Add Create*WalletDatabase functions

These functions doing the same things as WalletDatabase::Create,
CreateMock, and CreateDummy

src/wallet/walletdb.cpp

@@ -1023,3 +1023,22 @@ bool IsWalletLoaded(const fs::path& wallet_path)
 {
     return IsBDBWalletLoaded(wallet_path);
 }
+
+/** Return object for accessing database at specified path. */
+std::unique_ptr<BerkeleyDatabase> CreateWalletDatabase(const fs::path& path)
+{
+    std::string filename;
+    return MakeUnique<BerkeleyDatabase>(GetWalletEnv(path, filename), std::move(filename));
+}
+
+/** Return object for accessing dummy database with no read/write capabilities. */
+std::unique_ptr<BerkeleyDatabase> CreateDummyWalletDatabase()
+{
+    return MakeUnique<BerkeleyDatabase>();
+}
+
+/** Return object for accessing temporary in-memory database. */
+std::unique_ptr<BerkeleyDatabase> CreateMockWalletDatabase()
+{
+    return MakeUnique<BerkeleyDatabase>(std::make_shared<BerkeleyEnvironment>(), "");
+}

src/wallet/walletdb.h

@@ -293,4 +293,13 @@ bool ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue, st
 /** Return whether a wallet database is currently loaded. */
 bool IsWalletLoaded(const fs::path& wallet_path);
 
+/** Return object for accessing database at specified path. */
+std::unique_ptr<BerkeleyDatabase> CreateWalletDatabase(const fs::path& path);
+
+/** Return object for accessing dummy database with no read/write capabilities. */
+std::unique_ptr<BerkeleyDatabase> CreateDummyWalletDatabase();
+
+/** Return object for accessing temporary in-memory database. */
+std::unique_ptr<BerkeleyDatabase> CreateMockWalletDatabase();
+
 #endif // BITCOIN_WALLET_WALLETDB_H