db: Make reusable base class for index databases.

src/txdb.cpp

@@ -415,8 +415,12 @@ bool CCoinsViewDB::Upgrade() {
     return !ShutdownRequested();
 }
 
+BaseIndexDB::BaseIndexDB(const fs::path& path, size_t n_cache_size, bool f_memory, bool f_wipe, bool f_obfuscate) :
+    CDBWrapper(path, n_cache_size, f_memory, f_wipe, f_obfuscate)
+{}
+
 TxIndexDB::TxIndexDB(size_t n_cache_size, bool f_memory, bool f_wipe) :
-    CDBWrapper(GetDataDir() / "indexes" / "txindex", n_cache_size, f_memory, f_wipe)
+    BaseIndexDB(GetDataDir() / "indexes" / "txindex", n_cache_size, f_memory, f_wipe)
 {}
 
 bool TxIndexDB::ReadTxPos(const uint256 &txid, CDiskTxPos& pos) const
@@ -433,7 +437,7 @@ bool TxIndexDB::WriteTxs(const std::vector<std::pair<uint256, CDiskTxPos>>& v_po
     return WriteBatch(batch);
 }
 
-bool TxIndexDB::ReadBestBlock(CBlockLocator& locator) const
+bool BaseIndexDB::ReadBestBlock(CBlockLocator& locator) const
 {
     bool success = Read(DB_BEST_BLOCK, locator);
     if (!success) {
@@ -442,7 +446,7 @@ bool TxIndexDB::ReadBestBlock(CBlockLocator& locator) const
     return success;
 }
 
-bool TxIndexDB::WriteBestBlock(const CBlockLocator& locator)
+bool BaseIndexDB::WriteBestBlock(const CBlockLocator& locator)
 {
     return Write(DB_BEST_BLOCK, locator);
 }

src/txdb.h

@@ -123,6 +123,19 @@ class CBlockTreeDB : public CDBWrapper
     bool LoadBlockIndexGuts(const Consensus::Params& consensusParams, std::function<CBlockIndex*(const uint256&)> insertBlockIndex);
 };
 
+class BaseIndexDB : public CDBWrapper
+{
+public:
+    BaseIndexDB(const fs::path& path, size_t n_cache_size,
+                bool f_memory = false, bool f_wipe = false, bool f_obfuscate = false);
+
+    /// Read block locator of the chain that the index is in sync with.
+    bool ReadBestBlock(CBlockLocator& locator) const;
+
+    /// Write block locator of the chain that the index is in sync with.
+    bool WriteBestBlock(const CBlockLocator& locator);
+};
+
 /**
  * Access to the txindex database (indexes/txindex/)
  *
@@ -132,7 +145,7 @@ class CBlockTreeDB : public CDBWrapper
  * and block index entries may not be flushed to disk until after this database
  * is updated.
  */
-class TxIndexDB : public CDBWrapper
+class TxIndexDB : public BaseIndexDB
 {
 public:
     explicit TxIndexDB(size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
@@ -144,12 +157,6 @@ class TxIndexDB : public CDBWrapper
     /// Write a batch of transaction positions to the DB.
     bool WriteTxs(const std::vector<std::pair<uint256, CDiskTxPos>>& v_pos);
 
-    /// Read block locator of the chain that the txindex is in sync with.
-    bool ReadBestBlock(CBlockLocator& locator) const;
-
-    /// Write block locator of the chain that the txindex is in sync with.
-    bool WriteBestBlock(const CBlockLocator& locator);
-
     /// Migrate txindex data from the block tree DB, where it may be for older nodes that have not
     /// been upgraded yet to the new database.
     bool MigrateData(CBlockTreeDB& block_tree_db, const CBlockLocator& best_locator);