Merge #20749: [Bundle 1/n] Prune g_chainman usage related to ::LookupBlockIndex

67c9a83df19c6e2a2edb32336879204e7770b4a7 style-only: Remove redundant sentence in ActivateBestChain comment (Carl Dong)
b8e95658d5909f93dfc7d1e6532661db8919e5b7 style-only: Make TestBlockValidity signature readable (Carl Dong)
0cdad753903640ff4240b715dec9d62f68e51407 validation: Use accessible chainstate in ChainstateManager::ProcessNewBlock (Carl Dong)
ea4fed90219be17160136313c68c06d84176af08 validation: Use existing chainstate in ChainstateManager::ProcessNewBlockHeaders (Carl Dong)
e0dc3057277c9576ddbfb8541599db0149e08bb6 validation: Move LoadExternalBlockFile to CChainState (Carl Dong)
5f8cd7b3a527999512161956db4d718688cb956f validation: Remove global ::ActivateBestChain (Carl Dong)
2a696472a1423e877bfa83f016f66c7e45be7369 validation: Pass in chainstate to ::NotifyHeaderTip (Carl Dong)
9c300cc8b3ce3d82874982fbf3087e48a6ac0ef2 validation: Pass in chainstate to TestBlockValidity (Carl Dong)
0e17c833cda67cdba5338bd7409061772b6d5edb validation: Make CChainState.m_blockman public (Carl Dong)
d363d06bf7d6c3736140672ba8a7f82f4d6fb6ab validation: Pass in blockman to ContextualCheckBlockHeader (Carl Dong)
f11d11600ddb0ddff6538250ae2a35df6112c3db validation: Move GetLastCheckpoint to BlockManager (Carl Dong)
e4b95eefbc700ebc915bec312f77477ce3e87a7e validation: Move GetSpendHeight to BlockManager (Carl Dong)
b026e318c39f59a06e29f1b25c7f577e01b25ccb validation: Move FindForkInGlobalIndex to BlockManager (Carl Dong)
3664a150ac7547c9336b571557af223d9e31aac9 validation: Remove global LookupBlockIndex (Carl Dong)
eae54e6e60d7ed05b29d8345c0bb055397149ce8 scripted-diff: Use BlockManager::LookupBlockIndex (Carl Dong)
15d20f40e1321b24963b40c12958c7d30ad112ec validation: Move LookupBlockIndex to BlockManager (Carl Dong)
f92dc6557a153b390a1ae1d0808ff7ed5d02c66e validation: Guard the active_chainstate with cs_main (Carl Dong)

Pull request description:

  Overall PR: #20158 (tree-wide: De-globalize ChainstateManager)

  Note to reviewers:
  1. This bundle may _apparently_ introduce usage of `g_chainman` or `::Chain(state|)Active()` globals, but these are resolved later on in the overall PR. [Commits of overall PR](https://github.com/bitcoin/bitcoin/pull/20158/commits)
  2. There may be seemingly obvious local references to `ChainstateManager` or other validation objects which are not being used in callers of the current function in question, this is done intentionally to **_keep each commit centered around one function/method_** to ease review and to make the overall change systematic. We don't assume anything about our callers. Rest assured that once we are considering that particular caller in later commits, we will use the obvious local references. [Commits of overall PR](https://github.com/bitcoin/bitcoin/pull/20158/commits)
  3. When changing a function/method that has many callers (e.g. `LookupBlockIndex` with 55 callers), it is sometimes easier (and less error-prone) to use a scripted-diff. When doing so, there will be 3 commits in sequence so that every commit compiles like so:
  1. Add `new_function`, make `old_function` a wrapper of `new_function`, divert all calls to `old_function` to `new_function` **in the local module only**
  2. Scripted-diff to divert all calls to `old_function` to `new_function` **in the rest of the codebase**
  3. Remove `old_function`

ACKs for top commit:
  jnewbery:
    utACK 67c9a83df19c6e2a2edb32336879204e7770b4a7
  laanwj:
    re-ACK 67c9a83df19c6e2a2edb32336879204e7770b4a7
  ryanofsky:
    Code review ACK 67c9a83df19c6e2a2edb32336879204e7770b4a7. Changes since last review:

Tree-SHA512: 8744aba2dd57a40cd2fedca809b0fe24d771bc60da1bffde89601999384aa0df428057a86644a3f72fbeedbc8b04db6c4fd264ea0db2e73c279e5acc6d056cbf

1 files changed, 64 insertions, 41 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index 2aafc0d3fb..38df71b994 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -167,17 +167,19 @@ namespace {
     std::set<int> setDirtyFileInfo;
 } // anon namespace
 
-CBlockIndex* LookupBlockIndex(const uint256& hash)
+CBlockIndex* BlockManager::LookupBlockIndex(const uint256& hash)
 {
     AssertLockHeld(cs_main);
-    BlockMap::const_iterator it = g_chainman.BlockIndex().find(hash);
-    return it == g_chainman.BlockIndex().end() ? nullptr : it->second;
+    assert(std::addressof(g_chainman.BlockIndex()) == std::addressof(m_block_index));
+    BlockMap::const_iterator it = m_block_index.find(hash);
+    return it == m_block_index.end() ? nullptr : it->second;
 }
 
-CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator)
+CBlockIndex* BlockManager::FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator)
 {
     AssertLockHeld(cs_main);
 
+    assert(std::addressof(g_chainman.m_blockman) == std::addressof(*this));
     // Find the latest block common to locator and chain - we expect that
     // locator.vHave is sorted descending by height.
     for (const uint256& hash : locator.vHave) {
@@ -682,7 +684,7 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
         return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND, "non-BIP68-final");
 
     CAmount nFees = 0;
-    if (!Consensus::CheckTxInputs(tx, state, m_view, GetSpendHeight(m_view), nFees)) {
+    if (!Consensus::CheckTxInputs(tx, state, m_view, g_chainman.m_blockman.GetSpendHeight(m_view), nFees)) {
         return false; // state filled in by CheckTxInputs
     }
 
@@ -1262,8 +1264,8 @@ void CoinsViews::InitCache()
 }
 
 CChainState::CChainState(CTxMemPool& mempool, BlockManager& blockman, uint256 from_snapshot_blockhash)
-    : m_blockman(blockman),
-      m_mempool(mempool),
+    : m_mempool(mempool),
+      m_blockman(blockman),
       m_from_snapshot_blockhash(from_snapshot_blockhash) {}
 
 void CChainState::InitCoinsDB(
@@ -1410,9 +1412,10 @@ bool CScriptCheck::operator()() {
     return VerifyScript(scriptSig, m_tx_out.scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, m_tx_out.nValue, cacheStore, *txdata), &error);
 }
 
-int GetSpendHeight(const CCoinsViewCache& inputs)
+int BlockManager::GetSpendHeight(const CCoinsViewCache& inputs)
 {
-    LOCK(cs_main);
+    AssertLockHeld(cs_main);
+    assert(std::addressof(g_chainman.m_blockman) == std::addressof(*this));
     CBlockIndex* pindexPrev = LookupBlockIndex(inputs.GetBestBlock());
     return pindexPrev->nHeight + 1;
 }
@@ -2767,7 +2770,7 @@ static SynchronizationState GetSynchronizationState(bool init)
     return SynchronizationState::INIT_DOWNLOAD;
 }
 
-static bool NotifyHeaderTip() LOCKS_EXCLUDED(cs_main) {
+static bool NotifyHeaderTip(CChainState& chainstate) LOCKS_EXCLUDED(cs_main) {
     bool fNotify = false;
     bool fInitialBlockDownload = false;
     static CBlockIndex* pindexHeaderOld = nullptr;
@@ -2778,7 +2781,8 @@ static bool NotifyHeaderTip() LOCKS_EXCLUDED(cs_main) {
 
         if (pindexHeader != pindexHeaderOld) {
             fNotify = true;
-            fInitialBlockDownload = ::ChainstateActive().IsInitialBlockDownload();
+            assert(std::addressof(::ChainstateActive()) == std::addressof(chainstate));
+            fInitialBlockDownload = chainstate.IsInitialBlockDownload();
             pindexHeaderOld = pindexHeader;
         }
     }
@@ -2895,10 +2899,6 @@ bool CChainState::ActivateBestChain(BlockValidationState &state, const CChainPar
     return true;
 }
 
-bool ActivateBestChain(BlockValidationState &state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock) {
-    return ::ChainstateActive().ActivateBestChain(state, chainparams, std::move(pblock));
-}
-
 bool CChainState::PreciousBlock(BlockValidationState& state, const CChainParams& params, CBlockIndex *pindex)
 {
     {
@@ -3398,14 +3398,14 @@ std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBloc
     return commitment;
 }
 
-//! Returns last CBlockIndex* that is a checkpoint
-static CBlockIndex* GetLastCheckpoint(const CCheckpointData& data) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
+CBlockIndex* BlockManager::GetLastCheckpoint(const CCheckpointData& data)
 {
     const MapCheckpoints& checkpoints = data.mapCheckpoints;
 
     for (const MapCheckpoints::value_type& i : reverse_iterate(checkpoints))
     {
         const uint256& hash = i.second;
+        assert(std::addressof(g_chainman.m_blockman) == std::addressof(*this));
         CBlockIndex* pindex = LookupBlockIndex(hash);
         if (pindex) {
             return pindex;
@@ -3423,7 +3423,7 @@ static CBlockIndex* GetLastCheckpoint(const CCheckpointData& data) EXCLUSIVE_LOC
  *  in ConnectBlock().
  *  Note that -reindex-chainstate skips the validation that happens here!
  */
-static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidationState& state, const CChainParams& params, const CBlockIndex* pindexPrev, int64_t nAdjustedTime) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
+static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidationState& state, BlockManager& blockman, const CChainParams& params, const CBlockIndex* pindexPrev, int64_t nAdjustedTime) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
     assert(pindexPrev != nullptr);
     const int nHeight = pindexPrev->nHeight + 1;
@@ -3438,7 +3438,8 @@ static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidatio
         // Don't accept any forks from the main chain prior to last checkpoint.
         // GetLastCheckpoint finds the last checkpoint in MapCheckpoints that's in our
         // BlockIndex().
-        CBlockIndex* pcheckpoint = GetLastCheckpoint(params.Checkpoints());
+        assert(std::addressof(g_chainman.m_blockman) == std::addressof(blockman));
+        CBlockIndex* pcheckpoint = blockman.GetLastCheckpoint(params.Checkpoints());
         if (pcheckpoint && nHeight < pcheckpoint->nHeight) {
             LogPrintf("ERROR: %s: forked chain older than last checkpoint (height %d)\n", __func__, nHeight);
             return state.Invalid(BlockValidationResult::BLOCK_CHECKPOINT, "bad-fork-prior-to-checkpoint");
@@ -3588,7 +3589,7 @@ bool BlockManager::AcceptBlockHeader(const CBlockHeader& block, BlockValidationS
             LogPrintf("ERROR: %s: prev block invalid\n", __func__);
             return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk");
         }
-        if (!ContextualCheckBlockHeader(block, state, chainparams, pindexPrev, GetAdjustedTime()))
+        if (!ContextualCheckBlockHeader(block, state, *this, chainparams, pindexPrev, GetAdjustedTime()))
             return error("%s: Consensus::ContextualCheckBlockHeader: %s, %s", __func__, hash.ToString(), state.ToString());
 
         /* Determine if this block descends from any block which has been found
@@ -3641,6 +3642,7 @@ bool BlockManager::AcceptBlockHeader(const CBlockHeader& block, BlockValidationS
 // Exposed wrapper for AcceptBlockHeader
 bool ChainstateManager::ProcessNewBlockHeaders(const std::vector<CBlockHeader>& headers, BlockValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex)
 {
+    assert(std::addressof(::ChainstateActive()) == std::addressof(ActiveChainstate()));
     AssertLockNotHeld(cs_main);
     {
         LOCK(cs_main);
@@ -3648,7 +3650,7 @@ bool ChainstateManager::ProcessNewBlockHeaders(const std::vector<CBlockHeader>&
             CBlockIndex *pindex = nullptr; // Use a temp pindex instead of ppindex to avoid a const_cast
             bool accepted = m_blockman.AcceptBlockHeader(
                 header, state, chainparams, &pindex);
-            ::ChainstateActive().CheckBlockIndex(chainparams.GetConsensus());
+            ActiveChainstate().CheckBlockIndex(chainparams.GetConsensus());
 
             if (!accepted) {
                 return false;
@@ -3658,8 +3660,8 @@ bool ChainstateManager::ProcessNewBlockHeaders(const std::vector<CBlockHeader>&
             }
         }
     }
-    if (NotifyHeaderTip()) {
-        if (::ChainstateActive().IsInitialBlockDownload() && ppindex && *ppindex) {
+    if (NotifyHeaderTip(ActiveChainstate())) {
+        if (ActiveChainstate().IsInitialBlockDownload() && ppindex && *ppindex) {
             LogPrintf("Synchronizing blockheaders, height: %d (~%.2f%%)\n", (*ppindex)->nHeight, 100.0/((*ppindex)->nHeight+(GetAdjustedTime() - (*ppindex)->GetBlockTime()) / Params().GetConsensus().nPowTargetSpacing) * (*ppindex)->nHeight);
         }
     }
@@ -3771,6 +3773,7 @@ bool CChainState::AcceptBlock(const std::shared_ptr<const CBlock>& pblock, Block
 bool ChainstateManager::ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<const CBlock> pblock, bool fForceProcessing, bool* fNewBlock)
 {
     AssertLockNotHeld(cs_main);
+    assert(std::addressof(::ChainstateActive()) == std::addressof(ActiveChainstate()));
 
     {
         CBlockIndex *pindex = nullptr;
@@ -3786,7 +3789,7 @@ bool ChainstateManager::ProcessNewBlock(const CChainParams& chainparams, const s
         bool ret = CheckBlock(*pblock, state, chainparams.GetConsensus());
         if (ret) {
             // Store to disk
-            ret = ::ChainstateActive().AcceptBlock(pblock, state, chainparams, &pindex, fForceProcessing, nullptr, fNewBlock);
+            ret = ActiveChainstate().AcceptBlock(pblock, state, chainparams, &pindex, fForceProcessing, nullptr, fNewBlock);
         }
         if (!ret) {
             GetMainSignals().BlockChecked(*pblock, state);
@@ -3794,20 +3797,27 @@ bool ChainstateManager::ProcessNewBlock(const CChainParams& chainparams, const s
         }
     }
 
-    NotifyHeaderTip();
+    NotifyHeaderTip(ActiveChainstate());
 
     BlockValidationState state; // Only used to report errors, not invalidity - ignore it
-    if (!::ChainstateActive().ActivateBestChain(state, chainparams, pblock))
+    if (!ActiveChainstate().ActivateBestChain(state, chainparams, pblock))
         return error("%s: ActivateBestChain failed (%s)", __func__, state.ToString());
 
     return true;
 }
 
-bool TestBlockValidity(BlockValidationState& state, const CChainParams& chainparams, const CBlock& block, CBlockIndex* pindexPrev, bool fCheckPOW, bool fCheckMerkleRoot)
+bool TestBlockValidity(BlockValidationState& state,
+                       const CChainParams& chainparams,
+                       CChainState& chainstate,
+                       const CBlock& block,
+                       CBlockIndex* pindexPrev,
+                       bool fCheckPOW,
+                       bool fCheckMerkleRoot)
 {
     AssertLockHeld(cs_main);
-    assert(pindexPrev && pindexPrev == ::ChainActive().Tip());
-    CCoinsViewCache viewNew(&::ChainstateActive().CoinsTip());
+    assert(std::addressof(::ChainstateActive()) == std::addressof(chainstate));
+    assert(pindexPrev && pindexPrev == chainstate.m_chain.Tip());
+    CCoinsViewCache viewNew(&chainstate.CoinsTip());
     uint256 block_hash(block.GetHash());
     CBlockIndex indexDummy(block);
     indexDummy.pprev = pindexPrev;
@@ -3815,13 +3825,14 @@ bool TestBlockValidity(BlockValidationState& state, const CChainParams& chainpar
     indexDummy.phashBlock = &block_hash;
 
     // NOTE: CheckBlockHeader is called by CheckBlock
-    if (!ContextualCheckBlockHeader(block, state, chainparams, pindexPrev, GetAdjustedTime()))
+    assert(std::addressof(g_chainman.m_blockman) == std::addressof(chainstate.m_blockman));
+    if (!ContextualCheckBlockHeader(block, state, chainstate.m_blockman, chainparams, pindexPrev, GetAdjustedTime()))
         return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__, state.ToString());
     if (!CheckBlock(block, state, chainparams.GetConsensus(), fCheckPOW, fCheckMerkleRoot))
         return error("%s: Consensus::CheckBlock: %s", __func__, state.ToString());
     if (!ContextualCheckBlock(block, state, chainparams.GetConsensus(), pindexPrev))
         return error("%s: Consensus::ContextualCheckBlock: %s", __func__, state.ToString());
-    if (!::ChainstateActive().ConnectBlock(block, state, &indexDummy, viewNew, chainparams, true))
+    if (!chainstate.ConnectBlock(block, state, &indexDummy, viewNew, chainparams, true))
         return false;
     assert(state.IsValid());
 
@@ -4167,7 +4178,7 @@ bool CChainState::LoadChainTip(const CChainParams& chainparams)
     }
 
     // Load pointer to end of best chain
-    CBlockIndex* pindex = LookupBlockIndex(coins_cache.GetBestBlock());
+    CBlockIndex* pindex = m_blockman.LookupBlockIndex(coins_cache.GetBestBlock());
     if (!pindex) {
         return false;
     }
@@ -4597,7 +4608,7 @@ 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;
@@ -4646,7 +4657,8 @@ 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 && !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)
@@ -4655,10 +4667,12 @@ void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFi
                     }
 
                     // process in case the block isn't known yet
-                    CBlockIndex* pindex = 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()) {
@@ -4672,12 +4686,14 @@ 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;
+                    assert(std::addressof(::ChainstateActive()) == std::addressof(*this));
                     if (!ActivateBestChain(state, chainparams, nullptr)) {
                         break;
                     }
                 }
 
-                NotifyHeaderTip();
+                assert(std::addressof(::ChainstateActive()) == std::addressof(*this));
+                NotifyHeaderTip(*this);
 
                 // Recursively process earlier encountered successors of this block
                 std::deque<uint256> queue;
@@ -4695,7 +4711,8 @@ 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());
@@ -4703,7 +4720,8 @@ void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFi
                         }
                         range.first++;
                         mapBlocksUnknownParent.erase(it);
-                        NotifyHeaderTip();
+                        assert(std::addressof(::ChainstateActive()) == std::addressof(*this));
+                        NotifyHeaderTip(*this);
                     }
                 }
             } catch (const std::exception& e) {
@@ -5141,6 +5159,7 @@ double GuessVerificationProgress(const ChainTxData& data, const CBlockIndex *pin
 }
 
 Optional<uint256> ChainstateManager::SnapshotBlockhash() const {
+    LOCK(::cs_main);  // for m_active_chainstate access
     if (m_active_chainstate != nullptr) {
         // If a snapshot chainstate exists, it will always be our active.
         return m_active_chainstate->m_from_snapshot_blockhash;
@@ -5187,13 +5206,14 @@ CChainState& ChainstateManager::InitializeChainstate(CTxMemPool& mempool, const
 
 CChainState& ChainstateManager::ActiveChainstate() const
 {
+    LOCK(::cs_main);
     assert(m_active_chainstate);
     return *m_active_chainstate;
 }
 
 bool ChainstateManager::IsSnapshotActive() const
 {
-    return m_snapshot_chainstate && m_active_chainstate == m_snapshot_chainstate.get();
+    return m_snapshot_chainstate && WITH_LOCK(::cs_main, return m_active_chainstate) == m_snapshot_chainstate.get();
 }
 
 CChainState& ChainstateManager::ValidatedChainstate() const
@@ -5224,7 +5244,10 @@ void ChainstateManager::Reset()
 {
     m_ibd_chainstate.reset();
     m_snapshot_chainstate.reset();
-    m_active_chainstate = nullptr;
+    {
+        LOCK(::cs_main);
+        m_active_chainstate = nullptr;
+    }
     m_snapshot_validated = false;
 }