Merge #18152: qt: Use SynchronizationState enum for signals to GUI

a0d0f1c6c3d736bc0ee076b7f27a0ef59fd260bc refactor: Remove Node:: queries from GUI (Hennadii Stepanov)
06d519f0b43ed16252428e935d3aeb5a38f582e0 qt: Add SynchronizationState enum to signal parameter (Hennadii Stepanov)
3c709aa69d5bb5a1564c339a0e6a16bac8f02c98 refactor: Remove Node::getReindex() call from GUI (Hennadii Stepanov)
1dab574edf57ccd6cdf5ec706ac328c62142d7a2 refactor: Pass SynchronizationState enum to GUI (Hennadii Stepanov)
2bec309ad6d0f2543948d64ed26f7d9a903f67e5 refactor: Remove unused bool parameter in RPCNotifyBlockChange() (Hennadii Stepanov)
1df77014d8bb733d7d89e36b28671cb47f436292 refactor: Remove unused bool parameter in BlockNotifyGenesisWait() (Hennadii Stepanov)

Pull request description:

  This PR is a followup of #18121 and:
  - addresses confusion about GUI notification throttling conditions (**luke-jr**'s [comment](https://github.com/bitcoin/bitcoin/pull/18121#discussion_r378552386), **ryanofsky**'s [comment](https://github.com/bitcoin/bitcoin/pull/18121#discussion_r378975960))
  - removes `isInitialBlockDownload()` call from the GUI back to the node (on macOS). See:  **ryanofsky**'s [comment](https://github.com/bitcoin/bitcoin/pull/18121#pullrequestreview-357730284)

ACKs for top commit:
  jonasschnelli:
    Core Review ACK a0d0f1c6c3d736bc0ee076b7f27a0ef59fd260bc (modulo [question](https://github.com/bitcoin/bitcoin/pull/18152#pullrequestreview-414140601)).
  ryanofsky:
    Code review ACK a0d0f1c6c3d736bc0ee076b7f27a0ef59fd260bc. Only changes since last review were rebase and tweaking SynchronizationState enum declaration as suggested (thanks!)

Tree-SHA512: b6a712a710666e763aeee0d5440de1391a4c6c8f7fa661888773e1ba59e9e0f83654ee384d4edc704031be7eb25616e5eca2a6e26058d3efb7f64c47f9ed7316

14 files changed, 73 insertions, 50 deletions

diff --git a/src/init.cpp b/src/init.cpp
index 3b97ba08d9..341c37cc5a 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -59,9 +59,10 @@
 #include <validationinterface.h>
 #include <walletinitinterface.h>
 
+#include <functional>
+#include <set>
 #include <stdint.h>
 #include <stdio.h>
-#include <set>
 
 #ifndef WIN32
 #include <attributes.h>
@@ -350,13 +351,13 @@ static void registerSignalHandler(int signal, void(*handler)(int))
 static boost::signals2::connection rpc_notify_block_change_connection;
 static void OnRPCStarted()
 {
-    rpc_notify_block_change_connection = uiInterface.NotifyBlockTip_connect(&RPCNotifyBlockChange);
+    rpc_notify_block_change_connection = uiInterface.NotifyBlockTip_connect(std::bind(RPCNotifyBlockChange, std::placeholders::_2));
 }
 
 static void OnRPCStopped()
 {
     rpc_notify_block_change_connection.disconnect();
-    RPCNotifyBlockChange(false, nullptr);
+    RPCNotifyBlockChange(nullptr);
     g_best_block_cv.notify_all();
     LogPrint(BCLog::RPC, "RPC stopped.\n");
 }
@@ -604,9 +605,9 @@ std::string LicenseInfo()
 }
 
 #if HAVE_SYSTEM
-static void BlockNotifyCallback(bool initialSync, const CBlockIndex *pBlockIndex)
+static void BlockNotifyCallback(SynchronizationState sync_state, const CBlockIndex* pBlockIndex)
 {
-    if (initialSync || !pBlockIndex)
+    if (sync_state != SynchronizationState::POST_INIT || !pBlockIndex)
         return;
 
     std::string strCmd = gArgs.GetArg("-blocknotify", "");
@@ -622,7 +623,7 @@ static bool fHaveGenesis = false;
 static Mutex g_genesis_wait_mutex;
 static std::condition_variable g_genesis_wait_cv;
 
-static void BlockNotifyGenesisWait(bool, const CBlockIndex *pBlockIndex)
+static void BlockNotifyGenesisWait(const CBlockIndex* pBlockIndex)
 {
     if (pBlockIndex != nullptr) {
         {
@@ -1701,7 +1702,7 @@ bool AppInitMain(NodeContext& node)
                         }
 
                         const CBlockIndex* tip = chainstate->m_chain.Tip();
-                        RPCNotifyBlockChange(true, tip);
+                        RPCNotifyBlockChange(tip);
                         if (tip && tip->nTime > GetAdjustedTime() + 2 * 60 * 60) {
                             strLoadError = _("The block database contains a block which appears to be from the future. "
                                     "This may be due to your computer's date and time being set incorrectly. "
@@ -1826,7 +1827,7 @@ bool AppInitMain(NodeContext& node)
     // No locking, as this happens before any background thread is started.
     boost::signals2::connection block_notify_genesis_wait_connection;
     if (::ChainActive().Tip() == nullptr) {
-        block_notify_genesis_wait_connection = uiInterface.NotifyBlockTip_connect(BlockNotifyGenesisWait);
+        block_notify_genesis_wait_connection = uiInterface.NotifyBlockTip_connect(std::bind(BlockNotifyGenesisWait, std::placeholders::_2));
     } else {
         fHaveGenesis = true;
     }
diff --git a/src/interfaces/node.cpp b/src/interfaces/node.cpp
index 9e603a12cd..d619d2d67d 100644
--- a/src/interfaces/node.cpp
+++ b/src/interfaces/node.cpp
@@ -308,16 +308,16 @@ public:
     }
     std::unique_ptr<Handler> handleNotifyBlockTip(NotifyBlockTipFn fn) override
     {
-        return MakeHandler(::uiInterface.NotifyBlockTip_connect([fn](bool initial_download, const CBlockIndex* block) {
-            fn(initial_download, block->nHeight, block->GetBlockTime(),
+        return MakeHandler(::uiInterface.NotifyBlockTip_connect([fn](SynchronizationState sync_state, const CBlockIndex* block) {
+            fn(sync_state, block->nHeight, block->GetBlockTime(),
                 GuessVerificationProgress(Params().TxData(), block));
         }));
     }
     std::unique_ptr<Handler> handleNotifyHeaderTip(NotifyHeaderTipFn fn) override
     {
         return MakeHandler(
-            ::uiInterface.NotifyHeaderTip_connect([fn](bool initial_download, const CBlockIndex* block) {
-                fn(initial_download, block->nHeight, block->GetBlockTime(),
+            ::uiInterface.NotifyHeaderTip_connect([fn](SynchronizationState sync_state, const CBlockIndex* block) {
+                fn(sync_state, block->nHeight, block->GetBlockTime(),
                     /* verification progress is unused when a header was received */ 0);
             }));
     }
diff --git a/src/interfaces/node.h b/src/interfaces/node.h
index aef6b19458..45b0e18fae 100644
--- a/src/interfaces/node.h
+++ b/src/interfaces/node.h
@@ -27,6 +27,7 @@ class Coin;
 class RPCTimerInterface;
 class UniValue;
 class proxyType;
+enum class SynchronizationState;
 enum class WalletCreationStatus;
 struct CNodeStateStats;
 struct NodeContext;
@@ -249,12 +250,12 @@ public:
 
     //! Register handler for block tip messages.
     using NotifyBlockTipFn =
-        std::function<void(bool initial_download, int height, int64_t block_time, double verification_progress)>;
+        std::function<void(SynchronizationState, int height, int64_t block_time, double verification_progress)>;
     virtual std::unique_ptr<Handler> handleNotifyBlockTip(NotifyBlockTipFn fn) = 0;
 
     //! Register handler for header tip messages.
     using NotifyHeaderTipFn =
-        std::function<void(bool initial_download, int height, int64_t block_time, double verification_progress)>;
+        std::function<void(SynchronizationState, int height, int64_t block_time, double verification_progress)>;
     virtual std::unique_ptr<Handler> handleNotifyHeaderTip(NotifyHeaderTipFn fn) = 0;
 
     //! Return pointer to internal chain interface, useful for testing.
diff --git a/src/qt/bitcoin.cpp b/src/qt/bitcoin.cpp
index 8939b566f7..6fdf6322ff 100644
--- a/src/qt/bitcoin.cpp
+++ b/src/qt/bitcoin.cpp
@@ -34,6 +34,7 @@
 #include <uint256.h>
 #include <util/system.h>
 #include <util/threadnames.h>
+#include <validation.h>
 
 #include <memory>
 
@@ -61,6 +62,7 @@ Q_IMPORT_PLUGIN(QCocoaIntegrationPlugin);
 // Declare meta types used for QMetaObject::invokeMethod
 Q_DECLARE_METATYPE(bool*)
 Q_DECLARE_METATYPE(CAmount)
+Q_DECLARE_METATYPE(SynchronizationState)
 Q_DECLARE_METATYPE(uint256)
 
 static QString GetLangTerritory()
@@ -435,6 +437,7 @@ int GuiMain(int argc, char* argv[])
 
     // Register meta types used for QMetaObject::invokeMethod and Qt::QueuedConnection
     qRegisterMetaType<bool*>();
+    qRegisterMetaType<SynchronizationState>();
 #ifdef ENABLE_WALLET
     qRegisterMetaType<WalletModel*>();
 #endif
diff --git a/src/qt/bitcoingui.cpp b/src/qt/bitcoingui.cpp
index 3a1fdc22a6..4de4850903 100644
--- a/src/qt/bitcoingui.cpp
+++ b/src/qt/bitcoingui.cpp
@@ -37,6 +37,7 @@
 #include <ui_interface.h>
 #include <util/system.h>
 #include <util/translation.h>
+#include <validation.h>
 
 #include <QAction>
 #include <QApplication>
@@ -567,7 +568,7 @@ void BitcoinGUI::setClientModel(ClientModel *_clientModel)
         connect(_clientModel, &ClientModel::networkActiveChanged, this, &BitcoinGUI::setNetworkActive);
 
         modalOverlay->setKnownBestHeight(_clientModel->getHeaderTipHeight(), QDateTime::fromTime_t(_clientModel->getHeaderTipTime()));
-        setNumBlocks(m_node.getNumBlocks(), QDateTime::fromTime_t(m_node.getLastBlockTime()), m_node.getVerificationProgress(), false);
+        setNumBlocks(m_node.getNumBlocks(), QDateTime::fromTime_t(m_node.getLastBlockTime()), m_node.getVerificationProgress(), false, SynchronizationState::INIT_DOWNLOAD);
         connect(_clientModel, &ClientModel::numBlocksChanged, this, &BitcoinGUI::setNumBlocks);
 
         // Receive and report messages from client model
@@ -926,11 +927,15 @@ void BitcoinGUI::openOptionsDialogWithTab(OptionsDialog::Tab tab)
     dlg.exec();
 }
 
-void BitcoinGUI::setNumBlocks(int count, const QDateTime& blockDate, double nVerificationProgress, bool header)
+void BitcoinGUI::setNumBlocks(int count, const QDateTime& blockDate, double nVerificationProgress, bool header, SynchronizationState sync_state)
 {
 // Disabling macOS App Nap on initial sync, disk and reindex operations.
 #ifdef Q_OS_MAC
-    (m_node.isInitialBlockDownload() || m_node.getReindex() || m_node.getImporting()) ? m_app_nap_inhibitor->disableAppNap() : m_app_nap_inhibitor->enableAppNap();
+    if (sync_state == SynchronizationState::POST_INIT) {
+        m_app_nap_inhibitor->enableAppNap();
+    } else {
+        m_app_nap_inhibitor->disableAppNap();
+    }
 #endif
 
     if (modalOverlay)
diff --git a/src/qt/bitcoingui.h b/src/qt/bitcoingui.h
index 6733585f68..82a2db9ba2 100644
--- a/src/qt/bitcoingui.h
+++ b/src/qt/bitcoingui.h
@@ -38,6 +38,7 @@ class WalletFrame;
 class WalletModel;
 class HelpMessageDialog;
 class ModalOverlay;
+enum class SynchronizationState;
 
 namespace interfaces {
 class Handler;
@@ -213,7 +214,7 @@ public Q_SLOTS:
     /** Set network state shown in the UI */
     void setNetworkActive(bool networkActive);
     /** Set number of blocks and last block date shown in the UI */
-    void setNumBlocks(int count, const QDateTime& blockDate, double nVerificationProgress, bool headers);
+    void setNumBlocks(int count, const QDateTime& blockDate, double nVerificationProgress, bool headers, SynchronizationState sync_state);
 
     /** Notify the user of an event from the core network or transaction handling code.
        @param[in] title             the message box / notification title
diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp
index b94fcc9865..159b0d3df3 100644
--- a/src/qt/clientmodel.cpp
+++ b/src/qt/clientmodel.cpp
@@ -15,6 +15,7 @@
 #include <net.h>
 #include <netbase.h>
 #include <util/system.h>
+#include <validation.h>
 
 #include <stdint.h>
 
@@ -234,17 +235,8 @@ static void BannedListChanged(ClientModel *clientmodel)
     assert(invoked);
 }
 
-static void BlockTipChanged(ClientModel *clientmodel, bool initialSync, int height, int64_t blockTime, double verificationProgress, bool fHeader)
+static void BlockTipChanged(ClientModel* clientmodel, SynchronizationState sync_state, int height, int64_t blockTime, double verificationProgress, bool fHeader)
 {
-    // lock free async UI updates in case we have a new block tip
-    // during initial sync, only update the UI if the last update
-    // was > 250ms (MODEL_UPDATE_DELAY) ago
-    int64_t now = 0;
-    if (initialSync)
-        now = GetTimeMillis();
-
-    int64_t& nLastUpdateNotification = fHeader ? nLastHeaderTipUpdateNotification : nLastBlockTipUpdateNotification;
-
     if (fHeader) {
         // cache best headers time and height to reduce future cs_main locks
         clientmodel->cachedBestHeaderHeight = height;
@@ -253,17 +245,22 @@ static void BlockTipChanged(ClientModel *clientmodel, bool initialSync, int heig
         clientmodel->m_cached_num_blocks = height;
     }
 
-    // During initial sync, block notifications, and header notifications from reindexing are both throttled.
-    if (!initialSync || (fHeader && !clientmodel->node().getReindex()) || now - nLastUpdateNotification > MODEL_UPDATE_DELAY) {
-        //pass an async signal to the UI thread
-        bool invoked = QMetaObject::invokeMethod(clientmodel, "numBlocksChanged", Qt::QueuedConnection,
-                                  Q_ARG(int, height),
-                                  Q_ARG(QDateTime, QDateTime::fromTime_t(blockTime)),
-                                  Q_ARG(double, verificationProgress),
-                                  Q_ARG(bool, fHeader));
-        assert(invoked);
-        nLastUpdateNotification = now;
+    // Throttle GUI notifications about (a) blocks during initial sync, and (b) both blocks and headers during reindex.
+    const bool throttle = (sync_state != SynchronizationState::POST_INIT && !fHeader) || sync_state == SynchronizationState::INIT_REINDEX;
+    const int64_t now = throttle ? GetTimeMillis() : 0;
+    int64_t& nLastUpdateNotification = fHeader ? nLastHeaderTipUpdateNotification : nLastBlockTipUpdateNotification;
+    if (throttle && now < nLastUpdateNotification + MODEL_UPDATE_DELAY) {
+        return;
     }
+
+    bool invoked = QMetaObject::invokeMethod(clientmodel, "numBlocksChanged", Qt::QueuedConnection,
+        Q_ARG(int, height),
+        Q_ARG(QDateTime, QDateTime::fromTime_t(blockTime)),
+        Q_ARG(double, verificationProgress),
+        Q_ARG(bool, fHeader),
+        Q_ARG(SynchronizationState, sync_state));
+    assert(invoked);
+    nLastUpdateNotification = now;
 }
 
 void ClientModel::subscribeToCoreSignals()
diff --git a/src/qt/clientmodel.h b/src/qt/clientmodel.h
index 7ac4120a8f..ace77f5972 100644
--- a/src/qt/clientmodel.h
+++ b/src/qt/clientmodel.h
@@ -12,10 +12,10 @@
 #include <memory>
 
 class BanTableModel;
+class CBlockIndex;
 class OptionsModel;
 class PeerTableModel;
-
-class CBlockIndex;
+enum class SynchronizationState;
 
 namespace interfaces {
 class Handler;
@@ -100,7 +100,7 @@ private:
 
 Q_SIGNALS:
     void numConnectionsChanged(int count);
-    void numBlocksChanged(int count, const QDateTime& blockDate, double nVerificationProgress, bool header);
+    void numBlocksChanged(int count, const QDateTime& blockDate, double nVerificationProgress, bool header, SynchronizationState sync_state);
     void mempoolSizeChanged(long count, size_t mempoolSizeInBytes);
     void networkActiveChanged(bool networkActive);
     void alertsChanged(const QString &warnings);
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index f7ccbae706..2c984603ff 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -205,7 +205,7 @@ static UniValue getbestblockhash(const JSONRPCRequest& request)
     return ::ChainActive().Tip()->GetBlockHash().GetHex();
 }
 
-void RPCNotifyBlockChange(bool ibd, const CBlockIndex * pindex)
+void RPCNotifyBlockChange(const CBlockIndex* pindex)
 {
     if(pindex) {
         std::lock_guard<std::mutex> lock(cs_blockchange);
diff --git a/src/rpc/blockchain.h b/src/rpc/blockchain.h
index a02e5fae0e..54165af707 100644
--- a/src/rpc/blockchain.h
+++ b/src/rpc/blockchain.h
@@ -30,7 +30,7 @@ static constexpr int NUM_GETBLOCKSTATS_PERCENTILES = 5;
 double GetDifficulty(const CBlockIndex* blockindex);
 
 /** Callback for when block tip changed. */
-void RPCNotifyBlockChange(bool ibd, const CBlockIndex *);
+void RPCNotifyBlockChange(const CBlockIndex*);
 
 /** Block description to JSON */
 UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIndex* blockindex, bool txDetails = false) LOCKS_EXCLUDED(cs_main);
diff --git a/src/ui_interface.cpp b/src/ui_interface.cpp
index bb41154afc..15795bd67f 100644
--- a/src/ui_interface.cpp
+++ b/src/ui_interface.cpp
@@ -49,8 +49,8 @@ void CClientUIInterface::NotifyNumConnectionsChanged(int newNumConnections) { re
 void CClientUIInterface::NotifyNetworkActiveChanged(bool networkActive) { return g_ui_signals.NotifyNetworkActiveChanged(networkActive); }
 void CClientUIInterface::NotifyAlertChanged() { return g_ui_signals.NotifyAlertChanged(); }
 void CClientUIInterface::ShowProgress(const std::string& title, int nProgress, bool resume_possible) { return g_ui_signals.ShowProgress(title, nProgress, resume_possible); }
-void CClientUIInterface::NotifyBlockTip(bool b, const CBlockIndex* i) { return g_ui_signals.NotifyBlockTip(b, i); }
-void CClientUIInterface::NotifyHeaderTip(bool b, const CBlockIndex* i) { return g_ui_signals.NotifyHeaderTip(b, i); }
+void CClientUIInterface::NotifyBlockTip(SynchronizationState s, const CBlockIndex* i) { return g_ui_signals.NotifyBlockTip(s, i); }
+void CClientUIInterface::NotifyHeaderTip(SynchronizationState s, const CBlockIndex* i) { return g_ui_signals.NotifyHeaderTip(s, i); }
 void CClientUIInterface::BannedListChanged() { return g_ui_signals.BannedListChanged(); }
 
 bool InitError(const bilingual_str& str)
diff --git a/src/ui_interface.h b/src/ui_interface.h
index 9c49451e84..d45811178f 100644
--- a/src/ui_interface.h
+++ b/src/ui_interface.h
@@ -11,6 +11,7 @@
 #include <string>
 
 class CBlockIndex;
+enum class SynchronizationState;
 struct bilingual_str;
 
 namespace boost {
@@ -110,10 +111,10 @@ public:
     ADD_SIGNALS_DECL_WRAPPER(ShowProgress, void, const std::string& title, int nProgress, bool resume_possible);
 
     /** New block has been accepted */
-    ADD_SIGNALS_DECL_WRAPPER(NotifyBlockTip, void, bool, const CBlockIndex*);
+    ADD_SIGNALS_DECL_WRAPPER(NotifyBlockTip, void, SynchronizationState, const CBlockIndex*);
 
     /** Best header has changed */
-    ADD_SIGNALS_DECL_WRAPPER(NotifyHeaderTip, void, bool, const CBlockIndex*);
+    ADD_SIGNALS_DECL_WRAPPER(NotifyHeaderTip, void, SynchronizationState, const CBlockIndex*);
 
     /** Banlist did change. */
     ADD_SIGNALS_DECL_WRAPPER(BannedListChanged, void, void);
diff --git a/src/validation.cpp b/src/validation.cpp
index 8a454c8d1b..a9dfa5c171 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2800,6 +2800,13 @@ bool CChainState::ActivateBestChainStep(BlockValidationState& state, const CChai
     return true;
 }
 
+static SynchronizationState GetSynchronizationState(bool init)
+{
+    if (!init) return SynchronizationState::POST_INIT;
+    if (::fReindex) return SynchronizationState::INIT_REINDEX;
+    return SynchronizationState::INIT_DOWNLOAD;
+}
+
 static bool NotifyHeaderTip() LOCKS_EXCLUDED(cs_main) {
     bool fNotify = false;
     bool fInitialBlockDownload = false;
@@ -2817,7 +2824,7 @@ static bool NotifyHeaderTip() LOCKS_EXCLUDED(cs_main) {
     }
     // Send block tip changed notifications without cs_main
     if (fNotify) {
-        uiInterface.NotifyHeaderTip(fInitialBlockDownload, pindexHeader);
+        uiInterface.NotifyHeaderTip(GetSynchronizationState(fInitialBlockDownload), pindexHeader);
     }
     return fNotify;
 }
@@ -2906,7 +2913,7 @@ bool CChainState::ActivateBestChain(BlockValidationState &state, const CChainPar
                 GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload);
 
                 // Always notify the UI if a new block tip was connected
-                uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
+                uiInterface.NotifyBlockTip(GetSynchronizationState(fInitialDownload), pindexNewTip);
             }
         }
         // When we reach this point, we switched to a new tip (stored in pindexNewTip).
@@ -3097,7 +3104,7 @@ bool CChainState::InvalidateBlock(BlockValidationState& state, const CChainParam
 
     // Only notify about a new block tip if the active chain was modified.
     if (pindex_was_in_chain) {
-        uiInterface.NotifyBlockTip(IsInitialBlockDownload(), to_mark_failed->pprev);
+        uiInterface.NotifyBlockTip(GetSynchronizationState(IsInitialBlockDownload()), to_mark_failed->pprev);
     }
     return true;
 }
diff --git a/src/validation.h b/src/validation.h
index c4a5cc4593..cbab65e79e 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -103,6 +103,13 @@ struct BlockHasher
     size_t operator()(const uint256& hash) const { return ReadLE64(hash.begin()); }
 };
 
+/** Current sync state passed to tip changed callbacks. */
+enum class SynchronizationState {
+    INIT_REINDEX,
+    INIT_DOWNLOAD,
+    POST_INIT
+};
+
 extern RecursiveMutex cs_main;
 extern CBlockPolicyEstimator feeEstimator;
 extern CTxMemPool mempool;