validation: Move LoadExternalBlockFile to CChainState

[META] This commit should be followed up by removing the comments and
       assertions meant only to show that the change is correct.

LoadExternalBlockFile mainly acts on CChainState.

src/init.cpp

@@ -705,7 +705,7 @@ static void ThreadImport(ChainstateManager& chainman, std::vector<fs::path> vImp
             if (!file)
                 break; // This error is logged in OpenBlockFile
             LogPrintf("Reindexing block file blk%05u.dat...\n", (unsigned int)nFile);
-            LoadExternalBlockFile(chainparams, file, &pos);
+            ::ChainstateActive().LoadExternalBlockFile(chainparams, file, &pos);
             if (ShutdownRequested()) {
                 LogPrintf("Shutdown requested. Exit %s\n", __func__);
                 return;
@@ -724,7 +724,7 @@ static void ThreadImport(ChainstateManager& chainman, std::vector<fs::path> vImp
         FILE *file = fsbridge::fopen(path, "rb");
         if (file) {
             LogPrintf("Importing blocks file %s...\n", path.string());
-            LoadExternalBlockFile(chainparams, file);
+            ::ChainstateActive().LoadExternalBlockFile(chainparams, file);
             if (ShutdownRequested()) {
                 LogPrintf("Shutdown requested. Exit %s\n", __func__);
                 return;

src/test/fuzz/load_external_block_file.cpp

@@ -27,5 +27,5 @@ FUZZ_TARGET_INIT(load_external_block_file, initialize_load_external_block_file)
         return;
     }
     FlatFilePos flat_file_pos;
-    LoadExternalBlockFile(Params(), fuzzed_block_file, fuzzed_data_provider.ConsumeBool() ? &flat_file_pos : nullptr);
+    ::ChainstateActive().LoadExternalBlockFile(Params(), fuzzed_block_file, fuzzed_data_provider.ConsumeBool() ? &flat_file_pos : nullptr);
 }

src/validation.cpp

@@ -4602,7 +4602,7 @@ bool LoadGenesisBlock(const CChainParams& chainparams)
     return ::ChainstateActive().LoadGenesisBlock(chainparams);
 }
 
-void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFilePos* dbp)
+void CChainState::LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFilePos* dbp)
 {
     // Map of disk positions for blocks with unknown parent (only used for reindex)
     static std::multimap<uint256, FlatFilePos> mapBlocksUnknownParent;
@@ -4651,7 +4651,8 @@ void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFi
                 {
                     LOCK(cs_main);
                     // detect out of order blocks, and store them for later
-                    if (hash != chainparams.GetConsensus().hashGenesisBlock && !g_chainman.m_blockman.LookupBlockIndex(block.hashPrevBlock)) {
+                    assert(std::addressof(g_chainman.m_blockman) == std::addressof(m_blockman));
+                    if (hash != chainparams.GetConsensus().hashGenesisBlock && !m_blockman.LookupBlockIndex(block.hashPrevBlock)) {
                         LogPrint(BCLog::REINDEX, "%s: Out of order block %s, parent %s not known\n", __func__, hash.ToString(),
                                 block.hashPrevBlock.ToString());
                         if (dbp)
@@ -4660,10 +4661,12 @@ void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFi
                     }
 
                     // process in case the block isn't known yet
-                    CBlockIndex* pindex = g_chainman.m_blockman.LookupBlockIndex(hash);
+                    assert(std::addressof(g_chainman.m_blockman) == std::addressof(m_blockman));
+                    CBlockIndex* pindex = m_blockman.LookupBlockIndex(hash);
                     if (!pindex || (pindex->nStatus & BLOCK_HAVE_DATA) == 0) {
                       BlockValidationState state;
-                      if (::ChainstateActive().AcceptBlock(pblock, state, chainparams, nullptr, true, dbp, nullptr)) {
+                      assert(std::addressof(::ChainstateActive()) == std::addressof(*this));
+                      if (AcceptBlock(pblock, state, chainparams, nullptr, true, dbp, nullptr)) {
                           nLoaded++;
                       }
                       if (state.IsError()) {
@@ -4677,12 +4680,14 @@ void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFi
                 // Activate the genesis block so normal node progress can continue
                 if (hash == chainparams.GetConsensus().hashGenesisBlock) {
                     BlockValidationState state;
-                    if (!::ChainstateActive().ActivateBestChain(state, chainparams, nullptr)) {
+                    assert(std::addressof(::ChainstateActive()) == std::addressof(*this));
+                    if (!ActivateBestChain(state, chainparams, nullptr)) {
                         break;
                     }
                 }
 
-                NotifyHeaderTip(::ChainstateActive());
+                assert(std::addressof(::ChainstateActive()) == std::addressof(*this));
+                NotifyHeaderTip(*this);
 
                 // Recursively process earlier encountered successors of this block
                 std::deque<uint256> queue;
@@ -4700,7 +4705,8 @@ void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFi
                                     head.ToString());
                             LOCK(cs_main);
                             BlockValidationState dummy;
-                            if (::ChainstateActive().AcceptBlock(pblockrecursive, dummy, chainparams, nullptr, true, &it->second, nullptr))
+                            assert(std::addressof(::ChainstateActive()) == std::addressof(*this));
+                            if (AcceptBlock(pblockrecursive, dummy, chainparams, nullptr, true, &it->second, nullptr))
                             {
                                 nLoaded++;
                                 queue.push_back(pblockrecursive->GetHash());
@@ -4708,7 +4714,8 @@ void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFi
                         }
                         range.first++;
                         mapBlocksUnknownParent.erase(it);
-                        NotifyHeaderTip(::ChainstateActive());
+                        assert(std::addressof(::ChainstateActive()) == std::addressof(*this));
+                        NotifyHeaderTip(*this);
                     }
                 }
             } catch (const std::exception& e) {

src/validation.h

@@ -144,8 +144,6 @@ extern const std::vector<std::string> CHECKLEVEL_DOC;
 FILE* OpenBlockFile(const FlatFilePos &pos, bool fReadOnly = false);
 /** Translation to a filesystem path */
 fs::path GetBlockPosFilename(const FlatFilePos &pos);
-/** Import blocks from an external file */
-void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFilePos* dbp = nullptr);
 /** Ensures we have a genesis block in the block tree, possibly writing one to disk. */
 bool LoadGenesisBlock(const CChainParams& chainparams);
 /** Unload database information */
@@ -616,6 +614,9 @@ public:
     bool ResizeCoinsCaches(size_t coinstip_size, size_t coinsdb_size)
         EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 
+    /** Import blocks from an external file */
+    void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFilePos* dbp = nullptr);
+
     /**
      * Update the on-disk chain state.
      * The caches and indexes are flushed depending on the mode we're called with