add Transaction class as a wrapper for transactions

src/Makefile.dep

@@ -61,3 +61,5 @@ postgresqlexpression.o: fieldvaluehelper.h wrapper.h spacewrapper.h
 postgresqlexpression.o: baseobjectwrapper.h modelcontainerwrapper.h ft.h
 postgresqlqueryresult.o: postgresqlqueryresult.h queryresult.h
 queryresult.o: queryresult.h
+transaction.o: transaction.h modelconnector.h clearer.h ft.h dbconnector.h
+transaction.o: queryresult.h flatconnector.h

src/Makefile.o.dep

@@ -1 +1 @@
-o = baseexpression.o clearer.o dbconnector.o dbexpression.o flatconnector.o flatexpression.o jsonconnector.o jsonexpression.o model.o modelconnector.o postgresqlconnector.o postgresqlexpression.o postgresqlqueryresult.o queryresult.o 
+o = baseexpression.o clearer.o dbconnector.o dbexpression.o flatconnector.o flatexpression.o jsonconnector.o jsonexpression.o model.o modelconnector.o postgresqlconnector.o postgresqlexpression.o postgresqlqueryresult.o queryresult.o transaction.o 

src/morm.h

@@ -5,7 +5,7 @@
  */
 
 /*
- * Copyright (c) 2018-2019, Tomasz Sowa
+ * Copyright (c) 2018-2022, Tomasz Sowa
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -49,6 +49,7 @@
 #include "modelconnector.h"
 #include "clearer.h"
 
+#include "transaction.h"
 
 
 namespace morm

src/transaction.cpp

@@ -0,0 +1,249 @@
+/*
+ * 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) 2022, 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.
+ *
+ */
+
+#include "transaction.h"
+#include "dbconnector.h"
+
+
+namespace morm
+{
+
+Transaction::Transaction(ModelConnector * model_connector)
+{
+	this->model_connector = model_connector;
+	is_transaction_started = false;
+	is_transaction_successful = true;
+	begin();
+}
+
+
+Transaction::Transaction(ModelConnector * model_connector, bool auto_begin_transaction)
+{
+	this->model_connector = model_connector;
+	is_transaction_started = false;
+	is_transaction_successful = true;
+
+	if( auto_begin_transaction )
+	{
+		begin();
+	}
+}
+
+
+Transaction::~Transaction()
+{
+	if( is_transaction_started )
+	{
+		rollback();
+	}
+}
+
+
+
+bool Transaction::is_started()
+{
+	return is_transaction_started;
+}
+
+
+bool Transaction::is_successful()
+{
+	return is_transaction_successful;
+}
+
+
+void Transaction::set_successful(bool is_successful)
+{
+	is_transaction_successful = is_successful;
+}
+
+
+
+
+
+bool Transaction::begin()
+{
+	pt::Log * log = get_logger();
+
+	if( is_transaction_started )
+	{
+		if( log )
+		{
+			(*log) << pt::Log::log2 << "Morm: a transaction is already started - rollbacking existing transaction before creating a new one" << pt::Log::logend;
+		}
+
+		rollback(); // what if there is an error here? skip it at the moment
+	}
+
+	bool status = do_query("BEGIN");
+
+	if( status )
+	{
+		is_transaction_started = true;
+		is_transaction_successful = true;
+	}
+	else
+	{
+		is_transaction_started = false;
+		is_transaction_successful = false;
+
+		if( log )
+		{
+			(*log) << pt::Log::log1 << "Morm: I cannot start a transaction" << pt::Log::logend;
+		}
+	}
+
+	return status;
+}
+
+
+bool Transaction::begin_if_needed()
+{
+	bool status = true;
+
+	if( !is_transaction_started )
+	{
+		status = begin();
+	}
+
+	return status;
+}
+
+
+bool Transaction::rollback()
+{
+	bool status = false;
+
+	if( is_transaction_started )
+	{
+		status = do_query("ROLLBACK");
+
+		if( status )
+		{
+			is_transaction_started = false;
+		}
+	}
+	else
+	{
+		pt::Log * log = get_logger();
+
+		if( log )
+		{
+			(*log) << pt::Log::log1 << "Morm: not doing rollback, a transaction was not started - skipping" << pt::Log::logend;
+		}
+	}
+
+	return status;
+}
+
+
+bool Transaction::commit()
+{
+	bool status = false;
+
+	if( is_transaction_started )
+	{
+		status = do_query("COMMIT");
+
+		if( status )
+		{
+			is_transaction_started = false;
+		}
+	}
+	else
+	{
+		pt::Log * log = get_logger();
+
+		if( log )
+		{
+			(*log) << pt::Log::log1 << "Morm: not doing commit, a transaction was not started - skipping" << pt::Log::logend;
+		}
+	}
+
+	return status;
+}
+
+
+bool Transaction::finish()
+{
+	bool status = false;
+
+	if( is_transaction_successful )
+		status = commit();
+	else
+		status = rollback();
+
+	return status;
+}
+
+
+
+
+bool Transaction::do_query(const char * query)
+{
+	bool status = false;
+
+	if( model_connector )
+	{
+		DbConnector * db_connector = model_connector->get_db_connector();
+
+		if( db_connector )
+		{
+			status = db_connector->query(query);
+		}
+	}
+
+	return status;
+}
+
+
+
+pt::Log * Transaction::get_logger()
+{
+	pt::Log * logger = nullptr;
+
+	if( model_connector )
+	{
+		logger = model_connector->get_logger();
+	}
+
+	return logger;
+}
+
+
+
+
+} // namespace
+
+

src/transaction.h

@@ -0,0 +1,81 @@
+/*
+ * 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) 2022, 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_transaction
+#define headerfile_morm_transaction
+
+#include "log/log.h"
+#include "modelconnector.h"
+
+
+namespace morm
+{
+
+
+class Transaction
+{
+public:
+
+	Transaction(ModelConnector * model_connector);
+	Transaction(ModelConnector * model_connector, bool auto_begin_transaction);
+	virtual ~Transaction();
+
+	virtual bool is_started();
+
+	virtual bool is_successful();
+	virtual void set_successful(bool is_successful = true);
+
+	virtual bool begin();
+	virtual bool begin_if_needed();
+	virtual bool rollback();
+	virtual bool commit();
+	virtual bool finish();
+
+
+protected:
+
+	ModelConnector * model_connector;
+	bool is_transaction_started;
+	bool is_transaction_successful;
+
+	bool do_query(const char * query);
+	pt::Log * get_logger();
+
+};
+
+
+
+} // namespace
+
+#endif