From d1fbab9e475dd0ecf72ba9d3bdd07c1d61fa8b5a Mon Sep 17 00:00:00 2001
From: Frank Park <fpark12@icloud.com>
Date: Wed, 12 Apr 2017 01:26:11 -0400
Subject: [PATCH] enable direct query through pool_connection with limited
 functionality

---
 include/sqlpp11/pool_connection.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/include/sqlpp11/pool_connection.h b/include/sqlpp11/pool_connection.h
index cc9bfe09..436a5d5d 100644
--- a/include/sqlpp11/pool_connection.h
+++ b/include/sqlpp11/pool_connection.h
@@ -29,6 +29,7 @@
 
 #include <sqlpp11/connection.h>
 #include <sqlpp11/connection_pool.h>
+#include <sqlpp11/type_traits.h>
 #include <memory>
 
 namespace sqlpp
@@ -88,6 +89,30 @@ namespace sqlpp
     {
       return _impl->prepare(t);
     }
+
+    template<typename Query, typename Lambda,
+      typename std::enable_if<is_invocable<Lambda>::value ||
+      is_invocable<Lambda, sqlpp::exception>::value ||
+      is_invocable<Lambda, sqlpp::exception, decltype(pool_connection()(Query()))>::value &&
+      !is_invocable<Lambda, sqlpp::exception, decltype(pool_connection()(Query())), pool_connection>::value, int>::type = 0>
+    void operator()(Query query, Lambda callback)
+    {
+        try
+      {
+        invoke_callback(sqlpp::exception(sqlpp::exception::ok), pool_connection(), std::move(operator()(query)), callback);
+      }
+      catch (const std::exception& e)
+      {
+        invoke_callback(sqlpp::exception(sqlpp::exception::query_error, e.what()), pool_connection(), decltype(pool_connection()(Query()))(), callback);
+      }
+    }
+
+    template<typename Query, typename Lambda,
+      typename std::enable_if<is_invocable<Lambda, sqlpp::exception, decltype(pool_connection()(Query())), pool_connection>::value, int>::type = 0>
+      void operator()(Query query, Lambda callback)
+    {
+      static_assert(false, "Direct query with pool connection forbids callback with parameter of type connection.");
+    }
   };
 }