Add an interface to get the queue depth out of CValidationInterface

src/scheduler.cpp

@@ -186,3 +186,8 @@ void SingleThreadedSchedulerClient::EmptyQueue() {
         should_continue = !m_callbacks_pending.empty();
     }
 }
+
+size_t SingleThreadedSchedulerClient::CallbacksPending() {
+    LOCK(m_cs_callbacks_pending);
+    return m_callbacks_pending.size();
+}

src/scheduler.h

@@ -109,6 +109,8 @@ class SingleThreadedSchedulerClient {
     // Processes all remaining queue members on the calling thread, blocking until queue is empty
     // Must be called after the CScheduler has no remaining processing threads!
     void EmptyQueue();
+
+    size_t CallbacksPending();
 };
 
 #endif

src/validationinterface.cpp

@@ -72,6 +72,11 @@ void CMainSignals::FlushBackgroundCallbacks() {
     }
 }
 
+size_t CMainSignals::CallbacksPending() {
+    if (!m_internals) return 0;
+    return m_internals->m_schedulerClient.CallbacksPending();
+}
+
 void CMainSignals::RegisterWithMempoolSignals(CTxMemPool& pool) {
     pool.NotifyEntryRemoved.connect(std::bind(&CMainSignals::MempoolEntryRemoved, this, std::placeholders::_1, std::placeholders::_2));
 }

src/validationinterface.h

@@ -118,6 +118,8 @@ class CMainSignals {
     /** Call any remaining callbacks on the calling thread */
     void FlushBackgroundCallbacks();
 
+    size_t CallbacksPending();
+
     /** Register with mempool to call TransactionRemovedFromMempool callbacks */
     void RegisterWithMempoolSignals(CTxMemPool& pool);
     /** Unregister with mempool */