Merge bitcoin#15225: GUI: Change the receive button to respond to keypool state changing

2bc4c3e Notify the GUI that the keypool has changed to set the receive button (Andrew Chow)
14bcdbe Check for more than private keys disabled to show receive button (Andrew Chow)

Pull request description:

  Currently the Receive button in the GUI is displayed enabled or disabled by the initial state of the wallet when the wallet is first loaded. The button is only enabled or disabled depending on whether the disable private keys flag is set when the wallet is loaded. However, future changes to the wallet means that this initial state and check may no longer be accurate. bitcoin#14938 introduces empty wallets which do not have private keys. An empty wallet that is loaded should have the Receive button disabled, and then it should become enabled once `sethdseed` is used so that a keypool can be generated and new keys generated. Likewise, with bitcoin#14075, a wallet can be loaded with no keypool initially, so the button should be disabled. Later, public keys can be imported into the keypool, at which time the button should become enabled. When the keypool runs out again (no new keys are generated as the keypool only consists of imports), the button should become disabled.

  This PR makes it so that the button becomes enabled and disabled as the keypool state changes. The check for whether to enable or disable the receive button has changed to checking whether it is possible to get new keys. It now checks for whether the wallet has an HD seed and, if not, whether the private keys are disabled. When an action happens which would make it possible for a new address to be retrieved or make it possible for a no more addresses to be retrieved, a signal is emitted which has the GUI recheck the conditions for the Receive button. These actions are setting a new HD seed, topping up the keypool, retrieving a key from the keypool, and returning a key to the keypool.

Tree-SHA512: eff15a5337f4c64ecd7169414fb47053c04f6a0f0130341b6dd9799ac4d79f451e25284701c668971fca33f0909d5352a474a2c12349375bedfdb59b63077d50

Author: laanwj

src/interfaces/wallet.cpp

@@ -541,6 +541,10 @@ class WalletImpl : public Wallet
     {
         return MakeHandler(m_wallet.NotifyWatchonlyChanged.connect(fn));
     }
+    std::unique_ptr<Handler> handleCanGetAddressesChanged(CanGetAddressesChangedFn fn) override
+    {
+        return MakeHandler(m_wallet.NotifyCanGetAddressesChanged.connect(fn));
+    }
 
     std::shared_ptr<CWallet> m_shared_wallet;
     CWallet& m_wallet;

src/interfaces/wallet.h

@@ -300,6 +300,10 @@ class Wallet
     //! Register handler for watchonly changed messages.
     using WatchOnlyChangedFn = std::function<void(bool have_watch_only)>;
     virtual std::unique_ptr<Handler> handleWatchOnlyChanged(WatchOnlyChangedFn fn) = 0;
+
+    //! Register handler for keypool changed messages.
+    using CanGetAddressesChangedFn = std::function<void()>;
+    virtual std::unique_ptr<Handler> handleCanGetAddressesChanged(CanGetAddressesChangedFn fn) = 0;
 };
 
 //! Tracking object returned by CreateTransaction and passed to CommitTransaction.

src/qt/receivecoinsdialog.cpp

@@ -87,8 +87,13 @@ void ReceiveCoinsDialog::setModel(WalletModel *_model)
         // Last 2 columns are set by the columnResizingFixer, when the table geometry is ready.
         columnResizingFixer = new GUIUtil::TableViewLastColumnResizingFixer(tableView, AMOUNT_MINIMUM_COLUMN_WIDTH, DATE_COLUMN_WIDTH, this);
 
-        // eventually disable the main receive button if private key operations are disabled
-        ui->receiveButton->setEnabled(!model->privateKeysDisabled());
+        // Set the button to be enabled or disabled based on whether the wallet can give out new addresses.
+        ui->receiveButton->setEnabled(model->canGetAddresses());
+
+        // Enable/disable the receive button if the wallet is now able/unable to give out new addresses.
+        connect(model, &WalletModel::canGetAddressesChanged, [this] {
+            ui->receiveButton->setEnabled(model->canGetAddresses());
+        });
     }
 }
 

src/qt/walletmodel.cpp

@@ -487,6 +487,11 @@ static void NotifyWatchonlyChanged(WalletModel *walletmodel, bool fHaveWatchonly
                               Q_ARG(bool, fHaveWatchonly));
 }
 
+static void NotifyCanGetAddressesChanged(WalletModel* walletmodel)
+{
+    QMetaObject::invokeMethod(walletmodel, "canGetAddressesChanged");
+}
+
 void WalletModel::subscribeToCoreSignals()
 {
     // Connect signals to wallet
@@ -498,6 +503,7 @@ void WalletModel::subscribeToCoreSignals()
     m_handler_chainlock_received = m_wallet->handleChainLockReceived(std::bind(NotifyChainLockReceived, this, std::placeholders::_1));
     m_handler_show_progress = m_wallet->handleShowProgress(std::bind(ShowProgress, this, std::placeholders::_1, std::placeholders::_2));
     m_handler_watch_only_changed = m_wallet->handleWatchOnlyChanged(std::bind(NotifyWatchonlyChanged, this, std::placeholders::_1));
+    m_handler_can_get_addrs_changed = m_wallet->handleCanGetAddressesChanged(boost::bind(NotifyCanGetAddressesChanged, this));
 }
 
 void WalletModel::unsubscribeFromCoreSignals()
@@ -511,6 +517,7 @@ void WalletModel::unsubscribeFromCoreSignals()
     m_handler_chainlock_received->disconnect();
     m_handler_show_progress->disconnect();
     m_handler_watch_only_changed->disconnect();
+    m_handler_can_get_addrs_changed->disconnect();
 }
 
 // WalletModel::UnlockContext implementation
@@ -597,6 +604,16 @@ bool WalletModel::privateKeysDisabled() const
     return m_wallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
 }
 
+bool WalletModel::canGetAddresses() const
+{
+    // The wallet can provide a fresh address if:
+    // * hdEnabled(): an HD seed is present; or
+    // * it is a legacy wallet, because:
+    //     * !hdEnabled(): an HD seed is not present; and
+    //     * !IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS): private keys have not been disabled (which results in hdEnabled() == true)
+    return m_wallet->hdEnabled() || (!m_wallet->hdEnabled() && !m_wallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS));
+}
+
 QString WalletModel::getWalletName() const
 {
     return QString::fromStdString(m_wallet->getWalletName());

src/qt/walletmodel.h

@@ -196,6 +196,7 @@ class WalletModel : public QObject
 
     static bool isWalletEnabled();
     bool privateKeysDisabled() const;
+    bool canGetAddresses() const;
 
     int getNumBlocks() const;
     int getNumISLocks() const;
@@ -223,6 +224,7 @@ class WalletModel : public QObject
     std::unique_ptr<interfaces::Handler> m_handler_chainlock_received;
     std::unique_ptr<interfaces::Handler> m_handler_show_progress;
     std::unique_ptr<interfaces::Handler> m_handler_watch_only_changed;
+    std::unique_ptr<interfaces::Handler> m_handler_can_get_addrs_changed;
     interfaces::Node& m_node;
 
     bool fHaveWatchOnly;
@@ -276,6 +278,9 @@ class WalletModel : public QObject
     // Signal that wallet is about to be removed
     void unload();
 
+    // Notify that there are now keys in the keypool
+    void canGetAddressesChanged();
+
 public Q_SLOTS:
     /* Wallet status might have changed */
     void updateStatus();

src/wallet/wallet.cpp

@@ -4345,6 +4345,7 @@ bool CWallet::TopUpKeyPool(unsigned int kpSize)
             uiInterface.InitMessage(strMsg);
         }
     }
+    NotifyCanGetAddressesChanged();
     return true;
 }
 
@@ -4386,6 +4387,7 @@ bool CWallet::ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool fRe
         m_pool_key_to_index.erase(keypool.vchPubKey.GetID());
         WalletLogPrintf("keypool reserve %d\n", nIndex);
     }
+    NotifyCanGetAddressesChanged();
     return true;
 }
 
@@ -4414,6 +4416,7 @@ void CWallet::ReturnKey(int64_t nIndex, bool fInternal, const CPubKey& pubkey)
             setExternalKeyPool.insert(nIndex);
         }
         m_pool_key_to_index[pubkey.GetID()] = nIndex;
+        NotifyCanGetAddressesChanged();
     }
     WalletLogPrintf("keypool return %d\n", nIndex);
 }

src/wallet/wallet.h

@@ -1235,6 +1235,9 @@ class CWallet final : public CCryptoKeyStore, public CValidationInterface
     /** Watch-only address added */
     boost::signals2::signal<void (bool fHaveWatchOnly)> NotifyWatchonlyChanged;
 
+    /** Keypool has new keys */
+    boost::signals2::signal<void ()> NotifyCanGetAddressesChanged;
+
     /** IS-lock received */
     boost::signals2::signal<void ()> NotifyISLockReceived;