added Cursor class

git-svn-id: svn://ttmath.org/publicrep/morm/trunk@1140 e52654a7-88a9-db11-a3e9-0013d4bc506e

src/cursor.h

@@ -0,0 +1,312 @@
+/*
+ * This file is a part of morm
+ * and is distributed under the 2-Clause BSD licence.
+ * Author: Tomasz Sowa <t.sowa@ttmath.org>
+ */
+
+/*
+ * Copyright (c) 2018, Tomasz Sowa
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef headerfile_morm_cursor
+#define headerfile_morm_cursor
+
+#include "queryresult.h"
+#include "modelconnector.h"
+
+
+namespace morm
+{
+
+template<typename ModelClass>
+class Cursor
+{
+
+public:
+
+
+	Cursor()
+	{
+		set_default_values();
+	}
+
+
+	Cursor(const Cursor & c)
+	{
+		model_connector = c.model_connector;
+		model_data = c.model_data;
+		query_result = c.query_result;
+		select_status = c.select_status;
+
+		if( query_result )
+		{
+			query_result->references_count += 1;
+		}
+	}
+
+
+	Cursor & operator=(const Cursor & c) = delete;
+
+
+	virtual ~Cursor()
+	{
+		if( query_result && query_result->references_count > 0 )
+		{
+			query_result->references_count -= 1;
+		}
+
+		clear();
+	}
+
+
+	virtual void clear()
+	{
+		if( query_result && query_result->references_count == 0 )
+		{
+			query_result->clear();
+			delete query_result;
+		}
+
+		set_default_values();
+	}
+
+
+	virtual void set_model_connector(ModelConnector * model_connector)
+	{
+		this->model_connector = model_connector;
+	}
+
+
+	virtual void set_model_data(Model::ModelData * model_data)
+	{
+		this->model_data = model_data;
+	}
+
+
+	virtual void set_query_result(QueryResult * query_result)
+	{
+		this->query_result = query_result;
+	}
+
+
+	virtual void set_select_status(bool select_status)
+	{
+		this->select_status = select_status;
+	}
+
+
+	virtual QueryResult * get_query_result()
+	{
+		return query_result;
+	}
+
+
+	virtual bool has_next()
+	{
+		bool has = false;
+
+		if( model_connector && query_result && query_result->has_db_result() && select_status )
+		{
+			has = query_result->cur_row < query_result->result_rows;
+		}
+
+		return has;
+	}
+
+
+	virtual bool get(ModelClass & result)
+	{
+		bool res = false;
+		result.set_connector(model_connector);
+		result.clear();
+
+		if( model_connector && query_result && query_result->has_db_result() )
+		{
+			DbConnector * db_connector = model_connector->get_db_connector();
+
+			if( db_connector )
+			{
+				try
+				{
+					result.model_data = model_data;
+					result.before_select();
+					res = select_status;
+
+					if( res )
+					{
+						if( query_result->cur_row < query_result->result_rows )
+						{
+							result.set_save_mode(Model::DO_UPDATE_ON_SAVE); // IMPROVE ME check if there is a primary key
+							result.map_values_from_query(query_result);
+							result.after_select();
+							query_result->cur_row += 1;
+						}
+						else
+						{
+							res = false;
+							// log some error or throw an exception?
+						}
+					}
+					else
+					{
+						result.after_select_failure();
+					}
+				}
+				catch(...)
+				{
+					res = false;
+					// throw something?
+				}
+
+				result.model_data = nullptr;
+			}
+		}
+
+		return res;
+	}
+
+
+	virtual ModelClass get()
+	{
+		ModelClass model;
+
+		get(model);
+		return std::move(model);
+	}
+
+
+	virtual bool get_list(std::list<ModelClass> & result, bool clear_list = true)
+	{
+		bool res = false;
+
+		if( clear_list )
+		{
+			result.clear();
+		}
+
+		if( model_connector && query_result && query_result->has_db_result() )
+		{
+			DbConnector * db_connector = model_connector->get_db_connector();
+
+			if( db_connector )
+			{
+				res = select_status;
+
+				try
+				{
+					if( res )
+					{
+						res = add_models_to_list(result);
+					}
+					else
+					{
+						// add log
+
+						// if there was a failure we do not call after_select_failure()
+						// because there are no any objects in the list
+					}
+				}
+				catch(...)
+				{
+					res = false;
+					// throw or something?
+				}
+			}
+		}
+
+		return res;
+	}
+
+
+	virtual std::list<ModelClass> get_list()
+	{
+		std::list<ModelClass> result;
+
+		get_list(result, false);
+		return std::move(result);
+	}
+
+
+
+
+
+protected:
+
+	ModelConnector * model_connector;
+	Model::ModelData * model_data;
+	QueryResult * query_result;
+	bool select_status;
+
+
+	virtual void set_default_values()
+	{
+		model_connector = nullptr;
+		model_data = nullptr;
+		query_result = nullptr;
+		select_status = false;
+	}
+
+
+	template<typename ContainerType>
+	bool add_models_to_list(ContainerType & result)
+	{
+		bool res = true;
+
+		for(query_result->cur_row = 0 ; query_result->cur_row < query_result->result_rows ; query_result->cur_row += 1)
+		{
+			result.emplace_back(); // it returns a reference from c++17
+			ModelClass & added_model = result.back();
+
+			try
+			{
+				added_model.set_connector(model_connector);
+				added_model.clear();
+				added_model.set_save_mode(Model::DO_UPDATE_ON_SAVE); // IMPROVE ME check if there is a primary key
+				added_model.model_data = model_data;
+				added_model.before_select();
+				added_model.map_values_from_query(query_result);
+				added_model.after_select();
+			}
+			catch(...)
+			{
+				res = false;
+				// throw or something?
+			}
+
+			added_model.model_data = nullptr;
+		}
+
+		return res;
+	}
+
+
+
+};
+
+} // namespace
+
+#endif