mapnik/include/mapnik/xml_attribute_cast.hpp
2024-07-22 10:20:47 +01:00

246 lines
7.3 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2024 Artem Pavlenko
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
#ifndef MAPNIK_XML_ATTRIBUTE_CAST_HPP
#define MAPNIK_XML_ATTRIBUTE_CAST_HPP
// mapnik
#include <mapnik/debug.hpp>
#include <mapnik/value/types.hpp>
#include <mapnik/xml_tree.hpp>
#include <mapnik/enumeration.hpp>
#include <mapnik/boolean.hpp>
#include <mapnik/color.hpp>
#include <mapnik/color_factory.hpp>
#include <mapnik/expression.hpp>
#include <mapnik/util/conversions.hpp>
#include <mapnik/attribute.hpp>
#include <mapnik/text/font_feature_settings.hpp>
// stl
#include <string>
#include <map>
#include <typeinfo>
#include <utility>
#include <optional>
#include <stdexcept>
namespace mapnik {
namespace detail {
template<typename T>
struct do_xml_attribute_cast
{
static inline std::optional<T> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& /*source*/)
{
std::string err_msg("No conversion from std::string to ");
err_msg += std::string(typeid(T).name());
throw std::runtime_error(err_msg);
}
};
// specialization for mapnik::boolean_type
template<>
struct do_xml_attribute_cast<mapnik::boolean_type>
{
static inline std::optional<mapnik::boolean_type> xml_attribute_cast_impl(xml_tree const& /*tree*/,
std::string const& source)
{
bool result;
if (mapnik::util::string2bool(source, result))
return result;
return std::nullopt;
}
};
// specialization for mapnik::value_bool
template<>
struct do_xml_attribute_cast<mapnik::value_bool>
{
static inline std::optional<mapnik::value_bool> xml_attribute_cast_impl(xml_tree const& /*tree*/,
std::string const& source)
{
bool result;
if (mapnik::util::string2bool(source, result))
return result;
return std::nullopt;
}
};
// specialization for int
template<>
struct do_xml_attribute_cast<int>
{
static inline std::optional<int> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& source)
{
int result;
if (mapnik::util::string2int(source, result))
return result;
return std::nullopt;
}
};
#ifdef BIGINT
// specialization for long long
template<>
struct do_xml_attribute_cast<mapnik::value_integer>
{
static inline std::optional<mapnik::value_integer> xml_attribute_cast_impl(xml_tree const& /*tree*/,
std::string const& source)
{
int result;
if (mapnik::util::string2int(source, result))
return result;
return std::nullopt;
}
};
#endif
// specialization for unsigned
template<>
struct do_xml_attribute_cast<unsigned>
{
static inline std::optional<unsigned> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& source)
{
int result;
if (mapnik::util::string2int(source, result) && result >= 0)
return static_cast<unsigned>(result);
return std::nullopt;
}
};
// specialization for float
template<>
struct do_xml_attribute_cast<float>
{
static inline std::optional<float> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& source)
{
float result;
if (mapnik::util::string2float(source, result))
return result;
return std::nullopt;
}
};
// specialization for double
template<>
struct do_xml_attribute_cast<double>
{
static inline std::optional<double> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& source)
{
double result;
if (mapnik::util::string2double(source, result))
return result;
return std::nullopt;
}
};
// specialization for mapnik::enumeration<...>
template<typename ENUM,
char const* (*F_TO_STRING)(ENUM),
ENUM (*F_FROM_STRING)(const char*),
std::map<ENUM, std::string> (*F_LOOKUP)()>
struct do_xml_attribute_cast<mapnik::enumeration<ENUM, F_TO_STRING, F_FROM_STRING, F_LOOKUP>>
{
using Enum = mapnik::enumeration<ENUM, F_TO_STRING, F_FROM_STRING, F_LOOKUP>;
static inline std::optional<Enum> xml_attribute_cast_impl(xml_tree const& /*tree*/, std::string const& source)
{
try
{
Enum e;
e.from_string(source);
return e;
}
catch (illegal_enum_value const& ex)
{
MAPNIK_LOG_ERROR(do_xml_attribute_cast) << ex.what();
return std::nullopt;
;
}
}
};
// specialization for mapnik::color
template<>
struct do_xml_attribute_cast<mapnik::color>
{
static inline std::optional<mapnik::color> xml_attribute_cast_impl(xml_tree const&, std::string const& source)
{
return parse_color(source);
}
};
// specialization for std::string
template<>
struct do_xml_attribute_cast<std::string>
{
static inline std::optional<std::string> xml_attribute_cast_impl(xml_tree const&, std::string const& source)
{
return source;
}
};
// specialization for mapnik::expression_ptr
template<>
struct do_xml_attribute_cast<mapnik::expression_ptr>
{
static inline std::optional<mapnik::expression_ptr> xml_attribute_cast_impl(xml_tree const& tree,
std::string const& source)
{
std::map<std::string, mapnik::expression_ptr>::const_iterator itr = tree.expr_cache_.find(source);
if (itr != tree.expr_cache_.end())
{
return itr->second;
}
else
{
mapnik::expression_ptr expr = parse_expression(source);
tree.expr_cache_.emplace(source, expr);
return expr;
}
}
};
// specialization for mapnik::font_feature_settings
template<>
struct do_xml_attribute_cast<mapnik::font_feature_settings>
{
static inline std::optional<mapnik::font_feature_settings> xml_attribute_cast_impl(xml_tree const&,
std::string const& source)
{
return mapnik::font_feature_settings(source);
}
};
} // end namespace detail
template<typename T>
std::optional<T> xml_attribute_cast(xml_tree const& tree, std::string const& source)
{
return detail::do_xml_attribute_cast<T>::xml_attribute_cast_impl(tree, source);
}
} // end namespace mapnik
#endif // MAPNIK_XML_ATTRIBUTE_CAST_HPP