Merge #19980: refactor: Some wallet cleanups

9b74461fa293453a9eb0b1717b30b3f7fa778d91 refactor: Assert before dereference in CWallet::GetDatabase (João Barbosa)
021feb3187b207d511561c1f0ffd7f9e5e0c9c1d refactor: Drop redudant CWallet::GetDBHandle (João Barbosa)

Pull request description:

ACKs for top commit:
  achow101:
    Code Review ACK 9b74461fa293453a9eb0b1717b30b3f7fa778d91
  meshcollider:
    utACK 9b74461fa293453a9eb0b1717b30b3f7fa778d91
  ryanofsky:
    Code review ACK 9b74461fa293453a9eb0b1717b30b3f7fa778d91. Changes since last review: rebasing due to conflict, dropping wallet path commit c6a5cd7a64c78b162f545a3467d0fea7dcaadfcc as suggested in discussion, making GetDatabase() const in the earlier commit. Giving more descriptive title like

Tree-SHA512: 68cf3b5e9fe0acb3a5cd081086629989f213f1904cc344e5775767b56759a7d905b1e1c303afbe40f172ff81bf07f3719b59d8f6ec2de3fdd53cd0e2d220fb25

3 files changed, 34 insertions, 37 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 3019d53c6c..65b54f39b4 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -419,7 +419,7 @@ bool CWallet::ChangeWalletPassphrase(const SecureString& strOldWalletPassphrase,
                     return false;
                 if (!crypter.Encrypt(_vMasterKey, pMasterKey.second.vchCryptedKey))
                     return false;
-                WalletBatch(*database).WriteMasterKey(pMasterKey.first, pMasterKey.second);
+                WalletBatch(GetDatabase()).WriteMasterKey(pMasterKey.first, pMasterKey.second);
                 if (fWasLocked)
                     Lock();
                 return true;
@@ -432,7 +432,7 @@ bool CWallet::ChangeWalletPassphrase(const SecureString& strOldWalletPassphrase,
 
 void CWallet::chainStateFlushed(const CBlockLocator& loc)
 {
-    WalletBatch batch(*database);
+    WalletBatch batch(GetDatabase());
     batch.WriteBestBlock(loc);
 }
 
@@ -444,7 +444,7 @@ void CWallet::SetMinVersion(enum WalletFeature nVersion, WalletBatch* batch_in)
     nWalletVersion = nVersion;
 
     {
-        WalletBatch* batch = batch_in ? batch_in : new WalletBatch(*database);
+        WalletBatch* batch = batch_in ? batch_in : new WalletBatch(GetDatabase());
         if (nWalletVersion > 40000)
             batch->WriteMinVersion(nWalletVersion);
         if (!batch_in)
@@ -484,12 +484,12 @@ bool CWallet::HasWalletSpend(const uint256& txid) const
 
 void CWallet::Flush()
 {
-    database->Flush();
+    GetDatabase().Flush();
 }
 
 void CWallet::Close()
 {
-    database->Close();
+    GetDatabase().Close();
 }
 
 void CWallet::SyncMetaData(std::pair<TxSpends::iterator, TxSpends::iterator> range)
@@ -615,7 +615,7 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
     {
         LOCK(cs_wallet);
         mapMasterKeys[++nMasterKeyMaxID] = kMasterKey;
-        WalletBatch* encrypted_batch = new WalletBatch(*database);
+        WalletBatch* encrypted_batch = new WalletBatch(GetDatabase());
         if (!encrypted_batch->TxnBegin()) {
             delete encrypted_batch;
             encrypted_batch = nullptr;
@@ -667,12 +667,12 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
 
         // Need to completely rewrite the wallet file; if we don't, bdb might keep
         // bits of the unencrypted private key in slack space in the database file.
-        database->Rewrite();
+        GetDatabase().Rewrite();
 
         // BDB seems to have a bad habit of writing old data into
         // slack space in .dat files; that is bad if the old data is
         // unencrypted private keys. So:
-        database->ReloadDbEnv();
+        GetDatabase().ReloadDbEnv();
 
     }
     NotifyStatusChanged(this);
@@ -683,7 +683,7 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
 DBErrors CWallet::ReorderTransactions()
 {
     LOCK(cs_wallet);
-    WalletBatch batch(*database);
+    WalletBatch batch(GetDatabase());
 
     // Old wallets didn't have any defined order for transactions
     // Probably a bad idea to change the output of this
@@ -744,7 +744,7 @@ int64_t CWallet::IncOrderPosNext(WalletBatch* batch)
     if (batch) {
         batch->WriteOrderPosNext(nOrderPosNext);
     } else {
-        WalletBatch(*database).WriteOrderPosNext(nOrderPosNext);
+        WalletBatch(GetDatabase()).WriteOrderPosNext(nOrderPosNext);
     }
     return nRet;
 }
@@ -774,7 +774,7 @@ bool CWallet::MarkReplaced(const uint256& originalHash, const uint256& newHash)
 
     wtx.mapValue["replaced_by_txid"] = newHash.ToString();
 
-    WalletBatch batch(*database);
+    WalletBatch batch(GetDatabase());
 
     bool success = true;
     if (!batch.WriteTx(wtx)) {
@@ -846,7 +846,7 @@ CWalletTx* CWallet::AddToWallet(CTransactionRef tx, const CWalletTx::Confirmatio
 {
     LOCK(cs_wallet);
 
-    WalletBatch batch(*database, fFlushOnClose);
+    WalletBatch batch(GetDatabase(), fFlushOnClose);
 
     uint256 hash = tx->GetHash();
 
@@ -1045,7 +1045,7 @@ bool CWallet::AbandonTransaction(const uint256& hashTx)
 {
     LOCK(cs_wallet);
 
-    WalletBatch batch(*database);
+    WalletBatch batch(GetDatabase());
 
     std::set<uint256> todo;
     std::set<uint256> done;
@@ -1108,7 +1108,7 @@ void CWallet::MarkConflicted(const uint256& hashBlock, int conflicting_height, c
         return;
 
     // Do not flush the wallet here for performance reasons
-    WalletBatch batch(*database, false);
+    WalletBatch batch(GetDatabase(), false);
 
     std::set<uint256> todo;
     std::set<uint256> done;
@@ -1446,13 +1446,13 @@ void CWallet::SetWalletFlag(uint64_t flags)
 {
     LOCK(cs_wallet);
     m_wallet_flags |= flags;
-    if (!WalletBatch(*database).WriteWalletFlags(m_wallet_flags))
+    if (!WalletBatch(GetDatabase()).WriteWalletFlags(m_wallet_flags))
         throw std::runtime_error(std::string(__func__) + ": writing wallet flags failed");
 }
 
 void CWallet::UnsetWalletFlag(uint64_t flag)
 {
-    WalletBatch batch(*database);
+    WalletBatch batch(GetDatabase());
     UnsetWalletFlagWithDB(batch, flag);
 }
 
@@ -1491,7 +1491,7 @@ bool CWallet::AddWalletFlags(uint64_t flags)
     LOCK(cs_wallet);
     // We should never be writing unknown non-tolerable wallet flags
     assert(((flags & KNOWN_WALLET_FLAGS) >> 32) == (flags >> 32));
-    if (!WalletBatch(*database).WriteWalletFlags(flags)) {
+    if (!WalletBatch(GetDatabase()).WriteWalletFlags(flags)) {
         throw std::runtime_error(std::string(__func__) + ": writing wallet flags failed");
     }
 
@@ -1582,7 +1582,7 @@ bool CWallet::ImportScriptPubKeys(const std::string& label, const std::set<CScri
         return false;
     }
     if (apply_label) {
-        WalletBatch batch(*database);
+        WalletBatch batch(GetDatabase());
         for (const CScript& script : script_pub_keys) {
             CTxDestination dest;
             ExtractDestination(script, dest);
@@ -3177,10 +3177,10 @@ DBErrors CWallet::LoadWallet(bool& fFirstRunRet)
     LOCK(cs_wallet);
 
     fFirstRunRet = false;
-    DBErrors nLoadWalletRet = WalletBatch(*database).LoadWallet(this);
+    DBErrors nLoadWalletRet = WalletBatch(GetDatabase()).LoadWallet(this);
     if (nLoadWalletRet == DBErrors::NEED_REWRITE)
     {
-        if (database->Rewrite("\x04pool"))
+        if (GetDatabase().Rewrite("\x04pool"))
         {
             for (const auto& spk_man_pair : m_spk_managers) {
                 spk_man_pair.second->RewriteDB();
@@ -3204,7 +3204,7 @@ DBErrors CWallet::LoadWallet(bool& fFirstRunRet)
 DBErrors CWallet::ZapSelectTx(std::vector<uint256>& vHashIn, std::vector<uint256>& vHashOut)
 {
     AssertLockHeld(cs_wallet);
-    DBErrors nZapSelectTxRet = WalletBatch(*database).ZapSelectTx(vHashIn, vHashOut);
+    DBErrors nZapSelectTxRet = WalletBatch(GetDatabase()).ZapSelectTx(vHashIn, vHashOut);
     for (const uint256& hash : vHashOut) {
         const auto& it = mapWallet.find(hash);
         wtxOrdered.erase(it->second.m_it_wtxOrdered);
@@ -3216,7 +3216,7 @@ DBErrors CWallet::ZapSelectTx(std::vector<uint256>& vHashIn, std::vector<uint256
 
     if (nZapSelectTxRet == DBErrors::NEED_REWRITE)
     {
-        if (database->Rewrite("\x04pool"))
+        if (GetDatabase().Rewrite("\x04pool"))
         {
             for (const auto& spk_man_pair : m_spk_managers) {
                 spk_man_pair.second->RewriteDB();
@@ -3254,14 +3254,14 @@ bool CWallet::SetAddressBookWithDB(WalletBatch& batch, const CTxDestination& add
 
 bool CWallet::SetAddressBook(const CTxDestination& address, const std::string& strName, const std::string& strPurpose)
 {
-    WalletBatch batch(*database);
+    WalletBatch batch(GetDatabase());
     return SetAddressBookWithDB(batch, address, strName, strPurpose);
 }
 
 bool CWallet::DelAddressBook(const CTxDestination& address)
 {
     bool is_mine;
-    WalletBatch batch(*database);
+    WalletBatch batch(GetDatabase());
     {
         LOCK(cs_wallet);
         // If we want to delete receiving addresses, we need to take care that DestData "used" (and possibly newer DestData) gets preserved (and the "deleted" address transformed into a change entry instead of actually being deleted)
@@ -4008,7 +4008,7 @@ std::shared_ptr<CWallet> CWallet::Create(interfaces::Chain& chain, const std::st
     int rescan_height = 0;
     if (!gArgs.GetBoolArg("-rescan", false))
     {
-        WalletBatch batch(*walletInstance->database);
+        WalletBatch batch(walletInstance->GetDatabase());
         CBlockLocator locator;
         if (batch.ReadBestBlock(locator)) {
             if (const Optional<int> fork_height = chain.findLocatorFork(locator)) {
@@ -4071,7 +4071,7 @@ std::shared_ptr<CWallet> CWallet::Create(interfaces::Chain& chain, const std::st
             }
         }
         walletInstance->chainStateFlushed(chain.getTipLocator());
-        walletInstance->database->IncrementUpdateCounter();
+        walletInstance->GetDatabase().IncrementUpdateCounter();
     }
 
     {
@@ -4149,7 +4149,7 @@ void CWallet::postInitProcess()
 
 bool CWallet::BackupWallet(const std::string& strDest) const
 {
-    return database->Backup(strDest);
+    return GetDatabase().Backup(strDest);
 }
 
 CKeyPool::CKeyPool()
@@ -4452,7 +4452,7 @@ void CWallet::SetupDescriptorScriptPubKeyMans()
 
 void CWallet::AddActiveScriptPubKeyMan(uint256 id, OutputType type, bool internal)
 {
-    WalletBatch batch(*database);
+    WalletBatch batch(GetDatabase());
     if (!batch.WriteActiveScriptPubKeyMan(static_cast<uint8_t>(type), id, internal)) {
         throw std::runtime_error(std::string(__func__) + ": writing active ScriptPubKeyMan id failed");
     }
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 69cf6b66a4..e6beb111fb 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -695,7 +695,7 @@ private:
     std::string m_name;
 
     /** Internal database handle. */
-    std::unique_ptr<WalletDatabase> database;
+    std::unique_ptr<WalletDatabase> const m_database;
 
     /**
      * The following is used to keep track of how far behind the wallet is
@@ -729,14 +729,11 @@ public:
      */
     mutable RecursiveMutex cs_wallet;
 
-    /** Get database handle used by this wallet. Ideally this function would
-     * not be necessary.
-     */
-    WalletDatabase& GetDBHandle()
+    WalletDatabase& GetDatabase() const override
     {
-        return *database;
+        assert(static_cast<bool>(m_database));
+        return *m_database;
     }
-    WalletDatabase& GetDatabase() const override { return *database; }
 
     /**
      * Select a set of coins such that nValueRet >= nTargetValue and at least
@@ -758,7 +755,7 @@ public:
     CWallet(interfaces::Chain* chain, const std::string& name, std::unique_ptr<WalletDatabase> database)
         : m_chain(chain),
           m_name(name),
-          database(std::move(database))
+          m_database(std::move(database))
     {
     }
 
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index 45807ae6fd..c0521d3386 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -945,7 +945,7 @@ void MaybeCompactWalletDB()
     }
 
     for (const std::shared_ptr<CWallet>& pwallet : GetWallets()) {
-        WalletDatabase& dbh = pwallet->GetDBHandle();
+        WalletDatabase& dbh = pwallet->GetDatabase();
 
         unsigned int nUpdateCounter = dbh.nUpdateCounter;