0
0
mirror of https://github.com/rbock/sqlpp11.git synced 2024-11-16 04:47:18 +08:00
sqlpp11/include/sqlpp11/text.h
2014-08-03 09:27:20 +02:00

254 lines
6.3 KiB
C++

/*
* Copyright (c) 2013-2014, Roland Bock
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 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 SQLPP_TEXT_H
#define SQLPP_TEXT_H
#include <sqlpp11/basic_expression_operators.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/exception.h>
#include <sqlpp11/concat.h>
#include <sqlpp11/like.h>
#include <sqlpp11/result_field.h>
namespace sqlpp
{
// text value type
struct text
{
using _traits = make_traits<text, ::sqlpp::tag::is_text, ::sqlpp::tag::is_value_type>;
using _tag = ::sqlpp::tag::is_text;
using _cpp_value_type = std::string;
struct _parameter_t
{
using _value_type = text;
_parameter_t():
_value(""),
_is_null(true)
{}
_parameter_t(const _cpp_value_type& value):
_value(value),
_is_null(false)
{}
_parameter_t& operator=(const _cpp_value_type& value)
{
_value = value;
_is_null = false;
return *this;
}
_parameter_t& operator=(const std::nullptr_t&)
{
_value = "";
_is_null = true;
return *this;
}
bool is_null() const
{
return _is_null;
}
_cpp_value_type value() const
{
return _value;
}
operator _cpp_value_type() const { return value(); }
template<typename Target>
void _bind(Target& target, size_t index) const
{
target._bind_text_parameter(index, &_value, _is_null);
}
private:
_cpp_value_type _value;
bool _is_null;
};
template<typename T>
struct _is_valid_operand
{
static constexpr bool value =
is_expression_t<T>::value // expressions are OK
and is_text_t<T>::value // the correct value type is required, of course
;
};
template<typename Base>
struct expression_operators: public basic_expression_operators<Base, is_text_t>
{
template<typename T>
concat_t<Base, wrap_operand_t<T>> operator+(T t) const
{
using rhs = wrap_operand_t<T>;
static_assert(_is_valid_operand<rhs>::value, "invalid rhs operand");
return { *static_cast<const Base*>(this), {t} };
}
template<typename T>
like_t<Base, wrap_operand_t<T>> like(T t) const
{
using rhs = wrap_operand_t<T>;
static_assert(_is_valid_operand<rhs>::value, "invalid argument for like()");
return { *static_cast<const Base*>(this), {t} };
}
};
template<typename Base>
struct column_operators
{
template<typename T>
auto operator +=(T t) const -> assignment_t<Base, concat_t<Base, wrap_operand_t<T>>>
{
using rhs = wrap_operand_t<T>;
static_assert(_is_valid_operand<rhs>::value, "invalid rhs assignment operand");
return { *static_cast<const Base*>(this), { *static_cast<const Base*>(this), rhs{t} } };
}
};
};
template<typename Db, typename FieldSpec>
struct result_field_t<text, Db, FieldSpec>: public result_field_methods_t<result_field_t<text, Db, FieldSpec>>
{
static_assert(std::is_same<value_type_of<FieldSpec>, text>::value, "field type mismatch");
using _cpp_value_type = typename text::_cpp_value_type;
result_field_t():
_is_valid(false),
_value_ptr(nullptr),
_len(0)
{}
void _validate()
{
_is_valid = true;
}
void _invalidate()
{
_is_valid = false;
_value_ptr = nullptr;
_len = 0;
}
bool operator==(const _cpp_value_type& rhs) const { return value() == rhs; }
bool operator!=(const _cpp_value_type& rhs) const { return not operator==(rhs); }
bool is_null() const
{
if (not _is_valid)
throw exception("accessing is_null in non-existing row");
return _value_ptr == nullptr;
}
bool _is_trivial() const
{
if (not _is_valid)
throw exception("accessing is_null in non-existing row");
return value() == "";
}
_cpp_value_type value() const
{
if (not _is_valid)
throw exception("accessing value in non-existing row");
if (not _value_ptr)
{
if (enforce_null_result_treatment_t<Db>::value and not null_is_trivial_value_t<FieldSpec>::value)
{
throw exception("accessing value of NULL field");
}
else
{
return "";
}
}
return std::string(_value_ptr, _value_ptr + _len);
}
template<typename Target>
void _bind(Target& target, size_t i)
{
target._bind_text_result(i, &_value_ptr, &_len);
}
private:
bool _is_valid;
const char* _value_ptr;
size_t _len;
};
template<typename Context, typename Db, typename FieldSpec>
struct serializer_t<Context, result_field_t<text, Db, FieldSpec>>
{
using T = result_field_t<text, Db, FieldSpec>;
static Context& _(const T& t, Context& context)
{
if (t.is_null() and not null_is_trivial_value_t<T>::value)
{
context << "NULL";
}
else
{
context << '\'' << context.escape(t.value()) << '\'';
}
return context;
}
};
template<typename Db, typename FieldSpec>
inline std::ostream& operator<<(std::ostream& os, const result_field_t<text, Db, FieldSpec>& e)
{
if (e.is_null() and not null_is_trivial_value_t<FieldSpec>::value)
{
return os << "NULL";
}
else
{
return os << e.value();
}
}
using blob = text;
using varchar = text;
using char_ = text;
}
#endif