Add GetNewDestination to CWallet to fetch new destinations

Instead of having the same multiple lines of code everywhere
that new destinations are fetched, introduce GetNewDestination as
a member function of CWallet which does the key fetching, label
setting, script generation, and destination generation.

src/interfaces/wallet.cpp

@@ -140,9 +140,11 @@ public:
     void abortRescan() override { m_wallet->AbortRescan(); }
     bool backupWallet(const std::string& filename) override { return m_wallet->BackupWallet(filename); }
     std::string getWalletName() override { return m_wallet->GetName(); }
-    bool getKeyFromPool(bool internal, CPubKey& pub_key) override
+    bool getNewDestination(const OutputType type, const std::string label, CTxDestination& dest) override
     {
-        return m_wallet->GetKeyFromPool(pub_key, internal);
+        LOCK(m_wallet->cs_wallet);
+        std::string error;
+        return m_wallet->GetNewDestination(type, label, dest, error);
     }
     bool getPubKey(const CKeyID& address, CPubKey& pub_key) override { return m_wallet->GetPubKey(address, pub_key); }
     bool getPrivKey(const CKeyID& address, CKey& key) override { return m_wallet->GetKey(address, key); }

src/interfaces/wallet.h

@@ -76,8 +76,8 @@ public:
     //! Get wallet name.
     virtual std::string getWalletName() = 0;
 
-    // Get key from pool.
-    virtual bool getKeyFromPool(bool internal, CPubKey& pub_key) = 0;
+    // Get a new address.
+    virtual bool getNewDestination(const OutputType type, const std::string label, CTxDestination& dest) = 0;
 
     //! Get public key.
     virtual bool getPubKey(const CKeyID& address, CPubKey& pub_key) = 0;

src/qt/addresstablemodel.cpp

@@ -358,12 +358,15 @@ QString AddressTableModel::addRow(const QString &type, const QString &label, con
                 return QString();
             }
         }
+
+        // Add entry
+        walletModel->wallet().setAddressBook(DecodeDestination(strAddress), strLabel, "send");
     }
     else if(type == Receive)
     {
         // Generate a new address to associate with given label
-        CPubKey newKey;
-        if(!walletModel->wallet().getKeyFromPool(false /* internal */, newKey))
+        CTxDestination dest;
+        if(!walletModel->wallet().getNewDestination(address_type, strLabel, dest))
         {
             WalletModel::UnlockContext ctx(walletModel->requestUnlock());
             if(!ctx.isValid())
@@ -372,23 +375,18 @@ QString AddressTableModel::addRow(const QString &type, const QString &label, con
                 editStatus = WALLET_UNLOCK_FAILURE;
                 return QString();
             }
-            if(!walletModel->wallet().getKeyFromPool(false /* internal */, newKey))
+            if(!walletModel->wallet().getNewDestination(address_type, strLabel, dest))
             {
                 editStatus = KEY_GENERATION_FAILURE;
                 return QString();
             }
         }
-        walletModel->wallet().learnRelatedScripts(newKey, address_type);
-        strAddress = EncodeDestination(GetDestinationForKey(newKey, address_type));
+        strAddress = EncodeDestination(dest);
     }
     else
     {
         return QString();
     }
-
-    // Add entry
-    walletModel->wallet().setAddressBook(DecodeDestination(strAddress), strLabel,
-                           (type == Send ? "send" : "receive"));
     return QString::fromStdString(strAddress);
 }
 

src/qt/paymentserver.cpp

@@ -666,16 +666,14 @@ void PaymentServer::fetchPaymentACK(WalletModel* walletModel, const SendCoinsRec
     payment.add_transactions(transaction.data(), transaction.size());
 
     // Create a new refund address, or re-use:
-    CPubKey newKey;
-    if (walletModel->wallet().getKeyFromPool(false /* internal */, newKey)) {
+    CTxDestination dest;
+    const OutputType change_type = walletModel->wallet().getDefaultChangeType() != OutputType::CHANGE_AUTO ? walletModel->wallet().getDefaultChangeType() : walletModel->wallet().getDefaultAddressType();
+    if (walletModel->wallet().getNewDestination(change_type, "", dest)) {
         // BIP70 requests encode the scriptPubKey directly, so we are not restricted to address
         // types supported by the receiver. As a result, we choose the address format we also
         // use for change. Despite an actual payment and not change, this is a close match:
         // it's the output type we use subject to privacy issues, but not restricted by what
         // other software supports.
-        const OutputType change_type = walletModel->wallet().getDefaultChangeType() != OutputType::CHANGE_AUTO ? walletModel->wallet().getDefaultChangeType() : walletModel->wallet().getDefaultAddressType();
-        walletModel->wallet().learnRelatedScripts(newKey, change_type);
-        CTxDestination dest = GetDestinationForKey(newKey, change_type);
         std::string label = tr("Refund from %1").arg(recipient.authenticatedMerchant).toStdString();
         walletModel->wallet().setAddressBook(dest, label, "refund");
 

src/test/util.cpp

@@ -25,14 +25,9 @@ const std::string ADDRESS_BCRT1_UNSPENDABLE = "bcrt1qqqqqqqqqqqqqqqqqqqqqqqqqqqq
 std::string getnewaddress(CWallet& w)
 {
     constexpr auto output_type = OutputType::BECH32;
-
-    CPubKey new_key;
-    if (!w.GetKeyFromPool(new_key)) assert(false);
-
-    w.LearnRelatedScripts(new_key, output_type);
-    const auto dest = GetDestinationForKey(new_key, output_type);
-
-    w.SetAddressBook(dest, /* label */ "", "receive");
+    CTxDestination dest;
+    std::string error;
+    if (!w.GetNewDestination(output_type, "", dest, error)) assert(false);
 
     return EncodeDestination(dest);
 }

src/wallet/rpcwallet.cpp

@@ -185,20 +185,12 @@ static UniValue getnewaddress(const JSONRPCRequest& request)
         }
     }
 
-    if (!pwallet->IsLocked()) {
-        pwallet->TopUpKeyPool();
+    CTxDestination dest;
+    std::string error;
+    if (!pwallet->GetNewDestination(output_type, label, dest, error)) {
+        throw JSONRPCError(RPC_WALLET_KEYPOOL_RAN_OUT, error);
     }
 
-    // Generate a new key that is added to wallet
-    CPubKey newKey;
-    if (!pwallet->GetKeyFromPool(newKey)) {
-        throw JSONRPCError(RPC_WALLET_KEYPOOL_RAN_OUT, "Error: Keypool ran out, please call keypoolrefill first");
-    }
-    pwallet->LearnRelatedScripts(newKey, output_type);
-    CTxDestination dest = GetDestinationForKey(newKey, output_type);
-
-    pwallet->SetAddressBook(dest, label, "receive");
-
     return EncodeDestination(dest);
 }
 

src/wallet/test/wallet_tests.cpp

@@ -466,8 +466,9 @@ BOOST_FIXTURE_TEST_CASE(wallet_disableprivkeys, TestChain100Setup)
     wallet->SetMinVersion(FEATURE_LATEST);
     wallet->SetWalletFlag(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
     BOOST_CHECK(!wallet->TopUpKeyPool(1000));
-    CPubKey pubkey;
-    BOOST_CHECK(!wallet->GetKeyFromPool(pubkey, false));
+    CTxDestination dest;
+    std::string error;
+    BOOST_CHECK(!wallet->GetNewDestination(OutputType::BECH32, "", dest, error));
 }
 
 // Explicit calculation which is used to test the wallet constant

src/wallet/wallet.cpp

@@ -3513,6 +3513,27 @@ bool CWallet::GetKeyFromPool(CPubKey& result, bool internal)
     return true;
 }
 
+bool CWallet::GetNewDestination(const OutputType type, const std::string label, CTxDestination& dest, std::string& error)
+{
+    LOCK(cs_wallet);
+    error.clear();
+    if (!IsLocked()) {
+        TopUpKeyPool();
+    }
+
+    // Generate a new key that is added to wallet
+    CPubKey new_key;
+    if (!GetKeyFromPool(new_key)) {
+        error = "Error: Keypool ran out, please call keypoolrefill first";
+        return false;
+    }
+    LearnRelatedScripts(new_key, type);
+    dest = GetDestinationForKey(new_key, type);
+
+    SetAddressBook(dest, label, "receive");
+    return true;
+}
+
 static int64_t GetOldestKeyTimeInPool(const std::set<int64_t>& setKeyPool, WalletBatch& batch) {
     if (setKeyPool.empty()) {
         return GetTime();

src/wallet/wallet.h

@@ -815,6 +815,9 @@ private:
      */
     uint256 m_last_block_processed GUARDED_BY(cs_wallet);
 
+    //! Fetches a key from the keypool
+    bool GetKeyFromPool(CPubKey &key, bool internal = false);
+
 public:
     /*
      * Main wallet lock.
@@ -1110,7 +1113,6 @@ public:
     bool ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool fRequestedInternal);
     void KeepKey(int64_t nIndex);
     void ReturnKey(int64_t nIndex, bool fInternal, const CPubKey& pubkey);
-    bool GetKeyFromPool(CPubKey &key, bool internal = false);
     int64_t GetOldestKeyPoolTime();
     /**
      * Marks all keys in the keypool up to and including reserve_key as used.
@@ -1123,6 +1125,8 @@ public:
 
     std::set<CTxDestination> GetLabelAddresses(const std::string& label) const;
 
+    bool GetNewDestination(const OutputType type, const std::string label, CTxDestination& dest, std::string& error);
+
     isminetype IsMine(const CTxIn& txin) const;
     /**
      * Returns amount of debit if the input matches the