add support for declared cursors

Declare a cursor with the Finder::declare_cursor() method and next get the cursor with get_cursor(): morm::Cursor<MyObject> cursor = finder. declare_cursor("mycursorname"). select(). raw("ORDER BY column_name ASC"). get_cursor(); The cursor now can be used with fetch.*() methods and then get() or get_list(): MyObject myobject = cursor.fetch_next().get(); std::list<MyObject> myobjects = cursor.fetch_forward_count(10).get_list();
2023-07-16 04:03:03 +02:00
parent 6619f3ecb5
commit 21f12a8a98
8 changed files with 448 additions and 80 deletions
--- a/src/cursor.h
+++ b/src/cursor.h
@@ -63,9 +63,11 @@ public:
 		has_autogenerated_select = c.has_autogenerated_select;
 		use_table_prefix_for_fetching = c.use_table_prefix_for_fetching;
 		query_result = c.query_result;
-		select_status = c.select_status;
+		last_query_status = c.last_query_status;
 		select_flags = c.select_flags;
 		rows_counter = c.rows_counter;
+		cursor_name = c.cursor_name;
+		scroll_cursor = c.scroll_cursor;

 		if( query_result )
 		{
@@ -107,9 +109,11 @@ public:
 		cursor_helper.clear();
 		finder_helper.clear();
 		query_result = nullptr;
-		select_status = false;
+		last_query_status = false;
 		select_flags = Select::default_type;
 		rows_counter = 0;
+		cursor_name.clear();
+		scroll_cursor = false;
 	}


@@ -131,9 +135,9 @@ public:
 	}


-	virtual void set_select_status(bool select_status)
+	virtual void set_last_query_status(bool status)
 	{
-		this->select_status = select_status;
+		this->last_query_status = status;
 	}


@@ -171,7 +175,7 @@ public:
 	{
 		bool has = false;

-		if( model_connector && query_result && query_result->has_db_result() && select_status )
+		if( model_connector && query_result && query_result->has_db_result() && last_query_status )
 		{
 			has = query_result->cur_row < query_result->result_rows;
 		}
@@ -234,7 +238,7 @@ public:
 					}

 					result.before_select();
-					res = select_status;
+					res = last_query_status;

 					if( res )
 					{
@@ -326,6 +330,136 @@ public:
 	}


+	virtual void set_cursor_name(pt::TextStream & cursor_name)
+	{
+		this->cursor_name = cursor_name;
+	}
+
+
+	virtual void set_scroll_cursor(bool scroll_cursor)
+	{
+		this->scroll_cursor = scroll_cursor;
+	}
+
+
+	virtual Cursor & fetch(const char * fetch_str)
+	{
+		last_query_status = false;
+		rows_counter = 0;
+
+		if( query_result )
+		{
+			query_result->clear();
+
+			if( model_connector )
+			{
+				DbConnector * db_connector = model_connector->get_db_connector();
+
+				if( db_connector )
+				{
+					bool status = db_connector->query_select(fetch_str, *query_result);
+					last_query_status = status;
+				}
+			}
+		}
+
+		return *this;
+	}
+
+
+	virtual Cursor & fetch(pt::TextStream & str)
+	{
+		if( str.size() < 256 )
+		{
+			char str_buf[256];
+
+			if( str.to_str(str_buf, sizeof(str_buf) / sizeof(char)) )
+			{
+				fetch(str_buf);
+			}
+		}
+		else
+		{
+			put_cursor_fetch_query_too_long();
+		}
+
+		return *this;
+	}
+
+
+	virtual Cursor & fetch(pt::WTextStream & str)
+	{
+		if( str.size() < 256 )
+		{
+			char str_buf[256];
+
+			if( str.to_str(str_buf, sizeof(str_buf) / sizeof(char)) )
+			{
+				fetch(str_buf);
+			}
+		}
+		else
+		{
+			put_cursor_fetch_query_too_long();
+		}
+
+		return *this;
+	}
+
+
+	virtual Cursor & fetch_next()
+	{
+		return fetch(&DbExpression::prepare_fetch_next_query);
+	}
+
+
+	virtual Cursor & fetch_prior()
+	{
+		return fetch(&DbExpression::prepare_fetch_prior_query);
+	}
+
+
+	virtual Cursor & fetch_first()
+	{
+		return fetch(&DbExpression::prepare_fetch_first_query);
+	}
+
+
+	virtual Cursor & fetch_last()
+	{
+		return fetch(&DbExpression::prepare_fetch_last_query);
+	}
+
+
+	virtual Cursor & fetch_absolute(long position)
+	{
+		return fetch(&DbExpression::prepare_fetch_absotule_query, position);
+	}
+
+
+	virtual Cursor & fetch_relative(long position)
+	{
+		return fetch(&DbExpression::prepare_fetch_relative_query, position);
+	}
+
+
+	virtual Cursor & fetch_forward_count(size_t len)
+	{
+		return fetch(&DbExpression::prepare_fetch_forward_count_query, len);
+	}
+
+
+	virtual Cursor & fetch_backward_count(size_t len)
+	{
+		return fetch(&DbExpression::prepare_fetch_backward_count_query, len);
+	}
+
+
+	virtual Cursor & fetch_all()
+	{
+		return fetch(&DbExpression::prepare_fetch_all_query);
+	}
+

 protected:

@@ -336,11 +470,98 @@ protected:
 	CursorHelper cursor_helper;
 	FinderHelper finder_helper; // may CursorHelper and FinderHelper should be one class?
 	QueryResult * query_result;
-	bool select_status;
+	bool last_query_status;
 	Select select_flags;
 	size_t rows_counter;
 	std::wstring rows_counter_column_name;
+	pt::TextStream cursor_name;
+	bool scroll_cursor;

+	typedef void (DbExpression::*prepare_fetch_method_type)(const pt::TextStream & cursor_name, pt::TextStream & out_stream);
+	typedef void (DbExpression::*prepare_fetch_long_count_method_type)(const pt::TextStream & cursor_name, long count, pt::TextStream & out_stream);
+	typedef void (DbExpression::*prepare_fetch_size_count_method_type)(const pt::TextStream & cursor_name, size_t count, pt::TextStream & out_stream);
+
+
+	DbExpression * get_db_expression()
+	{
+		if( model_connector )
+		{
+			DbConnector * db_connector = model_connector->get_db_connector();
+
+			if( db_connector )
+			{
+				return db_connector->get_expression();
+			}
+		}
+
+		return nullptr;
+	}
+
+
+	virtual Cursor & fetch(prepare_fetch_method_type prepare_fetch_method)
+	{
+		if( !cursor_name.empty() )
+		{
+			DbExpression * db_expression = get_db_expression();
+
+			if( db_expression )
+			{
+				pt::TextStream str;
+				(db_expression->*prepare_fetch_method)(cursor_name, str);
+				fetch(str);
+			}
+		}
+		else
+		{
+			put_cursor_not_declared_log();
+		}
+
+		return *this;
+	}
+
+
+	virtual Cursor & fetch(prepare_fetch_long_count_method_type prepare_fetch_method, long count)
+	{
+		if( !cursor_name.empty() )
+		{
+			DbExpression * db_expression = get_db_expression();
+
+			if( db_expression )
+			{
+				pt::TextStream str;
+				(db_expression->*prepare_fetch_method)(cursor_name, count, str);
+				fetch(str);
+			}
+		}
+		else
+		{
+			put_cursor_not_declared_log();
+		}
+
+		return *this;
+	}
+
+
+	virtual Cursor & fetch(prepare_fetch_size_count_method_type prepare_fetch_method, size_t count)
+	{
+		if( !cursor_name.empty() )
+		{
+			DbExpression * db_expression = get_db_expression();
+
+			if( db_expression )
+			{
+				pt::TextStream str;
+				(db_expression->*prepare_fetch_method)(cursor_name, count, str);
+				fetch(str);
+			}
+		}
+		else
+		{
+			put_cursor_not_declared_log();
+		}
+
+		return *this;
+	}


 	template<typename ContainerType>
@@ -359,7 +580,7 @@ protected:

 			if( db_connector )
 			{
-				res = select_status;
+				res = last_query_status;

 				try
 				{
@@ -448,6 +669,38 @@ protected:
 	}


+	pt::Log * get_logger()
+	{
+		if( model_connector )
+		{
+			return model_connector->get_logger();
+		}
+
+		return nullptr;
+	}
+
+
+	void put_log(pt::Log::Manipulators level, const char * msg)
+	{
+		pt::Log * plog = get_logger();
+
+		if( plog )
+		{
+			(*plog) << level << msg << pt::Log::logend;
+		}
+	}
+
+
+	void put_cursor_fetch_query_too_long()
+	{
+		put_log(pt::Log::log2, "Morm: error: a fetch query should be less than 256 characters long");
+	}
+
+
+	void put_cursor_not_declared_log()
+	{
+		put_log(pt::Log::log2, "Morm: you cannot use fetch* methods, a cursor has not been declared, use Finder::declare_cursor(...) to declare a cursor");
+	}

 };