chainparams: add blockhash to AssumeutxoData

This allows us to reference assumeutxo configuration by blockhash as
well as height; this is helpful in future changes when we want to
reference assumeutxo configurations before the block index is loaded.

Author: jamesob

src/kernel/chainparams.cpp

@@ -172,8 +172,8 @@ class CMainParams : public CChainParams {
             }
         };
 
-        m_assumeutxo_data = MapAssumeutxo{
-         // TODO to be specified in a future patch.
+        m_assumeutxo_data = {
+            // TODO to be specified in a future patch.
         };
 
         chainTxData = ChainTxData{
@@ -266,7 +266,7 @@ class CTestNetParams : public CChainParams {
             }
         };
 
-        m_assumeutxo_data = MapAssumeutxo{
+        m_assumeutxo_data = {
             // TODO to be specified in a future patch.
         };
 
@@ -477,14 +477,12 @@ class CRegTestParams : public CChainParams
             }
         };
 
-        m_assumeutxo_data = MapAssumeutxo{
-            {
-                110,
-                {AssumeutxoHash{uint256S("0x1ebbf5850204c0bdb15bf030f47c7fe91d45c44c712697e4509ba67adb01c618")}, 110},
-            },
+        m_assumeutxo_data = {
             {
-                200,
-                {AssumeutxoHash{uint256S("0x51c8d11d8b5c1de51543c579736e786aa2736206d1e11e627568029ce092cf62")}, 200},
+                .height = 110,
+                .hash_serialized = AssumeutxoHash{uint256S("0x1ebbf5850204c0bdb15bf030f47c7fe91d45c44c712697e4509ba67adb01c618")},
+                .nChainTx = 110,
+                .blockhash = uint256S("0x696e92821f65549c7ee134edceeeeaaa4105647a3c4fd9f298c0aec0ab50425c")
             },
         };
 

src/kernel/chainparams.h

@@ -12,6 +12,7 @@
 #include <uint256.h>
 #include <util/chaintype.h>
 #include <util/hash_type.h>
+#include <util/vector.h>
 
 #include <cstdint>
 #include <iterator>
@@ -44,17 +45,21 @@ struct AssumeutxoHash : public BaseHash<uint256> {
  * as valid.
  */
 struct AssumeutxoData {
+    int height;
+
     //! The expected hash of the deserialized UTXO set.
-    const AssumeutxoHash hash_serialized;
+    AssumeutxoHash hash_serialized;
 
     //! Used to populate the nChainTx value, which is used during BlockManager::LoadBlockIndex().
     //!
     //! We need to hardcode the value here because this is computed cumulatively using block data,
     //! which we do not necessarily have at the time of snapshot load.
-    const unsigned int nChainTx;
-};
+    unsigned int nChainTx;
 
-using MapAssumeutxo = std::map<int, const AssumeutxoData>;
+    //! The hash of the base block for this snapshot. Used to refer to assumeutxo data
+    //! prior to having a loaded blockindex.
+    uint256 blockhash;
+};
 
 /**
  * Holds various statistics on transactions within a chain. Used to estimate
@@ -114,9 +119,14 @@ class CChainParams
     const std::vector<uint8_t>& FixedSeeds() const { return vFixedSeeds; }
     const CCheckpointData& Checkpoints() const { return checkpointData; }
 
-    //! Get allowed assumeutxo configuration.
-    //! @see ChainstateManager
-    const MapAssumeutxo& Assumeutxo() const { return m_assumeutxo_data; }
+    std::optional<AssumeutxoData> AssumeutxoForHeight(int height) const
+    {
+        return FindFirst(m_assumeutxo_data, [&](const auto& d) { return d.height == height; });
+    }
+    std::optional<AssumeutxoData> AssumeutxoForBlockhash(const uint256& blockhash) const
+    {
+        return FindFirst(m_assumeutxo_data, [&](const auto& d) { return d.blockhash == blockhash; });
+    }
 
     const ChainTxData& TxData() const { return chainTxData; }
 
@@ -169,7 +179,7 @@ class CChainParams
     bool fDefaultConsistencyChecks;
     bool m_is_mockable_chain;
     CCheckpointData checkpointData;
-    MapAssumeutxo m_assumeutxo_data;
+    std::vector<AssumeutxoData> m_assumeutxo_data;
     ChainTxData chainTxData;
 };
 

src/test/validation_chainstatemanager_tests.cpp

@@ -289,10 +289,10 @@ struct SnapshotTestSetup : TestChain100Setup {
             BOOST_CHECK(!chainman.ActiveChain().Genesis()->IsAssumedValid());
         }
 
-        const AssumeutxoData& au_data = *ExpectedAssumeutxo(snapshot_height, ::Params());
+        const auto& au_data = ::Params().AssumeutxoForHeight(snapshot_height);
         const CBlockIndex* tip = WITH_LOCK(chainman.GetMutex(), return chainman.ActiveTip());
 
-        BOOST_CHECK_EQUAL(tip->nChainTx, au_data.nChainTx);
+        BOOST_CHECK_EQUAL(tip->nChainTx, au_data->nChainTx);
 
         // To be checked against later when we try loading a subsequent snapshot.
         uint256 loaded_snapshot_blockhash{*chainman.SnapshotBlockhash()};

src/test/validation_tests.cpp

@@ -132,17 +132,17 @@ BOOST_AUTO_TEST_CASE(test_assumeutxo)
     std::vector<int> bad_heights{0, 100, 111, 115, 209, 211};
 
     for (auto empty : bad_heights) {
-        const auto out = ExpectedAssumeutxo(empty, *params);
+        const auto out = params->AssumeutxoForHeight(empty);
         BOOST_CHECK(!out);
     }
 
-    const auto out110 = *ExpectedAssumeutxo(110, *params);
+    const auto out110 = *params->AssumeutxoForHeight(110);
     BOOST_CHECK_EQUAL(out110.hash_serialized.ToString(), "1ebbf5850204c0bdb15bf030f47c7fe91d45c44c712697e4509ba67adb01c618");
     BOOST_CHECK_EQUAL(out110.nChainTx, 110U);
 
-    const auto out210 = *ExpectedAssumeutxo(200, *params);
-    BOOST_CHECK_EQUAL(out210.hash_serialized.ToString(), "51c8d11d8b5c1de51543c579736e786aa2736206d1e11e627568029ce092cf62");
-    BOOST_CHECK_EQUAL(out210.nChainTx, 200U);
+    const auto out110_2 = *params->AssumeutxoForBlockhash(uint256S("0x696e92821f65549c7ee134edceeeeaaa4105647a3c4fd9f298c0aec0ab50425c"));
+    BOOST_CHECK_EQUAL(out110_2.hash_serialized.ToString(), "1ebbf5850204c0bdb15bf030f47c7fe91d45c44c712697e4509ba67adb01c618");
+    BOOST_CHECK_EQUAL(out110_2.nChainTx, 110U);
 }
 
 BOOST_AUTO_TEST_SUITE_END()

src/util/vector.h

@@ -5,7 +5,9 @@
 #ifndef BITCOIN_UTIL_VECTOR_H
 #define BITCOIN_UTIL_VECTOR_H
 
+#include <functional>
 #include <initializer_list>
+#include <optional>
 #include <type_traits>
 #include <utility>
 #include <vector>
@@ -67,4 +69,15 @@ inline void ClearShrink(V& v) noexcept
     V{}.swap(v);
 }
 
+template<typename V, typename L>
+inline std::optional<V> FindFirst(const std::vector<V>& vec, const L fnc)
+{
+    for (const auto& el : vec) {
+        if (fnc(el)) {
+            return el;
+        }
+    }
+    return std::nullopt;
+}
+
 #endif // BITCOIN_UTIL_VECTOR_H

src/validation.cpp

@@ -5099,18 +5099,6 @@ Chainstate& ChainstateManager::InitializeChainstate(CTxMemPool* mempool)
     return *m_active_chainstate;
 }
 
-const AssumeutxoData* ExpectedAssumeutxo(
-    const int height, const CChainParams& chainparams)
-{
-    const MapAssumeutxo& valid_assumeutxos_map = chainparams.Assumeutxo();
-    const auto assumeutxo_found = valid_assumeutxos_map.find(height);
-
-    if (assumeutxo_found != valid_assumeutxos_map.end()) {
-        return &assumeutxo_found->second;
-    }
-    return nullptr;
-}
-
 [[nodiscard]] static bool DeleteCoinsDBFromDisk(const fs::path db_path, bool is_snapshot)
     EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
 {
@@ -5295,15 +5283,15 @@ bool ChainstateManager::PopulateAndValidateSnapshot(
     CBlockIndex* snapshot_start_block = WITH_LOCK(::cs_main, return m_blockman.LookupBlockIndex(base_blockhash));
 
     if (!snapshot_start_block) {
-        // Needed for ComputeUTXOStats and ExpectedAssumeutxo to determine the
+        // Needed for ComputeUTXOStats to determine the
         // height and to avoid a crash when base_blockhash.IsNull()
         LogPrintf("[snapshot] Did not find snapshot start blockheader %s\n",
                   base_blockhash.ToString());
         return false;
     }
 
     int base_height = snapshot_start_block->nHeight;
-    auto maybe_au_data = ExpectedAssumeutxo(base_height, GetParams());
+    const auto& maybe_au_data = GetParams().AssumeutxoForHeight(base_height);
 
     if (!maybe_au_data) {
         LogPrintf("[snapshot] assumeutxo height in snapshot metadata not recognized "
@@ -5572,7 +5560,7 @@ SnapshotCompletionResult ChainstateManager::MaybeCompleteSnapshotValidation()
     CCoinsViewDB& ibd_coins_db = m_ibd_chainstate->CoinsDB();
     m_ibd_chainstate->ForceFlushStateToDisk();
 
-    auto maybe_au_data = ExpectedAssumeutxo(curr_height, m_options.chainparams);
+    const auto& maybe_au_data = m_options.chainparams.AssumeutxoForHeight(curr_height);
     if (!maybe_au_data) {
         LogPrintf("[snapshot] assumeutxo data not found for height "
             "(%d) - refusing to validate snapshot\n", curr_height);

src/validation.h

@@ -1242,15 +1242,6 @@ bool DeploymentEnabled(const ChainstateManager& chainman, DEP dep)
     return DeploymentEnabled(chainman.GetConsensus(), dep);
 }
 
-/**
- * Return the expected assumeutxo value for a given height, if one exists.
- *
- * @param[in] height Get the assumeutxo value for this height.
- *
- * @returns empty if no assumeutxo configuration exists for the given height.
- */
-const AssumeutxoData* ExpectedAssumeutxo(const int height, const CChainParams& params);
-
 /** Identifies blocks that overwrote an existing coinbase output in the UTXO set (see BIP30) */
 bool IsBIP30Repeat(const CBlockIndex& block_index);