refactor: move EvoDb cache size to constructor, use std::unique_ptr

To harmonize with the rest of the `CDBWrapper` instantiations needed
for the next commit.

Author: kwvg

src/evo/evodb.cpp

@@ -32,10 +32,10 @@ void CEvoDBScopedCommitter::Rollback()
     evoDB.RollbackCurTransaction();
 }
 
-CEvoDB::CEvoDB(size_t nCacheSize, bool fMemory, bool fWipe) :
-    db{fMemory ? "" : (gArgs.GetDataDirNet() / "evodb"), nCacheSize, fMemory, fWipe},
-    rootBatch{db},
-    rootDBTransaction{db, rootBatch},
+CEvoDB::CEvoDB(bool fMemory, bool fWipe) :
+    db{std::make_unique<CDBWrapper>(fMemory ? "" : (gArgs.GetDataDirNet() / "evodb"), 64 << 20, fMemory, fWipe)},
+    rootBatch{*db},
+    rootDBTransaction{*db, rootBatch},
     curDBTransaction{rootDBTransaction, rootDBTransaction}
 {
 }
@@ -59,7 +59,7 @@ bool CEvoDB::CommitRootTransaction()
     LOCK(cs);
     assert(curDBTransaction.IsClean());
     rootDBTransaction.Commit();
-    bool ret = db.WriteBatch(rootBatch);
+    bool ret = db->WriteBatch(rootBatch);
     rootBatch.Clear();
     return ret;
 }

src/evo/evodb.h

@@ -36,7 +36,7 @@ class CEvoDB
 public:
     Mutex cs;
 private:
-    CDBWrapper db;
+    std::unique_ptr<CDBWrapper> db;
 
     using RootTransaction = CDBTransaction<CDBWrapper, CDBBatch>;
     using CurTransaction = CDBTransaction<RootTransaction, RootTransaction>;
@@ -49,7 +49,7 @@ class CEvoDB
     CEvoDB() = delete;
     CEvoDB(const CEvoDB&) = delete;
     CEvoDB& operator=(const CEvoDB&) = delete;
-    explicit CEvoDB(size_t nCacheSize, bool fMemory = false, bool fWipe = false);
+    explicit CEvoDB(bool fMemory, bool fWipe);
     ~CEvoDB();
 
     std::unique_ptr<CEvoDBScopedCommitter> BeginTransaction() EXCLUSIVE_LOCKS_REQUIRED(!cs)
@@ -94,7 +94,7 @@ class CEvoDB
 
     CDBWrapper& GetRawDB()
     {
-        return db;
+        return *db;
     }
 
     [[nodiscard]] size_t GetMemoryUsage() const
@@ -104,7 +104,7 @@ class CEvoDB
 
     bool CommitRootTransaction() EXCLUSIVE_LOCKS_REQUIRED(!cs);
 
-    bool IsEmpty() { return db.IsEmpty(); }
+    bool IsEmpty() { return db->IsEmpty(); }
 
     bool VerifyBestBlock(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(!cs);
     void WriteBestBlock(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(!cs);

src/node/chainstate.cpp

@@ -71,9 +71,8 @@ std::optional<ChainstateLoadingError> LoadChainstate(bool fReset,
 
     LOCK(cs_main);
 
-    int64_t nEvoDbCache{64 * 1024 * 1024}; // TODO
     evodb.reset();
-    evodb = std::make_unique<CEvoDB>(nEvoDbCache, false, fReset || fReindexChainState);
+    evodb = std::make_unique<CEvoDB>(/*fMemory=*/false, /*fWipe=*/fReset || fReindexChainState);
 
     mnhf_manager.reset();
     mnhf_manager = std::make_unique<CMNHFManager>(*evodb);

src/test/util/setup_common.cpp

@@ -214,7 +214,7 @@ BasicTestingSetup::BasicTestingSetup(const std::string& chainName, const std::ve
     m_node.connman = std::make_unique<ConnmanTestMsg>(0x1337, 0x1337, *m_node.addrman, *m_node.netgroupman); // Deterministic randomness for tests.
 
     fCheckBlockIndex = true;
-    m_node.evodb = std::make_unique<CEvoDB>(1 << 20, true, true);
+    m_node.evodb = std::make_unique<CEvoDB>(/*fMemory=*/true, /*fWipe=*/true);
     m_node.mnhf_manager = std::make_unique<CMNHFManager>(*m_node.evodb);
     m_node.cpoolman = std::make_unique<CCreditPoolManager>(*m_node.evodb);
     static bool noui_connected = false;