let validationinterface take shared_ptr

Fuzzbawls · Apr 7, 2024 · b01c3df · b01c3df
1 parent db78a7e
commit b01c3df
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Showing 2 changed files with 25 additions and 5 deletions.
diff --git a/src/validationinterface.cpp b/src/validationinterface.cpp
@@ -93,10 +93,11 @@ CMainSignals& GetMainSignals()
 {
     return g_signals;
 }
-
-void RegisterValidationInterface(CValidationInterface* pwalletIn)
+void RegisterSharedValidationInterface(std::shared_ptr<CValidationInterface> pwalletIn)
 {
-    ValidationInterfaceConnections& conns = g_signals.m_internals->m_connMainSignals[pwalletIn];
+    // Each connection captures pwalletIn to ensure that each callback is
+    // executed before pwalletIn is destroyed. For more details see bitcoin #18338
+    ValidationInterfaceConnections& conns = g_signals.m_internals->m_connMainSignals[pwalletIn.get()];
     conns.AcceptedBlockHeader = g_signals.m_internals->AcceptedBlockHeader.connect(std::bind(&CValidationInterface::AcceptedBlockHeader, pwalletIn, std::placeholders::_1));
     conns.UpdatedBlockTip = g_signals.m_internals->UpdatedBlockTip.connect(std::bind(&CValidationInterface::UpdatedBlockTip, pwalletIn, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));
     conns.TransactionAddedToMempool = g_signals.m_internals->TransactionAddedToMempool.connect(std::bind(&CValidationInterface::TransactionAddedToMempool, pwalletIn, std::placeholders::_1));
@@ -108,6 +109,12 @@ void RegisterValidationInterface(CValidationInterface* pwalletIn)
     conns.BlockChecked = g_signals.m_internals->BlockChecked.connect(std::bind(&CValidationInterface::BlockChecked, pwalletIn, std::placeholders::_1, std::placeholders::_2));
     conns.NotifyMasternodeListChanged = g_signals.m_internals->NotifyMasternodeListChanged.connect(std::bind(&CValidationInterface::NotifyMasternodeListChanged, pwalletIn, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3));
 }
+void RegisterValidationInterface(CValidationInterface* pwalletIn)
+{
+    // Create a shared_ptr with a no-op deleter - CValidationInterface lifecycle
+    // is managed by the caller.
+    RegisterSharedValidationInterface({pwalletIn, [](CValidationInterface*) {}});
+}
 
 void UnregisterValidationInterface(CValidationInterface* pwalletIn)
 {
@@ -116,6 +123,11 @@ void UnregisterValidationInterface(CValidationInterface* pwalletIn)
     }
 }
 
+void UnregisterSharedValidationInterface(std::shared_ptr<CValidationInterface> pwalletIn)
+{
+    UnregisterValidationInterface(pwalletIn.get());
+}
+
 void UnregisterAllValidationInterfaces()
 {
     if (!g_signals.m_internals) {

diff --git a/src/validationinterface.h b/src/validationinterface.h
@@ -34,6 +34,14 @@ void RegisterValidationInterface(CValidationInterface* pwalletIn);
 void UnregisterValidationInterface(CValidationInterface* pwalletIn);
 /** Unregister all wallets from core */
 void UnregisterAllValidationInterfaces();
+
+// Alternate registration functions that release a shared_ptr after the last
+// notification is sent. These are useful for race-free cleanup, since
+// unregistration is nonblocking and can return before the last notification is
+// processed.
+void RegisterSharedValidationInterface(std::shared_ptr<CValidationInterface> pwalletIn);
+void UnregisterSharedValidationInterface(std::shared_ptr<CValidationInterface> pwalletIn);
+
 /**
  * Pushes a function to callback onto the notification queue, guaranteeing any
  * callbacks generated prior to now are finished when the function is called.
@@ -147,7 +155,7 @@ class CValidationInterface {
     /** Tells listeners to broadcast their data. */
     virtual void ResendWalletTransactions(CConnman* connman) {}
     virtual void BlockChecked(const CBlock&, const CValidationState&) {}
-    friend void ::RegisterValidationInterface(CValidationInterface*);
+    friend void ::RegisterSharedValidationInterface(std::shared_ptr<CValidationInterface>);
     friend void ::UnregisterValidationInterface(CValidationInterface*);
     friend void ::UnregisterAllValidationInterfaces();
     /** Notifies listeners of updated deterministic masternode list */
@@ -159,7 +167,7 @@ class CMainSignals {
 private:
     std::unique_ptr<MainSignalsInstance> m_internals;
 
-    friend void ::RegisterValidationInterface(CValidationInterface*);
+    friend void ::RegisterSharedValidationInterface(std::shared_ptr<CValidationInterface>);
     friend void ::UnregisterValidationInterface(CValidationInterface*);
     friend void ::UnregisterAllValidationInterfaces();
     friend void ::CallFunctionInValidationInterfaceQueue(std::function<void ()> func);