From eac9200814fa01da6522625be01dded730b26751 Mon Sep 17 00:00:00 2001
From: Andrew Chow <achow101-github@achow101.com>
Date: Thu, 18 Jun 2020 16:15:33 -0400
Subject: [PATCH] walletdb: Refactor DatabaseBatch abstract class from
 BerkeleyBatch

---
 src/wallet/bdb.h | 79 +++++++++--------------------------------------
 src/wallet/db.h  | 80 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+), 65 deletions(-)

diff --git a/src/wallet/bdb.h b/src/wallet/bdb.h
index 599319482b..f3b1e5d0a3 100644
--- a/src/wallet/bdb.h
+++ b/src/wallet/bdb.h
@@ -172,7 +172,7 @@ private:
 };
 
 /** RAII class that provides access to a Berkeley database */
-class BerkeleyBatch
+class BerkeleyBatch : public DatabaseBatch
 {
     /** RAII class that automatically cleanses its data on destruction */
     class SafeDbt final
@@ -195,10 +195,10 @@ class BerkeleyBatch
     };
 
 private:
-    bool ReadKey(CDataStream&& key, CDataStream& value);
-    bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite = true);
-    bool EraseKey(CDataStream&& key);
-    bool HasKey(CDataStream&& key);
+    bool ReadKey(CDataStream&& key, CDataStream& value) override;
+    bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite = true) override;
+    bool EraseKey(CDataStream&& key) override;
+    bool HasKey(CDataStream&& key) override;
 
 protected:
     Db* pdb;
@@ -211,71 +211,20 @@ protected:
 
 public:
     explicit BerkeleyBatch(BerkeleyDatabase& database, const char* pszMode = "r+", bool fFlushOnCloseIn=true);
-    ~BerkeleyBatch() { Close(); }
+    ~BerkeleyBatch() override { Close(); }
 
     BerkeleyBatch(const BerkeleyBatch&) = delete;
     BerkeleyBatch& operator=(const BerkeleyBatch&) = delete;
 
-    void Flush();
-    void Close();
-
-    template <typename K, typename T>
-    bool Read(const K& key, T& value)
-    {
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
-        ssKey.reserve(1000);
-        ssKey << key;
-
-        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
-        if (!ReadKey(std::move(ssKey), ssValue)) return false;
-        try {
-            ssValue >> value;
-            return true;
-        } catch (const std::exception&) {
-            return false;
-        }
-    }
-
-    template <typename K, typename T>
-    bool Write(const K& key, const T& value, bool fOverwrite = true)
-    {
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
-        ssKey.reserve(1000);
-        ssKey << key;
-
-        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
-        ssValue.reserve(10000);
-        ssValue << value;
-
-        return WriteKey(std::move(ssKey), std::move(ssValue), fOverwrite);
-    }
-
-    template <typename K>
-    bool Erase(const K& key)
-    {
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
-        ssKey.reserve(1000);
-        ssKey << key;
-
-        return EraseKey(std::move(ssKey));
-    }
-
-    template <typename K>
-    bool Exists(const K& key)
-    {
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
-        ssKey.reserve(1000);
-        ssKey << key;
-
-        return HasKey(std::move(ssKey));
-    }
+    void Flush() override;
+    void Close() override;
 
-    bool StartCursor();
-    bool ReadAtCursor(CDataStream& ssKey, CDataStream& ssValue, bool& complete);
-    void CloseCursor();
-    bool TxnBegin();
-    bool TxnCommit();
-    bool TxnAbort();
+    bool StartCursor() override;
+    bool ReadAtCursor(CDataStream& ssKey, CDataStream& ssValue, bool& complete) override;
+    void CloseCursor() override;
+    bool TxnBegin() override;
+    bool TxnCommit() override;
+    bool TxnAbort() override;
 };
 
 std::string BerkeleyDatabaseVersion();
diff --git a/src/wallet/db.h b/src/wallet/db.h
index 1322bf54fa..76668f8dc2 100644
--- a/src/wallet/db.h
+++ b/src/wallet/db.h
@@ -6,7 +6,9 @@
 #ifndef BITCOIN_WALLET_DB_H
 #define BITCOIN_WALLET_DB_H
 
+#include <clientversion.h>
 #include <fs.h>
+#include <streams.h>
 
 #include <string>
 
@@ -14,4 +16,82 @@
 fs::path WalletDataFilePath(const fs::path& wallet_path);
 void SplitWalletPath(const fs::path& wallet_path, fs::path& env_directory, std::string& database_filename);
 
+/** 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;
+
+public:
+    explicit DatabaseBatch() {}
+    virtual ~DatabaseBatch() {}
+
+    DatabaseBatch(const DatabaseBatch&) = delete;
+    DatabaseBatch& operator=(const DatabaseBatch&) = delete;
+
+    virtual void Flush() = 0;
+    virtual void Close() = 0;
+
+    template <typename K, typename T>
+    bool Read(const K& key, T& value)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(1000);
+        ssKey << key;
+
+        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
+        if (!ReadKey(std::move(ssKey), ssValue)) return false;
+        try {
+            ssValue >> value;
+            return true;
+        } catch (const std::exception&) {
+            return false;
+        }
+    }
+
+    template <typename K, typename T>
+    bool Write(const K& key, const T& value, bool fOverwrite = true)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(1000);
+        ssKey << key;
+
+        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
+        ssValue.reserve(10000);
+        ssValue << value;
+
+        return WriteKey(std::move(ssKey), std::move(ssValue), fOverwrite);
+    }
+
+    template <typename K>
+    bool Erase(const K& key)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(1000);
+        ssKey << key;
+
+        return EraseKey(std::move(ssKey));
+    }
+
+    template <typename K>
+    bool Exists(const K& key)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        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 bool TxnBegin() = 0;
+    virtual bool TxnCommit() = 0;
+    virtual bool TxnAbort() = 0;
+};
+
 #endif // BITCOIN_WALLET_DB_H