polardbxengine/plugin/x/client/visitor/assign_visitor.h

124 lines
3.8 KiB
C++

/*
* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2.0,
* as published by the Free Software Foundation.
*
* This program is also distributed with certain software (including
* but not limited to OpenSSL) that is licensed under separate terms,
* as designated in a particular file or component or in included license
* documentation. The authors of MySQL hereby grant you an additional
* permission to link the program and your derivative works with the
* separately licensed software that they have included with MySQL.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License, version 2.0, for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef PLUGIN_X_CLIENT_VISITOR_ASSIGN_VISITOR_H_
#define PLUGIN_X_CLIENT_VISITOR_ASSIGN_VISITOR_H_
#include <string>
#include "mysqlxclient/xargument.h"
#include "plugin/x/client/visitor/default_visitor.h"
namespace xcl {
template <typename Destination_type>
class Assign_visitor : public Default_visitor {
public:
Destination_type m_destination;
bool m_set = false;
private:
/*
This template handles all other types than Destination_type
that are hold in Argument_value.
When user gets other type than stored in Argument_value, then this
callback is executed.
*/
template <typename Value1_type, typename Value2_type>
bool assign(Value1_type *value1, const Value2_type *value2) {
// Does nothing, types doesn't match
return false;
}
/*
This specialization template handles the Destination_type that is stored
in Argument_value.
When user gets correct type from Argument_value, then this callback is
executed.
*/
template <typename Value1_type>
bool assign(Value1_type *value1, const Value1_type *value2) {
*value1 = *value2;
return true;
}
template <typename Value1_type, typename Value2_type>
void store_and_mark(Value1_type *value1, const Value2_type *value2) {
m_set = assign(value1, value2);
}
private: // Visitor
void visit_integer(const int64_t value) {
store_and_mark(&m_destination, &value);
}
void visit_uinteger(const uint64_t value) {
store_and_mark(&m_destination, &value);
}
void visit_double(const double value) {
store_and_mark(&m_destination, &value);
}
void visit_float(const float value) {
store_and_mark(&m_destination, &value);
}
void visit_bool(const bool value) { store_and_mark(&m_destination, &value); }
void visit_object(const Argument_object &value) {
store_and_mark(&m_destination, &value);
}
void visit_uobject(const Argument_uobject &value) {
store_and_mark(&m_destination, &value);
}
void visit_array(const Argument_array &value) {
store_and_mark(&m_destination, &value);
}
void visit_string(const std::string &value) {
store_and_mark(&m_destination, &value);
}
void visit_octet(const std::string &value) {
store_and_mark(&m_destination, &value);
}
void visit_decimal(const std::string &value) {
store_and_mark(&m_destination, &value);
}
};
template <typename Destination_type>
bool get_argument_value(const Argument_value &value,
Destination_type *out_value) {
Assign_visitor<Destination_type> assign;
value.accept(&assign);
if (!assign.m_set) return false;
*out_value = assign.m_destination;
return true;
}
} // namespace xcl
#endif // PLUGIN_X_CLIENT_VISITOR_ASSIGN_VISITOR_H_