cpp: Implement UTXO snapshot loading interface and progress tracking

- Extend node interface with virtual functions for UTXO snapshot loading
- Add signal mechanism to monitor snapshot loading progress
- Include predefined signet UTXO dataset in chainparams for validation

Author: D33r-Gee

Diff for: src/interfaces/node.h

@@ -11,6 +11,7 @@
 #include <net_types.h>                 // For banmap_t
 #include <netaddress.h>                // For Network
 #include <netbase.h>                   // For ConnectionDirection
+#include <node/utxo_snapshot.h>         // For SnapshotMetadata
 #include <support/allocators/secure.h> // For SecureString
 #include <util/translation.h>
 
@@ -208,6 +209,9 @@ class Node
     //! List rpc commands.
     virtual std::vector<std::string> listRpcCommands() = 0;
 
+    //! Load UTXO Snapshot.
+    virtual bool loadSnapshot(AutoFile& afile, const node::SnapshotMetadata& metadata, bool in_memory) = 0;
+
     //! Set RPC timer interface if unset.
     virtual void rpcSetTimerInterfaceIfUnset(RPCTimerInterface* iface) = 0;
 
@@ -243,6 +247,10 @@ class Node
     using ShowProgressFn = std::function<void(const std::string& title, int progress, bool resume_possible)>;
     virtual std::unique_ptr<Handler> handleShowProgress(ShowProgressFn fn) = 0;
 
+    //! Register handler for snapshot load progress.
+    using SnapshotLoadProgressFn = std::function<void(double progress)>;
+    virtual std::unique_ptr<Handler> handleSnapshotLoadProgress(SnapshotLoadProgressFn fn) = 0;
+
     //! Register handler for wallet loader constructed messages.
     using InitWalletFn = std::function<void()>;
     virtual std::unique_ptr<Handler> handleInitWallet(InitWalletFn fn) = 0;

Diff for: src/kernel/chainparams.cpp

@@ -371,6 +371,13 @@ class SigNetParams : public CChainParams {
 
         vFixedSeeds.clear();
 
+        m_assumeutxo_data = MapAssumeutxo{
+            {
+                160000,
+                {AssumeutxoHash{uint256S("0x5225141cb62dee63ab3be95f9b03d60801f264010b1816d4bd00618b2736e7be")}, 1278002},
+            },
+        };
+
         base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
         base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
         base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);

Diff for: src/kernel/notifications_interface.h

@@ -40,6 +40,7 @@ class Notifications
     [[nodiscard]] virtual InterruptResult blockTip(SynchronizationState state, CBlockIndex& index) { return {}; }
     virtual void headerTip(SynchronizationState state, int64_t height, int64_t timestamp, bool presync) {}
     virtual void progress(const bilingual_str& title, int progress_percent, bool resume_possible) {}
+    virtual void snapshotLoadProgress(double progress) {}
     virtual void warning(const bilingual_str& warning) {}
 
     //! The flush error notification is sent to notify the user that an error

Diff for: src/node/interface_ui.cpp

@@ -21,6 +21,7 @@ struct UISignals {
     boost::signals2::signal<CClientUIInterface::NotifyNetworkActiveChangedSig> NotifyNetworkActiveChanged;
     boost::signals2::signal<CClientUIInterface::NotifyAlertChangedSig> NotifyAlertChanged;
     boost::signals2::signal<CClientUIInterface::ShowProgressSig> ShowProgress;
+    boost::signals2::signal<CClientUIInterface::SnapshotLoadProgressSig> SnapshotLoadProgress;
     boost::signals2::signal<CClientUIInterface::NotifyBlockTipSig> NotifyBlockTip;
     boost::signals2::signal<CClientUIInterface::NotifyHeaderTipSig> NotifyHeaderTip;
     boost::signals2::signal<CClientUIInterface::BannedListChangedSig> BannedListChanged;
@@ -44,6 +45,7 @@ ADD_SIGNALS_IMPL_WRAPPER(ShowProgress);
 ADD_SIGNALS_IMPL_WRAPPER(NotifyBlockTip);
 ADD_SIGNALS_IMPL_WRAPPER(NotifyHeaderTip);
 ADD_SIGNALS_IMPL_WRAPPER(BannedListChanged);
+ADD_SIGNALS_IMPL_WRAPPER(SnapshotLoadProgress);
 
 bool CClientUIInterface::ThreadSafeMessageBox(const bilingual_str& message, const std::string& caption, unsigned int style) { return g_ui_signals.ThreadSafeMessageBox(message, caption, style).value_or(false);}
 bool CClientUIInterface::ThreadSafeQuestion(const bilingual_str& message, const std::string& non_interactive_message, const std::string& caption, unsigned int style) { return g_ui_signals.ThreadSafeQuestion(message, non_interactive_message, caption, style).value_or(false);}
@@ -53,6 +55,7 @@ void CClientUIInterface::NotifyNumConnectionsChanged(PeersNumByType newNumConnec
 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::SnapshotLoadProgress(double progress) { return g_ui_signals.SnapshotLoadProgress(progress); }
 void CClientUIInterface::NotifyBlockTip(SynchronizationState s, const CBlockIndex* i) { return g_ui_signals.NotifyBlockTip(s, i); }
 void CClientUIInterface::NotifyHeaderTip(SynchronizationState s, int64_t height, int64_t timestamp, bool presync) { return g_ui_signals.NotifyHeaderTip(s, height, timestamp, presync); }
 void CClientUIInterface::BannedListChanged() { return g_ui_signals.BannedListChanged(); }

Diff for: src/node/interface_ui.h

@@ -109,6 +109,9 @@ class CClientUIInterface
      */
     ADD_SIGNALS_DECL_WRAPPER(ShowProgress, void, const std::string& title, int nProgress, bool resume_possible);
 
+    /** Snapshot load progress. */
+    ADD_SIGNALS_DECL_WRAPPER(SnapshotLoadProgress, void, double progress);
+
     /** New block has been accepted */
     ADD_SIGNALS_DECL_WRAPPER(NotifyBlockTip, void, SynchronizationState, const CBlockIndex*);
 

Diff for: src/node/interfaces.cpp

@@ -29,6 +29,7 @@
 #include <node/context.h>
 #include <node/interface_ui.h>
 #include <node/transaction.h>
+#include <node/utxo_snapshot.h>
 #include <policy/feerate.h>
 #include <policy/fees.h>
 #include <policy/policy.h>
@@ -378,6 +379,10 @@ class NodeImpl : public Node
     {
         return MakeSignalHandler(::uiInterface.ShowProgress_connect(fn));
     }
+    std::unique_ptr<Handler> handleSnapshotLoadProgress(SnapshotLoadProgressFn fn) override
+    {
+        return MakeSignalHandler(::uiInterface.SnapshotLoadProgress_connect(fn));
+    }
     std::unique_ptr<Handler> handleInitWallet(InitWalletFn fn) override
     {
         return MakeSignalHandler(::uiInterface.InitWallet_connect(fn));
@@ -417,6 +422,10 @@ class NodeImpl : public Node
     {
         m_context = context;
     }
+    bool loadSnapshot(AutoFile& afile, const node::SnapshotMetadata& metadata, bool in_memory) override
+    {
+        return chainman().ActivateSnapshot(afile, metadata, in_memory);
+    }
     ArgsManager& args() { return *Assert(Assert(m_context)->args); }
     ChainstateManager& chainman() { return *Assert(m_context->chainman); }
     NodeContext* m_context{nullptr};
@@ -532,7 +541,7 @@ class RpcHandlerImpl : public Handler
 class ChainImpl : public Chain
 {
 public:
-    explicit ChainImpl(NodeContext& node) : m_node(node) {}
+    explicit ChainImpl(node::NodeContext& node) : m_node(node) {}
     std::optional<int> getHeight() override
     {
         const int height{WITH_LOCK(::cs_main, return chainman().ActiveChain().Height())};

Diff for: src/node/kernel_notifications.cpp

@@ -78,6 +78,11 @@ void KernelNotifications::progress(const bilingual_str& title, int progress_perc
     uiInterface.ShowProgress(title.translated, progress_percent, resume_possible);
 }
 
+void KernelNotifications::snapshotLoadProgress(double progress)
+{
+    uiInterface.SnapshotLoadProgress(progress);
+}
+
 void KernelNotifications::warning(const bilingual_str& warning)
 {
     DoWarning(warning);

Diff for: src/node/kernel_notifications.h

@@ -31,6 +31,8 @@ class KernelNotifications : public kernel::Notifications
 
     void progress(const bilingual_str& title, int progress_percent, bool resume_possible) override;
 
+    void snapshotLoadProgress(double progress) override;
+
     void warning(const bilingual_str& warning) override;
 
     void flushError(const std::string& debug_message) override;

Diff for: src/validation.cpp

@@ -5261,6 +5261,10 @@ bool ChainstateManager::PopulateAndValidateSnapshot(
         --coins_left;
         ++coins_processed;
 
+        // Show Snapshot Loading progress
+        double progress = static_cast<double>(coins_processed) / static_cast<double>(coins_count);
+        GetNotifications().snapshotLoadProgress(progress);
+
         if (coins_processed % 1000000 == 0) {
             LogPrintf("[snapshot] %d coins loaded (%.2f%%, %.2f MB)\n",
                 coins_processed,