Merge bitcoin/bitcoin#30742: kernel: Use spans instead of vectors for passing block headers to validation functions

a2955f0979 validation: Use span for ImportBlocks paths (TheCharlatan)
20515ea3f5 validation: Use span for CalculateClaimedHeadersWork (TheCharlatan)
52575e96e7 validation: Use span for ProcessNewBlockHeaders (TheCharlatan)

Pull request description:

  Makes it friendlier for potential future users of the kernel library if they do not store the headers in a std::vector, but can guarantee contiguous memory.

  Take this opportunity to also change the argument of ImportBlocks previously taking a `std::vector` to a `std::span`.

ACKs for top commit:
  stickies-v:
    re-ACK a2955f0979 - no changes except further walking the ~file~ path of modernizing variable names.
  maflcko:
    ACK a2955f0979 🕑
  achow101:
    ACK a2955f0979
  danielabrozzoni:
    ACK a2955f0979

Tree-SHA512: 8b07f4ad26e270b65600d1968cd78847b85caca5bfbb83fd9860389f26656b1d9a40b85e0990339f50403d18cedcd2456990054f3b8b0bedce943e50222d2709

src/net_processing.cpp

@@ -4753,7 +4753,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
                 MaybeSendGetHeaders(pfrom, GetLocator(m_chainman.m_best_header), *peer);
             }
             return;
-        } else if (prev_block->nChainWork + CalculateClaimedHeadersWork({cmpctblock.header}) < GetAntiDoSWorkThreshold()) {
+        } else if (prev_block->nChainWork + CalculateClaimedHeadersWork({{cmpctblock.header}}) < GetAntiDoSWorkThreshold()) {
             // If we get a low-work header in a compact block, we can ignore it.
             LogDebug(BCLog::NET, "Ignoring low-work compact block from peer %d\n", pfrom.GetId());
             return;
@@ -4766,7 +4766,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
 
         const CBlockIndex *pindex = nullptr;
         BlockValidationState state;
-        if (!m_chainman.ProcessNewBlockHeaders({cmpctblock.header}, /*min_pow_checked=*/true, state, &pindex)) {
+        if (!m_chainman.ProcessNewBlockHeaders({{cmpctblock.header}}, /*min_pow_checked=*/true, state, &pindex)) {
             if (state.IsInvalid()) {
                 MaybePunishNodeForBlock(pfrom.GetId(), state, /*via_compact_block=*/true, "invalid header via cmpctblock");
                 return;
@@ -5070,7 +5070,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             mapBlockSource.emplace(hash, std::make_pair(pfrom.GetId(), true));
 
             // Check claimed work on this block against our anti-dos thresholds.
-            if (prev_block && prev_block->nChainWork + CalculateClaimedHeadersWork({pblock->GetBlockHeader()}) >= GetAntiDoSWorkThreshold()) {
+            if (prev_block && prev_block->nChainWork + CalculateClaimedHeadersWork({{pblock->GetBlockHeader()}}) >= GetAntiDoSWorkThreshold()) {
                 min_pow_checked = true;
             }
         }

src/node/blockstorage.cpp

@@ -1210,7 +1210,7 @@ public:
     }
 };
 
-void ImportBlocks(ChainstateManager& chainman, std::vector<fs::path> vImportFiles)
+void ImportBlocks(ChainstateManager& chainman, std::span<const fs::path> import_paths)
 {
     ImportingNow imp{chainman.m_blockman.m_importing};
 
@@ -1245,7 +1245,7 @@ void ImportBlocks(ChainstateManager& chainman, std::vector<fs::path> vImportFile
     }
 
     // -loadblock=
-    for (const fs::path& path : vImportFiles) {
+    for (const fs::path& path : import_paths) {
         AutoFile file{fsbridge::fopen(path, "rb")};
         if (!file.IsNull()) {
             LogPrintf("Importing blocks file %s...\n", fs::PathToString(path));

src/node/blockstorage.h

@@ -29,6 +29,7 @@
 #include <memory>
 #include <optional>
 #include <set>
+#include <span>
 #include <string>
 #include <unordered_map>
 #include <utility>
@@ -429,7 +430,7 @@ public:
     void CleanupBlockRevFiles() const;
 };
 
-void ImportBlocks(ChainstateManager& chainman, std::vector<fs::path> vImportFiles);
+void ImportBlocks(ChainstateManager& chainman, std::span<const fs::path> import_paths);
 } // namespace node
 
 #endif // BITCOIN_NODE_BLOCKSTORAGE_H

src/rpc/mining.cpp

@@ -1096,7 +1096,7 @@ static RPCHelpMan submitheader()
     }
 
     BlockValidationState state;
-    chainman.ProcessNewBlockHeaders({h}, /*min_pow_checked=*/true, state);
+    chainman.ProcessNewBlockHeaders({{h}}, /*min_pow_checked=*/true, state);
     if (state.IsValid()) return UniValue::VNULL;
     if (state.IsError()) {
         throw JSONRPCError(RPC_VERIFY_ERROR, state.ToString());

src/test/blockfilter_index_tests.cpp

@@ -103,7 +103,7 @@ bool BuildChainTestingSetup::BuildChain(const CBlockIndex* pindex,
         CBlockHeader header = block->GetBlockHeader();
 
         BlockValidationState state;
-        if (!Assert(m_node.chainman)->ProcessNewBlockHeaders({header}, true, state, &pindex)) {
+        if (!Assert(m_node.chainman)->ProcessNewBlockHeaders({{header}}, true, state, &pindex)) {
             return false;
         }
     }

src/test/fuzz/utxo_snapshot.cpp

@@ -58,7 +58,7 @@ void initialize_chain()
         auto& chainman{*setup->m_node.chainman};
         for (const auto& block : chain) {
             BlockValidationState dummy;
-            bool processed{chainman.ProcessNewBlockHeaders({*block}, true, dummy)};
+            bool processed{chainman.ProcessNewBlockHeaders({{block->GetBlockHeader()}}, true, dummy)};
             Assert(processed);
             const auto* index{WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(block->GetHash()))};
             Assert(index);
@@ -137,7 +137,7 @@ void utxo_snapshot_fuzz(FuzzBufferType buffer)
         if constexpr (!INVALID) {
             for (const auto& block : *g_chain) {
                 BlockValidationState dummy;
-                bool processed{chainman.ProcessNewBlockHeaders({*block}, true, dummy)};
+                bool processed{chainman.ProcessNewBlockHeaders({{block->GetBlockHeader()}}, true, dummy)};
                 Assert(processed);
                 const auto* index{WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(block->GetHash()))};
                 Assert(index);

src/test/validation_block_tests.cpp

@@ -101,7 +101,7 @@ std::shared_ptr<CBlock> MinerTestingSetup::FinalizeBlock(std::shared_ptr<CBlock>
     // submit block header, so that miner can get the block height from the
     // global state and the node has the topology of the chain
     BlockValidationState ignored;
-    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders({pblock->GetBlockHeader()}, true, ignored));
+    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders({{pblock->GetBlockHeader()}}, true, ignored));
 
     return pblock;
 }

src/validation.cpp

@@ -70,6 +70,7 @@
 #include <numeric>
 #include <optional>
 #include <ranges>
+#include <span>
 #include <string>
 #include <tuple>
 #include <utility>
@@ -4136,7 +4137,7 @@ bool IsBlockMutated(const CBlock& block, bool check_witness_root)
     return false;
 }
 
-arith_uint256 CalculateClaimedHeadersWork(const std::vector<CBlockHeader>& headers)
+arith_uint256 CalculateClaimedHeadersWork(std::span<const CBlockHeader> headers)
 {
     arith_uint256 total_work{0};
     for (const CBlockHeader& header : headers) {
@@ -4384,7 +4385,7 @@ bool ChainstateManager::AcceptBlockHeader(const CBlockHeader& block, BlockValida
 }
 
 // Exposed wrapper for AcceptBlockHeader
-bool ChainstateManager::ProcessNewBlockHeaders(const std::vector<CBlockHeader>& headers, bool min_pow_checked, BlockValidationState& state, const CBlockIndex** ppindex)
+bool ChainstateManager::ProcessNewBlockHeaders(std::span<const CBlockHeader> headers, bool min_pow_checked, BlockValidationState& state, const CBlockIndex** ppindex)
 {
     AssertLockNotHeld(cs_main);
     {

src/validation.h

@@ -39,6 +39,7 @@
 #include <memory>
 #include <optional>
 #include <set>
+#include <span>
 #include <stdint.h>
 #include <string>
 #include <thread>
@@ -407,7 +408,7 @@ bool HasValidProofOfWork(const std::vector<CBlockHeader>& headers, const Consens
 bool IsBlockMutated(const CBlock& block, bool check_witness_root);
 
 /** Return the sum of the claimed work on a given set of headers. No verification of PoW is done. */
-arith_uint256 CalculateClaimedHeadersWork(const std::vector<CBlockHeader>& headers);
+arith_uint256 CalculateClaimedHeadersWork(std::span<const CBlockHeader> headers);
 
 enum class VerifyDBResult {
     SUCCESS,
@@ -1217,12 +1218,12 @@ public:
      * May not be called in a
      * validationinterface callback.
      *
-     * @param[in]  block The block headers themselves
+     * @param[in]  headers The block headers themselves
      * @param[in]  min_pow_checked  True if proof-of-work anti-DoS checks have been done by caller for headers chain
      * @param[out] state This may be set to an Error state if any error occurred processing them
      * @param[out] ppindex If set, the pointer will be set to point to the last new block index object for the given headers
      */
-    bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& block, bool min_pow_checked, BlockValidationState& state, const CBlockIndex** ppindex = nullptr) LOCKS_EXCLUDED(cs_main);
+    bool ProcessNewBlockHeaders(std::span<const CBlockHeader> headers, bool min_pow_checked, BlockValidationState& state, const CBlockIndex** ppindex = nullptr) LOCKS_EXCLUDED(cs_main);
 
     /**
      * Sufficiently validate a block for disk storage (and store on disk).