Core/DBLayer: Implement async transaction completion callbacks

src/server/database/Database/DatabaseWorkerPool.cpp

@@ -261,6 +261,32 @@ void DatabaseWorkerPool<T>::CommitTransaction(SQLTransaction<T> transaction)
     Enqueue(new TransactionTask(transaction));
 }
 
+template <class T>
+TransactionCallback DatabaseWorkerPool<T>::AsyncCommitTransaction(SQLTransaction<T> transaction)
+{
+#ifdef TRINITY_DEBUG
+    //! Only analyze transaction weaknesses in Debug mode.
+    //! Ideally we catch the faults in Debug mode and then correct them,
+    //! so there's no need to waste these CPU cycles in Release mode.
+    switch (transaction->GetSize())
+    {
+        case 0:
+            TC_LOG_DEBUG("sql.driver", "Transaction contains 0 queries. Not executing.");
+            return;
+        case 1:
+            TC_LOG_DEBUG("sql.driver", "Warning: Transaction only holds 1 query, consider removing Transaction context in code.");
+            break;
+        default:
+            break;
+    }
+#endif // TRINITY_DEBUG
+
+    TransactionWithResultTask* task = new TransactionWithResultTask(transaction);
+    TransactionFuture result = task->GetFuture();
+    Enqueue(task);
+    return TransactionCallback(std::move(result));
+}
+
 template <class T>
 void DatabaseWorkerPool<T>::DirectCommitTransaction(SQLTransaction<T>& transaction)
 {