Merge #16237: Have the wallet give out destinations instead of keys

8e7f930828a9f8f9be1c90ff45e3fdfef1980eaf Add GetNewChangeDestination for getting new change Destinations (Andrew Chow)
33d13edd2bda0af90660e275ea4fa96ca9896f2a Replace CReserveKey with ReserveDestinatoin (Andrew Chow)
172213be5b174243dc501c1103ad5fe2fee67a16 Add GetNewDestination to CWallet to fetch new destinations (Andrew Chow)

Pull request description:

  The wallet should give out destinations instead of keys. It should be the one that handles the conversion from key to destination and the setting of the label, not the caller. In order to do this, two new member functions are introduced `GetNewDestination()` and `GetNewChangeDestination()`. Additionally, `CReserveKey` is changed to be `ReserveDestination` and represents destinations whose keys can be returned to the keypool.

ACKs for top commit:
  instagibbs:
    re-utACK https://github.com/bitcoin/bitcoin/pull/16237/commits/8e7f930828a9f8f9be1c90ff45e3fdfef1980eaf
  sipa:
    ACK 8e7f930828a9f8f9be1c90ff45e3fdfef1980eaf. Concept ACK as this gives a much cleaner abstraction to work with, and light code review ACK.
  laanwj:
    ACK 8e7f930828a9f8f9be1c90ff45e3fdfef1980eaf

Tree-SHA512: 5be7051409232b71e0ef2c1fd1a3e76964ed2f5b14d47d06edc2ad3b3687abd0be2803a1adc45c0433aa2c3bed172e14f8a7e9f4a23bff70f86260b5a0497500

2 files changed, 10 insertions, 14 deletions

diff --git a/src/qt/addresstablemodel.cpp b/src/qt/addresstablemodel.cpp
index fa6c9c9f7a..29423db3d0 100644
--- a/src/qt/addresstablemodel.cpp
+++ b/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);
 }
 
diff --git a/src/qt/paymentserver.cpp b/src/qt/paymentserver.cpp
index c99515fe1c..f3f5d28af9 100644
--- a/src/qt/paymentserver.cpp
+++ b/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");