[refactor] Make signals optional in mempool and chainman

This is done in preparation for the next two commits, where the
CMainSignals are de-globalized.

This avoids adding new constructor arguments to the ChainstateManager
and CTxMemPool classes over the next two commits.

This could also allow future tests that are only interested in the
internal behaviour of the classes to forgo instantiating the signals.

1 files changed, 36 insertions, 22 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index 0552bde665..b3a53a537d 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1224,13 +1224,14 @@ bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>&
         results.emplace(ws.m_ptx->GetWitnessHash(),
                         MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize,
                                          ws.m_base_fees, effective_feerate, effective_feerate_wtxids));
+        if (!m_pool.m_signals) continue;
         const CTransaction& tx = *ws.m_ptx;
         const auto tx_info = NewMempoolTransactionInfo(ws.m_ptx, ws.m_base_fees,
                                                        ws.m_vsize, ws.m_entry->GetHeight(),
                                                        args.m_bypass_limits, args.m_package_submission,
                                                        IsCurrentForFeeEstimation(m_active_chainstate),
                                                        m_pool.HasNoInputsOf(tx));
-        GetMainSignals().TransactionAddedToMempool(tx_info, m_pool.GetAndIncrementSequence());
+        m_pool.m_signals->TransactionAddedToMempool(tx_info, m_pool.GetAndIncrementSequence());
     }
     return all_submitted;
 }
@@ -1238,7 +1239,7 @@ bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>&
 MempoolAcceptResult MemPoolAccept::AcceptSingleTransaction(const CTransactionRef& ptx, ATMPArgs& args)
 {
     AssertLockHeld(cs_main);
-    LOCK(m_pool.cs); // mempool "read lock" (held through GetMainSignals().TransactionAddedToMempool())
+    LOCK(m_pool.cs); // mempool "read lock" (held through m_pool.m_signals->TransactionAddedToMempool())
 
     Workspace ws(ptx);
     const std::vector<Wtxid> single_wtxid{ws.m_ptx->GetWitnessHash()};
@@ -1273,13 +1274,15 @@ MempoolAcceptResult MemPoolAccept::AcceptSingleTransaction(const CTransactionRef
         return MempoolAcceptResult::FeeFailure(ws.m_state, CFeeRate(ws.m_modified_fees, ws.m_vsize), {ws.m_ptx->GetWitnessHash()});
     }
 
-    const CTransaction& tx = *ws.m_ptx;
-    const auto tx_info = NewMempoolTransactionInfo(ws.m_ptx, ws.m_base_fees,
-                                                   ws.m_vsize, ws.m_entry->GetHeight(),
-                                                   args.m_bypass_limits, args.m_package_submission,
-                                                   IsCurrentForFeeEstimation(m_active_chainstate),
-                                                   m_pool.HasNoInputsOf(tx));
-    GetMainSignals().TransactionAddedToMempool(tx_info, m_pool.GetAndIncrementSequence());
+    if (m_pool.m_signals) {
+        const CTransaction& tx = *ws.m_ptx;
+        const auto tx_info = NewMempoolTransactionInfo(ws.m_ptx, ws.m_base_fees,
+                                                       ws.m_vsize, ws.m_entry->GetHeight(),
+                                                       args.m_bypass_limits, args.m_package_submission,
+                                                       IsCurrentForFeeEstimation(m_active_chainstate),
+                                                       m_pool.HasNoInputsOf(tx));
+        m_pool.m_signals->TransactionAddedToMempool(tx_info, m_pool.GetAndIncrementSequence());
+    }
 
     return MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize, ws.m_base_fees,
                                         effective_feerate, single_wtxid);
@@ -2691,9 +2694,9 @@ bool Chainstate::FlushStateToDisk(
                    (bool)fFlushForPrune);
         }
     }
-    if (full_flush_completed) {
+    if (full_flush_completed && m_chainman.m_options.signals) {
         // Update best block in wallet (so we can detect restored wallets).
-        GetMainSignals().ChainStateFlushed(this->GetRole(), m_chain.GetLocator());
+        m_chainman.m_options.signals->ChainStateFlushed(this->GetRole(), m_chain.GetLocator());
     }
     } catch (const std::runtime_error& e) {
         return FatalError(m_chainman.GetNotifications(), state, std::string("System error while flushing: ") + e.what());
@@ -2860,7 +2863,9 @@ bool Chainstate::DisconnectTip(BlockValidationState& state, DisconnectedBlockTra
     UpdateTip(pindexDelete->pprev);
     // Let wallets know transactions went from 1-confirmed to
     // 0-confirmed or conflicted:
-    GetMainSignals().BlockDisconnected(pblock, pindexDelete);
+    if (m_chainman.m_options.signals) {
+        m_chainman.m_options.signals->BlockDisconnected(pblock, pindexDelete);
+    }
     return true;
 }
 
@@ -2945,7 +2950,9 @@ bool Chainstate::ConnectTip(BlockValidationState& state, CBlockIndex* pindexNew,
     {
         CCoinsViewCache view(&CoinsTip());
         bool rv = ConnectBlock(blockConnecting, state, pindexNew, view);
-        GetMainSignals().BlockChecked(blockConnecting, state);
+        if (m_chainman.m_options.signals) {
+            m_chainman.m_options.signals->BlockChecked(blockConnecting, state);
+        }
         if (!rv) {
             if (state.IsInvalid())
                 InvalidBlockFound(pindexNew, state);
@@ -3206,10 +3213,10 @@ static bool NotifyHeaderTip(ChainstateManager& chainman) LOCKS_EXCLUDED(cs_main)
     return fNotify;
 }
 
-static void LimitValidationInterfaceQueue() LOCKS_EXCLUDED(cs_main) {
+static void LimitValidationInterfaceQueue(CMainSignals& signals) LOCKS_EXCLUDED(cs_main) {
     AssertLockNotHeld(cs_main);
 
-    if (GetMainSignals().CallbacksPending() > 10) {
+    if (signals.CallbacksPending() > 10) {
         SyncWithValidationInterfaceQueue();
     }
 }
@@ -3248,7 +3255,7 @@ bool Chainstate::ActivateBestChain(BlockValidationState& state, std::shared_ptr<
         // Note that if a validationinterface callback ends up calling
         // ActivateBestChain this may lead to a deadlock! We should
         // probably have a DEBUG_LOCKORDER test for this in the future.
-        LimitValidationInterfaceQueue();
+        if (m_chainman.m_options.signals) LimitValidationInterfaceQueue(*m_chainman.m_options.signals);
 
         {
             LOCK(cs_main);
@@ -3287,7 +3294,9 @@ bool Chainstate::ActivateBestChain(BlockValidationState& state, std::shared_ptr<
 
                 for (const PerBlockConnectTrace& trace : connectTrace.GetBlocksConnected()) {
                     assert(trace.pblock && trace.pindex);
-                    GetMainSignals().BlockConnected(this->GetRole(), trace.pblock, trace.pindex);
+                    if (m_chainman.m_options.signals) {
+                        m_chainman.m_options.signals->BlockConnected(this->GetRole(), trace.pblock, trace.pindex);
+                    }
                 }
 
                 // This will have been toggled in
@@ -3313,7 +3322,9 @@ bool Chainstate::ActivateBestChain(BlockValidationState& state, std::shared_ptr<
             // Enqueue while holding cs_main to ensure that UpdatedBlockTip is called in the order in which blocks are connected
             if (this == &m_chainman.ActiveChainstate() && pindexFork != pindexNewTip) {
                 // Notify ValidationInterface subscribers
-                GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, still_in_ibd);
+                if (m_chainman.m_options.signals) {
+                    m_chainman.m_options.signals->UpdatedBlockTip(pindexNewTip, pindexFork, still_in_ibd);
+                }
 
                 // Always notify the UI if a new block tip was connected
                 if (kernel::IsInterrupted(m_chainman.GetNotifications().blockTip(GetSynchronizationState(still_in_ibd), *pindexNewTip))) {
@@ -3447,7 +3458,7 @@ bool Chainstate::InvalidateBlock(BlockValidationState& state, CBlockIndex* pinde
         if (m_chainman.m_interrupt) break;
 
         // Make sure the queue of validation callbacks doesn't grow unboundedly.
-        LimitValidationInterfaceQueue();
+        if (m_chainman.m_options.signals) LimitValidationInterfaceQueue(*m_chainman.m_options.signals);
 
         LOCK(cs_main);
         // Lock for as long as disconnectpool is in scope to make sure MaybeUpdateMempoolForReorg is
@@ -4155,8 +4166,9 @@ bool ChainstateManager::AcceptBlock(const std::shared_ptr<const CBlock>& pblock,
 
     // Header is valid/has work, merkle tree and segwit merkle tree are good...RELAY NOW
     // (but if it does not build on our best tip, let the SendMessages loop relay it)
-    if (!IsInitialBlockDownload() && ActiveTip() == pindex->pprev)
-        GetMainSignals().NewPoWValidBlock(pindex, pblock);
+    if (!IsInitialBlockDownload() && ActiveTip() == pindex->pprev && m_options.signals) {
+        m_options.signals->NewPoWValidBlock(pindex, pblock);
+    }
 
     // Write block to history file
     if (fNewBlock) *fNewBlock = true;
@@ -4209,7 +4221,9 @@ bool ChainstateManager::ProcessNewBlock(const std::shared_ptr<const CBlock>& blo
             ret = AcceptBlock(block, state, &pindex, force_processing, nullptr, new_block, min_pow_checked);
         }
         if (!ret) {
-            GetMainSignals().BlockChecked(*block, state);
+            if (m_options.signals) {
+                m_options.signals->BlockChecked(*block, state);
+            }
             return error("%s: AcceptBlock FAILED (%s)", __func__, state.ToString());
         }
     }