Add MySQL Cache Manager & code cleanup

cache_managers/mysql_cache_manager/include/query_result.h

@@ -0,0 +1,65 @@
+// Copyright 2016 Etix Labs
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+namespace etix {
+
+namespace cameradar {
+
+namespace mysql {
+
+enum class execute_result { success, not_found, no_row_updated, sql_error, error };
+
+//! Wrapper of a DB query result
+//! Templated on the data type we want to return (list<model>, bool, whatever)
+template <typename DataType>
+struct query_result {
+    DataType data;
+    execute_result state;
+    std::string error_msg;
+
+    inline bool
+    success(void) const {
+        return state == execute_result::success;
+    }
+    inline bool
+    error(void) const {
+        return not success();
+    }
+};
+
+//! Empty query result for when we just want to return the status
+//! of the request with no associated data
+template <>
+struct query_result<void> {
+    execute_result state;
+    std::string error_msg;
+
+    inline bool
+    success(void) const {
+        return state == execute_result::success;
+    }
+    inline bool
+    error(void) const {
+        return not success();
+    }
+};
+typedef query_result<void> empty_result;
+
+} //! mysql
+
+} //! cameradar
+
+} //! etix