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117 lines
3.4 KiB
C++
117 lines
3.4 KiB
C++
/*
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* Copyright (c) 2013-2016, Roland Bock
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice, this
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* list of conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef SQLPP11_RESULT_FIELD_BASE_H
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#define SQLPP11_RESULT_FIELD_BASE_H
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#include <sqlpp11/alias_operators.h>
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#include <sqlpp11/basic_expression_operators.h>
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#include <sqlpp11/exception.h>
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#include <sqlpp11/result_field.h>
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#include <sqlpp11/type_traits.h>
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#include <utility>
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namespace sqlpp
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{
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SQLPP_PORTABLE_STATIC_ASSERT(assert_result_field_value_is_safe_t, "result field value needs to be checked for NULL");
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template <typename Db, typename FieldSpec, typename StorageType = typename value_type_of<FieldSpec>::_cpp_value_type>
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struct result_field_base
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{
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using _db_t = Db;
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using _field_spec_t = FieldSpec;
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using _alias_t = typename FieldSpec::_alias_t;
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using _cpp_value_type = typename value_type_of<FieldSpec>::_cpp_value_type;
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using _cpp_storage_type = StorageType;
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using _traits = make_traits<value_type_of<_field_spec_t>,
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tag::is_result_field,
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tag::is_expression>;
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using _nodes = detail::type_vector<>;
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using _can_be_null = column_spec_can_be_null_t<_field_spec_t>;
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result_field_base() : _is_valid{false}, _is_null{true}, _value{}
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{
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}
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bool operator==(const _cpp_value_type& rhs) const
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{
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return value() == rhs;
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}
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bool operator!=(const _cpp_value_type& rhs) const
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{
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return not operator==(rhs);
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}
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void _validate()
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{
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_is_valid = true;
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}
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void _invalidate()
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{
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_is_valid = false;
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_is_null = true;
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_value = {};
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}
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bool is_null() const
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{
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if (not _is_valid)
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{
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throw exception("accessing is_null in non-existing row");
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}
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return _is_null;
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}
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_cpp_value_type value() const
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{
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if (not _is_valid)
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{
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throw exception("accessing value in non-existing row");
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}
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if (_is_null)
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{
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return {};
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}
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return _value;
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}
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operator _cpp_value_type() const
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{
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return value();
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}
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bool _is_valid;
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bool _is_null;
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_cpp_storage_type _value;
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};
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} // namespace sqlpp
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#endif
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