1 files changed, 54 insertions, 0 deletions
diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 5126db400..211e2f3ed 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -148,6 +148,60 @@ inline void lmdb_db_open(MDB_txn* txn, const char* name, int flags, MDB_dbi& dbi
 
 namespace cryptonote
 {
+  mdb_txn_safe::mdb_txn_safe() : m_txn(NULL) { }
+
+  mdb_txn_safe::~mdb_txn_safe()
+  {
+    LOG_PRINT_L3("mdb_txn_safe: destructor");
+    if (m_txn != NULL)
+    {
+      if (m_batch_txn) // this is a batch txn and should have been handled before this point for safety
+      {
+        LOG_PRINT_L0("WARNING: mdb_txn_safe: m_txn is a batch txn and it's not NULL in destructor - calling mdb_txn_abort()");
+      }
+      else
+      {
+        // Example of when this occurs: a lookup fails, so a read-only txn is
+        // aborted through this destructor. However, successful read-only txns
+        // ideally should have been committed when done and not end up here.
+        //
+        // NOTE: not sure if this is ever reached for a non-batch write
+        // transaction, but it's probably not ideal if it did.
+        LOG_PRINT_L3("mdb_txn_safe: m_txn not NULL in destructor - calling mdb_txn_abort()");
+      }
+      mdb_txn_abort(m_txn);
+    }
+  }
+
+  void mdb_txn_safe::commit(std::string message)
+  {
+    if (message.size() == 0)
+    {
+      message = "Failed to commit a transaction to the db";
+    }
+
+    if (mdb_txn_commit(m_txn))
+    {
+      m_txn = NULL;
+      LOG_PRINT_L0(message);
+      throw DB_ERROR(message.c_str());
+    }
+    m_txn = NULL;
+  }
+
+  void mdb_txn_safe::abort()
+  {
+    LOG_PRINT_L3("mdb_txn_safe: abort()");
+    if(m_txn != NULL)
+    {
+      mdb_txn_abort(m_txn);
+      m_txn = NULL;
+    }
+    else
+    {
+      LOG_PRINT_L0("WARNING: mdb_txn_safe: abort() called, but m_txn is NULL");
+    }
+  }
 
 // If m_batch_active is set, a batch transaction exists beyond this class, such
 // as a batch import with verification enabled, or possibly (later) a batch