1 files changed, 42 insertions, 22 deletions

diff --git a/src/wallet/db.h b/src/wallet/db.h
index f09844c37e..d4c590fac7 100644
--- a/src/wallet/db.h
+++ b/src/wallet/db.h
@@ -22,14 +22,33 @@ struct bilingual_str;
 namespace wallet {
 void SplitWalletPath(const fs::path& wallet_path, fs::path& env_directory, std::string& database_filename);
 
+class DatabaseCursor
+{
+public:
+    explicit DatabaseCursor() {}
+    virtual ~DatabaseCursor() {}
+
+    DatabaseCursor(const DatabaseCursor&) = delete;
+    DatabaseCursor& operator=(const DatabaseCursor&) = delete;
+
+    enum class Status
+    {
+        FAIL,
+        MORE,
+        DONE,
+    };
+
+    virtual Status Next(DataStream& key, DataStream& value) { return Status::FAIL; }
+};
+
 /** RAII class that provides access to a WalletDatabase */
 class DatabaseBatch
 {
 private:
-    virtual bool ReadKey(CDataStream&& key, CDataStream& value) = 0;
-    virtual bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite=true) = 0;
-    virtual bool EraseKey(CDataStream&& key) = 0;
-    virtual bool HasKey(CDataStream&& key) = 0;
+    virtual bool ReadKey(DataStream&& key, DataStream& value) = 0;
+    virtual bool WriteKey(DataStream&& key, DataStream&& value, bool overwrite = true) = 0;
+    virtual bool EraseKey(DataStream&& key) = 0;
+    virtual bool HasKey(DataStream&& key) = 0;
 
 public:
     explicit DatabaseBatch() {}
@@ -44,7 +63,7 @@ public:
     template <typename K, typename T>
     bool Read(const K& key, T& value)
     {
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        DataStream ssKey{};
         ssKey.reserve(1000);
         ssKey << key;
 
@@ -61,7 +80,7 @@ public:
     template <typename K, typename T>
     bool Write(const K& key, const T& value, bool fOverwrite = true)
     {
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        DataStream ssKey{};
         ssKey.reserve(1000);
         ssKey << key;
 
@@ -75,7 +94,7 @@ public:
     template <typename K>
     bool Erase(const K& key)
     {
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        DataStream ssKey{};
         ssKey.reserve(1000);
         ssKey << key;
 
@@ -85,16 +104,14 @@ public:
     template <typename K>
     bool Exists(const K& key)
     {
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        DataStream ssKey{};
         ssKey.reserve(1000);
         ssKey << key;
 
         return HasKey(std::move(ssKey));
     }
 
-    virtual bool StartCursor() = 0;
-    virtual bool ReadAtCursor(CDataStream& ssKey, CDataStream& ssValue, bool& complete) = 0;
-    virtual void CloseCursor() = 0;
+    virtual std::unique_ptr<DatabaseCursor> GetNewCursor() = 0;
     virtual bool TxnBegin() = 0;
     virtual bool TxnCommit() = 0;
     virtual bool TxnAbort() = 0;
@@ -106,7 +123,7 @@ class WalletDatabase
 {
 public:
     /** Create dummy DB handle */
-    WalletDatabase() : nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0) {}
+    WalletDatabase() : nUpdateCounter(0) {}
     virtual ~WalletDatabase() {};
 
     /** Open the database if it is not already opened. */
@@ -148,30 +165,33 @@ public:
     virtual std::string Format() = 0;
 
     std::atomic<unsigned int> nUpdateCounter;
-    unsigned int nLastSeen;
-    unsigned int nLastFlushed;
-    int64_t nLastWalletUpdate;
+    unsigned int nLastSeen{0};
+    unsigned int nLastFlushed{0};
+    int64_t nLastWalletUpdate{0};
 
     /** Make a DatabaseBatch connected to this database */
     virtual std::unique_ptr<DatabaseBatch> MakeBatch(bool flush_on_close = true) = 0;
 };
 
+class DummyCursor : public DatabaseCursor
+{
+    Status Next(DataStream& key, DataStream& value) override { return Status::FAIL; }
+};
+
 /** RAII class that provides access to a DummyDatabase. Never fails. */
 class DummyBatch : public DatabaseBatch
 {
 private:
-    bool ReadKey(CDataStream&& key, CDataStream& value) override { return true; }
-    bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite=true) override { return true; }
-    bool EraseKey(CDataStream&& key) override { return true; }
-    bool HasKey(CDataStream&& key) override { return true; }
+    bool ReadKey(DataStream&& key, DataStream& value) override { return true; }
+    bool WriteKey(DataStream&& key, DataStream&& value, bool overwrite = true) override { return true; }
+    bool EraseKey(DataStream&& key) override { return true; }
+    bool HasKey(DataStream&& key) override { return true; }
 
 public:
     void Flush() override {}
     void Close() override {}
 
-    bool StartCursor() override { return true; }
-    bool ReadAtCursor(CDataStream& ssKey, CDataStream& ssValue, bool& complete) override { return true; }
-    void CloseCursor() override {}
+    std::unique_ptr<DatabaseCursor> GetNewCursor() override { return std::make_unique<DummyCursor>(); }
     bool TxnBegin() override { return true; }
     bool TxnCommit() override { return true; }
     bool TxnAbort() override { return true; }