wallet: enable avoid_reuse feature

3 files changed, 65 insertions, 14 deletions

diff --git a/src/script/ismine.h b/src/script/ismine.h
index 55e28e225a..da3da7e324 100644
--- a/src/script/ismine.h
+++ b/src/script/ismine.h
@@ -20,7 +20,9 @@ enum isminetype
     ISMINE_NO         = 0,
     ISMINE_WATCH_ONLY = 1 << 0,
     ISMINE_SPENDABLE  = 1 << 1,
+    ISMINE_USED       = 1 << 2,
     ISMINE_ALL        = ISMINE_WATCH_ONLY | ISMINE_SPENDABLE,
+    ISMINE_ALL_USED   = ISMINE_ALL | ISMINE_USED,
     ISMINE_ENUM_ELEMENTS,
 };
 /** used for bitflags of isminetype */
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 2c51b6a8ba..6ac1a42bf5 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -945,6 +945,37 @@ bool CWallet::MarkReplaced(const uint256& originalHash, const uint256& newHash)
     return success;
 }
 
+void CWallet::SetUsedDestinationState(const uint256& hash, unsigned int n, bool used)
+{
+    const CWalletTx* srctx = GetWalletTx(hash);
+    if (!srctx) return;
+
+    CTxDestination dst;
+    if (ExtractDestination(srctx->tx->vout[n].scriptPubKey, dst)) {
+        if (::IsMine(*this, dst)) {
+            LOCK(cs_wallet);
+            if (used && !GetDestData(dst, "used", nullptr)) {
+                AddDestData(dst, "used", "p"); // p for "present", opposite of absent (null)
+            } else if (!used && GetDestData(dst, "used", nullptr)) {
+                EraseDestData(dst, "used");
+            }
+        }
+    }
+}
+
+bool CWallet::IsUsedDestination(const CTxDestination& dst) const
+{
+    LOCK(cs_wallet);
+    return ::IsMine(*this, dst) && GetDestData(dst, "used", nullptr);
+}
+
+bool CWallet::IsUsedDestination(const uint256& hash, unsigned int n) const
+{
+    CTxDestination dst;
+    const CWalletTx* srctx = GetWalletTx(hash);
+    return srctx && ExtractDestination(srctx->tx->vout[n].scriptPubKey, dst) && IsUsedDestination(dst);
+}
+
 bool CWallet::AddToWallet(const CWalletTx& wtxIn, bool fFlushOnClose)
 {
     LOCK(cs_wallet);
@@ -953,6 +984,14 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn, bool fFlushOnClose)
 
     uint256 hash = wtxIn.GetHash();
 
+    if (IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE)) {
+        // Mark used destinations
+        for (const CTxIn& txin : wtxIn.tx->vin) {
+            const COutPoint& op = txin.prevout;
+            SetUsedDestinationState(op.hash, op.n, true);
+        }
+    }
+
     // Inserts only if not already there, returns tx inserted or tx found
     std::pair<std::map<uint256, CWalletTx>::iterator, bool> ret = mapWallet.insert(std::make_pair(hash, wtxIn));
     CWalletTx& wtx = (*ret.first).second;
@@ -2072,7 +2111,7 @@ CAmount CWalletTx::GetAvailableCredit(interfaces::Chain::Lock& locked_chain, boo
         return 0;
 
     // Avoid caching ismine for NO or ALL cases (could remove this check and simplify in the future).
-    bool allow_cache = filter == ISMINE_SPENDABLE || filter == ISMINE_WATCH_ONLY;
+    bool allow_cache = (filter & ISMINE_ALL) && (filter & ISMINE_ALL) != ISMINE_ALL;
 
     // Must wait until coinbase is safely deep enough in the chain before valuing it
     if (IsImmatureCoinBase(locked_chain))
@@ -2082,12 +2121,12 @@ CAmount CWalletTx::GetAvailableCredit(interfaces::Chain::Lock& locked_chain, boo
         return m_amounts[AVAILABLE_CREDIT].m_value[filter];
     }
 
+    bool allow_used_addresses = (filter & ISMINE_USED) || !pwallet->IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE);
     CAmount nCredit = 0;
     uint256 hashTx = GetHash();
     for (unsigned int i = 0; i < tx->vout.size(); i++)
     {
-        if (!pwallet->IsSpent(locked_chain, hashTx, i))
-        {
+        if (!pwallet->IsSpent(locked_chain, hashTx, i) && (allow_used_addresses || !pwallet->IsUsedDestination(hashTx, i))) {
             const CTxOut &txout = tx->vout[i];
             nCredit += pwallet->GetCredit(txout, filter);
             if (!MoneyRange(nCredit))
@@ -2229,9 +2268,10 @@ void MaybeResendWalletTxs()
  */
 
 
-CWallet::Balance CWallet::GetBalance(const int min_depth) const
+CWallet::Balance CWallet::GetBalance(const int min_depth, bool avoid_reuse) const
 {
     Balance ret;
+    isminefilter reuse_filter = avoid_reuse ? 0 : ISMINE_USED;
     {
         auto locked_chain = chain().lock();
         LOCK(cs_wallet);
@@ -2240,8 +2280,8 @@ CWallet::Balance CWallet::GetBalance(const int min_depth) const
             const CWalletTx& wtx = entry.second;
             const bool is_trusted{wtx.IsTrusted(*locked_chain)};
             const int tx_depth{wtx.GetDepthInMainChain(*locked_chain)};
-            const CAmount tx_credit_mine{wtx.GetAvailableCredit(*locked_chain, /* fUseCache */ true, ISMINE_SPENDABLE)};
-            const CAmount tx_credit_watchonly{wtx.GetAvailableCredit(*locked_chain, /* fUseCache */ true, ISMINE_WATCH_ONLY)};
+            const CAmount tx_credit_mine{wtx.GetAvailableCredit(*locked_chain, /* fUseCache */ true, ISMINE_SPENDABLE | reuse_filter)};
+            const CAmount tx_credit_watchonly{wtx.GetAvailableCredit(*locked_chain, /* fUseCache */ true, ISMINE_WATCH_ONLY | reuse_filter)};
             if (is_trusted && tx_depth >= min_depth) {
                 ret.m_mine_trusted += tx_credit_mine;
                 ret.m_watchonly_trusted += tx_credit_watchonly;
@@ -2279,6 +2319,9 @@ void CWallet::AvailableCoins(interfaces::Chain::Lock& locked_chain, std::vector<
 
     vCoins.clear();
     CAmount nTotal = 0;
+    // Either the WALLET_FLAG_AVOID_REUSE flag is not set (in which case we always allow), or we default to avoiding, and only in the case where
+    // a coin control object is provided, and has the avoid address reuse flag set to false, do we allow already used addresses
+    bool allow_used_addresses = !IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE) || (coinControl && !coinControl->m_avoid_address_reuse);
 
     for (const auto& entry : mapWallet)
     {
@@ -2360,6 +2403,10 @@ void CWallet::AvailableCoins(interfaces::Chain::Lock& locked_chain, std::vector<
                 continue;
             }
 
+            if (!allow_used_addresses && IsUsedDestination(wtxid, i)) {
+                continue;
+            }
+
             bool solvable = IsSolvable(*this, wtx.tx->vout[i].scriptPubKey);
             bool spendable = ((mine & ISMINE_SPENDABLE) != ISMINE_NO) || (((mine & ISMINE_WATCH_ONLY) != ISMINE_NO) && (coinControl && coinControl->fAllowWatchOnly && solvable));
 
@@ -4150,16 +4197,12 @@ std::shared_ptr<CWallet> CWallet::CreateWalletFromFile(interfaces::Chain& chain,
         // ensure this wallet.dat can only be opened by clients supporting HD with chain split and expects no default key
         walletInstance->SetMinVersion(FEATURE_LATEST);
 
-        if ((wallet_creation_flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
-            //selective allow to set flags
-            walletInstance->SetWalletFlag(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
-        } else if (wallet_creation_flags & WALLET_FLAG_BLANK_WALLET) {
-            walletInstance->SetWalletFlag(WALLET_FLAG_BLANK_WALLET);
-        } else {
+        walletInstance->SetWalletFlags(wallet_creation_flags, false);
+        if (!(wallet_creation_flags & (WALLET_FLAG_DISABLE_PRIVATE_KEYS | WALLET_FLAG_BLANK_WALLET))) {
             // generate a new seed
             CPubKey seed = walletInstance->GenerateNewSeed();
             walletInstance->SetHDSeed(seed);
-        } // Otherwise, do not generate a new seed
+        }
 
         // Top up the keypool
         if (walletInstance->CanGenerateKeys() && !walletInstance->TopUpKeyPool()) {
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 4ff347a596..311a5030cc 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -941,6 +941,12 @@ public:
         std::set<CInputCoin>& setCoinsRet, CAmount& nValueRet, const CoinSelectionParams& coin_selection_params, bool& bnb_used) const;
 
     bool IsSpent(interfaces::Chain::Lock& locked_chain, const uint256& hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+
+    // Whether this or any UTXO with the same CTxDestination has been spent.
+    bool IsUsedDestination(const CTxDestination& dst) const;
+    bool IsUsedDestination(const uint256& hash, unsigned int n) const;
+    void SetUsedDestinationState(const uint256& hash, unsigned int n, bool used);
+
     std::vector<OutputGroup> GroupOutputs(const std::vector<COutput>& outputs, bool single_coin) const;
 
     bool IsLockedCoin(uint256 hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
@@ -1053,7 +1059,7 @@ public:
         CAmount m_watchonly_untrusted_pending{0};
         CAmount m_watchonly_immature{0};
     };
-    Balance GetBalance(int min_depth = 0) const;
+    Balance GetBalance(int min_depth = 0, bool avoid_reuse = true) const;
     CAmount GetAvailableBalance(const CCoinControl* coinControl = nullptr) const;
 
     OutputType TransactionChangeType(OutputType change_type, const std::vector<CRecipient>& vecSend);