walletdb: Handle cursor internally

Instead of returning a Dbc (BDB cursor object) and having the caller
deal with the cursor, make BerkeleyBatch handle the cursor internally.

This prepares BerkeleyBatch to work with other database systems as Dbc
objects are BDB specific.

1 files changed, 15 insertions, 13 deletions

diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index 2f6c2b883..027fc7397 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -699,8 +699,7 @@ DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
         }
 
         // Get cursor
-        Dbc* pcursor = m_batch.GetCursor();
-        if (!pcursor)
+        if (!m_batch.StartCursor())
         {
             pwallet->WalletLogPrintf("Error getting wallet database cursor\n");
             return DBErrors::CORRUPT;
@@ -711,11 +710,14 @@ DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
             // Read next record
             CDataStream ssKey(SER_DISK, CLIENT_VERSION);
             CDataStream ssValue(SER_DISK, CLIENT_VERSION);
-            int ret = m_batch.ReadAtCursor(pcursor, ssKey, ssValue);
-            if (ret == DB_NOTFOUND)
+            bool complete;
+            bool ret = m_batch.ReadAtCursor(ssKey, ssValue, complete);
+            if (complete) {
                 break;
-            else if (ret != 0)
+            }
+            else if (!ret)
             {
+                m_batch.CloseCursor();
                 pwallet->WalletLogPrintf("Error reading next record from wallet database\n");
                 return DBErrors::CORRUPT;
             }
@@ -742,10 +744,10 @@ DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
             if (!strErr.empty())
                 pwallet->WalletLogPrintf("%s\n", strErr);
         }
-        pcursor->close();
     } catch (...) {
         result = DBErrors::CORRUPT;
     }
+    m_batch.CloseCursor();
 
     // Set the active ScriptPubKeyMans
     for (auto spk_man_pair : wss.m_active_external_spks) {
@@ -849,8 +851,7 @@ DBErrors WalletBatch::FindWalletTx(std::vector<uint256>& vTxHash, std::list<CWal
         }
 
         // Get cursor
-        Dbc* pcursor = m_batch.GetCursor();
-        if (!pcursor)
+        if (!m_batch.StartCursor())
         {
             LogPrintf("Error getting wallet database cursor\n");
             return DBErrors::CORRUPT;
@@ -861,11 +862,12 @@ DBErrors WalletBatch::FindWalletTx(std::vector<uint256>& vTxHash, std::list<CWal
             // Read next record
             CDataStream ssKey(SER_DISK, CLIENT_VERSION);
             CDataStream ssValue(SER_DISK, CLIENT_VERSION);
-            int ret = m_batch.ReadAtCursor(pcursor, ssKey, ssValue);
-            if (ret == DB_NOTFOUND)
+            bool complete;
+            bool ret = m_batch.ReadAtCursor(ssKey, ssValue, complete);
+            if (complete) {
                 break;
-            else if (ret != 0)
-            {
+            } else if (!ret) {
+                m_batch.CloseCursor();
                 LogPrintf("Error reading next record from wallet database\n");
                 return DBErrors::CORRUPT;
             }
@@ -880,10 +882,10 @@ DBErrors WalletBatch::FindWalletTx(std::vector<uint256>& vTxHash, std::list<CWal
                 ssValue >> vWtx.back();
             }
         }
-        pcursor->close();
     } catch (...) {
         result = DBErrors::CORRUPT;
     }
+    m_batch.CloseCursor();
 
     return result;
 }