validation: Add and use HaveTxsDownloaded where appropriate

Author: MarcoFalke

src/chain.h

@@ -294,6 +294,15 @@ class CBlockIndex
         return *phashBlock;
     }
 
+    /**
+     * Check whether this block's and all previous blocks' transactions have been
+     * downloaded (and stored to disk) at some point.
+     *
+     * Does not imply the transactions are consensus-valid (ConnectTip might fail)
+     * Does not imply the transactions are still stored on disk. (IsBlockPruned might return true)
+     */
+    bool HaveTxsDownloaded() const { return nChainTx != 0; }
+
     int64_t GetBlockTime() const
     {
         return (int64_t)nTime;

src/net_processing.cpp

@@ -566,7 +566,7 @@ static void FindNextBlocksToDownload(NodeId nodeid, unsigned int count, std::vec
                 return;
             }
             if (pindex->nStatus & BLOCK_HAVE_DATA || chainActive.Contains(pindex)) {
-                if (pindex->nChainTx)
+                if (pindex->HaveTxsDownloaded())
                     state->pindexLastCommonBlock = pindex;
             } else if (mapBlocksInFlight.count(pindex->GetBlockHash()) == 0) {
                 // The block is not already downloaded, and not yet in flight.
@@ -1124,7 +1124,7 @@ void static ProcessGetBlockData(CNode* pfrom, const CChainParams& chainparams, c
         LOCK(cs_main);
         const CBlockIndex* pindex = LookupBlockIndex(inv.hash);
         if (pindex) {
-            if (pindex->nChainTx && !pindex->IsValid(BLOCK_VALID_SCRIPTS) &&
+            if (pindex->HaveTxsDownloaded() && !pindex->IsValid(BLOCK_VALID_SCRIPTS) &&
                     pindex->IsValid(BLOCK_VALID_TREE)) {
                 // If we have the block and all of its parents, but have not yet validated it,
                 // we might be in the middle of connecting it (ie in the unlock of cs_main

src/rpc/blockchain.cpp

@@ -1458,7 +1458,7 @@ static UniValue getchaintips(const JSONRPCRequest& request)
         } else if (block->nStatus & BLOCK_FAILED_MASK) {
             // This block or one of its ancestors is invalid.
             status = "invalid";
-        } else if (block->nChainTx == 0) {
+        } else if (!block->HaveTxsDownloaded()) {
             // This block cannot be connected because full block data for it or one of its parents is missing.
             status = "headers-only";
         } else if (block->IsValid(BLOCK_VALID_SCRIPTS)) {

src/validation.cpp

@@ -2487,7 +2487,7 @@ CBlockIndex* CChainState::FindMostWorkChain() {
         CBlockIndex *pindexTest = pindexNew;
         bool fInvalidAncestor = false;
         while (pindexTest && !chainActive.Contains(pindexTest)) {
-            assert(pindexTest->nChainTx || pindexTest->nHeight == 0);
+            assert(pindexTest->HaveTxsDownloaded() || pindexTest->nHeight == 0);
 
             // Pruned nodes may have entries in setBlockIndexCandidates for
             // which block files have been deleted.  Remove those as candidates
@@ -2777,7 +2777,7 @@ bool CChainState::PreciousBlock(CValidationState& state, const CChainParams& par
             // call preciousblock 2**31-1 times on the same set of tips...
             nBlockReverseSequenceId--;
         }
-        if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && pindex->nChainTx) {
+        if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && pindex->HaveTxsDownloaded()) {
             setBlockIndexCandidates.insert(pindex);
             PruneBlockIndexCandidates();
         }
@@ -2838,7 +2838,7 @@ bool CChainState::InvalidateBlock(CValidationState& state, const CChainParams& c
     // add it again.
     BlockMap::iterator it = mapBlockIndex.begin();
     while (it != mapBlockIndex.end()) {
-        if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && !setBlockIndexCandidates.value_comp()(it->second, chainActive.Tip())) {
+        if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->HaveTxsDownloaded() && !setBlockIndexCandidates.value_comp()(it->second, chainActive.Tip())) {
             setBlockIndexCandidates.insert(it->second);
         }
         it++;
@@ -2868,7 +2868,7 @@ void CChainState::ResetBlockFailureFlags(CBlockIndex *pindex) {
         if (!it->second->IsValid() && it->second->GetAncestor(nHeight) == pindex) {
             it->second->nStatus &= ~BLOCK_FAILED_MASK;
             setDirtyBlockIndex.insert(it->second);
-            if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && setBlockIndexCandidates.value_comp()(chainActive.Tip(), it->second)) {
+            if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->HaveTxsDownloaded() && setBlockIndexCandidates.value_comp()(chainActive.Tip(), it->second)) {
                 setBlockIndexCandidates.insert(it->second);
             }
             if (it->second == pindexBestInvalid) {
@@ -2946,7 +2946,7 @@ void CChainState::ReceivedBlockTransactions(const CBlock& block, CBlockIndex* pi
     pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS);
     setDirtyBlockIndex.insert(pindexNew);
 
-    if (pindexNew->pprev == nullptr || pindexNew->pprev->nChainTx) {
+    if (pindexNew->pprev == nullptr || pindexNew->pprev->HaveTxsDownloaded()) {
         // If pindexNew is the genesis block or all parents are BLOCK_VALID_TRANSACTIONS.
         std::deque<CBlockIndex*> queue;
         queue.push_back(pindexNew);
@@ -3839,7 +3839,7 @@ bool CChainState::LoadBlockIndex(const Consensus::Params& consensus_params, CBlo
         // Pruned nodes may have deleted the block.
         if (pindex->nTx > 0) {
             if (pindex->pprev) {
-                if (pindex->pprev->nChainTx) {
+                if (pindex->pprev->HaveTxsDownloaded()) {
                     pindex->nChainTx = pindex->pprev->nChainTx + pindex->nTx;
                 } else {
                     pindex->nChainTx = 0;
@@ -3853,7 +3853,7 @@ bool CChainState::LoadBlockIndex(const Consensus::Params& consensus_params, CBlo
             pindex->nStatus |= BLOCK_FAILED_CHILD;
             setDirtyBlockIndex.insert(pindex);
         }
-        if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && (pindex->nChainTx || pindex->pprev == nullptr))
+        if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && (pindex->HaveTxsDownloaded() || pindex->pprev == nullptr))
             setBlockIndexCandidates.insert(pindex);
         if (pindex->nStatus & BLOCK_FAILED_MASK && (!pindexBestInvalid || pindex->nChainWork > pindexBestInvalid->nChainWork))
             pindexBestInvalid = pindex;
@@ -4222,7 +4222,7 @@ bool CChainState::RewindBlockIndex(const CChainParams& params)
                     ++ret.first;
                 }
             }
-        } else if (pindexIter->IsValid(BLOCK_VALID_TRANSACTIONS) && pindexIter->nChainTx) {
+        } else if (pindexIter->IsValid(BLOCK_VALID_TRANSACTIONS) && pindexIter->HaveTxsDownloaded()) {
             setBlockIndexCandidates.insert(pindexIter);
         }
     }
@@ -4523,7 +4523,7 @@ void CChainState::CheckBlockIndex(const Consensus::Params& consensusParams)
             assert(pindex->GetBlockHash() == consensusParams.hashGenesisBlock); // Genesis block's hash must match.
             assert(pindex == chainActive.Genesis()); // The current active chain's genesis block must be this block.
         }
-        if (pindex->nChainTx == 0) assert(pindex->nSequenceId <= 0);  // nSequenceId can't be set positive for blocks that aren't linked (negative is used for preciousblock)
+        if (!pindex->HaveTxsDownloaded()) assert(pindex->nSequenceId <= 0); // nSequenceId can't be set positive for blocks that aren't linked (negative is used for preciousblock)
         // VALID_TRANSACTIONS is equivalent to nTx > 0 for all nodes (whether or not pruning has occurred).
         // HAVE_DATA is only equivalent to nTx > 0 (or VALID_TRANSACTIONS) if no pruning has occurred.
         if (!fHavePruned) {
@@ -4536,9 +4536,9 @@ void CChainState::CheckBlockIndex(const Consensus::Params& consensusParams)
         }
         if (pindex->nStatus & BLOCK_HAVE_UNDO) assert(pindex->nStatus & BLOCK_HAVE_DATA);
         assert(((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS) == (pindex->nTx > 0)); // This is pruning-independent.
-        // All parents having had data (at some point) is equivalent to all parents being VALID_TRANSACTIONS, which is equivalent to nChainTx being set.
-        assert((pindexFirstNeverProcessed != nullptr) == (pindex->nChainTx == 0)); // nChainTx != 0 is used to signal that all parent blocks have been processed (but may have been pruned).
-        assert((pindexFirstNotTransactionsValid != nullptr) == (pindex->nChainTx == 0));
+        // All parents having had data (at some point) is equivalent to all parents being VALID_TRANSACTIONS, which is equivalent to HaveTxsDownloaded().
+        assert((pindexFirstNeverProcessed == nullptr) == pindex->HaveTxsDownloaded());
+        assert((pindexFirstNotTransactionsValid == nullptr) == pindex->HaveTxsDownloaded());
         assert(pindex->nHeight == nHeight); // nHeight must be consistent.
         assert(pindex->pprev == nullptr || pindex->nChainWork >= pindex->pprev->nChainWork); // For every block except the genesis block, the chainwork must be larger than the parent's.
         assert(nHeight < 2 || (pindex->pskip && (pindex->pskip->nHeight < nHeight))); // The pskip pointer must point back for all but the first 2 blocks.