Merge #5737: backport: Merge bitcoin#18452, 19111, 19104

96ac317c27 Merge #19104: gui, refactor: Register Qt meta types in application constructor (Jonas Schnelli)
32f717c015 Merge #19111: Limit scope of all global std::once_flag (MarcoFalke)
7a6667f323 Merge #18452: qt: Fix shutdown when waitfor* cmds are called from RPC console (Jonas Schnelli)

Pull request description:

  ## Issue being fixed or feature implemented

  ## What was done?

  ## How Has This Been Tested?
  CI passing

  ## Breaking Changes
  None

  ## Checklist:
    _Go over all the following points, and put an `x` in all the boxes that apply._
  - [ ] I have performed a self-review of my own code
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have added or updated relevant unit/integration/functional/e2e tests
  - [ ] I have made corresponding changes to the documentation
  - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

Top commit has no ACKs.

Tree-SHA512: a1a9d18674b7c55549edd684211bb9de983a67876ed292d90ef3dccb126122af9b5d8c887608bbce74b7fa92c020a542d2ea1acdc693d85eba889aa8c56ac8df

src/node/interfaces.cpp

@@ -254,7 +254,15 @@ public:
         StartRestart();
         PrepareShutdown(*m_context);
     }
-    void startShutdown() override { StartShutdown(); }
+    void startShutdown() override
+    {
+        StartShutdown();
+        // Stop RPC for clean shutdown if any of waitfor* commands is executed.
+        if (gArgs.GetBoolArg("-server", false)) {
+            InterruptRPC();
+            StopRPC();
+        }
+    }
     bool shutdownRequested() override { return ShutdownRequested(); }
     void mapPort(bool use_upnp, bool use_natpmp) override { StartMapPort(use_upnp, use_natpmp); }
     bool getProxy(Network net, proxyType& proxy_info) override { return GetProxy(net, proxy_info); }

src/qt/bitcoin.cpp

@@ -74,6 +74,24 @@ Q_DECLARE_METATYPE(CAmount)
 Q_DECLARE_METATYPE(SynchronizationState)
 Q_DECLARE_METATYPE(uint256)
 
+static void RegisterMetaTypes()
+{
+    // Register meta types used for QMetaObject::invokeMethod and Qt::QueuedConnection
+    qRegisterMetaType<bool*>();
+    qRegisterMetaType<SynchronizationState>();
+  #ifdef ENABLE_WALLET
+    qRegisterMetaType<WalletModel*>();
+  #endif
+    // Register typedefs (see http://qt-project.org/doc/qt-5/qmetatype.html#qRegisterMetaType)
+    // IMPORTANT: if CAmount is no longer a typedef use the normal variant above (see https://doc.qt.io/qt-5/qmetatype.html#qRegisterMetaType-1)
+    qRegisterMetaType<CAmount>("CAmount");
+    qRegisterMetaType<size_t>("size_t");
+
+    qRegisterMetaType<std::function<void()>>("std::function<void()>");
+    qRegisterMetaType<QMessageBox::Icon>("QMessageBox::Icon");
+    qRegisterMetaType<interfaces::BlockAndHeaderTipInfo>("interfaces::BlockAndHeaderTipInfo");
+}
+
 static QString GetLangTerritory()
 {
     QSettings settings;
@@ -262,6 +280,7 @@ BitcoinApplication::BitcoinApplication():
     pollShutdownTimer(nullptr),
     returnValue(0)
 {
+    RegisterMetaTypes();
     // Qt runs setlocale(LC_ALL, "") on initialization.
     setQuitOnLastWindowClosed(false);
 }
@@ -543,21 +562,6 @@ int GuiMain(int argc, char* argv[])
 
     BitcoinApplication app;
 
-    // Register meta types used for QMetaObject::invokeMethod and Qt::QueuedConnection
-    qRegisterMetaType<bool*>();
-    qRegisterMetaType<SynchronizationState>();
-#ifdef ENABLE_WALLET
-    qRegisterMetaType<WalletModel*>();
-#endif
-    // Register typedefs (see http://qt-project.org/doc/qt-5/qmetatype.html#qRegisterMetaType)
-    // IMPORTANT: if CAmount is no longer a typedef use the normal variant above (see https://doc.qt.io/qt-5/qmetatype.html#qRegisterMetaType-1)
-    qRegisterMetaType<CAmount>("CAmount");
-    qRegisterMetaType<size_t>("size_t");
-
-    qRegisterMetaType<std::function<void()>>("std::function<void()>");
-    qRegisterMetaType<QMessageBox::Icon>("QMessageBox::Icon");
-    qRegisterMetaType<interfaces::BlockAndHeaderTipInfo>("interfaces::BlockAndHeaderTipInfo");
-
     /// 2. Parse command-line options. We do this after qt in order to show an error if there are problems parsing these
     // Command-line options take precedence:
     SetupServerArgs(node_context);

src/rpc/server.cpp

@@ -18,7 +18,9 @@
 
 #include <algorithm>
 #include <atomic>
+#include <cassert>
 #include <memory> // for unique_ptr
+#include <mutex>
 #include <unordered_map>
 
 static Mutex g_rpc_warmup_mutex;
@@ -325,17 +327,26 @@ void StartRPC()
 
 void InterruptRPC()
 {
-    LogPrint(BCLog::RPC, "Interrupting RPC\n");
-    // Interrupt e.g. running longpolls
-    g_rpc_running = false;
+    static std::once_flag g_rpc_interrupt_flag;
+    // This function could be called twice if the GUI has been started with -server=1.
+    std::call_once(g_rpc_interrupt_flag, []() {
+        LogPrint(BCLog::RPC, "Interrupting RPC\n");
+        // Interrupt e.g. running longpolls
+        g_rpc_running = false;
+    });
 }
 
 void StopRPC()
 {
-    LogPrint(BCLog::RPC, "Stopping RPC\n");
-    WITH_LOCK(g_deadline_timers_mutex, deadlineTimers.clear());
-    DeleteAuthCookie();
-    g_rpcSignals.Stopped();
+    static std::once_flag g_rpc_stop_flag;
+    // This function could be called twice if the GUI has been started with -server=1.
+    assert(!g_rpc_running);
+    std::call_once(g_rpc_stop_flag, []() {
+        LogPrint(BCLog::RPC, "Stopping RPC\n");
+        WITH_LOCK(g_deadline_timers_mutex, deadlineTimers.clear());
+        DeleteAuthCookie();
+        g_rpcSignals.Stopped();
+    });
 }
 
 bool IsRPCRunning()

src/support/lockedpool.cpp

@@ -29,7 +29,6 @@
 #endif
 
 LockedPoolManager* LockedPoolManager::_instance = nullptr;
-std::once_flag LockedPoolManager::init_flag;
 
 /*******************************************************************************/
 // Utilities

src/support/lockedpool.h

@@ -221,7 +221,8 @@ public:
     /** Return the current instance, or create it once */
     static LockedPoolManager& Instance()
     {
-        std::call_once(LockedPoolManager::init_flag, LockedPoolManager::CreateInstance);
+        static std::once_flag init_flag;
+        std::call_once(init_flag, LockedPoolManager::CreateInstance);
         return *LockedPoolManager::_instance;
     }
 
@@ -234,7 +235,6 @@ private:
     static bool LockingFailed();
 
     static LockedPoolManager* _instance;
-    static std::once_flag init_flag;
 };
 
 #endif // BITCOIN_SUPPORT_LOCKEDPOOL_H