: 8075925d2adb64737c691e988d74a37bc326711aaee2c37327361679c051f219fa500e14cbcdb6a169352bcdbab160e11df4276b2657e19e12908ee2d4444d30

src/wallet/wallet.cpp

@@ -531,14 +531,11 @@ void CWallet::SyncMetaData(std::pair<TxSpends::iterator, TxSpends::iterator> ran
 
     int nMinOrderPos = std::numeric_limits<int>::max();
     const CWalletTx* copyFrom = nullptr;
-    for (TxSpends::iterator it = range.first; it != range.second; ++it)
-    {
-        const uint256& hash = it->second;
-        int n = mapWallet[hash].nOrderPos;
-        if (n < nMinOrderPos)
-        {
-            nMinOrderPos = n;
-            copyFrom = &mapWallet[hash];
+    for (TxSpends::iterator it = range.first; it != range.second; ++it) {
+        const CWalletTx* wtx = &mapWallet[it->second];
+        if (wtx->nOrderPos < nMinOrderPos) {
+            nMinOrderPos = wtx->nOrderPos;;
+            copyFrom = wtx;
         }
     }
 
@@ -988,9 +985,7 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn, bool fFlushOnClose)
 bool CWallet::LoadToWallet(const CWalletTx& wtxIn)
 {
     uint256 hash = wtxIn.GetHash();
-
-    mapWallet[hash] = wtxIn;
-    CWalletTx& wtx = mapWallet[hash];
+    CWalletTx& wtx = mapWallet.emplace(hash, wtxIn).first->second;
     wtx.BindWallet(this);
     wtxOrdered.insert(std::make_pair(wtx.nOrderPos, TxPair(&wtx, nullptr)));
     AddToSpends(hash);