node/chainstate: Decouple from concept of uiInterface

...instead allow the caller to optionally pass in callbacks which are
triggered for certain events.

Behaviour change: The string "Verifying blocks..." was previously
printed for each chainstate in chainman which did not have an
effectively empty coinsview, now it will be printed once unconditionally
before we call VerifyLoadedChain.

src/init.cpp

@@ -1427,7 +1427,12 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
                                  fReindexChainState,
                                  nBlockTreeDBCache,
                                  nCoinDBCache,
-                                 nCoinCacheUsage);
+                                 nCoinCacheUsage,
+                                 []() {
+                                     uiInterface.ThreadSafeMessageBox(
+                                         _("Error reading from database, shutting down."),
+                                         "", CClientUIInterface::MSG_ERROR);
+                                 });
         if (rv.has_value()) {
             switch (rv.value()) {
             case ChainstateLoadingError::ERROR_LOADING_BLOCK_DB:
@@ -1463,6 +1468,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
                 break;
             }
         } else {
+            uiInterface.InitMessage(_("Verifying blocks…").translated);
             auto rv2 = VerifyLoadedChainstate(chainman,
                                               fReset,
                                               fReindexChainState,

src/node/chainstate.cpp

@@ -8,7 +8,6 @@
 #include <rpc/blockchain.h> // for RPCNotifyBlockChange
 #include <util/time.h> // for GetTime
 #include <node/blockstorage.h> // for CleanupBlockRevFiles, fHavePruned, fReindex
-#include <node/ui_interface.h> // for InitError, uiInterface, and CClientUIInterface member access
 #include <shutdown.h> // for ShutdownRequested
 #include <validation.h> // for a lot of things
 
@@ -20,7 +19,8 @@ std::optional<ChainstateLoadingError> LoadChainstate(bool fReset,
                                                      bool fReindexChainState,
                                                      int64_t nBlockTreeDBCache,
                                                      int64_t nCoinDBCache,
-                                                     int64_t nCoinCacheUsage)
+                                                     int64_t nCoinCacheUsage,
+                                                     std::function<void()> coins_error_cb)
 {
     auto is_coinsview_empty = [&](CChainState* chainstate) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
         return fReset || fReindexChainState || chainstate->CoinsTip().GetBestBlock().IsNull();
@@ -86,11 +86,9 @@ std::optional<ChainstateLoadingError> LoadChainstate(bool fReset,
                 /* in_memory */ false,
                 /* should_wipe */ fReset || fReindexChainState);
 
-            chainstate->CoinsErrorCatcher().AddReadErrCallback([]() {
-                uiInterface.ThreadSafeMessageBox(
-                    _("Error reading from database, shutting down."),
-                    "", CClientUIInterface::MSG_ERROR);
-            });
+            if (coins_error_cb) {
+                chainstate->CoinsErrorCatcher().AddReadErrCallback(coins_error_cb);
+            }
 
             // If necessary, upgrade from older database format.
             // This is a no-op if we cleared the coinsviewdb with -reindex or -reindex-chainstate
@@ -148,7 +146,6 @@ std::optional<ChainstateLoadVerifyError> VerifyLoadedChainstate(ChainstateManage
 
         for (CChainState* chainstate : chainman.GetAll()) {
             if (!is_coinsview_empty(chainstate)) {
-                uiInterface.InitMessage(_("Verifying blocks…").translated);
                 if (fHavePruned && check_blocks > MIN_BLOCKS_TO_KEEP) {
                     LogPrintf("Prune: pruned datadir may not have more than %d blocks; only checking available blocks\n",
                         MIN_BLOCKS_TO_KEEP);

src/node/chainstate.h

@@ -6,6 +6,7 @@
 #define BITCOIN_NODE_CHAINSTATE_H
 
 #include <cstdint> // for int64_t
+#include <functional> // for std::function
 #include <optional> // for std::optional
 
 class CChainParams;
@@ -59,7 +60,8 @@ std::optional<ChainstateLoadingError> LoadChainstate(bool fReset,
                                                      bool fReindexChainState,
                                                      int64_t nBlockTreeDBCache,
                                                      int64_t nCoinDBCache,
-                                                     int64_t nCoinCacheUsage);
+                                                     int64_t nCoinCacheUsage,
+                                                     std::function<void()> coins_error_cb = nullptr);
 
 enum class ChainstateLoadVerifyError {
     ERROR_BLOCK_FROM_FUTURE,