any_map.hpp

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#pragma once
#include <ossia/detail/config.hpp>
 
#include <ossia/detail/any.hpp>
#include <ossia/detail/optional.hpp>
#include <ossia/detail/string_map.hpp>
 
namespace ossia
{
using any_map = string_map<ossia::any>;
 
using extended_attributes = any_map;
template <typename T>
auto get_attribute(const any_map& e, std::string_view name)
{
  auto it = e.find(name);
  if(it != e.cend())
  {
    auto val = ossia::any_cast<T>(&it->second);
    if(val)
      return *val;
  }
 
  return T{};
}
 
template <typename T>
std::optional<T> get_optional_attribute(const any_map& e, std::string_view name)
{
  auto it = e.find(name);
  if(it != e.cend())
  {
    auto val = ossia::any_cast<T>(&it->second);
    if(val)
      return *val;
  }
 
  return std::nullopt;
}
 
struct is_empty_value
{
  template <typename T>
  bool operator()(const T&) noexcept
  {
    return false;
  }
  bool operator()(const std::string& v) noexcept { return v.empty(); }
  bool operator()(const std::string_view& v) noexcept { return v.empty(); }
  template <typename T>
  bool operator()(const std::vector<T>& v) noexcept
  {
    return v.empty();
  }
};
 
OSSIA_EXPORT
void unset_attribute(any_map& e, std::string_view str);
 
template <typename T>
void set_attribute(any_map& e, std::string_view str, const T& val)
{
  if(!is_empty_value{}(val))
  {
    // TODO insert_or_assign
    auto it = e.find(str);
    if(it != e.end())
      it->second = val;
    else
      e.insert(std::make_pair(std::string(str), ossia::any{val}));
  }
  else
  {
    unset_attribute(e, str);
  }
}
 
OSSIA_EXPORT
bool has_attribute(const any_map& e, std::string_view str) noexcept;
 
OSSIA_EXPORT
void set_attribute(any_map& e, std::string_view str);
 
template <typename T>
void set_attribute(any_map& e, std::string_view str, T&& val)
{
  if(!is_empty_value{}(val))
  {
    // TODO insert_or_assign
    auto it = e.find(str);
    if(it != e.end())
      it->second = std::move(val);
    else
      e.insert(std::make_pair(std::string(str), ossia::any{std::move(val)}));
  }
  else
  {
    unset_attribute(e, str);
  }
}
 
OSSIA_EXPORT
void set_attribute(any_map& e, std::string_view str, std::nullopt_t);
 
template <typename T>
void set_optional_attribute(
    any_map& e, std::string_view str, const std::optional<T>& opt)
{
  if(opt && !is_empty_value{}(*opt))
    set_attribute(e, str, *opt);
  else
    set_attribute(e, str, std::nullopt);
}
 
template <typename T>
void set_optional_attribute(any_map& e, std::string_view str, std::optional<T>&& opt)
{
  if(opt && !is_empty_value{}(*opt))
    set_attribute(e, str, *std::move(opt));
  else
    set_attribute(e, str, std::nullopt);
}
}